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hwmon: ad7414 driver
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Driver for the Analog Devices AD7414 temperature monitoring chip.

Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
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Sean MacLennan authored and Jean Delvare committed Aug 6, 2008
1 parent 84f768c commit 6c633c3
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10 changes: 10 additions & 0 deletions drivers/hwmon/Kconfig
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Expand Up @@ -57,6 +57,16 @@ config SENSORS_ABITUGURU3
This driver can also be built as a module. If so, the module
will be called abituguru3.

config SENSORS_AD7414
tristate "Analog Devices AD7414"
depends on I2C && EXPERIMENTAL
help
If you say yes here you get support for the Analog Devices
AD7414 temperature monitoring chip.

This driver can also be built as a module. If so, the module
will be called ad7414.

config SENSORS_AD7418
tristate "Analog Devices AD7416, AD7417 and AD7418"
depends on I2C && EXPERIMENTAL
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1 change: 1 addition & 0 deletions drivers/hwmon/Makefile
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Expand Up @@ -15,6 +15,7 @@ obj-$(CONFIG_SENSORS_W83791D) += w83791d.o

obj-$(CONFIG_SENSORS_ABITUGURU) += abituguru.o
obj-$(CONFIG_SENSORS_ABITUGURU3)+= abituguru3.o
obj-$(CONFIG_SENSORS_AD7414) += ad7414.o
obj-$(CONFIG_SENSORS_AD7418) += ad7418.o
obj-$(CONFIG_SENSORS_ADM1021) += adm1021.o
obj-$(CONFIG_SENSORS_ADM1025) += adm1025.o
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268 changes: 268 additions & 0 deletions drivers/hwmon/ad7414.c
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@@ -0,0 +1,268 @@
/*
* An hwmon driver for the Analog Devices AD7414
*
* Copyright 2006 Stefan Roese <sr at denx.de>, DENX Software Engineering
*
* Copyright (c) 2008 PIKA Technologies
* Sean MacLennan <smaclennan@pikatech.com>
*
* Copyright (c) 2008 Spansion Inc.
* Frank Edelhaeuser <frank.edelhaeuser at spansion.com>
* (converted to "new style" I2C driver model, removed checkpatch.pl warnings)
*
* Based on ad7418.c
* Copyright 2006 Tower Technologies, Alessandro Zummo <a.zummo at towertech.it>
*
* 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/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>


/* AD7414 registers */
#define AD7414_REG_TEMP 0x00
#define AD7414_REG_CONF 0x01
#define AD7414_REG_T_HIGH 0x02
#define AD7414_REG_T_LOW 0x03

static u8 AD7414_REG_LIMIT[] = { AD7414_REG_T_HIGH, AD7414_REG_T_LOW };

struct ad7414_data {
struct device *hwmon_dev;
struct mutex lock; /* atomic read data updates */
char valid; /* !=0 if following fields are valid */
unsigned long next_update; /* In jiffies */
s16 temp_input; /* Register values */
s8 temps[ARRAY_SIZE(AD7414_REG_LIMIT)];
};

/* REG: (0.25C/bit, two's complement) << 6 */
static inline int ad7414_temp_from_reg(s16 reg)
{
/* use integer division instead of equivalent right shift to
* guarantee arithmetic shift and preserve the sign
*/
return ((int)reg / 64) * 250;
}

static inline int ad7414_read(struct i2c_client *client, u8 reg)
{
if (reg == AD7414_REG_TEMP) {
int value = i2c_smbus_read_word_data(client, reg);
return (value < 0) ? value : swab16(value);
} else
return i2c_smbus_read_byte_data(client, reg);
}

static inline int ad7414_write(struct i2c_client *client, u8 reg, u8 value)
{
return i2c_smbus_write_byte_data(client, reg, value);
}

struct ad7414_data *ad7414_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ad7414_data *data = i2c_get_clientdata(client);

mutex_lock(&data->lock);

if (time_after(jiffies, data->next_update) || !data->valid) {
int value, i;

dev_dbg(&client->dev, "starting ad7414 update\n");

value = ad7414_read(client, AD7414_REG_TEMP);
if (value < 0)
dev_dbg(&client->dev, "AD7414_REG_TEMP err %d\n",
value);
else
data->temp_input = value;

for (i = 0; i < ARRAY_SIZE(AD7414_REG_LIMIT); ++i) {
value = ad7414_read(client, AD7414_REG_LIMIT[i]);
if (value < 0)
dev_dbg(&client->dev, "AD7414 reg %d err %d\n",
AD7414_REG_LIMIT[i], value);
else
data->temps[i] = value;
}

data->next_update = jiffies + HZ + HZ / 2;
data->valid = 1;
}

mutex_unlock(&data->lock);

return data;
}

static ssize_t show_temp_input(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ad7414_data *data = ad7414_update_device(dev);
return sprintf(buf, "%d\n", ad7414_temp_from_reg(data->temp_input));
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);

static ssize_t show_max_min(struct device *dev, struct device_attribute *attr,
char *buf)
{
int index = to_sensor_dev_attr(attr)->index;
struct ad7414_data *data = ad7414_update_device(dev);
return sprintf(buf, "%d\n", data->temps[index] * 1000);
}

static ssize_t set_max_min(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct ad7414_data *data = i2c_get_clientdata(client);
int index = to_sensor_dev_attr(attr)->index;
u8 reg = AD7414_REG_LIMIT[index];
long temp = simple_strtol(buf, NULL, 10);

temp = SENSORS_LIMIT(temp, -40000, 85000);
temp = (temp + (temp < 0 ? -500 : 500)) / 1000;

mutex_lock(&data->lock);
data->temps[index] = temp;
ad7414_write(client, reg, temp);
mutex_unlock(&data->lock);
return count;
}

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_max_min, set_max_min, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
show_max_min, set_max_min, 1);

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct ad7414_data *data = ad7414_update_device(dev);
int value = (data->temp_input >> bitnr) & 1;
return sprintf(buf, "%d\n", value);
}

static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 4);

static struct attribute *ad7414_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
NULL
};

static const struct attribute_group ad7414_group = {
.attrs = ad7414_attributes,
};

static int ad7414_probe(struct i2c_client *client,
const struct i2c_device_id *dev_id)
{
struct ad7414_data *data;
int conf;
int err = 0;

if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_READ_WORD_DATA))
goto exit;

data = kzalloc(sizeof(struct ad7414_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}

i2c_set_clientdata(client, data);
mutex_init(&data->lock);

dev_info(&client->dev, "chip found\n");

/* Make sure the chip is powered up. */
conf = i2c_smbus_read_byte_data(client, AD7414_REG_CONF);
if (conf < 0)
dev_warn(&client->dev,
"ad7414_probe unable to read config register.\n");
else {
conf &= ~(1 << 7);
i2c_smbus_write_byte_data(client, AD7414_REG_CONF, conf);
}

/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &ad7414_group);
if (err)
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;
}

return 0;

exit_remove:
sysfs_remove_group(&client->dev.kobj, &ad7414_group);
exit_free:
kfree(data);
exit:
return err;
}

static int __devexit ad7414_remove(struct i2c_client *client)
{
struct ad7414_data *data = i2c_get_clientdata(client);

hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &ad7414_group);
kfree(data);
return 0;
}

static const struct i2c_device_id ad7414_id[] = {
{ "ad7414", 0 },
{}
};

static struct i2c_driver ad7414_driver = {
.driver = {
.name = "ad7414",
},
.probe = ad7414_probe,
.remove = __devexit_p(ad7414_remove),
.id_table = ad7414_id,
};

static int __init ad7414_init(void)
{
return i2c_add_driver(&ad7414_driver);
}
module_init(ad7414_init);

static void __exit ad7414_exit(void)
{
i2c_del_driver(&ad7414_driver);
}
module_exit(ad7414_exit);

MODULE_AUTHOR("Stefan Roese <sr at denx.de>, "
"Frank Edelhaeuser <frank.edelhaeuser at spansion.com>");

MODULE_DESCRIPTION("AD7414 driver");
MODULE_LICENSE("GPL");

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