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linux-sg2042/drivers/hwmon/max6642.c

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/*
* Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
* with Overtemperature Alarm
*
* Copyright (C) 2011 AppearTV AS
*
* Derived from:
*
* Based on the max1619 driver.
* Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
* Jean Delvare <khali@linux-fr.org>
*
* The MAX6642 is a sensor chip made by Maxim.
* It reports up to two temperatures (its own plus up to
* one external one). Complete datasheet can be
* obtained from Maxim's website at:
* http://datasheets.maxim-ic.com/en/ds/MAX6642.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.
*
* 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>
static const unsigned short normal_i2c[] = {
0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/*
* The MAX6642 registers
*/
#define MAX6642_REG_R_MAN_ID 0xFE
#define MAX6642_REG_R_CONFIG 0x03
#define MAX6642_REG_W_CONFIG 0x09
#define MAX6642_REG_R_STATUS 0x02
#define MAX6642_REG_R_LOCAL_TEMP 0x00
#define MAX6642_REG_R_LOCAL_TEMPL 0x11
#define MAX6642_REG_R_LOCAL_HIGH 0x05
#define MAX6642_REG_W_LOCAL_HIGH 0x0B
#define MAX6642_REG_R_REMOTE_TEMP 0x01
#define MAX6642_REG_R_REMOTE_TEMPL 0x10
#define MAX6642_REG_R_REMOTE_HIGH 0x07
#define MAX6642_REG_W_REMOTE_HIGH 0x0D
/*
* Conversions
*/
static int temp_from_reg10(int val)
{
return val * 250;
}
static int temp_from_reg(int val)
{
return val * 1000;
}
static int temp_to_reg(int val)
{
return val / 1000;
}
/*
* Client data (each client gets its own)
*/
struct max6642_data {
struct device *hwmon_dev;
struct mutex update_lock;
bool valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* registers values */
u16 temp_input[2]; /* local/remote */
u16 temp_high[2]; /* local/remote */
u8 alarms;
};
/*
* Real code
*/
static void max6642_init_client(struct i2c_client *client)
{
u8 config;
struct max6642_data *data = i2c_get_clientdata(client);
/*
* Start the conversions.
*/
config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
if (config & 0x40)
i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
config & 0xBF); /* run */
data->temp_high[0] = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_LOCAL_HIGH);
data->temp_high[1] = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_REMOTE_HIGH);
}
/* Return 0 if detection is successful, -ENODEV otherwise */
static int max6642_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
u8 reg_config, reg_status, man_id;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
/* identification */
man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
if (man_id != 0x4D)
return -ENODEV;
/* sanity check */
if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
|| i2c_smbus_read_byte_data(client, 0x06) != 0x4D
|| i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
return -ENODEV;
/*
* We read the config and status register, the 4 lower bits in the
* config register should be zero and bit 5, 3, 1 and 0 should be
* zero in the status register.
*/
reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
if ((reg_config & 0x0f) != 0x00)
return -ENODEV;
/* in between, another round of sanity checks */
if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
|| i2c_smbus_read_byte_data(client, 0x06) != reg_config
|| i2c_smbus_read_byte_data(client, 0xff) != reg_config)
return -ENODEV;
reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
if ((reg_status & 0x2b) != 0x00)
return -ENODEV;
strlcpy(info->type, "max6642", I2C_NAME_SIZE);
return 0;
}
static struct max6642_data *max6642_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct max6642_data *data = i2c_get_clientdata(client);
u16 val, tmp;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
dev_dbg(&client->dev, "Updating max6642 data.\n");
val = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_LOCAL_TEMPL);
tmp = (val >> 6) & 3;
val = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_LOCAL_TEMP);
val = (val << 2) | tmp;
data->temp_input[0] = val;
val = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_REMOTE_TEMPL);
tmp = (val >> 6) & 3;
val = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_REMOTE_TEMP);
val = (val << 2) | tmp;
data->temp_input[1] = val;
data->alarms = i2c_smbus_read_byte_data(client,
MAX6642_REG_R_STATUS);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
/*
* Sysfs stuff
*/
static ssize_t show_temp_max10(struct device *dev,
struct device_attribute *dev_attr, char *buf)
{
struct max6642_data *data = max6642_update_device(dev);
struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
return sprintf(buf, "%d\n",
temp_from_reg10(data->temp_input[attr->index]));
}
static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct max6642_data *data = max6642_update_device(dev);
struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
}
static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
unsigned long val;
int err;
struct i2c_client *client = to_i2c_client(dev);
struct max6642_data *data = i2c_get_clientdata(client);
struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
err = kstrtoul(buf, 10, &val);
if (err < 0)
return err;
mutex_lock(&data->update_lock);
data->temp_high[attr2->nr] = SENSORS_LIMIT(temp_to_reg(val), 0, 255);
i2c_smbus_write_byte_data(client, attr2->index,
data->temp_high[attr2->nr]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct max6642_data *data = max6642_update_device(dev);
return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_max10, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_max10, NULL, 1);
static SENSOR_DEVICE_ATTR_2(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
set_temp_max, 0, MAX6642_REG_W_LOCAL_HIGH);
static SENSOR_DEVICE_ATTR_2(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
set_temp_max, 1, MAX6642_REG_W_REMOTE_HIGH);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
static struct attribute *max6642_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp2_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp2_max.dev_attr.attr,
&sensor_dev_attr_temp2_fault.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
NULL
};
static const struct attribute_group max6642_group = {
.attrs = max6642_attributes,
};
static int max6642_probe(struct i2c_client *new_client,
const struct i2c_device_id *id)
{
struct max6642_data *data;
int err;
data = devm_kzalloc(&new_client->dev, sizeof(struct max6642_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(new_client, data);
mutex_init(&data->update_lock);
/* Initialize the MAX6642 chip */
max6642_init_client(new_client);
/* Register sysfs hooks */
err = sysfs_create_group(&new_client->dev.kobj, &max6642_group);
if (err)
return err;
data->hwmon_dev = hwmon_device_register(&new_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(&new_client->dev.kobj, &max6642_group);
return err;
}
static int max6642_remove(struct i2c_client *client)
{
struct max6642_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &max6642_group);
return 0;
}
/*
* Driver data (common to all clients)
*/
static const struct i2c_device_id max6642_id[] = {
{ "max6642", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max6642_id);
static struct i2c_driver max6642_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "max6642",
},
.probe = max6642_probe,
.remove = max6642_remove,
.id_table = max6642_id,
.detect = max6642_detect,
.address_list = normal_i2c,
};
module_i2c_driver(max6642_driver);
MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
MODULE_DESCRIPTION("MAX6642 sensor driver");
MODULE_LICENSE("GPL");
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