333 lines
8.3 KiB
C
333 lines
8.3 KiB
C
/* tmp421.c
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*
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* Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
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* Preliminary support by:
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* Melvin Rook, Raymond Ng
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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* Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
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* Supported models: TMP421, TMP422, TMP423
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/sysfs.h>
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/* Addresses to scan */
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static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
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I2C_CLIENT_END };
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enum chips { tmp421, tmp422, tmp423 };
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/* The TMP421 registers */
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#define TMP421_CONFIG_REG_1 0x09
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#define TMP421_CONVERSION_RATE_REG 0x0B
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#define TMP421_MANUFACTURER_ID_REG 0xFE
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#define TMP421_DEVICE_ID_REG 0xFF
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static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
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static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
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/* Flags */
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#define TMP421_CONFIG_SHUTDOWN 0x40
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#define TMP421_CONFIG_RANGE 0x04
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/* Manufacturer / Device ID's */
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#define TMP421_MANUFACTURER_ID 0x55
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#define TMP421_DEVICE_ID 0x21
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#define TMP422_DEVICE_ID 0x22
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#define TMP423_DEVICE_ID 0x23
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static const struct i2c_device_id tmp421_id[] = {
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{ "tmp421", 2 },
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{ "tmp422", 3 },
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{ "tmp423", 4 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, tmp421_id);
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struct tmp421_data {
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struct device *hwmon_dev;
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struct mutex update_lock;
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char valid;
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unsigned long last_updated;
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int channels;
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u8 config;
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s16 temp[4];
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};
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static int temp_from_s16(s16 reg)
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{
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/* Mask out status bits */
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int temp = reg & ~0xf;
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return (temp * 1000 + 128) / 256;
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}
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static int temp_from_u16(u16 reg)
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{
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/* Mask out status bits */
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int temp = reg & ~0xf;
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/* Add offset for extended temperature range. */
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temp -= 64 * 256;
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return (temp * 1000 + 128) / 256;
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}
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static struct tmp421_data *tmp421_update_device(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct tmp421_data *data = i2c_get_clientdata(client);
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int i;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
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data->config = i2c_smbus_read_byte_data(client,
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TMP421_CONFIG_REG_1);
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for (i = 0; i < data->channels; i++) {
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data->temp[i] = i2c_smbus_read_byte_data(client,
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TMP421_TEMP_MSB[i]) << 8;
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data->temp[i] |= i2c_smbus_read_byte_data(client,
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TMP421_TEMP_LSB[i]);
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}
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data->last_updated = jiffies;
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data->valid = 1;
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}
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mutex_unlock(&data->update_lock);
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return data;
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}
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static ssize_t show_temp_value(struct device *dev,
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struct device_attribute *devattr, char *buf)
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{
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int index = to_sensor_dev_attr(devattr)->index;
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struct tmp421_data *data = tmp421_update_device(dev);
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int temp;
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mutex_lock(&data->update_lock);
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if (data->config & TMP421_CONFIG_RANGE)
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temp = temp_from_u16(data->temp[index]);
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else
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temp = temp_from_s16(data->temp[index]);
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mutex_unlock(&data->update_lock);
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return sprintf(buf, "%d\n", temp);
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}
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static ssize_t show_fault(struct device *dev,
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struct device_attribute *devattr, char *buf)
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{
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int index = to_sensor_dev_attr(devattr)->index;
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struct tmp421_data *data = tmp421_update_device(dev);
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/*
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* The OPEN bit signals a fault. This is bit 0 of the temperature
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* register (low byte).
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*/
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if (data->temp[index] & 0x01)
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return sprintf(buf, "1\n");
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else
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return sprintf(buf, "0\n");
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}
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static umode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
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int n)
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{
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struct device *dev = container_of(kobj, struct device, kobj);
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struct tmp421_data *data = dev_get_drvdata(dev);
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struct device_attribute *devattr;
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unsigned int index;
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devattr = container_of(a, struct device_attribute, attr);
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index = to_sensor_dev_attr(devattr)->index;
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if (index < data->channels)
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return a->mode;
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return 0;
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}
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
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static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
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static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
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static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
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static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
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static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
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static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
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static struct attribute *tmp421_attr[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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&sensor_dev_attr_temp2_input.dev_attr.attr,
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&sensor_dev_attr_temp2_fault.dev_attr.attr,
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&sensor_dev_attr_temp3_input.dev_attr.attr,
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&sensor_dev_attr_temp3_fault.dev_attr.attr,
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&sensor_dev_attr_temp4_input.dev_attr.attr,
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&sensor_dev_attr_temp4_fault.dev_attr.attr,
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NULL
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};
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static const struct attribute_group tmp421_group = {
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.attrs = tmp421_attr,
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.is_visible = tmp421_is_visible,
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};
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static int tmp421_init_client(struct i2c_client *client)
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{
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int config, config_orig;
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/* Set the conversion rate to 2 Hz */
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i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
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/* Start conversions (disable shutdown if necessary) */
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config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
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if (config < 0) {
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dev_err(&client->dev, "Could not read configuration"
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" register (%d)\n", config);
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return -ENODEV;
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}
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config_orig = config;
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config &= ~TMP421_CONFIG_SHUTDOWN;
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if (config != config_orig) {
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dev_info(&client->dev, "Enable monitoring chip\n");
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i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
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}
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return 0;
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}
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static int tmp421_detect(struct i2c_client *client,
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struct i2c_board_info *info)
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{
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enum chips kind;
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struct i2c_adapter *adapter = client->adapter;
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const char *names[] = { "TMP421", "TMP422", "TMP423" };
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u8 reg;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
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if (reg != TMP421_MANUFACTURER_ID)
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return -ENODEV;
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reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
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switch (reg) {
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case TMP421_DEVICE_ID:
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kind = tmp421;
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break;
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case TMP422_DEVICE_ID:
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kind = tmp422;
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break;
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case TMP423_DEVICE_ID:
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kind = tmp423;
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break;
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default:
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return -ENODEV;
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}
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strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
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dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
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names[kind], client->addr);
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return 0;
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}
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static int tmp421_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct tmp421_data *data;
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int err;
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data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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data->channels = id->driver_data;
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err = tmp421_init_client(client);
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if (err)
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goto exit_free;
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err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
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if (err)
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goto exit_free;
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data->hwmon_dev = hwmon_device_register(&client->dev);
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if (IS_ERR(data->hwmon_dev)) {
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err = PTR_ERR(data->hwmon_dev);
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data->hwmon_dev = NULL;
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goto exit_remove;
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}
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return 0;
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exit_remove:
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sysfs_remove_group(&client->dev.kobj, &tmp421_group);
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exit_free:
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kfree(data);
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return err;
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}
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static int tmp421_remove(struct i2c_client *client)
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{
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struct tmp421_data *data = i2c_get_clientdata(client);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&client->dev.kobj, &tmp421_group);
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kfree(data);
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return 0;
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}
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static struct i2c_driver tmp421_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "tmp421",
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},
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.probe = tmp421_probe,
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.remove = tmp421_remove,
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.id_table = tmp421_id,
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.detect = tmp421_detect,
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.address_list = normal_i2c,
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};
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module_i2c_driver(tmp421_driver);
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MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
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MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
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" driver");
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MODULE_LICENSE("GPL");
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