linux/drivers/hwmon/lm75.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

372 lines
9.7 KiB
C

/*
lm75.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#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 "lm75.h"
/*
* This driver handles the LM75 and compatible digital temperature sensors.
*/
enum lm75_type { /* keep sorted in alphabetical order */
ds1775,
ds75,
lm75,
lm75a,
max6625,
max6626,
mcp980x,
stds75,
tcn75,
tmp100,
tmp101,
tmp105,
tmp175,
tmp275,
tmp75,
};
/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* The LM75 registers */
#define LM75_REG_CONF 0x01
static const u8 LM75_REG_TEMP[3] = {
0x00, /* input */
0x03, /* max */
0x02, /* hyst */
};
/* Each client has this additional data */
struct lm75_data {
struct device *hwmon_dev;
struct mutex update_lock;
u8 orig_conf;
char valid; /* !=0 if registers are valid */
unsigned long last_updated; /* In jiffies */
u16 temp[3]; /* Register values,
0 = input
1 = max
2 = hyst */
};
static int lm75_read_value(struct i2c_client *client, u8 reg);
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
static struct lm75_data *lm75_update_device(struct device *dev);
/*-----------------------------------------------------------------------*/
/* sysfs attributes for hwmon */
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = lm75_update_device(dev);
return sprintf(buf, "%d\n",
LM75_TEMP_FROM_REG(data->temp[attr->index]));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
int nr = attr->index;
long temp = simple_strtol(buf, NULL, 10);
mutex_lock(&data->update_lock);
data->temp[nr] = LM75_TEMP_TO_REG(temp);
lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static struct attribute *lm75_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
NULL
};
static const struct attribute_group lm75_group = {
.attrs = lm75_attributes,
};
/*-----------------------------------------------------------------------*/
/* device probe and removal */
static int
lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct lm75_data *data;
int status;
u8 set_mask, clr_mask;
int new;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
return -EIO;
data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
* Then tweak to be more precise when appropriate.
*/
set_mask = 0;
clr_mask = (1 << 0) /* continuous conversions */
| (1 << 6) | (1 << 5); /* 9-bit mode */
/* configure as specified */
status = lm75_read_value(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
goto exit_free;
}
data->orig_conf = status;
new = status & ~clr_mask;
new |= set_mask;
if (status != new)
lm75_write_value(client, LM75_REG_CONF, new);
dev_dbg(&client->dev, "Config %02x\n", new);
/* Register sysfs hooks */
status = sysfs_create_group(&client->dev.kobj, &lm75_group);
if (status)
goto exit_free;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
status = PTR_ERR(data->hwmon_dev);
goto exit_remove;
}
dev_info(&client->dev, "%s: sensor '%s'\n",
dev_name(data->hwmon_dev), client->name);
return 0;
exit_remove:
sysfs_remove_group(&client->dev.kobj, &lm75_group);
exit_free:
kfree(data);
return status;
}
static int lm75_remove(struct i2c_client *client)
{
struct lm75_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm75_group);
lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
kfree(data);
return 0;
}
static const struct i2c_device_id lm75_ids[] = {
{ "ds1775", ds1775, },
{ "ds75", ds75, },
{ "lm75", lm75, },
{ "lm75a", lm75a, },
{ "max6625", max6625, },
{ "max6626", max6626, },
{ "mcp980x", mcp980x, },
{ "stds75", stds75, },
{ "tcn75", tcn75, },
{ "tmp100", tmp100, },
{ "tmp101", tmp101, },
{ "tmp105", tmp105, },
{ "tmp175", tmp175, },
{ "tmp275", tmp275, },
{ "tmp75", tmp75, },
{ /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm75_ids);
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm75_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
int i;
int cur, conf, hyst, os;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
/* Now, we do the remaining detection. There is no identification-
dedicated register so we have to rely on several tricks:
unused bits, registers cycling over 8-address boundaries,
addresses 0x04-0x07 returning the last read value.
The cycling+unused addresses combination is not tested,
since it would significantly slow the detection down and would
hardly add any value. */
/* Unused addresses */
cur = i2c_smbus_read_word_data(new_client, 0);
conf = i2c_smbus_read_byte_data(new_client, 1);
hyst = i2c_smbus_read_word_data(new_client, 2);
if (i2c_smbus_read_word_data(new_client, 4) != hyst
|| i2c_smbus_read_word_data(new_client, 5) != hyst
|| i2c_smbus_read_word_data(new_client, 6) != hyst
|| i2c_smbus_read_word_data(new_client, 7) != hyst)
return -ENODEV;
os = i2c_smbus_read_word_data(new_client, 3);
if (i2c_smbus_read_word_data(new_client, 4) != os
|| i2c_smbus_read_word_data(new_client, 5) != os
|| i2c_smbus_read_word_data(new_client, 6) != os
|| i2c_smbus_read_word_data(new_client, 7) != os)
return -ENODEV;
/* Unused bits */
if (conf & 0xe0)
return -ENODEV;
/* Addresses cycling */
for (i = 8; i < 0xff; i += 8) {
if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
|| i2c_smbus_read_word_data(new_client, i + 2) != hyst
|| i2c_smbus_read_word_data(new_client, i + 3) != os)
return -ENODEV;
}
strlcpy(info->type, "lm75", I2C_NAME_SIZE);
return 0;
}
static struct i2c_driver lm75_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm75",
},
.probe = lm75_probe,
.remove = lm75_remove,
.id_table = lm75_ids,
.detect = lm75_detect,
.address_list = normal_i2c,
};
/*-----------------------------------------------------------------------*/
/* register access */
/* All registers are word-sized, except for the configuration register.
LM75 uses a high-byte first convention, which is exactly opposite to
the SMBus standard. */
static int lm75_read_value(struct i2c_client *client, u8 reg)
{
int value;
if (reg == LM75_REG_CONF)
return i2c_smbus_read_byte_data(client, reg);
value = i2c_smbus_read_word_data(client, reg);
return (value < 0) ? value : swab16(value);
}
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
{
if (reg == LM75_REG_CONF)
return i2c_smbus_write_byte_data(client, reg, value);
else
return i2c_smbus_write_word_data(client, reg, swab16(value));
}
static struct lm75_data *lm75_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
int i;
dev_dbg(&client->dev, "Starting lm75 update\n");
for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
int status;
status = lm75_read_value(client, LM75_REG_TEMP[i]);
if (status < 0)
dev_dbg(&client->dev, "reg %d, err %d\n",
LM75_REG_TEMP[i], status);
else
data->temp[i] = status;
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
/*-----------------------------------------------------------------------*/
/* module glue */
static int __init sensors_lm75_init(void)
{
return i2c_add_driver(&lm75_driver);
}
static void __exit sensors_lm75_exit(void)
{
i2c_del_driver(&lm75_driver);
}
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");
module_init(sensors_lm75_init);
module_exit(sensors_lm75_exit);