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therm_windtunnel.c

/* 
 *   Creation Date: <2003/03/14 20:54:13 samuel>
 *   Time-stamp: <2004/03/20 14:20:59 samuel>
 *   
 *    <therm_windtunnel.c>
 *    
 *    The G4 "windtunnel" has a single fan controlled by an
 *    ADM1030 fan controller and a DS1775 thermostat.
 *
 *    The fan controller is equipped with a temperature sensor
 *    which measures the case temperature. The DS1775 sensor
 *    measures the CPU temperature. This driver tunes the
 *    behavior of the fan. It is based upon empirical observations
 *    of the 'AppleFan' driver under Mac OS X.
 *
 *    WARNING: This driver has only been testen on Apple's
 *    1.25 MHz Dual G4 (March 03). It is tuned for a CPU
 *    temperatur around 57 C.
 *
 *   Copyright (C) 2003, 2004 Samuel Rydh (samuel@ibrium.se)
 *
 *   Loosely based upon 'thermostat.c' written by Benjamin Herrenschmidt
 *   
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation
 *   
 */

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

#define LOG_TEMP        0                 /* continously log temperature */

#define I2C_DRIVERID_G4FAN    0x9001                  /* fixme */

static int              do_probe( struct i2c_adapter *adapter, int addr, int kind);

/* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
static unsigned short         normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
                                     0x4c, 0x4d, 0x4e, 0x4f,
                                     0x2c, 0x2d, 0x2e, 0x2f,
                                     I2C_CLIENT_END };

I2C_CLIENT_INSMOD;

static struct {
      volatile int            running;
      struct completion completion;
      pid_t             poll_task;
      
      struct semaphore  lock;
      struct of_device  *of_dev;
      
      struct i2c_client *thermostat;
      struct i2c_client *fan;

      int               overheat_temp;          /* 100% fan at this temp */
      int               overheat_hyst;
      int               temp;
      int               casetemp;
      int               fan_level;        /* active fan_table setting */

      int               downind;
      int               upind;

      int               r0, r1, r20, r23, r25;  /* saved register */
} x;

#define T(x,y)                (((x)<<8) | (y)*0x100/10 )

static struct {
      int               fan_down_setting;
      int               temp;
      int               fan_up_setting;
} fan_table[] = {
      { 11, T(0,0),  11 },    /* min fan */
      { 11, T(55,0), 11 },
      {  6, T(55,3), 11 },
      {  7, T(56,0), 11 },
      {  8, T(57,0), 8 },
      {  7, T(58,3), 7 },
      {  6, T(58,8), 6 },
      {  5, T(59,2), 5 },
      {  4, T(59,6), 4 },
      {  3, T(59,9), 3 },
      {  2, T(60,1), 2 },
      {  1, 0xfffff, 1 }      /* on fire */
};

static void
print_temp( const char *s, int temp )
{
      printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
}

static ssize_t
show_cpu_temperature( struct device *dev, struct device_attribute *attr, char *buf )
{
      return sprintf(buf, "%d.%d\n", x.temp>>8, (x.temp & 255)*10/256 );
}

static ssize_t
show_case_temperature( struct device *dev, struct device_attribute *attr, char *buf )
{
      return sprintf(buf, "%d.%d\n", x.casetemp>>8, (x.casetemp & 255)*10/256 );
}

static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );



/************************************************************************/
/*    controller thread                               */
/************************************************************************/

static int
write_reg( struct i2c_client *cl, int reg, int data, int len )
{
      u8 tmp[3];

      if( len < 1 || len > 2 || data < 0 )
            return -EINVAL;

      tmp[0] = reg;
      tmp[1] = (len == 1) ? data : (data >> 8);
      tmp[2] = data;
      len++;
      
      if( i2c_master_send(cl, tmp, len) != len )
            return -ENODEV;
      return 0;
}

static int
read_reg( struct i2c_client *cl, int reg, int len )
{
      u8 buf[2];

      if( len != 1 && len != 2 )
            return -EINVAL;
      buf[0] = reg;
      if( i2c_master_send(cl, buf, 1) != 1 )
            return -ENODEV;
      if( i2c_master_recv(cl, buf, len) != len )
            return -ENODEV;
      return (len == 2)? ((unsigned int)buf[0] << 8) | buf[1] : buf[0];
}

static void
tune_fan( int fan_setting )
{
      int val = (fan_setting << 3) | 7;

      /* write_reg( x.fan, 0x24, val, 1 ); */
      write_reg( x.fan, 0x25, val, 1 );
      write_reg( x.fan, 0x20, 0, 1 );
      print_temp("CPU-temp: ", x.temp );
      if( x.casetemp )
            print_temp(", Case: ", x.casetemp );
      printk(",  Fan: %d (tuned %+d)\n", 11-fan_setting, x.fan_level-fan_setting );

      x.fan_level = fan_setting;
}

static void
poll_temp( void )
{
      int temp, i, level, casetemp;

      temp = read_reg( x.thermostat, 0, 2 );

      /* this actually occurs when the computer is loaded */
      if( temp < 0 )
            return;

      casetemp = read_reg(x.fan, 0x0b, 1) << 8;
      casetemp |= (read_reg(x.fan, 0x06, 1) & 0x7) << 5;

      if( LOG_TEMP && x.temp != temp ) {
            print_temp("CPU-temp: ", temp );
            print_temp(", Case: ", casetemp );
            printk(",  Fan: %d\n", 11-x.fan_level );
      }
      x.temp = temp;
      x.casetemp = casetemp;

      level = -1;
      for( i=0; (temp & 0xffff) > fan_table[i].temp ; i++ )
            ;
      if( i < x.downind )
            level = fan_table[i].fan_down_setting;
      x.downind = i;

      for( i=0; (temp & 0xffff) >= fan_table[i+1].temp ; i++ )
            ;
      if( x.upind < i )
            level = fan_table[i].fan_up_setting;
      x.upind = i;

      if( level >= 0 )
            tune_fan( level );
}


static void
setup_hardware( void )
{
      int val;

      /* save registers (if we unload the module) */
      x.r0 = read_reg( x.fan, 0x00, 1 );
      x.r1 = read_reg( x.fan, 0x01, 1 );
      x.r20 = read_reg( x.fan, 0x20, 1 );
      x.r23 = read_reg( x.fan, 0x23, 1 );
      x.r25 = read_reg( x.fan, 0x25, 1 );

      /* improve measurement resolution (convergence time 1.5s) */
      if( (val=read_reg(x.thermostat, 1, 1)) >= 0 ) {
            val |= 0x60;
            if( write_reg( x.thermostat, 1, val, 1 ) )
                  printk("Failed writing config register\n");
      }
      /* disable interrupts and TAC input */
      write_reg( x.fan, 0x01, 0x01, 1 );
      /* enable filter */
      write_reg( x.fan, 0x23, 0x91, 1 );
      /* remote temp. controls fan */
      write_reg( x.fan, 0x00, 0x95, 1 );

      /* The thermostat (which besides measureing temperature controls
       * has a THERM output which puts the fan on 100%) is usually
       * set to kick in at 80 C (chip default). We reduce this a bit
       * to be on the safe side (OSX doesn't)...
       */
      if( x.overheat_temp == (80 << 8) ) {
            x.overheat_temp = 65 << 8;
            x.overheat_hyst = 60 << 8;
            write_reg( x.thermostat, 2, x.overheat_hyst, 2 );
            write_reg( x.thermostat, 3, x.overheat_temp, 2 );

            print_temp("Reducing overheating limit to ", x.overheat_temp );
            print_temp(" (Hyst: ", x.overheat_hyst );
            printk(")\n");
      }

      /* set an initial fan setting */
      x.downind = 0xffff;
      x.upind = -1;
      /* tune_fan( fan_up_table[x.upind].fan_setting ); */

      device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
      device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
}

static void
restore_regs( void )
{
      device_remove_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
      device_remove_file( &x.of_dev->dev, &dev_attr_case_temperature );

      write_reg( x.fan, 0x01, x.r1, 1 );
      write_reg( x.fan, 0x20, x.r20, 1 );
      write_reg( x.fan, 0x23, x.r23, 1 );
      write_reg( x.fan, 0x25, x.r25, 1 );
      write_reg( x.fan, 0x00, x.r0, 1 );
}

static int
control_loop( void *dummy )
{
      daemonize("g4fand");

      down( &x.lock );
      setup_hardware();

      while( x.running ) {
            up( &x.lock );

            msleep_interruptible(8000);
            
            down( &x.lock );
            poll_temp();
      }

      restore_regs();
      up( &x.lock );

      complete_and_exit( &x.completion, 0 );
}


/************************************************************************/
/*    i2c probing and setup                                 */
/************************************************************************/

static int
do_attach( struct i2c_adapter *adapter )
{
      int ret = 0;

      if( strncmp(adapter->name, "uni-n", 5) )
            return 0;

      if( !x.running ) {
            ret = i2c_probe( adapter, &addr_data, &do_probe );
            if( x.thermostat && x.fan ) {
                  x.running = 1;
                  init_completion( &x.completion );
                  x.poll_task = kernel_thread( control_loop, NULL, SIGCHLD | CLONE_KERNEL );
            }
      }
      return ret;
}

static int
do_detach( struct i2c_client *client )
{
      int err;

      if( (err=i2c_detach_client(client)) )
            printk(KERN_ERR "failed to detach thermostat client\n");
      else {
            if( x.running ) {
                  x.running = 0;
                  wait_for_completion( &x.completion );
            }
            if( client == x.thermostat )
                  x.thermostat = NULL;
            else if( client == x.fan )
                  x.fan = NULL;
            else {
                  printk(KERN_ERR "g4fan: bad client\n");
            }
            kfree( client );
      }
      return err;
}

static struct i2c_driver g4fan_driver = {  
      .driver = {
            .name = "therm_windtunnel",
      },
      .id         = I2C_DRIVERID_G4FAN,
      .attach_adapter = do_attach,
      .detach_client    = do_detach,
};

static int
attach_fan( struct i2c_client *cl )
{
      if( x.fan )
            goto out;

      /* check that this is an ADM1030 */
      if( read_reg(cl, 0x3d, 1) != 0x30 || read_reg(cl, 0x3e, 1) != 0x41 )
            goto out;
      printk("ADM1030 fan controller [@%02x]\n", cl->addr );

      strlcpy( cl->name, "ADM1030 fan controller", sizeof(cl->name) );

      if( !i2c_attach_client(cl) )
            x.fan = cl;
 out:
      if( cl != x.fan )
            kfree( cl );
      return 0;
}

static int
attach_thermostat( struct i2c_client *cl ) 
{
      int hyst_temp, os_temp, temp;

      if( x.thermostat )
            goto out;

      if( (temp=read_reg(cl, 0, 2)) < 0 )
            goto out;
      
      /* temperature sanity check */
      if( temp < 0x1600 || temp > 0x3c00 )
            goto out;
      hyst_temp = read_reg(cl, 2, 2);
      os_temp = read_reg(cl, 3, 2);
      if( hyst_temp < 0 || os_temp < 0 )
            goto out;

      printk("DS1775 digital thermometer [@%02x]\n", cl->addr );
      print_temp("Temp: ", temp );
      print_temp("  Hyst: ", hyst_temp );
      print_temp("  OS: ", os_temp );
      printk("\n");

      x.temp = temp;
      x.overheat_temp = os_temp;
      x.overheat_hyst = hyst_temp;
      
      strlcpy( cl->name, "DS1775 thermostat", sizeof(cl->name) );

      if( !i2c_attach_client(cl) )
            x.thermostat = cl;
out:
      if( cl != x.thermostat )
            kfree( cl );
      return 0;
}

static int
do_probe( struct i2c_adapter *adapter, int addr, int kind )
{
      struct i2c_client *cl;

      if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
                             | I2C_FUNC_SMBUS_WRITE_BYTE) )
            return 0;

      if( !(cl=kzalloc(sizeof(*cl), GFP_KERNEL)) )
            return -ENOMEM;

      cl->addr = addr;
      cl->adapter = adapter;
      cl->driver = &g4fan_driver;
      cl->flags = 0;

      if( addr < 0x48 )
            return attach_fan( cl );
      return attach_thermostat( cl );
}


/************************************************************************/
/*    initialization / cleanup                              */
/************************************************************************/

static int
therm_of_probe( struct of_device *dev, const struct of_device_id *match )
{
      return i2c_add_driver( &g4fan_driver );
}

static int
therm_of_remove( struct of_device *dev )
{
      i2c_del_driver( &g4fan_driver );
      return 0;
}

static struct of_device_id therm_of_match[] = {{
      .name       = "fan",
      .compatible = "adm1030"
    }, {}
};

static struct of_platform_driver therm_of_driver = {
      .name       = "temperature",
      .match_table      = therm_of_match,
      .probe            = therm_of_probe,
      .remove           = therm_of_remove,
};

struct apple_thermal_info {
      u8          id;               /* implementation ID */
      u8          fan_count;        /* number of fans */
      u8          thermostat_count; /* number of thermostats */
      u8          unused;
};

static int __init
g4fan_init( void )
{
      const struct apple_thermal_info *info;
      struct device_node *np;

      init_MUTEX( &x.lock );

      if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
            return -ENODEV;
      info = of_get_property(np, "thermal-info", NULL);
      of_node_put(np);

      if( !info || !machine_is_compatible("PowerMac3,6") )
            return -ENODEV;

      if( info->id != 3 ) {
            printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
            return -ENODEV;
      }
      if( !(np=of_find_node_by_name(NULL, "fan")) )
            return -ENODEV;
      x.of_dev = of_platform_device_create(np, "temperature", NULL);
      of_node_put( np );

      if( !x.of_dev ) {
            printk(KERN_ERR "Can't register fan controller!\n");
            return -ENODEV;
      }

      of_register_platform_driver( &therm_of_driver );
      return 0;
}

static void __exit
g4fan_exit( void )
{
      of_unregister_platform_driver( &therm_of_driver );

      if( x.of_dev )
            of_device_unregister( x.of_dev );
}

module_init(g4fan_init);
module_exit(g4fan_exit);

MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
MODULE_LICENSE("GPL");

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