therm_windtunnel.c

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/* 
 *   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
 *  temperature around 57 C.
 *
 *   Copyright (C) 2003, 2004 Samuel Rydh ([email protected])
 *
 *   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/init.h>
#include <linux/kthread.h>
#include <linux/of_platform.h>

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

#define LOG_TEMP        0           /* continuously log temperature */

static struct {
    volatile int        running;
    struct task_struct  *poll_task;
    
    struct mutex        lock;
    struct platform_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;
    int err;

    /* 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 = 75 << 8;
        x.overheat_hyst = 70 << 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 ); */

    err = device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
    err |= device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
    if (err)
        printk(KERN_WARNING
            "Failed to create temperature attribute file(s).\n");
}

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)
{
    mutex_lock(&x.lock);
    setup_hardware();
    mutex_unlock(&x.lock);

    for (;;) {
        msleep_interruptible(8000);
        if (kthread_should_stop())
            break;

        mutex_lock(&x.lock);
        poll_temp();
        mutex_unlock(&x.lock);
    }

    mutex_lock(&x.lock);
    restore_regs();
    mutex_unlock(&x.lock);

    return 0;
}


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

static int
do_attach( struct i2c_adapter *adapter )
{
    /* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
    static const unsigned short scan_ds1775[] = {
        0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
        I2C_CLIENT_END
    };
    static const unsigned short scan_adm1030[] = {
        0x2c, 0x2d, 0x2e, 0x2f,
        I2C_CLIENT_END
    };

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

    if( !x.running ) {
        struct i2c_board_info info;

        memset(&info, 0, sizeof(struct i2c_board_info));
        strlcpy(info.type, "therm_ds1775", I2C_NAME_SIZE);
        i2c_new_probed_device(adapter, &info, scan_ds1775, NULL);

        strlcpy(info.type, "therm_adm1030", I2C_NAME_SIZE);
        i2c_new_probed_device(adapter, &info, scan_adm1030, NULL);

        if( x.thermostat && x.fan ) {
            x.running = 1;
            x.poll_task = kthread_run(control_loop, NULL, "g4fand");
        }
    }
    return 0;
}

static int
do_remove(struct i2c_client *client)
{
    if (x.running) {
        x.running = 0;
        kthread_stop(x.poll_task);
        x.poll_task = NULL;
    }
    if (client == x.thermostat)
        x.thermostat = NULL;
    else if (client == x.fan)
        x.fan = NULL;
    else
        printk(KERN_ERR "g4fan: bad client\n");

    return 0;
}

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 );

    x.fan = cl;
 out:
    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;
    x.thermostat = cl;
out:
    return 0;
}

enum chip { ds1775, adm1030 };

static const struct i2c_device_id therm_windtunnel_id[] = {
    { "therm_ds1775", ds1775 },
    { "therm_adm1030", adm1030 },
    { }
};

static int
do_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
    struct i2c_adapter *adapter = cl->adapter;

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

    switch (id->driver_data) {
    case adm1030:
        return attach_fan( cl );
    case ds1775:
        return attach_thermostat(cl);
    }
    return 0;
}

static struct i2c_driver g4fan_driver = {
    .driver = {
        .name   = "therm_windtunnel",
    },
    .attach_adapter = do_attach,
    .probe      = do_probe,
    .remove     = do_remove,
    .id_table   = therm_windtunnel_id,
};


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

static int therm_of_probe(struct platform_device *dev)
{
    return i2c_add_driver( &g4fan_driver );
}

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

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

static struct platform_driver therm_of_driver = {
    .driver = {
        .name = "temperature",
        .owner = THIS_MODULE,
        .of_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;

    mutex_init(&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 || !of_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;
    }

    platform_driver_register( &therm_of_driver );
    return 0;
}

static void __exit
g4fan_exit( void )
{
    platform_driver_unregister( &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 <[email protected]>");
MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
MODULE_LICENSE("GPL");