549 lines
14 KiB
C
549 lines
14 KiB
C
/*
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* lm75.c - Part of lm_sensors, Linux kernel modules for hardware
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* monitoring
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* Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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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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#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/of.h>
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#include <linux/thermal.h>
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#include "lm75.h"
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/*
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* This driver handles the LM75 and compatible digital temperature sensors.
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*/
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enum lm75_type { /* keep sorted in alphabetical order */
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adt75,
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ds1775,
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ds75,
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ds7505,
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g751,
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lm75,
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lm75a,
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max6625,
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max6626,
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mcp980x,
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stds75,
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tcn75,
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tmp100,
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tmp101,
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tmp105,
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tmp175,
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tmp275,
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tmp75,
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};
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/* Addresses scanned */
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static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
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0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
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/* The LM75 registers */
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#define LM75_REG_CONF 0x01
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static const u8 LM75_REG_TEMP[3] = {
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0x00, /* input */
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0x03, /* max */
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0x02, /* hyst */
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};
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/* Each client has this additional data */
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struct lm75_data {
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struct device *hwmon_dev;
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struct thermal_zone_device *tz;
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struct mutex update_lock;
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u8 orig_conf;
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u8 resolution; /* In bits, between 9 and 12 */
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u8 resolution_limits;
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char valid; /* !=0 if registers are valid */
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unsigned long last_updated; /* In jiffies */
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unsigned long sample_time; /* In jiffies */
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s16 temp[3]; /* Register values,
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0 = input
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1 = max
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2 = hyst */
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};
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static int lm75_read_value(struct i2c_client *client, u8 reg);
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static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
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static struct lm75_data *lm75_update_device(struct device *dev);
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/*-----------------------------------------------------------------------*/
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static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
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{
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return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
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}
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/* sysfs attributes for hwmon */
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static int lm75_read_temp(void *dev, long *temp)
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{
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struct lm75_data *data = lm75_update_device(dev);
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if (IS_ERR(data))
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return PTR_ERR(data);
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*temp = lm75_reg_to_mc(data->temp[0], data->resolution);
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return 0;
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}
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static ssize_t show_temp(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct lm75_data *data = lm75_update_device(dev);
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if (IS_ERR(data))
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return PTR_ERR(data);
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return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
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data->resolution));
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}
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static ssize_t set_temp(struct device *dev, struct device_attribute *da,
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const char *buf, size_t count)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct i2c_client *client = to_i2c_client(dev);
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struct lm75_data *data = i2c_get_clientdata(client);
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int nr = attr->index;
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long temp;
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int error;
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u8 resolution;
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error = kstrtol(buf, 10, &temp);
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if (error)
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return error;
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/*
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* Resolution of limit registers is assumed to be the same as the
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* temperature input register resolution unless given explicitly.
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*/
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if (attr->index && data->resolution_limits)
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resolution = data->resolution_limits;
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else
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resolution = data->resolution;
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mutex_lock(&data->update_lock);
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temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
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data->temp[nr] = DIV_ROUND_CLOSEST(temp << (resolution - 8),
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1000) << (16 - resolution);
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lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
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mutex_unlock(&data->update_lock);
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return count;
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}
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static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
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show_temp, set_temp, 1);
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static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
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show_temp, set_temp, 2);
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static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
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static struct attribute *lm75_attributes[] = {
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&sensor_dev_attr_temp1_input.dev_attr.attr,
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&sensor_dev_attr_temp1_max.dev_attr.attr,
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&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
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NULL
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};
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static const struct attribute_group lm75_group = {
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.attrs = lm75_attributes,
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};
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/*-----------------------------------------------------------------------*/
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/* device probe and removal */
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static int
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lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
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{
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struct lm75_data *data;
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int status;
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u8 set_mask, clr_mask;
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int new;
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enum lm75_type kind = id->driver_data;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
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return -EIO;
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data = devm_kzalloc(&client->dev, sizeof(struct lm75_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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/* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
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* Then tweak to be more precise when appropriate.
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*/
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set_mask = 0;
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clr_mask = LM75_SHUTDOWN; /* continuous conversions */
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switch (kind) {
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case adt75:
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clr_mask |= 1 << 5; /* not one-shot mode */
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data->resolution = 12;
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data->sample_time = HZ / 8;
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break;
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case ds1775:
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case ds75:
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case stds75:
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clr_mask |= 3 << 5;
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set_mask |= 2 << 5; /* 11-bit mode */
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data->resolution = 11;
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data->sample_time = HZ;
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break;
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case ds7505:
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set_mask |= 3 << 5; /* 12-bit mode */
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data->resolution = 12;
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data->sample_time = HZ / 4;
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break;
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case g751:
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case lm75:
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case lm75a:
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data->resolution = 9;
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data->sample_time = HZ / 2;
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break;
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case max6625:
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data->resolution = 9;
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data->sample_time = HZ / 4;
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break;
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case max6626:
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data->resolution = 12;
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data->resolution_limits = 9;
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data->sample_time = HZ / 4;
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break;
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case tcn75:
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data->resolution = 9;
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data->sample_time = HZ / 8;
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break;
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case mcp980x:
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data->resolution_limits = 9;
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/* fall through */
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case tmp100:
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case tmp101:
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set_mask |= 3 << 5; /* 12-bit mode */
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data->resolution = 12;
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data->sample_time = HZ;
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clr_mask |= 1 << 7; /* not one-shot mode */
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break;
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case tmp105:
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case tmp175:
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case tmp275:
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case tmp75:
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set_mask |= 3 << 5; /* 12-bit mode */
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clr_mask |= 1 << 7; /* not one-shot mode */
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data->resolution = 12;
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data->sample_time = HZ / 2;
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break;
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}
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/* configure as specified */
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status = lm75_read_value(client, LM75_REG_CONF);
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if (status < 0) {
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dev_dbg(&client->dev, "Can't read config? %d\n", status);
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return status;
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}
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data->orig_conf = status;
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new = status & ~clr_mask;
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new |= set_mask;
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if (status != new)
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lm75_write_value(client, LM75_REG_CONF, new);
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dev_dbg(&client->dev, "Config %02x\n", new);
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/* Register sysfs hooks */
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status = sysfs_create_group(&client->dev.kobj, &lm75_group);
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if (status)
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return status;
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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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status = PTR_ERR(data->hwmon_dev);
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goto exit_remove;
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}
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data->tz = thermal_zone_of_sensor_register(&client->dev,
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0,
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&client->dev,
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lm75_read_temp, NULL);
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if (IS_ERR(data->tz))
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data->tz = NULL;
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dev_info(&client->dev, "%s: sensor '%s'\n",
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dev_name(data->hwmon_dev), client->name);
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return 0;
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exit_remove:
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sysfs_remove_group(&client->dev.kobj, &lm75_group);
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return status;
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}
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static int lm75_remove(struct i2c_client *client)
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{
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struct lm75_data *data = i2c_get_clientdata(client);
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thermal_zone_of_sensor_unregister(&client->dev, data->tz);
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hwmon_device_unregister(data->hwmon_dev);
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sysfs_remove_group(&client->dev.kobj, &lm75_group);
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lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
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return 0;
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}
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static const struct i2c_device_id lm75_ids[] = {
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{ "adt75", adt75, },
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{ "ds1775", ds1775, },
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{ "ds75", ds75, },
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{ "ds7505", ds7505, },
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{ "g751", g751, },
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{ "lm75", lm75, },
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{ "lm75a", lm75a, },
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{ "max6625", max6625, },
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{ "max6626", max6626, },
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{ "mcp980x", mcp980x, },
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{ "stds75", stds75, },
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{ "tcn75", tcn75, },
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{ "tmp100", tmp100, },
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{ "tmp101", tmp101, },
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{ "tmp105", tmp105, },
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{ "tmp175", tmp175, },
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{ "tmp275", tmp275, },
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{ "tmp75", tmp75, },
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{ /* LIST END */ }
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};
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MODULE_DEVICE_TABLE(i2c, lm75_ids);
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#define LM75A_ID 0xA1
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/* Return 0 if detection is successful, -ENODEV otherwise */
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static int lm75_detect(struct i2c_client *new_client,
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struct i2c_board_info *info)
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{
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struct i2c_adapter *adapter = new_client->adapter;
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int i;
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int conf, hyst, os;
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bool is_lm75a = 0;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
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I2C_FUNC_SMBUS_WORD_DATA))
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return -ENODEV;
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/*
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* Now, we do the remaining detection. There is no identification-
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* dedicated register so we have to rely on several tricks:
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* unused bits, registers cycling over 8-address boundaries,
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* addresses 0x04-0x07 returning the last read value.
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* The cycling+unused addresses combination is not tested,
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* since it would significantly slow the detection down and would
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* hardly add any value.
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*
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* The National Semiconductor LM75A is different than earlier
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* LM75s. It has an ID byte of 0xaX (where X is the chip
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* revision, with 1 being the only revision in existence) in
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* register 7, and unused registers return 0xff rather than the
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* last read value.
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*
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* Note that this function only detects the original National
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* Semiconductor LM75 and the LM75A. Clones from other vendors
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* aren't detected, on purpose, because they are typically never
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* found on PC hardware. They are found on embedded designs where
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* they can be instantiated explicitly so detection is not needed.
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* The absence of identification registers on all these clones
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* would make their exhaustive detection very difficult and weak,
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* and odds are that the driver would bind to unsupported devices.
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*/
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/* Unused bits */
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conf = i2c_smbus_read_byte_data(new_client, 1);
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if (conf & 0xe0)
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return -ENODEV;
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/* First check for LM75A */
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if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
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/* LM75A returns 0xff on unused registers so
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just to be sure we check for that too. */
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if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
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|| i2c_smbus_read_byte_data(new_client, 5) != 0xff
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|| i2c_smbus_read_byte_data(new_client, 6) != 0xff)
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return -ENODEV;
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is_lm75a = 1;
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hyst = i2c_smbus_read_byte_data(new_client, 2);
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os = i2c_smbus_read_byte_data(new_client, 3);
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} else { /* Traditional style LM75 detection */
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/* Unused addresses */
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hyst = i2c_smbus_read_byte_data(new_client, 2);
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if (i2c_smbus_read_byte_data(new_client, 4) != hyst
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|| i2c_smbus_read_byte_data(new_client, 5) != hyst
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|| i2c_smbus_read_byte_data(new_client, 6) != hyst
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|| i2c_smbus_read_byte_data(new_client, 7) != hyst)
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return -ENODEV;
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os = i2c_smbus_read_byte_data(new_client, 3);
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if (i2c_smbus_read_byte_data(new_client, 4) != os
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|| i2c_smbus_read_byte_data(new_client, 5) != os
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|| i2c_smbus_read_byte_data(new_client, 6) != os
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|| i2c_smbus_read_byte_data(new_client, 7) != os)
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return -ENODEV;
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}
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/* Addresses cycling */
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for (i = 8; i <= 248; i += 40) {
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if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
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|| i2c_smbus_read_byte_data(new_client, i + 2) != hyst
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|| i2c_smbus_read_byte_data(new_client, i + 3) != os)
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return -ENODEV;
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if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
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!= LM75A_ID)
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return -ENODEV;
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}
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strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
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return 0;
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}
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#ifdef CONFIG_PM
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static int lm75_suspend(struct device *dev)
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{
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int status;
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struct i2c_client *client = to_i2c_client(dev);
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status = lm75_read_value(client, LM75_REG_CONF);
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if (status < 0) {
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dev_dbg(&client->dev, "Can't read config? %d\n", status);
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return status;
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}
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status = status | LM75_SHUTDOWN;
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lm75_write_value(client, LM75_REG_CONF, status);
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return 0;
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}
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static int lm75_resume(struct device *dev)
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{
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int status;
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struct i2c_client *client = to_i2c_client(dev);
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status = lm75_read_value(client, LM75_REG_CONF);
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if (status < 0) {
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dev_dbg(&client->dev, "Can't read config? %d\n", status);
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return status;
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}
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status = status & ~LM75_SHUTDOWN;
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lm75_write_value(client, LM75_REG_CONF, status);
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return 0;
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}
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static const struct dev_pm_ops lm75_dev_pm_ops = {
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.suspend = lm75_suspend,
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.resume = lm75_resume,
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};
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#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
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#else
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#define LM75_DEV_PM_OPS NULL
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#endif /* CONFIG_PM */
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static struct i2c_driver lm75_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "lm75",
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.pm = LM75_DEV_PM_OPS,
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},
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.probe = lm75_probe,
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.remove = lm75_remove,
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.id_table = lm75_ids,
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.detect = lm75_detect,
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.address_list = normal_i2c,
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};
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/*-----------------------------------------------------------------------*/
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/* register access */
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/*
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* All registers are word-sized, except for the configuration register.
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* LM75 uses a high-byte first convention, which is exactly opposite to
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* the SMBus standard.
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*/
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static int lm75_read_value(struct i2c_client *client, u8 reg)
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{
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if (reg == LM75_REG_CONF)
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return i2c_smbus_read_byte_data(client, reg);
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else
|
|
return i2c_smbus_read_word_swapped(client, reg);
|
|
}
|
|
|
|
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_swapped(client, reg, 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);
|
|
struct lm75_data *ret = data;
|
|
|
|
mutex_lock(&data->update_lock);
|
|
|
|
if (time_after(jiffies, data->last_updated + data->sample_time)
|
|
|| !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 (unlikely(status < 0)) {
|
|
dev_dbg(dev,
|
|
"LM75: Failed to read value: reg %d, error %d\n",
|
|
LM75_REG_TEMP[i], status);
|
|
ret = ERR_PTR(status);
|
|
data->valid = 0;
|
|
goto abort;
|
|
}
|
|
data->temp[i] = status;
|
|
}
|
|
data->last_updated = jiffies;
|
|
data->valid = 1;
|
|
}
|
|
|
|
abort:
|
|
mutex_unlock(&data->update_lock);
|
|
return ret;
|
|
}
|
|
|
|
module_i2c_driver(lm75_driver);
|
|
|
|
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
|
|
MODULE_DESCRIPTION("LM75 driver");
|
|
MODULE_LICENSE("GPL");
|