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therm_pm72.c

/*
 * Device driver for the thermostats & fan controller of  the
 * Apple G5 "PowerMac7,2" desktop machines.
 *
 * (c) Copyright IBM Corp. 2003-2004
 *
 * Maintained by: Benjamin Herrenschmidt
 *                <benh@kernel.crashing.org>
 * 
 *
 * The algorithm used is the PID control algorithm, used the same
 * way the published Darwin code does, using the same values that
 * are present in the Darwin 7.0 snapshot property lists.
 *
 * As far as the CPUs control loops are concerned, I use the
 * calibration & PID constants provided by the EEPROM,
 * I do _not_ embed any value from the property lists, as the ones
 * provided by Darwin 7.0 seem to always have an older version that
 * what I've seen on the actual computers.
 * It would be interesting to verify that though. Darwin has a
 * version code of 1.0.0d11 for all control loops it seems, while
 * so far, the machines EEPROMs contain a dataset versioned 1.0.0f
 *
 * Darwin doesn't provide source to all parts, some missing
 * bits like the AppleFCU driver or the actual scale of some
 * of the values returned by sensors had to be "guessed" some
 * way... or based on what Open Firmware does.
 *
 * I didn't yet figure out how to get the slots power consumption
 * out of the FCU, so that part has not been implemented yet and
 * the slots fan is set to a fixed 50% PWM, hoping this value is
 * safe enough ...
 *
 * Note: I have observed strange oscillations of the CPU control
 * loop on a dual G5 here. When idle, the CPU exhaust fan tend to
 * oscillates slowly (over several minutes) between the minimum
 * of 300RPMs and approx. 1000 RPMs. I don't know what is causing
 * this, it could be some incorrect constant or an error in the
 * way I ported the algorithm, or it could be just normal. I
 * don't have full understanding on the way Apple tweaked the PID
 * algorithm for the CPU control, it is definitely not a standard
 * implementation...
 *
 * TODO:  - Check MPU structure version/signature
 *        - Add things like /sbin/overtemp for non-critical
 *          overtemp conditions so userland can take some policy
 *          decisions, like slewing down CPUs
 *      - Deal with fan and i2c failures in a better way
 *      - Maybe do a generic PID based on params used for
 *        U3 and Drives ? Definitely need to factor code a bit
 *          bettter... also make sensor detection more robust using
 *          the device-tree to probe for them
 *        - Figure out how to get the slots consumption and set the
 *          slots fan accordingly
 *
 * History:
 *
 *  Nov. 13, 2003 : 0.5
 *    - First release
 *
 *  Nov. 14, 2003 : 0.6
 *    - Read fan speed from FCU, low level fan routines now deal
 *      with errors & check fan status, though higher level don't
 *      do much.
 *    - Move a bunch of definitions to .h file
 *
 *  Nov. 18, 2003 : 0.7
 *    - Fix build on ppc64 kernel
 *    - Move back statics definitions to .c file
 *    - Avoid calling schedule_timeout with a negative number
 *
 *  Dec. 18, 2003 : 0.8
 *    - Fix typo when reading back fan speed on 2 CPU machines
 *
 *  Mar. 11, 2004 : 0.9
 *    - Rework code accessing the ADC chips, make it more robust and
 *      closer to the chip spec. Also make sure it is configured properly,
 *        I've seen yet unexplained cases where on startup, I would have stale
 *        values in the configuration register
 *    - Switch back to use of target fan speed for PID, thus lowering
 *        pressure on i2c
 *
 *  Oct. 20, 2004 : 1.1
 *    - Add device-tree lookup for fan IDs, should detect liquid cooling
 *        pumps when present
 *    - Enable driver for PowerMac7,3 machines
 *    - Split the U3/Backside cooling on U3 & U3H versions as Darwin does
 *    - Add new CPU cooling algorithm for machines with liquid cooling
 *    - Workaround for some PowerMac7,3 with empty "fan" node in the devtree
 *    - Fix a signed/unsigned compare issue in some PID loops
 *
 *  Mar. 10, 2005 : 1.2
 *    - Add basic support for Xserve G5
 *    - Retreive pumps min/max from EEPROM image in device-tree (broken)
 *    - Use min/max macros here or there
 *    - Latest darwin updated U3H min fan speed to 20% PWM
 *
 *  July. 06, 2006 : 1.3
 *    - Fix setting of RPM fans on Xserve G5 (they were going too fast)
 *      - Add missing slots fan control loop for Xserve G5
 *    - Lower fixed slots fan speed from 50% to 40% on desktop G5s. We
 *        still can't properly implement the control loop for these, so let's
 *        reduce the noise a little bit, it appears that 40% still gives us
 *        a pretty good air flow
 *    - Add code to "tickle" the FCU regulary so it doesn't think that
 *        we are gone while in fact, the machine just didn't need any fan
 *        speed change lately
 *
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/reboot.h>
#include <linux/kmod.h>
#include <linux/i2c.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/sections.h>
#include <asm/of_device.h>
#include <asm/macio.h>
#include <asm/of_platform.h>

#include "therm_pm72.h"

#define VERSION "1.3"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif


/*
 * Driver statics
 */

static struct of_device *           of_dev;
static struct i2c_adapter *         u3_0;
static struct i2c_adapter *         u3_1;
static struct i2c_adapter *         k2;
static struct i2c_client *          fcu;
static struct cpu_pid_state         cpu_state[2];
static struct basckside_pid_params  backside_params;
static struct backside_pid_state    backside_state;
static struct drives_pid_state            drives_state;
static struct dimm_pid_state        dimms_state;
static struct slots_pid_state       slots_state;
static int                    state;
static int                    cpu_count;
static int                    cpu_pid_type;
static pid_t                        ctrl_task;
static struct completion            ctrl_complete;
static int                    critical_state;
static int                    rackmac;
static s32                    dimm_output_clamp;
static int                    fcu_rpm_shift;
static int                    fcu_tickle_ticks;
static DECLARE_MUTEX(driver_lock);

/*
 * We have 3 types of CPU PID control. One is "split" old style control
 * for intake & exhaust fans, the other is "combined" control for both
 * CPUs that also deals with the pumps when present. To be "compatible"
 * with OS X at this point, we only use "COMBINED" on the machines that
 * are identified as having the pumps (though that identification is at
 * least dodgy). Ultimately, we could probably switch completely to this
 * algorithm provided we hack it to deal with the UP case
 */
#define CPU_PID_TYPE_SPLIT    0
#define CPU_PID_TYPE_COMBINED 1
#define CPU_PID_TYPE_RACKMAC  2

/*
 * This table describes all fans in the FCU. The "id" and "type" values
 * are defaults valid for all earlier machines. Newer machines will
 * eventually override the table content based on the device-tree
 */
struct fcu_fan_table
{
      char* loc;  /* location code */
      int   type; /* 0 = rpm, 1 = pwm, 2 = pump */
      int   id;   /* id or -1 */
};

#define FCU_FAN_RPM           0
#define FCU_FAN_PWM           1

#define FCU_FAN_ABSENT_ID     -1

#define FCU_FAN_COUNT         ARRAY_SIZE(fcu_fans)

struct fcu_fan_table    fcu_fans[] = {
      [BACKSIDE_FAN_PWM_INDEX] = {
            .loc  = "BACKSIDE,SYS CTRLR FAN",
            .type = FCU_FAN_PWM,
            .id   = BACKSIDE_FAN_PWM_DEFAULT_ID,
      },
      [DRIVES_FAN_RPM_INDEX] = {
            .loc  = "DRIVE BAY",
            .type = FCU_FAN_RPM,
            .id   = DRIVES_FAN_RPM_DEFAULT_ID,
      },
      [SLOTS_FAN_PWM_INDEX] = {
            .loc  = "SLOT,PCI FAN",
            .type = FCU_FAN_PWM,
            .id   = SLOTS_FAN_PWM_DEFAULT_ID,
      },
      [CPUA_INTAKE_FAN_RPM_INDEX] = {
            .loc  = "CPU A INTAKE",
            .type = FCU_FAN_RPM,
            .id   = CPUA_INTAKE_FAN_RPM_DEFAULT_ID,
      },
      [CPUA_EXHAUST_FAN_RPM_INDEX] = {
            .loc  = "CPU A EXHAUST",
            .type = FCU_FAN_RPM,
            .id   = CPUA_EXHAUST_FAN_RPM_DEFAULT_ID,
      },
      [CPUB_INTAKE_FAN_RPM_INDEX] = {
            .loc  = "CPU B INTAKE",
            .type = FCU_FAN_RPM,
            .id   = CPUB_INTAKE_FAN_RPM_DEFAULT_ID,
      },
      [CPUB_EXHAUST_FAN_RPM_INDEX] = {
            .loc  = "CPU B EXHAUST",
            .type = FCU_FAN_RPM,
            .id   = CPUB_EXHAUST_FAN_RPM_DEFAULT_ID,
      },
      /* pumps aren't present by default, have to be looked up in the
       * device-tree
       */
      [CPUA_PUMP_RPM_INDEX] = {
            .loc  = "CPU A PUMP",
            .type = FCU_FAN_RPM,          
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPUB_PUMP_RPM_INDEX] = {
            .loc  = "CPU B PUMP",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      /* Xserve fans */
      [CPU_A1_FAN_RPM_INDEX] = {
            .loc  = "CPU A 1",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPU_A2_FAN_RPM_INDEX] = {
            .loc  = "CPU A 2",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPU_A3_FAN_RPM_INDEX] = {
            .loc  = "CPU A 3",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPU_B1_FAN_RPM_INDEX] = {
            .loc  = "CPU B 1",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPU_B2_FAN_RPM_INDEX] = {
            .loc  = "CPU B 2",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
      [CPU_B3_FAN_RPM_INDEX] = {
            .loc  = "CPU B 3",
            .type = FCU_FAN_RPM,
            .id   = FCU_FAN_ABSENT_ID,
      },
};

/*
 * i2c_driver structure to attach to the host i2c controller
 */

static int therm_pm72_attach(struct i2c_adapter *adapter);
static int therm_pm72_detach(struct i2c_adapter *adapter);

static struct i2c_driver therm_pm72_driver =
{
      .driver = {
            .name = "therm_pm72",
      },
      .attach_adapter   = therm_pm72_attach,
      .detach_adapter   = therm_pm72_detach,
};

/*
 * Utility function to create an i2c_client structure and
 * attach it to one of u3 adapters
 */
static struct i2c_client *attach_i2c_chip(int id, const char *name)
{
      struct i2c_client *clt;
      struct i2c_adapter *adap;

      if (id & 0x200)
            adap = k2;
      else if (id & 0x100)
            adap = u3_1;
      else
            adap = u3_0;
      if (adap == NULL)
            return NULL;

      clt = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
      if (clt == NULL)
            return NULL;

      clt->addr = (id >> 1) & 0x7f;
      clt->adapter = adap;
      clt->driver = &therm_pm72_driver;
      strncpy(clt->name, name, I2C_NAME_SIZE-1);

      if (i2c_attach_client(clt)) {
            printk(KERN_ERR "therm_pm72: Failed to attach to i2c ID 0x%x\n", id);
            kfree(clt);
            return NULL;
      }
      return clt;
}

/*
 * Utility function to get rid of the i2c_client structure
 * (will also detach from the adapter hopepfully)
 */
static void detach_i2c_chip(struct i2c_client *clt)
{
      i2c_detach_client(clt);
      kfree(clt);
}

/*
 * Here are the i2c chip access wrappers
 */

static void initialize_adc(struct cpu_pid_state *state)
{
      int rc;
      u8 buf[2];

      /* Read ADC the configuration register and cache it. We
       * also make sure Config2 contains proper values, I've seen
       * cases where we got stale grabage in there, thus preventing
       * proper reading of conv. values
       */

      /* Clear Config2 */
      buf[0] = 5;
      buf[1] = 0;
      i2c_master_send(state->monitor, buf, 2);

      /* Read & cache Config1 */
      buf[0] = 1;
      rc = i2c_master_send(state->monitor, buf, 1);
      if (rc > 0) {
            rc = i2c_master_recv(state->monitor, buf, 1);
            if (rc > 0) {
                  state->adc_config = buf[0];
                  DBG("ADC config reg: %02x\n", state->adc_config);
                  /* Disable shutdown mode */
                        state->adc_config &= 0xfe;
                  buf[0] = 1;
                  buf[1] = state->adc_config;
                  rc = i2c_master_send(state->monitor, buf, 2);
            }
      }
      if (rc <= 0)
            printk(KERN_ERR "therm_pm72: Error reading ADC config"
                   " register !\n");
}

static int read_smon_adc(struct cpu_pid_state *state, int chan)
{
      int rc, data, tries = 0;
      u8 buf[2];

      for (;;) {
            /* Set channel */
            buf[0] = 1;
            buf[1] = (state->adc_config & 0x1f) | (chan << 5);
            rc = i2c_master_send(state->monitor, buf, 2);
            if (rc <= 0)
                  goto error;
            /* Wait for convertion */
            msleep(1);
            /* Switch to data register */
            buf[0] = 4;
            rc = i2c_master_send(state->monitor, buf, 1);
            if (rc <= 0)
                  goto error;
            /* Read result */
            rc = i2c_master_recv(state->monitor, buf, 2);
            if (rc < 0)
                  goto error;
            data = ((u16)buf[0]) << 8 | (u16)buf[1];
            return data >> 6;
      error:
            DBG("Error reading ADC, retrying...\n");
            if (++tries > 10) {
                  printk(KERN_ERR "therm_pm72: Error reading ADC !\n");
                  return -1;
            }
            msleep(10);
      }
}

static int read_lm87_reg(struct i2c_client * chip, int reg)
{
      int rc, tries = 0;
      u8 buf;

      for (;;) {
            /* Set address */
            buf = (u8)reg;
            rc = i2c_master_send(chip, &buf, 1);
            if (rc <= 0)
                  goto error;
            rc = i2c_master_recv(chip, &buf, 1);
            if (rc <= 0)
                  goto error;
            return (int)buf;
      error:
            DBG("Error reading LM87, retrying...\n");
            if (++tries > 10) {
                  printk(KERN_ERR "therm_pm72: Error reading LM87 !\n");
                  return -1;
            }
            msleep(10);
      }
}

static int fan_read_reg(int reg, unsigned char *buf, int nb)
{
      int tries, nr, nw;

      buf[0] = reg;
      tries = 0;
      for (;;) {
            nw = i2c_master_send(fcu, buf, 1);
            if (nw > 0 || (nw < 0 && nw != -EIO) || tries >= 100)
                  break;
            msleep(10);
            ++tries;
      }
      if (nw <= 0) {
            printk(KERN_ERR "Failure writing address to FCU: %d", nw);
            return -EIO;
      }
      tries = 0;
      for (;;) {
            nr = i2c_master_recv(fcu, buf, nb);
            if (nr > 0 || (nr < 0 && nr != ENODEV) || tries >= 100)
                  break;
            msleep(10);
            ++tries;
      }
      if (nr <= 0)
            printk(KERN_ERR "Failure reading data from FCU: %d", nw);
      return nr;
}

static int fan_write_reg(int reg, const unsigned char *ptr, int nb)
{
      int tries, nw;
      unsigned char buf[16];

      buf[0] = reg;
      memcpy(buf+1, ptr, nb);
      ++nb;
      tries = 0;
      for (;;) {
            nw = i2c_master_send(fcu, buf, nb);
            if (nw > 0 || (nw < 0 && nw != EIO) || tries >= 100)
                  break;
            msleep(10);
            ++tries;
      }
      if (nw < 0)
            printk(KERN_ERR "Failure writing to FCU: %d", nw);
      return nw;
}

static int start_fcu(void)
{
      unsigned char buf = 0xff;
      int rc;

      rc = fan_write_reg(0xe, &buf, 1);
      if (rc < 0)
            return -EIO;
      rc = fan_write_reg(0x2e, &buf, 1);
      if (rc < 0)
            return -EIO;
      rc = fan_read_reg(0, &buf, 1);
      if (rc < 0)
            return -EIO;
      fcu_rpm_shift = (buf == 1) ? 2 : 3;
      printk(KERN_DEBUG "FCU Initialized, RPM fan shift is %d\n",
             fcu_rpm_shift);

      return 0;
}

static int set_rpm_fan(int fan_index, int rpm)
{
      unsigned char buf[2];
      int rc, id, min, max;

      if (fcu_fans[fan_index].type != FCU_FAN_RPM)
            return -EINVAL;
      id = fcu_fans[fan_index].id; 
      if (id == FCU_FAN_ABSENT_ID)
            return -EINVAL;

      min = 2400 >> fcu_rpm_shift;
      max = 56000 >> fcu_rpm_shift;

      if (rpm < min)
            rpm = min;
      else if (rpm > max)
            rpm = max;
      buf[0] = rpm >> (8 - fcu_rpm_shift);
      buf[1] = rpm << fcu_rpm_shift;
      rc = fan_write_reg(0x10 + (id * 2), buf, 2);
      if (rc < 0)
            return -EIO;
      return 0;
}

static int get_rpm_fan(int fan_index, int programmed)
{
      unsigned char failure;
      unsigned char active;
      unsigned char buf[2];
      int rc, id, reg_base;

      if (fcu_fans[fan_index].type != FCU_FAN_RPM)
            return -EINVAL;
      id = fcu_fans[fan_index].id; 
      if (id == FCU_FAN_ABSENT_ID)
            return -EINVAL;

      rc = fan_read_reg(0xb, &failure, 1);
      if (rc != 1)
            return -EIO;
      if ((failure & (1 << id)) != 0)
            return -EFAULT;
      rc = fan_read_reg(0xd, &active, 1);
      if (rc != 1)
            return -EIO;
      if ((active & (1 << id)) == 0)
            return -ENXIO;

      /* Programmed value or real current speed */
      reg_base = programmed ? 0x10 : 0x11;
      rc = fan_read_reg(reg_base + (id * 2), buf, 2);
      if (rc != 2)
            return -EIO;

      return (buf[0] << (8 - fcu_rpm_shift)) | buf[1] >> fcu_rpm_shift;
}

static int set_pwm_fan(int fan_index, int pwm)
{
      unsigned char buf[2];
      int rc, id;

      if (fcu_fans[fan_index].type != FCU_FAN_PWM)
            return -EINVAL;
      id = fcu_fans[fan_index].id; 
      if (id == FCU_FAN_ABSENT_ID)
            return -EINVAL;

      if (pwm < 10)
            pwm = 10;
      else if (pwm > 100)
            pwm = 100;
      pwm = (pwm * 2559) / 1000;
      buf[0] = pwm;
      rc = fan_write_reg(0x30 + (id * 2), buf, 1);
      if (rc < 0)
            return rc;
      return 0;
}

static int get_pwm_fan(int fan_index)
{
      unsigned char failure;
      unsigned char active;
      unsigned char buf[2];
      int rc, id;

      if (fcu_fans[fan_index].type != FCU_FAN_PWM)
            return -EINVAL;
      id = fcu_fans[fan_index].id; 
      if (id == FCU_FAN_ABSENT_ID)
            return -EINVAL;

      rc = fan_read_reg(0x2b, &failure, 1);
      if (rc != 1)
            return -EIO;
      if ((failure & (1 << id)) != 0)
            return -EFAULT;
      rc = fan_read_reg(0x2d, &active, 1);
      if (rc != 1)
            return -EIO;
      if ((active & (1 << id)) == 0)
            return -ENXIO;

      /* Programmed value or real current speed */
      rc = fan_read_reg(0x30 + (id * 2), buf, 1);
      if (rc != 1)
            return -EIO;

      return (buf[0] * 1000) / 2559;
}

static void tickle_fcu(void)
{
      int pwm;

      pwm = get_pwm_fan(SLOTS_FAN_PWM_INDEX);

      DBG("FCU Tickle, slots fan is: %d\n", pwm);
      if (pwm < 0)
            pwm = 100;

      if (!rackmac) {
            pwm = SLOTS_FAN_DEFAULT_PWM;
      } else if (pwm < SLOTS_PID_OUTPUT_MIN)
            pwm = SLOTS_PID_OUTPUT_MIN;

      /* That is hopefully enough to make the FCU happy */
      set_pwm_fan(SLOTS_FAN_PWM_INDEX, pwm);
}


/*
 * Utility routine to read the CPU calibration EEPROM data
 * from the device-tree
 */
static int read_eeprom(int cpu, struct mpu_data *out)
{
      struct device_node *np;
      char nodename[64];
      const u8 *data;
      int len;

      /* prom.c routine for finding a node by path is a bit brain dead
       * and requires exact @xxx unit numbers. This is a bit ugly but
       * will work for these machines
       */
      sprintf(nodename, "/u3@0,f8000000/i2c@f8001000/cpuid@a%d", cpu ? 2 : 0);
      np = of_find_node_by_path(nodename);
      if (np == NULL) {
            printk(KERN_ERR "therm_pm72: Failed to retrieve cpuid node from device-tree\n");
            return -ENODEV;
      }
      data = of_get_property(np, "cpuid", &len);
      if (data == NULL) {
            printk(KERN_ERR "therm_pm72: Failed to retrieve cpuid property from device-tree\n");
            of_node_put(np);
            return -ENODEV;
      }
      memcpy(out, data, sizeof(struct mpu_data));
      of_node_put(np);
      
      return 0;
}

static void fetch_cpu_pumps_minmax(void)
{
      struct cpu_pid_state *state0 = &cpu_state[0];
      struct cpu_pid_state *state1 = &cpu_state[1];
      u16 pump_min = 0, pump_max = 0xffff;
      u16 tmp[4];

      /* Try to fetch pumps min/max infos from eeprom */

      memcpy(&tmp, &state0->mpu.processor_part_num, 8);
      if (tmp[0] != 0xffff && tmp[1] != 0xffff) {
            pump_min = max(pump_min, tmp[0]);
            pump_max = min(pump_max, tmp[1]);
      }
      if (tmp[2] != 0xffff && tmp[3] != 0xffff) {
            pump_min = max(pump_min, tmp[2]);
            pump_max = min(pump_max, tmp[3]);
      }

      /* Double check the values, this _IS_ needed as the EEPROM on
       * some dual 2.5Ghz G5s seem, at least, to have both min & max
       * same to the same value ... (grrrr)
       */
      if (pump_min == pump_max || pump_min == 0 || pump_max == 0xffff) {
            pump_min = CPU_PUMP_OUTPUT_MIN;
            pump_max = CPU_PUMP_OUTPUT_MAX;
      }

      state0->pump_min = state1->pump_min = pump_min;
      state0->pump_max = state1->pump_max = pump_max;
}

/* 
 * Now, unfortunately, sysfs doesn't give us a nice void * we could
 * pass around to the attribute functions, so we don't really have
 * choice but implement a bunch of them...
 *
 * That sucks a bit, we take the lock because FIX32TOPRINT evaluates
 * the input twice... I accept patches :)
 */
#define BUILD_SHOW_FUNC_FIX(name, data)                     \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)  \
{                                               \
      ssize_t r;                                \
      down(&driver_lock);                             \
      r = sprintf(buf, "%d.%03d", FIX32TOPRINT(data));      \
      up(&driver_lock);                         \
      return r;                                 \
}
#define BUILD_SHOW_FUNC_INT(name, data)                     \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)  \
{                                               \
      return sprintf(buf, "%d", data);                \
}

BUILD_SHOW_FUNC_FIX(cpu0_temperature, cpu_state[0].last_temp)
BUILD_SHOW_FUNC_FIX(cpu0_voltage, cpu_state[0].voltage)
BUILD_SHOW_FUNC_FIX(cpu0_current, cpu_state[0].current_a)
BUILD_SHOW_FUNC_INT(cpu0_exhaust_fan_rpm, cpu_state[0].rpm)
BUILD_SHOW_FUNC_INT(cpu0_intake_fan_rpm, cpu_state[0].intake_rpm)

BUILD_SHOW_FUNC_FIX(cpu1_temperature, cpu_state[1].last_temp)
BUILD_SHOW_FUNC_FIX(cpu1_voltage, cpu_state[1].voltage)
BUILD_SHOW_FUNC_FIX(cpu1_current, cpu_state[1].current_a)
BUILD_SHOW_FUNC_INT(cpu1_exhaust_fan_rpm, cpu_state[1].rpm)
BUILD_SHOW_FUNC_INT(cpu1_intake_fan_rpm, cpu_state[1].intake_rpm)

BUILD_SHOW_FUNC_FIX(backside_temperature, backside_state.last_temp)
BUILD_SHOW_FUNC_INT(backside_fan_pwm, backside_state.pwm)

BUILD_SHOW_FUNC_FIX(drives_temperature, drives_state.last_temp)
BUILD_SHOW_FUNC_INT(drives_fan_rpm, drives_state.rpm)

BUILD_SHOW_FUNC_FIX(slots_temperature, slots_state.last_temp)
BUILD_SHOW_FUNC_INT(slots_fan_pwm, slots_state.pwm)

BUILD_SHOW_FUNC_FIX(dimms_temperature, dimms_state.last_temp)

static DEVICE_ATTR(cpu0_temperature,S_IRUGO,show_cpu0_temperature,NULL);
static DEVICE_ATTR(cpu0_voltage,S_IRUGO,show_cpu0_voltage,NULL);
static DEVICE_ATTR(cpu0_current,S_IRUGO,show_cpu0_current,NULL);
static DEVICE_ATTR(cpu0_exhaust_fan_rpm,S_IRUGO,show_cpu0_exhaust_fan_rpm,NULL);
static DEVICE_ATTR(cpu0_intake_fan_rpm,S_IRUGO,show_cpu0_intake_fan_rpm,NULL);

static DEVICE_ATTR(cpu1_temperature,S_IRUGO,show_cpu1_temperature,NULL);
static DEVICE_ATTR(cpu1_voltage,S_IRUGO,show_cpu1_voltage,NULL);
static DEVICE_ATTR(cpu1_current,S_IRUGO,show_cpu1_current,NULL);
static DEVICE_ATTR(cpu1_exhaust_fan_rpm,S_IRUGO,show_cpu1_exhaust_fan_rpm,NULL);
static DEVICE_ATTR(cpu1_intake_fan_rpm,S_IRUGO,show_cpu1_intake_fan_rpm,NULL);

static DEVICE_ATTR(backside_temperature,S_IRUGO,show_backside_temperature,NULL);
static DEVICE_ATTR(backside_fan_pwm,S_IRUGO,show_backside_fan_pwm,NULL);

static DEVICE_ATTR(drives_temperature,S_IRUGO,show_drives_temperature,NULL);
static DEVICE_ATTR(drives_fan_rpm,S_IRUGO,show_drives_fan_rpm,NULL);

static DEVICE_ATTR(slots_temperature,S_IRUGO,show_slots_temperature,NULL);
static DEVICE_ATTR(slots_fan_pwm,S_IRUGO,show_slots_fan_pwm,NULL);

static DEVICE_ATTR(dimms_temperature,S_IRUGO,show_dimms_temperature,NULL);

/*
 * CPUs fans control loop
 */

static int do_read_one_cpu_values(struct cpu_pid_state *state, s32 *temp, s32 *power)
{
      s32 ltemp, volts, amps;
      int index, rc = 0;

      /* Default (in case of error) */
      *temp = state->cur_temp;
      *power = state->cur_power;

      if (cpu_pid_type == CPU_PID_TYPE_RACKMAC)
            index = (state->index == 0) ?
                  CPU_A1_FAN_RPM_INDEX : CPU_B1_FAN_RPM_INDEX;
      else
            index = (state->index == 0) ?
                  CPUA_EXHAUST_FAN_RPM_INDEX : CPUB_EXHAUST_FAN_RPM_INDEX;

      /* Read current fan status */
      rc = get_rpm_fan(index, !RPM_PID_USE_ACTUAL_SPEED);
      if (rc < 0) {
            /* XXX What do we do now ? Nothing for now, keep old value, but
             * return error upstream
             */
            DBG("  cpu %d, fan reading error !\n", state->index);
      } else {
            state->rpm = rc;
            DBG("  cpu %d, exhaust RPM: %d\n", state->index, state->rpm);
      }

      /* Get some sensor readings and scale it */
      ltemp = read_smon_adc(state, 1);
      if (ltemp == -1) {
            /* XXX What do we do now ? */
            state->overtemp++;
            if (rc == 0)
                  rc = -EIO;
            DBG("  cpu %d, temp reading error !\n", state->index);
      } else {
            /* Fixup temperature according to diode calibration
             */
            DBG("  cpu %d, temp raw: %04x, m_diode: %04x, b_diode: %04x\n",
                state->index,
                ltemp, state->mpu.mdiode, state->mpu.bdiode);
            *temp = ((s32)ltemp * (s32)state->mpu.mdiode + ((s32)state->mpu.bdiode << 12)) >> 2;
            state->last_temp = *temp;
            DBG("  temp: %d.%03d\n", FIX32TOPRINT((*temp)));
      }

      /*
       * Read voltage & current and calculate power
       */
      volts = read_smon_adc(state, 3);
      amps = read_smon_adc(state, 4);

      /* Scale voltage and current raw sensor values according to fixed scales
       * obtained in Darwin and calculate power from I and V
       */
      volts *= ADC_CPU_VOLTAGE_SCALE;
      amps *= ADC_CPU_CURRENT_SCALE;
      *power = (((u64)volts) * ((u64)amps)) >> 16;
      state->voltage = volts;
      state->current_a = amps;
      state->last_power = *power;

      DBG("  cpu %d, current: %d.%03d, voltage: %d.%03d, power: %d.%03d W\n",
          state->index, FIX32TOPRINT(state->current_a),
          FIX32TOPRINT(state->voltage), FIX32TOPRINT(*power));

      return 0;
}

static void do_cpu_pid(struct cpu_pid_state *state, s32 temp, s32 power)
{
      s32 power_target, integral, derivative, proportional, adj_in_target, sval;
      s64 integ_p, deriv_p, prop_p, sum; 
      int i;

      /* Calculate power target value (could be done once for all)
       * and convert to a 16.16 fp number
       */
      power_target = ((u32)(state->mpu.pmaxh - state->mpu.padjmax)) << 16;
      DBG("  power target: %d.%03d, error: %d.%03d\n",
          FIX32TOPRINT(power_target), FIX32TOPRINT(power_target - power));

      /* Store temperature and power in history array */
      state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
      state->temp_history[state->cur_temp] = temp;
      state->cur_power = (state->cur_power + 1) % state->count_power;
      state->power_history[state->cur_power] = power;
      state->error_history[state->cur_power] = power_target - power;
      
      /* If first loop, fill the history table */
      if (state->first) {
            for (i = 0; i < (state->count_power - 1); i++) {
                  state->cur_power = (state->cur_power + 1) % state->count_power;
                  state->power_history[state->cur_power] = power;
                  state->error_history[state->cur_power] = power_target - power;
            }
            for (i = 0; i < (CPU_TEMP_HISTORY_SIZE - 1); i++) {
                  state->cur_temp = (state->cur_temp + 1) % CPU_TEMP_HISTORY_SIZE;
                  state->temp_history[state->cur_temp] = temp;                
            }
            state->first = 0;
      }

      /* Calculate the integral term normally based on the "power" values */
      sum = 0;
      integral = 0;
      for (i = 0; i < state->count_power; i++)
            integral += state->error_history[i];
      integral *= CPU_PID_INTERVAL;
      DBG("  integral: %08x\n", integral);

      /* Calculate the adjusted input (sense value).
       *   G_r is 12.20
       *   integ is 16.16
       *   so the result is 28.36
       *
       * input target is mpu.ttarget, input max is mpu.tmax
       */
      integ_p = ((s64)state->mpu.pid_gr) * (s64)integral;
      DBG("   integ_p: %d\n", (int)(integ_p >> 36));
      sval = (state->mpu.tmax << 16) - ((integ_p >> 20) & 0xffffffff);
      adj_in_target = (state->mpu.ttarget << 16);
      if (adj_in_target > sval)
            adj_in_target = sval;
      DBG("   adj_in_target: %d.%03d, ttarget: %d\n", FIX32TOPRINT(adj_in_target),
          state->mpu.ttarget);

      /* Calculate the derivative term */
      derivative = state->temp_history[state->cur_temp] -
            state->temp_history[(state->cur_temp + CPU_TEMP_HISTORY_SIZE - 1)
                            % CPU_TEMP_HISTORY_SIZE];
      derivative /= CPU_PID_INTERVAL;
      deriv_p = ((s64)state->mpu.pid_gd) * (s64)derivative;
      DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
      sum += deriv_p;

      /* Calculate the proportional term */
      proportional = temp - adj_in_target;
      prop_p = ((s64)state->mpu.pid_gp) * (s64)proportional;
      DBG("   prop_p: %d\n", (int)(prop_p >> 36));
      sum += prop_p;

      /* Scale sum */
      sum >>= 36;

      DBG("   sum: %d\n", (int)sum);
      state->rpm += (s32)sum;
}

static void do_monitor_cpu_combined(void)
{
      struct cpu_pid_state *state0 = &cpu_state[0];
      struct cpu_pid_state *state1 = &cpu_state[1];
      s32 temp0, power0, temp1, power1;
      s32 temp_combi, power_combi;
      int rc, intake, pump;

      rc = do_read_one_cpu_values(state0, &temp0, &power0);
      if (rc < 0) {
            /* XXX What do we do now ? */
      }
      state1->overtemp = 0;
      rc = do_read_one_cpu_values(state1, &temp1, &power1);
      if (rc < 0) {
            /* XXX What do we do now ? */
      }
      if (state1->overtemp)
            state0->overtemp++;

      temp_combi = max(temp0, temp1);
      power_combi = max(power0, power1);

      /* Check tmax, increment overtemp if we are there. At tmax+8, we go
       * full blown immediately and try to trigger a shutdown
       */
      if (temp_combi >= ((state0->mpu.tmax + 8) << 16)) {
            printk(KERN_WARNING "Warning ! Temperature way above maximum (%d) !\n",
                   temp_combi >> 16);
            state0->overtemp += CPU_MAX_OVERTEMP / 4;
      } else if (temp_combi > (state0->mpu.tmax << 16))
            state0->overtemp++;
      else
            state0->overtemp = 0;
      if (state0->overtemp >= CPU_MAX_OVERTEMP)
            critical_state = 1;
      if (state0->overtemp > 0) {
            state0->rpm = state0->mpu.rmaxn_exhaust_fan;
            state0->intake_rpm = intake = state0->mpu.rmaxn_intake_fan;
            pump = state0->pump_max;
            goto do_set_fans;
      }

      /* Do the PID */
      do_cpu_pid(state0, temp_combi, power_combi);

      /* Range check */
      state0->rpm = max(state0->rpm, (int)state0->mpu.rminn_exhaust_fan);
      state0->rpm = min(state0->rpm, (int)state0->mpu.rmaxn_exhaust_fan);

      /* Calculate intake fan speed */
      intake = (state0->rpm * CPU_INTAKE_SCALE) >> 16;
      intake = max(intake, (int)state0->mpu.rminn_intake_fan);
      intake = min(intake, (int)state0->mpu.rmaxn_intake_fan);
      state0->intake_rpm = intake;

      /* Calculate pump speed */
      pump = (state0->rpm * state0->pump_max) /
            state0->mpu.rmaxn_exhaust_fan;
      pump = min(pump, state0->pump_max);
      pump = max(pump, state0->pump_min);
      
 do_set_fans:
      /* We copy values from state 0 to state 1 for /sysfs */
      state1->rpm = state0->rpm;
      state1->intake_rpm = state0->intake_rpm;

      DBG("** CPU %d RPM: %d Ex, %d, Pump: %d, In, overtemp: %d\n",
          state1->index, (int)state1->rpm, intake, pump, state1->overtemp);

      /* We should check for errors, shouldn't we ? But then, what
       * do we do once the error occurs ? For FCU notified fan
       * failures (-EFAULT) we probably want to notify userland
       * some way...
       */
      set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
      set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state0->rpm);
      set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
      set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state0->rpm);

      if (fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
            set_rpm_fan(CPUA_PUMP_RPM_INDEX, pump);
      if (fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID)
            set_rpm_fan(CPUB_PUMP_RPM_INDEX, pump);
}

static void do_monitor_cpu_split(struct cpu_pid_state *state)
{
      s32 temp, power;
      int rc, intake;

      /* Read current fan status */
      rc = do_read_one_cpu_values(state, &temp, &power);
      if (rc < 0) {
            /* XXX What do we do now ? */
      }

      /* Check tmax, increment overtemp if we are there. At tmax+8, we go
       * full blown immediately and try to trigger a shutdown
       */
      if (temp >= ((state->mpu.tmax + 8) << 16)) {
            printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
                   " (%d) !\n",
                   state->index, temp >> 16);
            state->overtemp += CPU_MAX_OVERTEMP / 4;
      } else if (temp > (state->mpu.tmax << 16))
            state->overtemp++;
      else
            state->overtemp = 0;
      if (state->overtemp >= CPU_MAX_OVERTEMP)
            critical_state = 1;
      if (state->overtemp > 0) {
            state->rpm = state->mpu.rmaxn_exhaust_fan;
            state->intake_rpm = intake = state->mpu.rmaxn_intake_fan;
            goto do_set_fans;
      }

      /* Do the PID */
      do_cpu_pid(state, temp, power);

      /* Range check */
      state->rpm = max(state->rpm, (int)state->mpu.rminn_exhaust_fan);
      state->rpm = min(state->rpm, (int)state->mpu.rmaxn_exhaust_fan);

      /* Calculate intake fan */
      intake = (state->rpm * CPU_INTAKE_SCALE) >> 16;
      intake = max(intake, (int)state->mpu.rminn_intake_fan);
      intake = min(intake, (int)state->mpu.rmaxn_intake_fan);
      state->intake_rpm = intake;

 do_set_fans:
      DBG("** CPU %d RPM: %d Ex, %d In, overtemp: %d\n",
          state->index, (int)state->rpm, intake, state->overtemp);

      /* We should check for errors, shouldn't we ? But then, what
       * do we do once the error occurs ? For FCU notified fan
       * failures (-EFAULT) we probably want to notify userland
       * some way...
       */
      if (state->index == 0) {
            set_rpm_fan(CPUA_INTAKE_FAN_RPM_INDEX, intake);
            set_rpm_fan(CPUA_EXHAUST_FAN_RPM_INDEX, state->rpm);
      } else {
            set_rpm_fan(CPUB_INTAKE_FAN_RPM_INDEX, intake);
            set_rpm_fan(CPUB_EXHAUST_FAN_RPM_INDEX, state->rpm);
      }
}

static void do_monitor_cpu_rack(struct cpu_pid_state *state)
{
      s32 temp, power, fan_min;
      int rc;

      /* Read current fan status */
      rc = do_read_one_cpu_values(state, &temp, &power);
      if (rc < 0) {
            /* XXX What do we do now ? */
      }

      /* Check tmax, increment overtemp if we are there. At tmax+8, we go
       * full blown immediately and try to trigger a shutdown
       */
      if (temp >= ((state->mpu.tmax + 8) << 16)) {
            printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
                   " (%d) !\n",
                   state->index, temp >> 16);
            state->overtemp = CPU_MAX_OVERTEMP / 4;
      } else if (temp > (state->mpu.tmax << 16))
            state->overtemp++;
      else
            state->overtemp = 0;
      if (state->overtemp >= CPU_MAX_OVERTEMP)
            critical_state = 1;
      if (state->overtemp > 0) {
            state->rpm = state->intake_rpm = state->mpu.rmaxn_intake_fan;
            goto do_set_fans;
      }

      /* Do the PID */
      do_cpu_pid(state, temp, power);

      /* Check clamp from dimms */
      fan_min = dimm_output_clamp;
      fan_min = max(fan_min, (int)state->mpu.rminn_intake_fan);

      DBG(" CPU min mpu = %d, min dimm = %d\n",
          state->mpu.rminn_intake_fan, dimm_output_clamp);

      state->rpm = max(state->rpm, (int)fan_min);
      state->rpm = min(state->rpm, (int)state->mpu.rmaxn_intake_fan);
      state->intake_rpm = state->rpm;

 do_set_fans:
      DBG("** CPU %d RPM: %d overtemp: %d\n",
          state->index, (int)state->rpm, state->overtemp);

      /* We should check for errors, shouldn't we ? But then, what
       * do we do once the error occurs ? For FCU notified fan
       * failures (-EFAULT) we probably want to notify userland
       * some way...
       */
      if (state->index == 0) {
            set_rpm_fan(CPU_A1_FAN_RPM_INDEX, state->rpm);
            set_rpm_fan(CPU_A2_FAN_RPM_INDEX, state->rpm);
            set_rpm_fan(CPU_A3_FAN_RPM_INDEX, state->rpm);
      } else {
            set_rpm_fan(CPU_B1_FAN_RPM_INDEX, state->rpm);
            set_rpm_fan(CPU_B2_FAN_RPM_INDEX, state->rpm);
            set_rpm_fan(CPU_B3_FAN_RPM_INDEX, state->rpm);
      }
}

/*
 * Initialize the state structure for one CPU control loop
 */
static int init_cpu_state(struct cpu_pid_state *state, int index)
{
      state->index = index;
      state->first = 1;
      state->rpm = (cpu_pid_type == CPU_PID_TYPE_RACKMAC) ? 4000 : 1000;
      state->overtemp = 0;
      state->adc_config = 0x00;


      if (index == 0)
            state->monitor = attach_i2c_chip(SUPPLY_MONITOR_ID, "CPU0_monitor");
      else if (index == 1)
            state->monitor = attach_i2c_chip(SUPPLY_MONITORB_ID, "CPU1_monitor");
      if (state->monitor == NULL)
            goto fail;

      if (read_eeprom(index, &state->mpu))
            goto fail;

      state->count_power = state->mpu.tguardband;
      if (state->count_power > CPU_POWER_HISTORY_SIZE) {
            printk(KERN_WARNING "Warning ! too many power history slots\n");
            state->count_power = CPU_POWER_HISTORY_SIZE;
      }
      DBG("CPU %d Using %d power history entries\n", index, state->count_power);

      if (index == 0) {
            device_create_file(&of_dev->dev, &dev_attr_cpu0_temperature);
            device_create_file(&of_dev->dev, &dev_attr_cpu0_voltage);
            device_create_file(&of_dev->dev, &dev_attr_cpu0_current);
            device_create_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
            device_create_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
      } else {
            device_create_file(&of_dev->dev, &dev_attr_cpu1_temperature);
            device_create_file(&of_dev->dev, &dev_attr_cpu1_voltage);
            device_create_file(&of_dev->dev, &dev_attr_cpu1_current);
            device_create_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
            device_create_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
      }

      return 0;
 fail:
      if (state->monitor)
            detach_i2c_chip(state->monitor);
      state->monitor = NULL;
      
      return -ENODEV;
}

/*
 * Dispose of the state data for one CPU control loop
 */
static void dispose_cpu_state(struct cpu_pid_state *state)
{
      if (state->monitor == NULL)
            return;

      if (state->index == 0) {
            device_remove_file(&of_dev->dev, &dev_attr_cpu0_temperature);
            device_remove_file(&of_dev->dev, &dev_attr_cpu0_voltage);
            device_remove_file(&of_dev->dev, &dev_attr_cpu0_current);
            device_remove_file(&of_dev->dev, &dev_attr_cpu0_exhaust_fan_rpm);
            device_remove_file(&of_dev->dev, &dev_attr_cpu0_intake_fan_rpm);
      } else {
            device_remove_file(&of_dev->dev, &dev_attr_cpu1_temperature);
            device_remove_file(&of_dev->dev, &dev_attr_cpu1_voltage);
            device_remove_file(&of_dev->dev, &dev_attr_cpu1_current);
            device_remove_file(&of_dev->dev, &dev_attr_cpu1_exhaust_fan_rpm);
            device_remove_file(&of_dev->dev, &dev_attr_cpu1_intake_fan_rpm);
      }

      detach_i2c_chip(state->monitor);
      state->monitor = NULL;
}

/*
 * Motherboard backside & U3 heatsink fan control loop
 */
static void do_monitor_backside(struct backside_pid_state *state)
{
      s32 temp, integral, derivative, fan_min;
      s64 integ_p, deriv_p, prop_p, sum; 
      int i, rc;

      if (--state->ticks != 0)
            return;
      state->ticks = backside_params.interval;

      DBG("backside:\n");

      /* Check fan status */
      rc = get_pwm_fan(BACKSIDE_FAN_PWM_INDEX);
      if (rc < 0) {
            printk(KERN_WARNING "Error %d reading backside fan !\n", rc);
            /* XXX What do we do now ? */
      } else
            state->pwm = rc;
      DBG("  current pwm: %d\n", state->pwm);

      /* Get some sensor readings */
      temp = i2c_smbus_read_byte_data(state->monitor, MAX6690_EXT_TEMP) << 16;
      state->last_temp = temp;
      DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
          FIX32TOPRINT(backside_params.input_target));

      /* Store temperature and error in history array */
      state->cur_sample = (state->cur_sample + 1) % BACKSIDE_PID_HISTORY_SIZE;
      state->sample_history[state->cur_sample] = temp;
      state->error_history[state->cur_sample] = temp - backside_params.input_target;
      
      /* If first loop, fill the history table */
      if (state->first) {
            for (i = 0; i < (BACKSIDE_PID_HISTORY_SIZE - 1); i++) {
                  state->cur_sample = (state->cur_sample + 1) %
                        BACKSIDE_PID_HISTORY_SIZE;
                  state->sample_history[state->cur_sample] = temp;
                  state->error_history[state->cur_sample] =
                        temp - backside_params.input_target;
            }
            state->first = 0;
      }

      /* Calculate the integral term */
      sum = 0;
      integral = 0;
      for (i = 0; i < BACKSIDE_PID_HISTORY_SIZE; i++)
            integral += state->error_history[i];
      integral *= backside_params.interval;
      DBG("  integral: %08x\n", integral);
      integ_p = ((s64)backside_params.G_r) * (s64)integral;
      DBG("   integ_p: %d\n", (int)(integ_p >> 36));
      sum += integ_p;

      /* Calculate the derivative term */
      derivative = state->error_history[state->cur_sample] -
            state->error_history[(state->cur_sample + BACKSIDE_PID_HISTORY_SIZE - 1)
                            % BACKSIDE_PID_HISTORY_SIZE];
      derivative /= backside_params.interval;
      deriv_p = ((s64)backside_params.G_d) * (s64)derivative;
      DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
      sum += deriv_p;

      /* Calculate the proportional term */
      prop_p = ((s64)backside_params.G_p) * (s64)(state->error_history[state->cur_sample]);
      DBG("   prop_p: %d\n", (int)(prop_p >> 36));
      sum += prop_p;

      /* Scale sum */
      sum >>= 36;

      DBG("   sum: %d\n", (int)sum);
      if (backside_params.additive)
            state->pwm += (s32)sum;
      else
            state->pwm = sum;

      /* Check for clamp */
      fan_min = (dimm_output_clamp * 100) / 14000;
      fan_min = max(fan_min, backside_params.output_min);

      state->pwm = max(state->pwm, fan_min);
      state->pwm = min(state->pwm, backside_params.output_max);

      DBG("** BACKSIDE PWM: %d\n", (int)state->pwm);
      set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, state->pwm);
}

/*
 * Initialize the state structure for the backside fan control loop
 */
static int init_backside_state(struct backside_pid_state *state)
{
      struct device_node *u3;
      int u3h = 1; /* conservative by default */

      /*
       * There are different PID params for machines with U3 and machines
       * with U3H, pick the right ones now
       */
      u3 = of_find_node_by_path("/u3@0,f8000000");
      if (u3 != NULL) {
            const u32 *vers = of_get_property(u3, "device-rev", NULL);
            if (vers)
                  if (((*vers) & 0x3f) < 0x34)
                        u3h = 0;
            of_node_put(u3);
      }

      if (rackmac) {
            backside_params.G_d = BACKSIDE_PID_RACK_G_d;
            backside_params.input_target = BACKSIDE_PID_RACK_INPUT_TARGET;
            backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
            backside_params.interval = BACKSIDE_PID_RACK_INTERVAL;
            backside_params.G_p = BACKSIDE_PID_RACK_G_p;
            backside_params.G_r = BACKSIDE_PID_G_r;
            backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
            backside_params.additive = 0;
      } else if (u3h) {
            backside_params.G_d = BACKSIDE_PID_U3H_G_d;
            backside_params.input_target = BACKSIDE_PID_U3H_INPUT_TARGET;
            backside_params.output_min = BACKSIDE_PID_U3H_OUTPUT_MIN;
            backside_params.interval = BACKSIDE_PID_INTERVAL;
            backside_params.G_p = BACKSIDE_PID_G_p;
            backside_params.G_r = BACKSIDE_PID_G_r;
            backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
            backside_params.additive = 1;
      } else {
            backside_params.G_d = BACKSIDE_PID_U3_G_d;
            backside_params.input_target = BACKSIDE_PID_U3_INPUT_TARGET;
            backside_params.output_min = BACKSIDE_PID_U3_OUTPUT_MIN;
            backside_params.interval = BACKSIDE_PID_INTERVAL;
            backside_params.G_p = BACKSIDE_PID_G_p;
            backside_params.G_r = BACKSIDE_PID_G_r;
            backside_params.output_max = BACKSIDE_PID_OUTPUT_MAX;
            backside_params.additive = 1;
      }

      state->ticks = 1;
      state->first = 1;
      state->pwm = 50;

      state->monitor = attach_i2c_chip(BACKSIDE_MAX_ID, "backside_temp");
      if (state->monitor == NULL)
            return -ENODEV;

      device_create_file(&of_dev->dev, &dev_attr_backside_temperature);
      device_create_file(&of_dev->dev, &dev_attr_backside_fan_pwm);

      return 0;
}

/*
 * Dispose of the state data for the backside control loop
 */
static void dispose_backside_state(struct backside_pid_state *state)
{
      if (state->monitor == NULL)
            return;

      device_remove_file(&of_dev->dev, &dev_attr_backside_temperature);
      device_remove_file(&of_dev->dev, &dev_attr_backside_fan_pwm);

      detach_i2c_chip(state->monitor);
      state->monitor = NULL;
}
 
/*
 * Drives bay fan control loop
 */
static void do_monitor_drives(struct drives_pid_state *state)
{
      s32 temp, integral, derivative;
      s64 integ_p, deriv_p, prop_p, sum; 
      int i, rc;

      if (--state->ticks != 0)
            return;
      state->ticks = DRIVES_PID_INTERVAL;

      DBG("drives:\n");

      /* Check fan status */
      rc = get_rpm_fan(DRIVES_FAN_RPM_INDEX, !RPM_PID_USE_ACTUAL_SPEED);
      if (rc < 0) {
            printk(KERN_WARNING "Error %d reading drives fan !\n", rc);
            /* XXX What do we do now ? */
      } else
            state->rpm = rc;
      DBG("  current rpm: %d\n", state->rpm);

      /* Get some sensor readings */
      temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor,
                                        DS1775_TEMP)) << 8;
      state->last_temp = temp;
      DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
          FIX32TOPRINT(DRIVES_PID_INPUT_TARGET));

      /* Store temperature and error in history array */
      state->cur_sample = (state->cur_sample + 1) % DRIVES_PID_HISTORY_SIZE;
      state->sample_history[state->cur_sample] = temp;
      state->error_history[state->cur_sample] = temp - DRIVES_PID_INPUT_TARGET;
      
      /* If first loop, fill the history table */
      if (state->first) {
            for (i = 0; i < (DRIVES_PID_HISTORY_SIZE - 1); i++) {
                  state->cur_sample = (state->cur_sample + 1) %
                        DRIVES_PID_HISTORY_SIZE;
                  state->sample_history[state->cur_sample] = temp;
                  state->error_history[state->cur_sample] =
                        temp - DRIVES_PID_INPUT_TARGET;
            }
            state->first = 0;
      }

      /* Calculate the integral term */
      sum = 0;
      integral = 0;
      for (i = 0; i < DRIVES_PID_HISTORY_SIZE; i++)
            integral += state->error_history[i];
      integral *= DRIVES_PID_INTERVAL;
      DBG("  integral: %08x\n", integral);
      integ_p = ((s64)DRIVES_PID_G_r) * (s64)integral;
      DBG("   integ_p: %d\n", (int)(integ_p >> 36));
      sum += integ_p;

      /* Calculate the derivative term */
      derivative = state->error_history[state->cur_sample] -
            state->error_history[(state->cur_sample + DRIVES_PID_HISTORY_SIZE - 1)
                            % DRIVES_PID_HISTORY_SIZE];
      derivative /= DRIVES_PID_INTERVAL;
      deriv_p = ((s64)DRIVES_PID_G_d) * (s64)derivative;
      DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
      sum += deriv_p;

      /* Calculate the proportional term */
      prop_p = ((s64)DRIVES_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
      DBG("   prop_p: %d\n", (int)(prop_p >> 36));
      sum += prop_p;

      /* Scale sum */
      sum >>= 36;

      DBG("   sum: %d\n", (int)sum);
      state->rpm += (s32)sum;

      state->rpm = max(state->rpm, DRIVES_PID_OUTPUT_MIN);
      state->rpm = min(state->rpm, DRIVES_PID_OUTPUT_MAX);

      DBG("** DRIVES RPM: %d\n", (int)state->rpm);
      set_rpm_fan(DRIVES_FAN_RPM_INDEX, state->rpm);
}

/*
 * Initialize the state structure for the drives bay fan control loop
 */
static int init_drives_state(struct drives_pid_state *state)
{
      state->ticks = 1;
      state->first = 1;
      state->rpm = 1000;

      state->monitor = attach_i2c_chip(DRIVES_DALLAS_ID, "drives_temp");
      if (state->monitor == NULL)
            return -ENODEV;

      device_create_file(&of_dev->dev, &dev_attr_drives_temperature);
      device_create_file(&of_dev->dev, &dev_attr_drives_fan_rpm);

      return 0;
}

/*
 * Dispose of the state data for the drives control loop
 */
static void dispose_drives_state(struct drives_pid_state *state)
{
      if (state->monitor == NULL)
            return;

      device_remove_file(&of_dev->dev, &dev_attr_drives_temperature);
      device_remove_file(&of_dev->dev, &dev_attr_drives_fan_rpm);

      detach_i2c_chip(state->monitor);
      state->monitor = NULL;
}

/*
 * DIMMs temp control loop
 */
static void do_monitor_dimms(struct dimm_pid_state *state)
{
      s32 temp, integral, derivative, fan_min;
      s64 integ_p, deriv_p, prop_p, sum;
      int i;

      if (--state->ticks != 0)
            return;
      state->ticks = DIMM_PID_INTERVAL;

      DBG("DIMM:\n");

      DBG("  current value: %d\n", state->output);

      temp = read_lm87_reg(state->monitor, LM87_INT_TEMP);
      if (temp < 0)
            return;
      temp <<= 16;
      state->last_temp = temp;
      DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
          FIX32TOPRINT(DIMM_PID_INPUT_TARGET));

      /* Store temperature and error in history array */
      state->cur_sample = (state->cur_sample + 1) % DIMM_PID_HISTORY_SIZE;
      state->sample_history[state->cur_sample] = temp;
      state->error_history[state->cur_sample] = temp - DIMM_PID_INPUT_TARGET;

      /* If first loop, fill the history table */
      if (state->first) {
            for (i = 0; i < (DIMM_PID_HISTORY_SIZE - 1); i++) {
                  state->cur_sample = (state->cur_sample + 1) %
                        DIMM_PID_HISTORY_SIZE;
                  state->sample_history[state->cur_sample] = temp;
                  state->error_history[state->cur_sample] =
                        temp - DIMM_PID_INPUT_TARGET;
            }
            state->first = 0;
      }

      /* Calculate the integral term */
      sum = 0;
      integral = 0;
      for (i = 0; i < DIMM_PID_HISTORY_SIZE; i++)
            integral += state->error_history[i];
      integral *= DIMM_PID_INTERVAL;
      DBG("  integral: %08x\n", integral);
      integ_p = ((s64)DIMM_PID_G_r) * (s64)integral;
      DBG("   integ_p: %d\n", (int)(integ_p >> 36));
      sum += integ_p;

      /* Calculate the derivative term */
      derivative = state->error_history[state->cur_sample] -
            state->error_history[(state->cur_sample + DIMM_PID_HISTORY_SIZE - 1)
                            % DIMM_PID_HISTORY_SIZE];
      derivative /= DIMM_PID_INTERVAL;
      deriv_p = ((s64)DIMM_PID_G_d) * (s64)derivative;
      DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
      sum += deriv_p;

      /* Calculate the proportional term */
      prop_p = ((s64)DIMM_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
      DBG("   prop_p: %d\n", (int)(prop_p >> 36));
      sum += prop_p;

      /* Scale sum */
      sum >>= 36;

      DBG("   sum: %d\n", (int)sum);
      state->output = (s32)sum;
      state->output = max(state->output, DIMM_PID_OUTPUT_MIN);
      state->output = min(state->output, DIMM_PID_OUTPUT_MAX);
      dimm_output_clamp = state->output;

      DBG("** DIMM clamp value: %d\n", (int)state->output);

      /* Backside PID is only every 5 seconds, force backside fan clamping now */
      fan_min = (dimm_output_clamp * 100) / 14000;
      fan_min = max(fan_min, backside_params.output_min);
      if (backside_state.pwm < fan_min) {
            backside_state.pwm = fan_min;
            DBG(" -> applying clamp to backside fan now: %d  !\n", fan_min);
            set_pwm_fan(BACKSIDE_FAN_PWM_INDEX, fan_min);
      }
}

/*
 * Initialize the state structure for the DIMM temp control loop
 */
static int init_dimms_state(struct dimm_pid_state *state)
{
      state->ticks = 1;
      state->first = 1;
      state->output = 4000;

      state->monitor = attach_i2c_chip(XSERVE_DIMMS_LM87, "dimms_temp");
      if (state->monitor == NULL)
            return -ENODEV;

            device_create_file(&of_dev->dev, &dev_attr_dimms_temperature);

      return 0;
}

/*
 * Dispose of the state data for the DIMM control loop
 */
static void dispose_dimms_state(struct dimm_pid_state *state)
{
      if (state->monitor == NULL)
            return;

      device_remove_file(&of_dev->dev, &dev_attr_dimms_temperature);

      detach_i2c_chip(state->monitor);
      state->monitor = NULL;
}

/*
 * Slots fan control loop
 */
static void do_monitor_slots(struct slots_pid_state *state)
{
      s32 temp, integral, derivative;
      s64 integ_p, deriv_p, prop_p, sum;
      int i, rc;

      if (--state->ticks != 0)
            return;
      state->ticks = SLOTS_PID_INTERVAL;

      DBG("slots:\n");

      /* Check fan status */
      rc = get_pwm_fan(SLOTS_FAN_PWM_INDEX);
      if (rc < 0) {
            printk(KERN_WARNING "Error %d reading slots fan !\n", rc);
            /* XXX What do we do now ? */
      } else
            state->pwm = rc;
      DBG("  current pwm: %d\n", state->pwm);

      /* Get some sensor readings */
      temp = le16_to_cpu(i2c_smbus_read_word_data(state->monitor,
                                        DS1775_TEMP)) << 8;
      state->last_temp = temp;
      DBG("  temp: %d.%03d, target: %d.%03d\n", FIX32TOPRINT(temp),
          FIX32TOPRINT(SLOTS_PID_INPUT_TARGET));

      /* Store temperature and error in history array */
      state->cur_sample = (state->cur_sample + 1) % SLOTS_PID_HISTORY_SIZE;
      state->sample_history[state->cur_sample] = temp;
      state->error_history[state->cur_sample] = temp - SLOTS_PID_INPUT_TARGET;

      /* If first loop, fill the history table */
      if (state->first) {
            for (i = 0; i < (SLOTS_PID_HISTORY_SIZE - 1); i++) {
                  state->cur_sample = (state->cur_sample + 1) %
                        SLOTS_PID_HISTORY_SIZE;
                  state->sample_history[state->cur_sample] = temp;
                  state->error_history[state->cur_sample] =
                        temp - SLOTS_PID_INPUT_TARGET;
            }
            state->first = 0;
      }

      /* Calculate the integral term */
      sum = 0;
      integral = 0;
      for (i = 0; i < SLOTS_PID_HISTORY_SIZE; i++)
            integral += state->error_history[i];
      integral *= SLOTS_PID_INTERVAL;
      DBG("  integral: %08x\n", integral);
      integ_p = ((s64)SLOTS_PID_G_r) * (s64)integral;
      DBG("   integ_p: %d\n", (int)(integ_p >> 36));
      sum += integ_p;

      /* Calculate the derivative term */
      derivative = state->error_history[state->cur_sample] -
            state->error_history[(state->cur_sample + SLOTS_PID_HISTORY_SIZE - 1)
                            % SLOTS_PID_HISTORY_SIZE];
      derivative /= SLOTS_PID_INTERVAL;
      deriv_p = ((s64)SLOTS_PID_G_d) * (s64)derivative;
      DBG("   deriv_p: %d\n", (int)(deriv_p >> 36));
      sum += deriv_p;

      /* Calculate the proportional term */
      prop_p = ((s64)SLOTS_PID_G_p) * (s64)(state->error_history[state->cur_sample]);
      DBG("   prop_p: %d\n", (int)(prop_p >> 36));
      sum += prop_p;

      /* Scale sum */
      sum >>= 36;

      DBG("   sum: %d\n", (int)sum);
      state->pwm = (s32)sum;

      state->pwm = max(state->pwm, SLOTS_PID_OUTPUT_MIN);
      state->pwm = min(state->pwm, SLOTS_PID_OUTPUT_MAX);

      DBG("** DRIVES PWM: %d\n", (int)state->pwm);
      set_pwm_fan(SLOTS_FAN_PWM_INDEX, state->pwm);
}

/*
 * Initialize the state structure for the slots bay fan control loop
 */
static int init_slots_state(struct slots_pid_state *state)
{
      state->ticks = 1;
      state->first = 1;
      state->pwm = 50;

      state->monitor = attach_i2c_chip(XSERVE_SLOTS_LM75, "slots_temp");
      if (state->monitor == NULL)
            return -ENODEV;

      device_create_file(&of_dev->dev, &dev_attr_slots_temperature);
      device_create_file(&of_dev->dev, &dev_attr_slots_fan_pwm);

      return 0;
}

/*
 * Dispose of the state data for the slots control loop
 */
static void dispose_slots_state(struct slots_pid_state *state)
{
      if (state->monitor == NULL)
            return;

      device_remove_file(&of_dev->dev, &dev_attr_slots_temperature);
      device_remove_file(&of_dev->dev, &dev_attr_slots_fan_pwm);

      detach_i2c_chip(state->monitor);
      state->monitor = NULL;
}


static int call_critical_overtemp(void)
{
      char *argv[] = { critical_overtemp_path, NULL };
      static char *envp[] = { "HOME=/",
                        "TERM=linux",
                        "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                        NULL };

      return call_usermodehelper(critical_overtemp_path,
                           argv, envp, UMH_WAIT_EXEC);
}


/*
 * Here's the kernel thread that calls the various control loops
 */
static int main_control_loop(void *x)
{
      daemonize("kfand");

      DBG("main_control_loop started\n");

      down(&driver_lock);

      if (start_fcu() < 0) {
            printk(KERN_ERR "kfand: failed to start FCU\n");
            up(&driver_lock);
            goto out;
      }

      /* Set the PCI fan once for now on non-RackMac */
      if (!rackmac)
            set_pwm_fan(SLOTS_FAN_PWM_INDEX, SLOTS_FAN_DEFAULT_PWM);

      /* Initialize ADCs */
      initialize_adc(&cpu_state[0]);
      if (cpu_state[1].monitor != NULL)
            initialize_adc(&cpu_state[1]);

      fcu_tickle_ticks = FCU_TICKLE_TICKS;

      up(&driver_lock);

      while (state == state_attached) {
            unsigned long elapsed, start;

            start = jiffies;

            down(&driver_lock);

            /* Tickle the FCU just in case */
            if (--fcu_tickle_ticks < 0) {
                  fcu_tickle_ticks = FCU_TICKLE_TICKS;
                  tickle_fcu();
            }

            /* First, we always calculate the new DIMMs state on an Xserve */
            if (rackmac)
                  do_monitor_dimms(&dimms_state);

            /* Then, the CPUs */
            if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
                  do_monitor_cpu_combined();
            else if (cpu_pid_type == CPU_PID_TYPE_RACKMAC) {
                  do_monitor_cpu_rack(&cpu_state[0]);
                  if (cpu_state[1].monitor != NULL)
                        do_monitor_cpu_rack(&cpu_state[1]);
                  // better deal with UP
            } else {
                  do_monitor_cpu_split(&cpu_state[0]);
                  if (cpu_state[1].monitor != NULL)
                        do_monitor_cpu_split(&cpu_state[1]);
                  // better deal with UP
            }
            /* Then, the rest */
            do_monitor_backside(&backside_state);
            if (rackmac)
                  do_monitor_slots(&slots_state);
            else
                  do_monitor_drives(&drives_state);
            up(&driver_lock);

            if (critical_state == 1) {
                  printk(KERN_WARNING "Temperature control detected a critical condition\n");
                  printk(KERN_WARNING "Attempting to shut down...\n");
                  if (call_critical_overtemp()) {
                        printk(KERN_WARNING "Can't call %s, power off now!\n",
                               critical_overtemp_path);
                        machine_power_off();
                  }
            }
            if (critical_state > 0)
                  critical_state++;
            if (critical_state > MAX_CRITICAL_STATE) {
                  printk(KERN_WARNING "Shutdown timed out, power off now !\n");
                  machine_power_off();
            }

            // FIXME: Deal with signals
            elapsed = jiffies - start;
            if (elapsed < HZ)
                  schedule_timeout_interruptible(HZ - elapsed);
      }

 out:
      DBG("main_control_loop ended\n");

      ctrl_task = 0;
      complete_and_exit(&ctrl_complete, 0);
}

/*
 * Dispose the control loops when tearing down
 */
static void dispose_control_loops(void)
{
      dispose_cpu_state(&cpu_state[0]);
      dispose_cpu_state(&cpu_state[1]);
      dispose_backside_state(&backside_state);
      dispose_drives_state(&drives_state);
      dispose_slots_state(&slots_state);
      dispose_dimms_state(&dimms_state);
}

/*
 * Create the control loops. U3-0 i2c bus is up, so we can now
 * get to the various sensors
 */
static int create_control_loops(void)
{
      struct device_node *np;

      /* Count CPUs from the device-tree, we don't care how many are
       * actually used by Linux
       */
      cpu_count = 0;
      for (np = NULL; NULL != (np = of_find_node_by_type(np, "cpu"));)
            cpu_count++;

      DBG("counted %d CPUs in the device-tree\n", cpu_count);

      /* Decide the type of PID algorithm to use based on the presence of
       * the pumps, though that may not be the best way, that is good enough
       * for now
       */
      if (rackmac)
            cpu_pid_type = CPU_PID_TYPE_RACKMAC;
      else if (machine_is_compatible("PowerMac7,3")
          && (cpu_count > 1)
          && fcu_fans[CPUA_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID
          && fcu_fans[CPUB_PUMP_RPM_INDEX].id != FCU_FAN_ABSENT_ID) {
            printk(KERN_INFO "Liquid cooling pumps detected, using new algorithm !\n");
            cpu_pid_type = CPU_PID_TYPE_COMBINED;
      } else
            cpu_pid_type = CPU_PID_TYPE_SPLIT;

      /* Create control loops for everything. If any fail, everything
       * fails
       */
      if (init_cpu_state(&cpu_state[0], 0))
            goto fail;
      if (cpu_pid_type == CPU_PID_TYPE_COMBINED)
            fetch_cpu_pumps_minmax();

      if (cpu_count > 1 && init_cpu_state(&cpu_state[1], 1))
            goto fail;
      if (init_backside_state(&backside_state))
            goto fail;
      if (rackmac && init_dimms_state(&dimms_state))
            goto fail;
      if (rackmac && init_slots_state(&slots_state))
            goto fail;
      if (!rackmac && init_drives_state(&drives_state))
            goto fail;

      DBG("all control loops up !\n");

      return 0;
      
 fail:
      DBG("failure creating control loops, disposing\n");

      dispose_control_loops();

      return -ENODEV;
}

/*
 * Start the control loops after everything is up, that is create
 * the thread that will make them run
 */
static void start_control_loops(void)
{
      init_completion(&ctrl_complete);

      ctrl_task = kernel_thread(main_control_loop, NULL, SIGCHLD | CLONE_KERNEL);
}

/*
 * Stop the control loops when tearing down
 */
static void stop_control_loops(void)
{
      if (ctrl_task != 0)
            wait_for_completion(&ctrl_complete);
}

/*
 * Attach to the i2c FCU after detecting U3-1 bus
 */
static int attach_fcu(void)
{
      fcu = attach_i2c_chip(FAN_CTRLER_ID, "fcu");
      if (fcu == NULL)
            return -ENODEV;

      DBG("FCU attached\n");

      return 0;
}

/*
 * Detach from the i2c FCU when tearing down
 */
static void detach_fcu(void)
{
      if (fcu)
            detach_i2c_chip(fcu);
      fcu = NULL;
}

/*
 * Attach to the i2c controller. We probe the various chips based
 * on the device-tree nodes and build everything for the driver to
 * run, we then kick the driver monitoring thread
 */
static int therm_pm72_attach(struct i2c_adapter *adapter)
{
      down(&driver_lock);

      /* Check state */
      if (state == state_detached)
            state = state_attaching;
      if (state != state_attaching) {
            up(&driver_lock);
            return 0;
      }

      /* Check if we are looking for one of these */
      if (u3_0 == NULL && !strcmp(adapter->name, "u3 0")) {
            u3_0 = adapter;
            DBG("found U3-0\n");
            if (k2 || !rackmac)
                  if (create_control_loops())
                        u3_0 = NULL;
      } else if (u3_1 == NULL && !strcmp(adapter->name, "u3 1")) {
            u3_1 = adapter;
            DBG("found U3-1, attaching FCU\n");
            if (attach_fcu())
                  u3_1 = NULL;
      } else if (k2 == NULL && !strcmp(adapter->name, "mac-io 0")) {
            k2 = adapter;
            DBG("Found K2\n");
            if (u3_0 && rackmac)
                  if (create_control_loops())
                        k2 = NULL;
      }
      /* We got all we need, start control loops */
      if (u3_0 != NULL && u3_1 != NULL && (k2 || !rackmac)) {
            DBG("everything up, starting control loops\n");
            state = state_attached;
            start_control_loops();
      }
      up(&driver_lock);

      return 0;
}

/*
 * Called on every adapter when the driver or the i2c controller
 * is going away.
 */
static int therm_pm72_detach(struct i2c_adapter *adapter)
{
      down(&driver_lock);

      if (state != state_detached)
            state = state_detaching;

      /* Stop control loops if any */
      DBG("stopping control loops\n");
      up(&driver_lock);
      stop_control_loops();
      down(&driver_lock);

      if (u3_0 != NULL && !strcmp(adapter->name, "u3 0")) {
            DBG("lost U3-0, disposing control loops\n");
            dispose_control_loops();
            u3_0 = NULL;
      }
      
      if (u3_1 != NULL && !strcmp(adapter->name, "u3 1")) {
            DBG("lost U3-1, detaching FCU\n");
            detach_fcu();
            u3_1 = NULL;
      }
      if (u3_0 == NULL && u3_1 == NULL)
            state = state_detached;

      up(&driver_lock);

      return 0;
}

static int fan_check_loc_match(const char *loc, int fan)
{
      char  tmp[64];
      char  *c, *e;

      strlcpy(tmp, fcu_fans[fan].loc, 64);

      c = tmp;
      for (;;) {
            e = strchr(c, ',');
            if (e)
                  *e = 0;
            if (strcmp(loc, c) == 0)
                  return 1;
            if (e == NULL)
                  break;
            c = e + 1;
      }
      return 0;
}

static void fcu_lookup_fans(struct device_node *fcu_node)
{
      struct device_node *np = NULL;
      int i;

      /* The table is filled by default with values that are suitable
       * for the old machines without device-tree informations. We scan
       * the device-tree and override those values with whatever is
       * there
       */

      DBG("Looking up FCU controls in device-tree...\n");

      while ((np = of_get_next_child(fcu_node, np)) != NULL) {
            int type = -1;
            const char *loc;
            const u32 *reg;

            DBG(" control: %s, type: %s\n", np->name, np->type);

            /* Detect control type */
            if (!strcmp(np->type, "fan-rpm-control") ||
                !strcmp(np->type, "fan-rpm"))
                  type = FCU_FAN_RPM;
            if (!strcmp(np->type, "fan-pwm-control") ||
                !strcmp(np->type, "fan-pwm"))
                  type = FCU_FAN_PWM;
            /* Only care about fans for now */
            if (type == -1)
                  continue;

            /* Lookup for a matching location */
            loc = of_get_property(np, "location", NULL);
            reg = of_get_property(np, "reg", NULL);
            if (loc == NULL || reg == NULL)
                  continue;
            DBG(" matching location: %s, reg: 0x%08x\n", loc, *reg);

            for (i = 0; i < FCU_FAN_COUNT; i++) {
                  int fan_id;

                  if (!fan_check_loc_match(loc, i))
                        continue;
                  DBG(" location match, index: %d\n", i);
                  fcu_fans[i].id = FCU_FAN_ABSENT_ID;
                  if (type != fcu_fans[i].type) {
                        printk(KERN_WARNING "therm_pm72: Fan type mismatch "
                               "in device-tree for %s\n", np->full_name);
                        break;
                  }
                  if (type == FCU_FAN_RPM)
                        fan_id = ((*reg) - 0x10) / 2;
                  else
                        fan_id = ((*reg) - 0x30) / 2;
                  if (fan_id > 7) {
                        printk(KERN_WARNING "therm_pm72: Can't parse "
                               "fan ID in device-tree for %s\n", np->full_name);
                        break;
                  }
                  DBG(" fan id -> %d, type -> %d\n", fan_id, type);
                  fcu_fans[i].id = fan_id;
            }
      }

      /* Now dump the array */
      printk(KERN_INFO "Detected fan controls:\n");
      for (i = 0; i < FCU_FAN_COUNT; i++) {
            if (fcu_fans[i].id == FCU_FAN_ABSENT_ID)
                  continue;
            printk(KERN_INFO "  %d: %s fan, id %d, location: %s\n", i,
                   fcu_fans[i].type == FCU_FAN_RPM ? "RPM" : "PWM",
                   fcu_fans[i].id, fcu_fans[i].loc);
      }
}

static int fcu_of_probe(struct of_device* dev, const struct of_device_id *match)
{
      state = state_detached;

      /* Lookup the fans in the device tree */
      fcu_lookup_fans(dev->node);

      /* Add the driver */
      return i2c_add_driver(&therm_pm72_driver);
}

static int fcu_of_remove(struct of_device* dev)
{
      i2c_del_driver(&therm_pm72_driver);

      return 0;
}

static struct of_device_id fcu_match[] = 
{
      {
      .type       = "fcu",
      },
      {},
};

static struct of_platform_driver fcu_of_platform_driver = 
{
      .name             = "temperature",
      .match_table      = fcu_match,
      .probe            = fcu_of_probe,
      .remove           = fcu_of_remove
};

/*
 * Check machine type, attach to i2c controller
 */
static int __init therm_pm72_init(void)
{
      struct device_node *np;

      rackmac = machine_is_compatible("RackMac3,1");

      if (!machine_is_compatible("PowerMac7,2") &&
          !machine_is_compatible("PowerMac7,3") &&
          !rackmac)
            return -ENODEV;

      printk(KERN_INFO "PowerMac G5 Thermal control driver %s\n", VERSION);

      np = of_find_node_by_type(NULL, "fcu");
      if (np == NULL) {
            /* Some machines have strangely broken device-tree */
            np = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/fan@15e");
            if (np == NULL) {
                      printk(KERN_ERR "Can't find FCU in device-tree !\n");
                      return -ENODEV;
            }
      }
      of_dev = of_platform_device_create(np, "temperature", NULL);
      if (of_dev == NULL) {
            printk(KERN_ERR "Can't register FCU platform device !\n");
            return -ENODEV;
      }

      of_register_platform_driver(&fcu_of_platform_driver);
      
      return 0;
}

static void __exit therm_pm72_exit(void)
{
      of_unregister_platform_driver(&fcu_of_platform_driver);

      if (of_dev)
            of_device_unregister(of_dev);
}

module_init(therm_pm72_init);
module_exit(therm_pm72_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("Driver for Apple's PowerMac G5 thermal control");
MODULE_LICENSE("GPL");


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