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linux/drivers/hwmon/ds1621.c
Jean Delvare 90f4102ce5 hwmon: Use i2c_smbus_{read,write}_word_swapped 
Make use of the new i2c_smbus_{read,write}_word_swapped functions.
This makes the driver code more compact and readable. It also ensures
proper error handling.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Dirk Eibach <eibach@gdsys.de>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Cc: Guillaume Ligneul <guillaume.ligneul@gmail.com>
2011-11-04 12:00:47 +01:00

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/*
ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Christian W. Zuckschwerdt <zany@triq.net> 2000-11-23
based on lm75.c by Frodo Looijaard <frodol@dds.nl>
Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
the help of Jean Delvare <khali@linux-fr.org>
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 <linux/sysfs.h>
#include "lm75.h"
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* Insmod parameters */
static int polarity = -1;
module_param(polarity, int, 0);
MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
/* Many DS1621 constants specified below */
/* Config register used for detection */
/* 7 6 5 4 3 2 1 0 */
/* |Done|THF |TLF |NVB | X | X |POL |1SHOT| */
#define DS1621_REG_CONFIG_NVB 0x10
#define DS1621_REG_CONFIG_POLARITY 0x02
#define DS1621_REG_CONFIG_1SHOT 0x01
#define DS1621_REG_CONFIG_DONE 0x80
/* The DS1621 registers */
static const u8 DS1621_REG_TEMP[3] = {
0xAA, /* input, word, RO */
0xA2, /* min, word, RW */
0xA1, /* max, word, RW */
};
#define DS1621_REG_CONF 0xAC /* byte, RW */
#define DS1621_COM_START 0xEE /* no data */
#define DS1621_COM_STOP 0x22 /* no data */
/* The DS1621 configuration register */
#define DS1621_ALARM_TEMP_HIGH 0x40
#define DS1621_ALARM_TEMP_LOW 0x20
/* Conversions */
#define ALARMS_FROM_REG(val) ((val) & \
(DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
/* Each client has this additional data */
struct ds1621_data {
struct device *hwmon_dev;
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
u16 temp[3]; /* Register values, word */
u8 conf; /* Register encoding, combined */
};
static void ds1621_init_client(struct i2c_client *client)
{
u8 conf, new_conf;
new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
/* switch to continuous conversion mode */
new_conf &= ~DS1621_REG_CONFIG_1SHOT;
/* setup output polarity */
if (polarity == 0)
new_conf &= ~DS1621_REG_CONFIG_POLARITY;
else if (polarity == 1)
new_conf |= DS1621_REG_CONFIG_POLARITY;
if (conf != new_conf)
i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
/* start conversion */
i2c_smbus_write_byte(client, DS1621_COM_START);
}
static struct ds1621_data *ds1621_update_client(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1621_data *data = i2c_get_clientdata(client);
u8 new_conf;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
int i;
dev_dbg(&client->dev, "Starting ds1621 update\n");
data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
for (i = 0; i < ARRAY_SIZE(data->temp); i++)
data->temp[i] = i2c_smbus_read_word_swapped(client,
DS1621_REG_TEMP[i]);
/* reset alarms if necessary */
new_conf = data->conf;
if (data->temp[0] > data->temp[1]) /* input > min */
new_conf &= ~DS1621_ALARM_TEMP_LOW;
if (data->temp[0] < data->temp[2]) /* input < max */
new_conf &= ~DS1621_ALARM_TEMP_HIGH;
if (data->conf != new_conf)
i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
new_conf);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
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 ds1621_data *data = ds1621_update_client(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 ds1621_data *data = i2c_get_clientdata(client);
u16 val = LM75_TEMP_TO_REG(simple_strtol(buf, NULL, 10));
mutex_lock(&data->update_lock);
data->temp[attr->index] = val;
i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
data->temp[attr->index]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
char *buf)
{
struct ds1621_data *data = ds1621_update_client(dev);
return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds1621_data *data = ds1621_update_client(dev);
return sprintf(buf, "%d\n", !!(data->conf & attr->index));
}
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
DS1621_ALARM_TEMP_LOW);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
DS1621_ALARM_TEMP_HIGH);
static struct attribute *ds1621_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
&dev_attr_alarms.attr,
NULL
};
static const struct attribute_group ds1621_group = {
.attrs = ds1621_attributes,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int ds1621_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
int conf, temp;
int i;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_WORD_DATA
| I2C_FUNC_SMBUS_WRITE_BYTE))
return -ENODEV;
/* Now, we do the remaining detection. It is lousy. */
/* The NVB bit should be low if no EEPROM write has been requested
during the latest 10ms, which is highly improbable in our case. */
conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
return -ENODEV;
/* The 7 lowest bits of a temperature should always be 0. */
for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
if (temp < 0 || (temp & 0x7f00))
return -ENODEV;
}
strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
return 0;
}
static int ds1621_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds1621_data *data;
int err;
data = kzalloc(sizeof(struct ds1621_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* Initialize the DS1621 chip */
ds1621_init_client(client);
/* Register sysfs hooks */
if ((err = sysfs_create_group(&client->dev.kobj, &ds1621_group)))
goto exit_free;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
goto exit_remove_files;
}
return 0;
exit_remove_files:
sysfs_remove_group(&client->dev.kobj, &ds1621_group);
exit_free:
kfree(data);
exit:
return err;
}
static int ds1621_remove(struct i2c_client *client)
{
struct ds1621_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &ds1621_group);
kfree(data);
return 0;
}
static const struct i2c_device_id ds1621_id[] = {
{ "ds1621", 0 },
{ "ds1625", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1621_id);
/* This is the driver that will be inserted */
static struct i2c_driver ds1621_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "ds1621",
},
.probe = ds1621_probe,
.remove = ds1621_remove,
.id_table = ds1621_id,
.detect = ds1621_detect,
.address_list = normal_i2c,
};
static int __init ds1621_init(void)
{
return i2c_add_driver(&ds1621_driver);
}
static void __exit ds1621_exit(void)
{
i2c_del_driver(&ds1621_driver);
}
MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
MODULE_DESCRIPTION("DS1621 driver");
MODULE_LICENSE("GPL");
module_init(ds1621_init);
module_exit(ds1621_exit);
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