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0001 /* 
0002  *   Creation Date: <2003/03/14 20:54:13 samuel>
0003  *   Time-stamp: <2004/03/20 14:20:59 samuel>
0004  *   
0005  *  <therm_windtunnel.c>
0006  *  
0007  *  The G4 "windtunnel" has a single fan controlled by an
0008  *  ADM1030 fan controller and a DS1775 thermostat.
0009  *
0010  *  The fan controller is equipped with a temperature sensor
0011  *  which measures the case temperature. The DS1775 sensor
0012  *  measures the CPU temperature. This driver tunes the
0013  *  behavior of the fan. It is based upon empirical observations
0014  *  of the 'AppleFan' driver under Mac OS X.
0015  *
0016  *  WARNING: This driver has only been testen on Apple's
0017  *  1.25 MHz Dual G4 (March 03). It is tuned for a CPU
0018  *  temperature around 57 C.
0019  *
0020  *   Copyright (C) 2003, 2004 Samuel Rydh (samuel@ibrium.se)
0021  *
0022  *   Loosely based upon 'thermostat.c' written by Benjamin Herrenschmidt
0023  *   
0024  *   This program is free software; you can redistribute it and/or
0025  *   modify it under the terms of the GNU General Public License
0026  *   as published by the Free Software Foundation
0027  *   
0028  */
0029 
0030 #include <linux/types.h>
0031 #include <linux/module.h>
0032 #include <linux/errno.h>
0033 #include <linux/kernel.h>
0034 #include <linux/delay.h>
0035 #include <linux/sched.h>
0036 #include <linux/i2c.h>
0037 #include <linux/init.h>
0038 #include <linux/kthread.h>
0039 #include <linux/of_platform.h>
0040 
0041 #include <asm/machdep.h>
0042 #include <asm/io.h>
0043 #include <asm/sections.h>
0044 #include <asm/macio.h>
0045 
0046 #define LOG_TEMP        0           /* continuously log temperature */
0047 
0048 static struct {
0049     volatile int        running;
0050     struct task_struct  *poll_task;
0051     
0052     struct mutex        lock;
0053     struct platform_device  *of_dev;
0054     
0055     struct i2c_client   *thermostat;
0056     struct i2c_client   *fan;
0057 
0058     int         overheat_temp;      /* 100% fan at this temp */
0059     int         overheat_hyst;
0060     int         temp;
0061     int         casetemp;
0062     int         fan_level;      /* active fan_table setting */
0063 
0064     int         downind;
0065     int         upind;
0066 
0067     int         r0, r1, r20, r23, r25;  /* saved register */
0068 } x;
0069 
0070 #define T(x,y)          (((x)<<8) | (y)*0x100/10 )
0071 
0072 static struct {
0073     int         fan_down_setting;
0074     int         temp;
0075     int         fan_up_setting;
0076 } fan_table[] = {
0077     { 11, T(0,0),  11 },    /* min fan */
0078     { 11, T(55,0), 11 },
0079     {  6, T(55,3), 11 },
0080     {  7, T(56,0), 11 },
0081     {  8, T(57,0), 8 },
0082     {  7, T(58,3), 7 },
0083     {  6, T(58,8), 6 },
0084     {  5, T(59,2), 5 },
0085     {  4, T(59,6), 4 },
0086     {  3, T(59,9), 3 },
0087     {  2, T(60,1), 2 },
0088     {  1, 0xfffff, 1 }  /* on fire */
0089 };
0090 
0091 static void
0092 print_temp( const char *s, int temp )
0093 {
0094     printk("%s%d.%d C", s ? s : "", temp>>8, (temp & 255)*10/256 );
0095 }
0096 
0097 static ssize_t
0098 show_cpu_temperature( struct device *dev, struct device_attribute *attr, char *buf )
0099 {
0100     return sprintf(buf, "%d.%d\n", x.temp>>8, (x.temp & 255)*10/256 );
0101 }
0102 
0103 static ssize_t
0104 show_case_temperature( struct device *dev, struct device_attribute *attr, char *buf )
0105 {
0106     return sprintf(buf, "%d.%d\n", x.casetemp>>8, (x.casetemp & 255)*10/256 );
0107 }
0108 
0109 static DEVICE_ATTR(cpu_temperature, S_IRUGO, show_cpu_temperature, NULL );
0110 static DEVICE_ATTR(case_temperature, S_IRUGO, show_case_temperature, NULL );
0111 
0112 
0113 
0114 /************************************************************************/
0115 /*  controller thread                       */
0116 /************************************************************************/
0117 
0118 static int
0119 write_reg( struct i2c_client *cl, int reg, int data, int len )
0120 {
0121     u8 tmp[3];
0122 
0123     if( len < 1 || len > 2 || data < 0 )
0124         return -EINVAL;
0125 
0126     tmp[0] = reg;
0127     tmp[1] = (len == 1) ? data : (data >> 8);
0128     tmp[2] = data;
0129     len++;
0130     
0131     if( i2c_master_send(cl, tmp, len) != len )
0132         return -ENODEV;
0133     return 0;
0134 }
0135 
0136 static int
0137 read_reg( struct i2c_client *cl, int reg, int len )
0138 {
0139     u8 buf[2];
0140 
0141     if( len != 1 && len != 2 )
0142         return -EINVAL;
0143     buf[0] = reg;
0144     if( i2c_master_send(cl, buf, 1) != 1 )
0145         return -ENODEV;
0146     if( i2c_master_recv(cl, buf, len) != len )
0147         return -ENODEV;
0148     return (len == 2)? ((unsigned int)buf[0] << 8) | buf[1] : buf[0];
0149 }
0150 
0151 static void
0152 tune_fan( int fan_setting )
0153 {
0154     int val = (fan_setting << 3) | 7;
0155 
0156     /* write_reg( x.fan, 0x24, val, 1 ); */
0157     write_reg( x.fan, 0x25, val, 1 );
0158     write_reg( x.fan, 0x20, 0, 1 );
0159     print_temp("CPU-temp: ", x.temp );
0160     if( x.casetemp )
0161         print_temp(", Case: ", x.casetemp );
0162     printk(",  Fan: %d (tuned %+d)\n", 11-fan_setting, x.fan_level-fan_setting );
0163 
0164     x.fan_level = fan_setting;
0165 }
0166 
0167 static void
0168 poll_temp( void )
0169 {
0170     int temp, i, level, casetemp;
0171 
0172     temp = read_reg( x.thermostat, 0, 2 );
0173 
0174     /* this actually occurs when the computer is loaded */
0175     if( temp < 0 )
0176         return;
0177 
0178     casetemp = read_reg(x.fan, 0x0b, 1) << 8;
0179     casetemp |= (read_reg(x.fan, 0x06, 1) & 0x7) << 5;
0180 
0181     if( LOG_TEMP && x.temp != temp ) {
0182         print_temp("CPU-temp: ", temp );
0183         print_temp(", Case: ", casetemp );
0184         printk(",  Fan: %d\n", 11-x.fan_level );
0185     }
0186     x.temp = temp;
0187     x.casetemp = casetemp;
0188 
0189     level = -1;
0190     for( i=0; (temp & 0xffff) > fan_table[i].temp ; i++ )
0191         ;
0192     if( i < x.downind )
0193         level = fan_table[i].fan_down_setting;
0194     x.downind = i;
0195 
0196     for( i=0; (temp & 0xffff) >= fan_table[i+1].temp ; i++ )
0197         ;
0198     if( x.upind < i )
0199         level = fan_table[i].fan_up_setting;
0200     x.upind = i;
0201 
0202     if( level >= 0 )
0203         tune_fan( level );
0204 }
0205 
0206 
0207 static void
0208 setup_hardware( void )
0209 {
0210     int val;
0211     int err;
0212 
0213     /* save registers (if we unload the module) */
0214     x.r0 = read_reg( x.fan, 0x00, 1 );
0215     x.r1 = read_reg( x.fan, 0x01, 1 );
0216     x.r20 = read_reg( x.fan, 0x20, 1 );
0217     x.r23 = read_reg( x.fan, 0x23, 1 );
0218     x.r25 = read_reg( x.fan, 0x25, 1 );
0219 
0220     /* improve measurement resolution (convergence time 1.5s) */
0221     if( (val=read_reg(x.thermostat, 1, 1)) >= 0 ) {
0222         val |= 0x60;
0223         if( write_reg( x.thermostat, 1, val, 1 ) )
0224             printk("Failed writing config register\n");
0225     }
0226     /* disable interrupts and TAC input */
0227     write_reg( x.fan, 0x01, 0x01, 1 );
0228     /* enable filter */
0229     write_reg( x.fan, 0x23, 0x91, 1 );
0230     /* remote temp. controls fan */
0231     write_reg( x.fan, 0x00, 0x95, 1 );
0232 
0233     /* The thermostat (which besides measureing temperature controls
0234      * has a THERM output which puts the fan on 100%) is usually
0235      * set to kick in at 80 C (chip default). We reduce this a bit
0236      * to be on the safe side (OSX doesn't)...
0237      */
0238     if( x.overheat_temp == (80 << 8) ) {
0239         x.overheat_temp = 75 << 8;
0240         x.overheat_hyst = 70 << 8;
0241         write_reg( x.thermostat, 2, x.overheat_hyst, 2 );
0242         write_reg( x.thermostat, 3, x.overheat_temp, 2 );
0243 
0244         print_temp("Reducing overheating limit to ", x.overheat_temp );
0245         print_temp(" (Hyst: ", x.overheat_hyst );
0246         printk(")\n");
0247     }
0248 
0249     /* set an initial fan setting */
0250     x.downind = 0xffff;
0251     x.upind = -1;
0252     /* tune_fan( fan_up_table[x.upind].fan_setting ); */
0253 
0254     err = device_create_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
0255     err |= device_create_file( &x.of_dev->dev, &dev_attr_case_temperature );
0256     if (err)
0257         printk(KERN_WARNING
0258             "Failed to create temperature attribute file(s).\n");
0259 }
0260 
0261 static void
0262 restore_regs( void )
0263 {
0264     device_remove_file( &x.of_dev->dev, &dev_attr_cpu_temperature );
0265     device_remove_file( &x.of_dev->dev, &dev_attr_case_temperature );
0266 
0267     write_reg( x.fan, 0x01, x.r1, 1 );
0268     write_reg( x.fan, 0x20, x.r20, 1 );
0269     write_reg( x.fan, 0x23, x.r23, 1 );
0270     write_reg( x.fan, 0x25, x.r25, 1 );
0271     write_reg( x.fan, 0x00, x.r0, 1 );
0272 }
0273 
0274 static int control_loop(void *dummy)
0275 {
0276     mutex_lock(&x.lock);
0277     setup_hardware();
0278     mutex_unlock(&x.lock);
0279 
0280     for (;;) {
0281         msleep_interruptible(8000);
0282         if (kthread_should_stop())
0283             break;
0284 
0285         mutex_lock(&x.lock);
0286         poll_temp();
0287         mutex_unlock(&x.lock);
0288     }
0289 
0290     mutex_lock(&x.lock);
0291     restore_regs();
0292     mutex_unlock(&x.lock);
0293 
0294     return 0;
0295 }
0296 
0297 
0298 /************************************************************************/
0299 /*  i2c probing and setup                       */
0300 /************************************************************************/
0301 
0302 static void do_attach(struct i2c_adapter *adapter)
0303 {
0304     struct i2c_board_info info = { };
0305     struct device_node *np;
0306 
0307     /* scan 0x48-0x4f (DS1775) and 0x2c-2x2f (ADM1030) */
0308     static const unsigned short scan_ds1775[] = {
0309         0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
0310         I2C_CLIENT_END
0311     };
0312     static const unsigned short scan_adm1030[] = {
0313         0x2c, 0x2d, 0x2e, 0x2f,
0314         I2C_CLIENT_END
0315     };
0316 
0317     if (x.running || strncmp(adapter->name, "uni-n", 5))
0318         return;
0319 
0320     np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,ds1775");
0321     if (np) {
0322         of_node_put(np);
0323     } else {
0324         strlcpy(info.type, "MAC,ds1775", I2C_NAME_SIZE);
0325         i2c_new_scanned_device(adapter, &info, scan_ds1775, NULL);
0326     }
0327 
0328     np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,adm1030");
0329     if (np) {
0330         of_node_put(np);
0331     } else {
0332         strlcpy(info.type, "MAC,adm1030", I2C_NAME_SIZE);
0333         i2c_new_scanned_device(adapter, &info, scan_adm1030, NULL);
0334     }
0335 }
0336 
0337 static int
0338 do_remove(struct i2c_client *client)
0339 {
0340     if (x.running) {
0341         x.running = 0;
0342         kthread_stop(x.poll_task);
0343         x.poll_task = NULL;
0344     }
0345     if (client == x.thermostat)
0346         x.thermostat = NULL;
0347     else if (client == x.fan)
0348         x.fan = NULL;
0349     else
0350         printk(KERN_ERR "g4fan: bad client\n");
0351 
0352     return 0;
0353 }
0354 
0355 static int
0356 attach_fan( struct i2c_client *cl )
0357 {
0358     if( x.fan )
0359         goto out;
0360 
0361     /* check that this is an ADM1030 */
0362     if( read_reg(cl, 0x3d, 1) != 0x30 || read_reg(cl, 0x3e, 1) != 0x41 )
0363         goto out;
0364     printk("ADM1030 fan controller [@%02x]\n", cl->addr );
0365 
0366     x.fan = cl;
0367  out:
0368     return 0;
0369 }
0370 
0371 static int
0372 attach_thermostat( struct i2c_client *cl ) 
0373 {
0374     int hyst_temp, os_temp, temp;
0375 
0376     if( x.thermostat )
0377         goto out;
0378 
0379     if( (temp=read_reg(cl, 0, 2)) < 0 )
0380         goto out;
0381     
0382     /* temperature sanity check */
0383     if( temp < 0x1600 || temp > 0x3c00 )
0384         goto out;
0385     hyst_temp = read_reg(cl, 2, 2);
0386     os_temp = read_reg(cl, 3, 2);
0387     if( hyst_temp < 0 || os_temp < 0 )
0388         goto out;
0389 
0390     printk("DS1775 digital thermometer [@%02x]\n", cl->addr );
0391     print_temp("Temp: ", temp );
0392     print_temp("  Hyst: ", hyst_temp );
0393     print_temp("  OS: ", os_temp );
0394     printk("\n");
0395 
0396     x.temp = temp;
0397     x.overheat_temp = os_temp;
0398     x.overheat_hyst = hyst_temp;
0399     x.thermostat = cl;
0400 out:
0401     return 0;
0402 }
0403 
0404 enum chip { ds1775, adm1030 };
0405 
0406 static const struct i2c_device_id therm_windtunnel_id[] = {
0407     { "MAC,ds1775", ds1775 },
0408     { "MAC,adm1030", adm1030 },
0409     { }
0410 };
0411 MODULE_DEVICE_TABLE(i2c, therm_windtunnel_id);
0412 
0413 static int
0414 do_probe(struct i2c_client *cl, const struct i2c_device_id *id)
0415 {
0416     struct i2c_adapter *adapter = cl->adapter;
0417     int ret = 0;
0418 
0419     if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
0420                      | I2C_FUNC_SMBUS_WRITE_BYTE) )
0421         return 0;
0422 
0423     switch (id->driver_data) {
0424     case adm1030:
0425         ret = attach_fan(cl);
0426         break;
0427     case ds1775:
0428         ret = attach_thermostat(cl);
0429         break;
0430     }
0431 
0432     if (!x.running && x.thermostat && x.fan) {
0433         x.running = 1;
0434         x.poll_task = kthread_run(control_loop, NULL, "g4fand");
0435     }
0436 
0437     return ret;
0438 }
0439 
0440 static struct i2c_driver g4fan_driver = {
0441     .driver = {
0442         .name   = "therm_windtunnel",
0443     },
0444     .probe      = do_probe,
0445     .remove     = do_remove,
0446     .id_table   = therm_windtunnel_id,
0447 };
0448 
0449 
0450 /************************************************************************/
0451 /*  initialization / cleanup                    */
0452 /************************************************************************/
0453 
0454 static int therm_of_probe(struct platform_device *dev)
0455 {
0456     struct i2c_adapter *adap;
0457     int ret, i = 0;
0458 
0459     adap = i2c_get_adapter(0);
0460     if (!adap)
0461         return -EPROBE_DEFER;
0462 
0463     ret = i2c_add_driver(&g4fan_driver);
0464     if (ret) {
0465         i2c_put_adapter(adap);
0466         return ret;
0467     }
0468 
0469     /* We assume Macs have consecutive I2C bus numbers starting at 0 */
0470     while (adap) {
0471         do_attach(adap);
0472         if (x.running)
0473             return 0;
0474         i2c_put_adapter(adap);
0475         adap = i2c_get_adapter(++i);
0476     }
0477 
0478     return -ENODEV;
0479 }
0480 
0481 static int
0482 therm_of_remove( struct platform_device *dev )
0483 {
0484     i2c_del_driver( &g4fan_driver );
0485     return 0;
0486 }
0487 
0488 static const struct of_device_id therm_of_match[] = {{
0489     .name       = "fan",
0490     .compatible = "adm1030"
0491     }, {}
0492 };
0493 MODULE_DEVICE_TABLE(of, therm_of_match);
0494 
0495 static struct platform_driver therm_of_driver = {
0496     .driver = {
0497         .name = "temperature",
0498         .of_match_table = therm_of_match,
0499     },
0500     .probe      = therm_of_probe,
0501     .remove     = therm_of_remove,
0502 };
0503 
0504 struct apple_thermal_info {
0505     u8      id;         /* implementation ID */
0506     u8      fan_count;      /* number of fans */
0507     u8      thermostat_count;   /* number of thermostats */
0508     u8      unused;
0509 };
0510 
0511 static int __init
0512 g4fan_init( void )
0513 {
0514     const struct apple_thermal_info *info;
0515     struct device_node *np;
0516 
0517     mutex_init(&x.lock);
0518 
0519     if( !(np=of_find_node_by_name(NULL, "power-mgt")) )
0520         return -ENODEV;
0521     info = of_get_property(np, "thermal-info", NULL);
0522     of_node_put(np);
0523 
0524     if( !info || !of_machine_is_compatible("PowerMac3,6") )
0525         return -ENODEV;
0526 
0527     if( info->id != 3 ) {
0528         printk(KERN_ERR "therm_windtunnel: unsupported thermal design %d\n", info->id );
0529         return -ENODEV;
0530     }
0531     if( !(np=of_find_node_by_name(NULL, "fan")) )
0532         return -ENODEV;
0533     x.of_dev = of_platform_device_create(np, "temperature", NULL);
0534     of_node_put( np );
0535 
0536     if( !x.of_dev ) {
0537         printk(KERN_ERR "Can't register fan controller!\n");
0538         return -ENODEV;
0539     }
0540 
0541     platform_driver_register( &therm_of_driver );
0542     return 0;
0543 }
0544 
0545 static void __exit
0546 g4fan_exit( void )
0547 {
0548     platform_driver_unregister( &therm_of_driver );
0549 
0550     if( x.of_dev )
0551         of_device_unregister( x.of_dev );
0552 }
0553 
0554 module_init(g4fan_init);
0555 module_exit(g4fan_exit);
0556 
0557 MODULE_AUTHOR("Samuel Rydh <samuel@ibrium.se>");
0558 MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
0559 MODULE_LICENSE("GPL");
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