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linux/drivers/macintosh/therm_windtunnel.c
Wolfram Sang 38b17afb0e macintosh: therm_windtunnel: fix regression when instantiating devices 
Removing attach_adapter from this driver caused a regression for at
least some machines. Those machines had the sensors described in their
DT, too, so they didn't need manual creation of the sensor devices. The
old code worked, though, because manual creation came first. Creation of
DT devices then failed later and caused error logs, but the sensors
worked nonetheless because of the manually created devices.

When removing attach_adaper, manual creation now comes later and loses
the race. The sensor devices were already registered via DT, yet with
another binding, so the driver could not be bound to it.

This fix refactors the code to remove the race and only manually creates
devices if there are no DT nodes present. Also, the DT binding is updated
to match both, the DT and manually created devices. Because we don't
know which device creation will be used at runtime, the code to start
the kthread is moved to do_probe() which will be called by both methods.

Fixes: 3e7bed5271 ("macintosh: therm_windtunnel: drop using attach_adapter")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201723
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Tested-by: Erhard Furtner <erhard_f@mailbox.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org # v4.19+
2020-02-29 21:13:22 +01:00

561 lines
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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 (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/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 void do_attach(struct i2c_adapter *adapter)
{
struct i2c_board_info info = { };
struct device_node *np;
/* 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 (x.running || strncmp(adapter->name, "uni-n", 5))
return;
np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,ds1775");
if (np) {
of_node_put(np);
} else {
strlcpy(info.type, "MAC,ds1775", I2C_NAME_SIZE);
i2c_new_probed_device(adapter, &info, scan_ds1775, NULL);
}
np = of_find_compatible_node(adapter->dev.of_node, NULL, "MAC,adm1030");
if (np) {
of_node_put(np);
} else {
strlcpy(info.type, "MAC,adm1030", I2C_NAME_SIZE);
i2c_new_probed_device(adapter, &info, scan_adm1030, NULL);
}
}
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[] = {
{ "MAC,ds1775", ds1775 },
{ "MAC,adm1030", adm1030 },
{ }
};
MODULE_DEVICE_TABLE(i2c, therm_windtunnel_id);
static int
do_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = cl->adapter;
int ret = 0;
if( !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA
| I2C_FUNC_SMBUS_WRITE_BYTE) )
return 0;
switch (id->driver_data) {
case adm1030:
ret = attach_fan(cl);
break;
case ds1775:
ret = attach_thermostat(cl);
break;
}
if (!x.running && x.thermostat && x.fan) {
x.running = 1;
x.poll_task = kthread_run(control_loop, NULL, "g4fand");
}
return ret;
}
static struct i2c_driver g4fan_driver = {
.driver = {
.name = "therm_windtunnel",
},
.probe = do_probe,
.remove = do_remove,
.id_table = therm_windtunnel_id,
};
/************************************************************************/
/* initialization / cleanup */
/************************************************************************/
static int therm_of_probe(struct platform_device *dev)
{
struct i2c_adapter *adap;
int ret, i = 0;
adap = i2c_get_adapter(0);
if (!adap)
return -EPROBE_DEFER;
ret = i2c_add_driver(&g4fan_driver);
if (ret) {
i2c_put_adapter(adap);
return ret;
}
/* We assume Macs have consecutive I2C bus numbers starting at 0 */
while (adap) {
do_attach(adap);
if (x.running)
return 0;
i2c_put_adapter(adap);
adap = i2c_get_adapter(++i);
}
return -ENODEV;
}
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"
}, {}
};
MODULE_DEVICE_TABLE(of, therm_of_match);
static struct platform_driver therm_of_driver = {
.driver = {
.name = "temperature",
.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 <samuel@ibrium.se>");
MODULE_DESCRIPTION("Apple G4 (windtunnel) fan controller");
MODULE_LICENSE("GPL");
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