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linux/drivers/hwmon/g760a.c
Wolfram Sang fbae3fb154 i2c: Remove all i2c_set_clientdata(client, NULL) in drivers 
I2C drivers can use the clientdata-pointer to point to private data. As I2C
devices are not really unregistered, but merely detached from their driver, it
used to be the drivers obligation to clear this pointer during remove() or a
failed probe(). As a couple of drivers forgot to do this, it was agreed that it
was cleaner if the i2c-core does this clearance when appropriate, as there is
no guarantee for the lifetime of the clientdata-pointer after remove() anyhow.
This feature was added to the core with commit
e4a7b9b04d to fix the faulty drivers.

As there is no need anymore to clear the clientdata-pointer, remove all current
occurrences in the drivers to simplify the code and prevent confusion.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Richard Purdie <rpurdie@linux.intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-06-03 11:33:58 +02:00

271 lines
6.7 KiB
C
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/*
g760a - Driver for the Global Mixed-mode Technology Inc. G760A
fan speed PWM controller chip
Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org>
Complete datasheet is available at GMT's website:
http://www.gmt.com.tw/datasheet/g760a.pdf
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; either version 2 of the License, or
(at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
static const struct i2c_device_id g760a_id[] = {
{ "g760a", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, g760a_id);
enum g760a_regs {
G760A_REG_SET_CNT = 0x00,
G760A_REG_ACT_CNT = 0x01,
G760A_REG_FAN_STA = 0x02
};
#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */
/* register data is read (and cached) at most once per second */
#define G760A_UPDATE_INTERVAL (HZ)
struct g760a_data {
struct i2c_client *client;
struct device *hwmon_dev;
struct mutex update_lock;
/* board specific parameters */
u32 clk; /* default 32kHz */
u16 fan_div; /* default P=2 */
/* g760a register cache */
unsigned int valid:1;
unsigned long last_updated; /* In jiffies */
u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */
u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
* outside requested fan speed
* bit 1: set when fan speed below 1920 rpm */
};
#define G760A_DEFAULT_CLK 32768
#define G760A_DEFAULT_FAN_DIV 2
#define PWM_FROM_CNT(cnt) (0xff-(cnt))
#define PWM_TO_CNT(pwm) (0xff-(pwm))
static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
{
return ((val == 0x00) ? 0 : ((clk*30)/(val*div)));
}
/* new-style driver model */
static int g760a_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int g760a_remove(struct i2c_client *client);
static struct i2c_driver g760a_driver = {
.driver = {
.name = "g760a",
},
.probe = g760a_probe,
.remove = g760a_remove,
.id_table = g760a_id,
};
/* read/write wrappers */
static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
{
return i2c_smbus_read_byte_data(client, reg);
}
static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
u16 value)
{
return i2c_smbus_write_byte_data(client, reg, value);
}
/****************************************************************************
* sysfs attributes
*/
static struct g760a_data *g760a_update_client(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct g760a_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
|| !data->valid) {
dev_dbg(&client->dev, "Starting g760a update\n");
data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static ssize_t show_fan(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
unsigned int rpm = 0;
mutex_lock(&data->update_lock);
if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
mutex_unlock(&data->update_lock);
return sprintf(buf, "%d\n", rpm);
}
static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;
return sprintf(buf, "%d\n", fan_alarm);
}
static ssize_t get_pwm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct g760a_data *data = g760a_update_client(dev);
return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt));
}
static ssize_t set_pwm(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct g760a_data *data = g760a_update_client(dev);
unsigned long val;
if (strict_strtoul(buf, 10, &val))
return -EINVAL;
mutex_lock(&data->update_lock);
data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255));
g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
mutex_unlock(&data->update_lock);
return count;
}
static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
static struct attribute *g760a_attributes[] = {
&dev_attr_pwm1.attr,
&dev_attr_fan1_input.attr,
&dev_attr_fan1_alarm.attr,
NULL
};
static const struct attribute_group g760a_group = {
.attrs = g760a_attributes,
};
/****************************************************************************
* new-style driver model code
*/
static int g760a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct g760a_data *data;
int err;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA))
return -EIO;
data = kzalloc(sizeof(struct g760a_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
data->client = client;
mutex_init(&data->update_lock);
/* setup default configuration for now */
data->fan_div = G760A_DEFAULT_FAN_DIV;
data->clk = G760A_DEFAULT_CLK;
/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &g760a_group);
if (err)
goto error_sysfs_create_group;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
goto error_hwmon_device_register;
}
return 0;
error_hwmon_device_register:
sysfs_remove_group(&client->dev.kobj, &g760a_group);
error_sysfs_create_group:
kfree(data);
return err;
}
static int g760a_remove(struct i2c_client *client)
{
struct g760a_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &g760a_group);
kfree(data);
return 0;
}
/* module management */
static int __init g760a_init(void)
{
return i2c_add_driver(&g760a_driver);
}
static void __exit g760a_exit(void)
{
i2c_del_driver(&g760a_driver);
}
MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
MODULE_DESCRIPTION("GMT G760A driver");
MODULE_LICENSE("GPL");
module_init(g760a_init);
module_exit(g760a_exit);
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