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therm_adt746x.c

/*
 * Device driver for the i2c thermostat found on the iBook G4, Albook G4
 *
 * Copyright (C) 2003, 2004 Colin Leroy, Rasmus Rohde, Benjamin Herrenschmidt
 *
 * Documentation from
 * http://www.analog.com/UploadedFiles/Data_Sheets/115254175ADT7467_pra.pdf
 * http://www.analog.com/UploadedFiles/Data_Sheets/3686221171167ADT7460_b.pdf
 *
 */

#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/i2c.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/suspend.h>
#include <linux/kthread.h>
#include <linux/moduleparam.h>
#include <linux/freezer.h>

#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/sections.h>
#include <asm/of_platform.h>

#undef DEBUG

#define CONFIG_REG   0x40
#define MANUAL_MASK  0xe0
#define AUTO_MASK    0x20

static u8 TEMP_REG[3]    = {0x26, 0x25, 0x27}; /* local, sensor1, sensor2 */
static u8 LIMIT_REG[3]   = {0x6b, 0x6a, 0x6c}; /* local, sensor1, sensor2 */
static u8 MANUAL_MODE[2] = {0x5c, 0x5d};       
static u8 REM_CONTROL[2] = {0x00, 0x40};
static u8 FAN_SPEED[2]   = {0x28, 0x2a};
static u8 FAN_SPD_SET[2] = {0x30, 0x31};

static u8 default_limits_local[3] = {70, 50, 70};    /* local, sensor1, sensor2 */
static u8 default_limits_chip[3] = {80, 65, 80};    /* local, sensor1, sensor2 */
static const char *sensor_location[3];

static int limit_adjust;
static int fan_speed = -1;
static int verbose;

MODULE_AUTHOR("Colin Leroy <colin@colino.net>");
MODULE_DESCRIPTION("Driver for ADT746x thermostat in iBook G4 and "
               "Powerbook G4 Alu");
MODULE_LICENSE("GPL");

module_param(limit_adjust, int, 0644);
MODULE_PARM_DESC(limit_adjust,"Adjust maximum temperatures (50 sensor1, 70 sensor2) "
             "by N degrees.");

module_param(fan_speed, int, 0644);
MODULE_PARM_DESC(fan_speed,"Specify starting fan speed (0-255) "
             "(default 64)");

module_param(verbose, bool, 0);
MODULE_PARM_DESC(verbose,"Verbose log operations "
             "(default 0)");

struct thermostat {
      struct i2c_client clt;
      u8                temps[3];
      u8                cached_temp[3];
      u8                initial_limits[3];
      u8                limits[3];
      int               last_speed[2];
      int               last_var[2];
};

static enum {ADT7460, ADT7467} therm_type;
static int therm_bus, therm_address;
static struct of_device * of_dev;
static struct thermostat* thermostat;
static struct task_struct *thread_therm = NULL;

static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
                         int busno);

static void write_both_fan_speed(struct thermostat *th, int speed);
static void write_fan_speed(struct thermostat *th, int speed, int fan);

static int
write_reg(struct thermostat* th, int reg, u8 data)
{
      u8 tmp[2];
      int rc;
      
      tmp[0] = reg;
      tmp[1] = data;
      rc = i2c_master_send(&th->clt, (const char *)tmp, 2);
      if (rc < 0)
            return rc;
      if (rc != 2)
            return -ENODEV;
      return 0;
}

static int
read_reg(struct thermostat* th, int reg)
{
      u8 reg_addr, data;
      int rc;

      reg_addr = (u8)reg;
      rc = i2c_master_send(&th->clt, &reg_addr, 1);
      if (rc < 0)
            return rc;
      if (rc != 1)
            return -ENODEV;
      rc = i2c_master_recv(&th->clt, (char *)&data, 1);
      if (rc < 0)
            return rc;
      return data;
}

static int
attach_thermostat(struct i2c_adapter *adapter)
{
      unsigned long bus_no;

      if (strncmp(adapter->name, "uni-n", 5))
            return -ENODEV;
      bus_no = simple_strtoul(adapter->name + 6, NULL, 10);
      if (bus_no != therm_bus)
            return -ENODEV;
      return attach_one_thermostat(adapter, therm_address, bus_no);
}

static int
detach_thermostat(struct i2c_adapter *adapter)
{
      struct thermostat* th;
      int i;
      
      if (thermostat == NULL)
            return 0;

      th = thermostat;

      if (thread_therm != NULL) {
            kthread_stop(thread_therm);
      }

      printk(KERN_INFO "adt746x: Putting max temperatures back from "
                   "%d, %d, %d to %d, %d, %d\n",
            th->limits[0], th->limits[1], th->limits[2],
            th->initial_limits[0], th->initial_limits[1],
            th->initial_limits[2]);

      for (i = 0; i < 3; i++)
            write_reg(th, LIMIT_REG[i], th->initial_limits[i]);

      write_both_fan_speed(th, -1);

      i2c_detach_client(&th->clt);

      thermostat = NULL;

      kfree(th);

      return 0;
}

static struct i2c_driver thermostat_driver = {  
      .driver = {
            .name = "therm_adt746x",
      },
      .attach_adapter   = attach_thermostat,
      .detach_adapter   = detach_thermostat,
};

static int read_fan_speed(struct thermostat *th, u8 addr)
{
      u8 tmp[2];
      u16 res;
      
      /* should start with low byte */
      tmp[1] = read_reg(th, addr);
      tmp[0] = read_reg(th, addr + 1);
      
      res = tmp[1] + (tmp[0] << 8);
      /* "a value of 0xffff means that the fan has stopped" */
      return (res == 0xffff ? 0 : (90000*60)/res);
}

static void write_both_fan_speed(struct thermostat *th, int speed)
{
      write_fan_speed(th, speed, 0);
      if (therm_type == ADT7460)
            write_fan_speed(th, speed, 1);
}

static void write_fan_speed(struct thermostat *th, int speed, int fan)
{
      u8 manual;
      
      if (speed > 0xff) 
            speed = 0xff;
      else if (speed < -1) 
            speed = 0;
      
      if (therm_type == ADT7467 && fan == 1)
            return;
      
      if (th->last_speed[fan] != speed) {
            if (verbose) {
                  if (speed == -1)
                        printk(KERN_DEBUG "adt746x: Setting speed to automatic "
                              "for %s fan.\n", sensor_location[fan+1]);
                  else
                        printk(KERN_DEBUG "adt746x: Setting speed to %d "
                              "for %s fan.\n", speed, sensor_location[fan+1]);
            }
      } else
            return;
      
      if (speed >= 0) {
            manual = read_reg(th, MANUAL_MODE[fan]);
            write_reg(th, MANUAL_MODE[fan], manual|MANUAL_MASK);
            write_reg(th, FAN_SPD_SET[fan], speed);
      } else {
            /* back to automatic */
            if(therm_type == ADT7460) {
                  manual = read_reg(th,
                        MANUAL_MODE[fan]) & (~MANUAL_MASK);

                  write_reg(th,
                        MANUAL_MODE[fan], manual|REM_CONTROL[fan]);
            } else {
                  manual = read_reg(th, MANUAL_MODE[fan]);
                  write_reg(th, MANUAL_MODE[fan], manual&(~AUTO_MASK));
            }
      }
      
      th->last_speed[fan] = speed;              
}

static void read_sensors(struct thermostat *th)
{
      int i = 0;

      for (i = 0; i < 3; i++)
            th->temps[i]  = read_reg(th, TEMP_REG[i]);
}

#ifdef DEBUG
static void display_stats(struct thermostat *th)
{
      if (th->temps[0] != th->cached_temp[0]
      ||  th->temps[1] != th->cached_temp[1]
      ||  th->temps[2] != th->cached_temp[2]) {
            printk(KERN_INFO "adt746x: Temperature infos:"
                         " thermostats: %d,%d,%d;"
                         " limits: %d,%d,%d;"
                         " fan speed: %d RPM\n",
                         th->temps[0], th->temps[1], th->temps[2],
                         th->limits[0],  th->limits[1],  th->limits[2],
                         read_fan_speed(th, FAN_SPEED[0]));
      }
      th->cached_temp[0] = th->temps[0];
      th->cached_temp[1] = th->temps[1];
      th->cached_temp[2] = th->temps[2];
}
#endif

static void update_fans_speed (struct thermostat *th)
{
      int lastvar = 0; /* last variation, for iBook */
      int i = 0;

      /* we don't care about local sensor, so we start at sensor 1 */
      for (i = 1; i < 3; i++) {
            int started = 0;
            int fan_number = (therm_type == ADT7460 && i == 2);
            int var = th->temps[i] - th->limits[i];

            if (var > -1) {
                  int step = (255 - fan_speed) / 7;
                  int new_speed = 0;

                  /* hysteresis : change fan speed only if variation is
                   * more than two degrees */
                  if (abs(var - th->last_var[fan_number]) < 2)
                        continue;

                  started = 1;
                  new_speed = fan_speed + ((var-1)*step);

                  if (new_speed < fan_speed)
                        new_speed = fan_speed;
                  if (new_speed > 255)
                        new_speed = 255;

                  if (verbose)
                        printk(KERN_DEBUG "adt746x: Setting fans speed to %d "
                                     "(limit exceeded by %d on %s) \n",
                                    new_speed, var,
                                    sensor_location[fan_number+1]);
                  write_both_fan_speed(th, new_speed);
                  th->last_var[fan_number] = var;
            } else if (var < -2) {
                  /* don't stop fan if sensor2 is cold and sensor1 is not
                   * so cold (lastvar >= -1) */
                  if (i == 2 && lastvar < -1) {
                        if (th->last_speed[fan_number] != 0)
                              if (verbose)
                                    printk(KERN_DEBUG "adt746x: Stopping "
                                          "fans.\n");
                        write_both_fan_speed(th, 0);
                  }
            }

            lastvar = var;

            if (started)
                  return; /* we don't want to re-stop the fan
                        * if sensor1 is heating and sensor2 is not */
      }
}

static int monitor_task(void *arg)
{
      struct thermostat* th = arg;

      set_freezable();
      while(!kthread_should_stop()) {
            try_to_freeze();
            msleep_interruptible(2000);

#ifndef DEBUG
            if (fan_speed != -1)
                  read_sensors(th);
#else
            read_sensors(th);
#endif            

            if (fan_speed != -1)
                  update_fans_speed(th);

#ifdef DEBUG
            display_stats(th);
#endif

      }

      return 0;
}

static void set_limit(struct thermostat *th, int i)
{
            /* Set sensor1 limit higher to avoid powerdowns */
            th->limits[i] = default_limits_chip[i] + limit_adjust;
            write_reg(th, LIMIT_REG[i], th->limits[i]);
            
            /* set our limits to normal */
            th->limits[i] = default_limits_local[i] + limit_adjust;
}

static int attach_one_thermostat(struct i2c_adapter *adapter, int addr,
                         int busno)
{
      struct thermostat* th;
      int rc;
      int i;

      if (thermostat)
            return 0;

      th = kzalloc(sizeof(struct thermostat), GFP_KERNEL);
      if (!th)
            return -ENOMEM;

      th->clt.addr = addr;
      th->clt.adapter = adapter;
      th->clt.driver = &thermostat_driver;
      strcpy(th->clt.name, "thermostat");

      rc = read_reg(th, 0);
      if (rc < 0) {
            printk(KERN_ERR "adt746x: Thermostat failed to read config "
                        "from bus %d !\n",
                        busno);
            kfree(th);
            return -ENODEV;
      }

      /* force manual control to start the fan quieter */
      if (fan_speed == -1)
            fan_speed = 64;
      
      if(therm_type == ADT7460) {
            printk(KERN_INFO "adt746x: ADT7460 initializing\n");
            /* The 7460 needs to be started explicitly */
            write_reg(th, CONFIG_REG, 1);
      } else
            printk(KERN_INFO "adt746x: ADT7467 initializing\n");

      for (i = 0; i < 3; i++) {
            th->initial_limits[i] = read_reg(th, LIMIT_REG[i]);
            set_limit(th, i);
      }

      printk(KERN_INFO "adt746x: Lowering max temperatures from %d, %d, %d"
                   " to %d, %d, %d\n",
                   th->initial_limits[0], th->initial_limits[1],
                   th->initial_limits[2], th->limits[0], th->limits[1],
                   th->limits[2]);

      thermostat = th;

      if (i2c_attach_client(&th->clt)) {
            printk(KERN_INFO "adt746x: Thermostat failed to attach "
                         "client !\n");
            thermostat = NULL;
            kfree(th);
            return -ENODEV;
      }

      /* be sure to really write fan speed the first time */
      th->last_speed[0] = -2;
      th->last_speed[1] = -2;
      th->last_var[0] = -80;
      th->last_var[1] = -80;

      if (fan_speed != -1) {
            /* manual mode, stop fans */
            write_both_fan_speed(th, 0);
      } else {
            /* automatic mode */
            write_both_fan_speed(th, -1);
      }
      
      thread_therm = kthread_run(monitor_task, th, "kfand");

      if (thread_therm == ERR_PTR(-ENOMEM)) {
            printk(KERN_INFO "adt746x: Kthread creation failed\n");
            thread_therm = NULL;
            return -ENOMEM;
      }

      return 0;
}

/* 
 * 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...
 *
 * FIXME, it does now...
 */
#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\n", data);              \
}

#define BUILD_SHOW_FUNC_STR(name, data)                     \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
{                                               \
      return sprintf(buf, "%s\n", data);              \
}

#define BUILD_SHOW_FUNC_FAN(name, data)                     \
static ssize_t show_##name(struct device *dev, struct device_attribute *attr, char *buf)       \
{                                               \
      return sprintf(buf, "%d (%d rpm)\n",                  \
            thermostat->last_speed[data],             \
            read_fan_speed(thermostat, FAN_SPEED[data])     \
            );                                  \
}

#define BUILD_STORE_FUNC_DEG(name, data)              \
static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
{                                               \
      int val;                                  \
      int i;                                          \
      val = simple_strtol(buf, NULL, 10);             \
      printk(KERN_INFO "Adjusting limits by %d degrees\n", val);  \
      limit_adjust = val;                             \
      for (i=0; i < 3; i++)                           \
            set_limit(thermostat, i);                 \
      return n;                                 \
}

#define BUILD_STORE_FUNC_INT(name, data)              \
static ssize_t store_##name(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) \
{                                               \
      u32 val;                                  \
      val = simple_strtoul(buf, NULL, 10);                  \
      if (val < 0 || val > 255)                       \
            return -EINVAL;                           \
      printk(KERN_INFO "Setting specified fan speed to %d\n", val);     \
      data = val;                               \
      return n;                                 \
}

BUILD_SHOW_FUNC_INT(sensor1_temperature,   (read_reg(thermostat, TEMP_REG[1])))
BUILD_SHOW_FUNC_INT(sensor2_temperature,   (read_reg(thermostat, TEMP_REG[2])))
BUILD_SHOW_FUNC_INT(sensor1_limit,         thermostat->limits[1])
BUILD_SHOW_FUNC_INT(sensor2_limit,         thermostat->limits[2])
BUILD_SHOW_FUNC_STR(sensor1_location,            sensor_location[1])
BUILD_SHOW_FUNC_STR(sensor2_location,            sensor_location[2])

BUILD_SHOW_FUNC_INT(specified_fan_speed, fan_speed)
BUILD_SHOW_FUNC_FAN(sensor1_fan_speed,     0)
BUILD_SHOW_FUNC_FAN(sensor2_fan_speed,     1)

BUILD_STORE_FUNC_INT(specified_fan_speed,fan_speed)
BUILD_SHOW_FUNC_INT(limit_adjust,    limit_adjust)
BUILD_STORE_FUNC_DEG(limit_adjust,   thermostat)
            
static DEVICE_ATTR(sensor1_temperature,   S_IRUGO,
               show_sensor1_temperature,NULL);
static DEVICE_ATTR(sensor2_temperature,   S_IRUGO,
               show_sensor2_temperature,NULL);
static DEVICE_ATTR(sensor1_limit, S_IRUGO,
               show_sensor1_limit,  NULL);
static DEVICE_ATTR(sensor2_limit, S_IRUGO,
               show_sensor2_limit,  NULL);
static DEVICE_ATTR(sensor1_location, S_IRUGO,
               show_sensor1_location, NULL);
static DEVICE_ATTR(sensor2_location, S_IRUGO,
               show_sensor2_location, NULL);

static DEVICE_ATTR(specified_fan_speed,   S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
               show_specified_fan_speed,store_specified_fan_speed);

static DEVICE_ATTR(sensor1_fan_speed,     S_IRUGO,
               show_sensor1_fan_speed,    NULL);
static DEVICE_ATTR(sensor2_fan_speed,     S_IRUGO,
               show_sensor2_fan_speed,    NULL);

static DEVICE_ATTR(limit_adjust,    S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH,
               show_limit_adjust,   store_limit_adjust);


static int __init
thermostat_init(void)
{
      struct device_node* np;
      const u32 *prop;
      int i = 0, offset = 0;
      
      np = of_find_node_by_name(NULL, "fan");
      if (!np)
            return -ENODEV;
      if (of_device_is_compatible(np, "adt7460"))
            therm_type = ADT7460;
      else if (of_device_is_compatible(np, "adt7467"))
            therm_type = ADT7467;
      else
            return -ENODEV;

      prop = of_get_property(np, "hwsensor-params-version", NULL);
      printk(KERN_INFO "adt746x: version %d (%ssupported)\n", *prop,
                   (*prop == 1)?"":"un");
      if (*prop != 1)
            return -ENODEV;

      prop = of_get_property(np, "reg", NULL);
      if (!prop)
            return -ENODEV;

      /* look for bus either by path or using "reg" */
      if (strstr(np->full_name, "/i2c-bus@") != NULL) {
            const char *tmp_bus = (strstr(np->full_name, "/i2c-bus@") + 9);
            therm_bus = tmp_bus[0]-'0';
      } else {
            therm_bus = ((*prop) >> 8) & 0x0f;
      }

      therm_address = ((*prop) & 0xff) >> 1;

      printk(KERN_INFO "adt746x: Thermostat bus: %d, address: 0x%02x, "
                   "limit_adjust: %d, fan_speed: %d\n",
                   therm_bus, therm_address, limit_adjust, fan_speed);

      if (of_get_property(np, "hwsensor-location", NULL)) {
            for (i = 0; i < 3; i++) {
                  sensor_location[i] = of_get_property(np,
                              "hwsensor-location", NULL) + offset;

                  if (sensor_location[i] == NULL)
                        sensor_location[i] = "";

                  printk(KERN_INFO "sensor %d: %s\n", i, sensor_location[i]);
                  offset += strlen(sensor_location[i]) + 1;
            }
      } else {
            sensor_location[0] = "?";
            sensor_location[1] = "?";
            sensor_location[2] = "?";
      }

      of_dev = of_platform_device_create(np, "temperatures", NULL);
      
      if (of_dev == NULL) {
            printk(KERN_ERR "Can't register temperatures device !\n");
            return -ENODEV;
      }
      
      device_create_file(&of_dev->dev, &dev_attr_sensor1_temperature);
      device_create_file(&of_dev->dev, &dev_attr_sensor2_temperature);
      device_create_file(&of_dev->dev, &dev_attr_sensor1_limit);
      device_create_file(&of_dev->dev, &dev_attr_sensor2_limit);
      device_create_file(&of_dev->dev, &dev_attr_sensor1_location);
      device_create_file(&of_dev->dev, &dev_attr_sensor2_location);
      device_create_file(&of_dev->dev, &dev_attr_limit_adjust);
      device_create_file(&of_dev->dev, &dev_attr_specified_fan_speed);
      device_create_file(&of_dev->dev, &dev_attr_sensor1_fan_speed);
      if(therm_type == ADT7460)
            device_create_file(&of_dev->dev, &dev_attr_sensor2_fan_speed);

#ifndef CONFIG_I2C_POWERMAC
      request_module("i2c-powermac");
#endif

      return i2c_add_driver(&thermostat_driver);
}

static void __exit
thermostat_exit(void)
{
      if (of_dev) {
            device_remove_file(&of_dev->dev, &dev_attr_sensor1_temperature);
            device_remove_file(&of_dev->dev, &dev_attr_sensor2_temperature);
            device_remove_file(&of_dev->dev, &dev_attr_sensor1_limit);
            device_remove_file(&of_dev->dev, &dev_attr_sensor2_limit);
            device_remove_file(&of_dev->dev, &dev_attr_sensor1_location);
            device_remove_file(&of_dev->dev, &dev_attr_sensor2_location);
            device_remove_file(&of_dev->dev, &dev_attr_limit_adjust);
            device_remove_file(&of_dev->dev, &dev_attr_specified_fan_speed);
            device_remove_file(&of_dev->dev, &dev_attr_sensor1_fan_speed);

            if(therm_type == ADT7460)
                  device_remove_file(&of_dev->dev,
                                 &dev_attr_sensor2_fan_speed);

            of_device_unregister(of_dev);
      }
      i2c_del_driver(&thermostat_driver);
}

module_init(thermostat_init);
module_exit(thermostat_exit);

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