259 lines
6.4 KiB
C
259 lines
6.4 KiB
C
/*
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* g760a - Driver for the Global Mixed-mode Technology Inc. G760A
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* fan speed PWM controller chip
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*
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* Copyright (C) 2007 Herbert Valerio Riedel <hvr@gnu.org>
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*
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* Complete datasheet is available at GMT's website:
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* http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf
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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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#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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static const struct i2c_device_id g760a_id[] = {
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{ "g760a", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, g760a_id);
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enum g760a_regs {
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G760A_REG_SET_CNT = 0x00,
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G760A_REG_ACT_CNT = 0x01,
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G760A_REG_FAN_STA = 0x02
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};
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#define G760A_REG_FAN_STA_RPM_OFF 0x1 /* +/-20% off */
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#define G760A_REG_FAN_STA_RPM_LOW 0x2 /* below 1920rpm */
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/* register data is read (and cached) at most once per second */
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#define G760A_UPDATE_INTERVAL (HZ)
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struct g760a_data {
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struct i2c_client *client;
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struct device *hwmon_dev;
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struct mutex update_lock;
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/* board specific parameters */
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u32 clk; /* default 32kHz */
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u16 fan_div; /* default P=2 */
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/* g760a register cache */
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unsigned int valid:1;
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unsigned long last_updated; /* In jiffies */
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u8 set_cnt; /* PWM (period) count number; 0xff stops fan */
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u8 act_cnt; /* formula: cnt = (CLK * 30)/(rpm * P) */
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u8 fan_sta; /* bit 0: set when actual fan speed more than 20%
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* outside requested fan speed
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* bit 1: set when fan speed below 1920 rpm
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*/
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};
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#define G760A_DEFAULT_CLK 32768
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#define G760A_DEFAULT_FAN_DIV 2
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#define PWM_FROM_CNT(cnt) (0xff-(cnt))
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#define PWM_TO_CNT(pwm) (0xff-(pwm))
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static inline unsigned int rpm_from_cnt(u8 val, u32 clk, u16 div)
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{
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return ((val == 0x00) ? 0 : ((clk*30)/(val*div)));
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}
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/* new-style driver model */
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static int g760a_probe(struct i2c_client *client,
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const struct i2c_device_id *id);
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static int g760a_remove(struct i2c_client *client);
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static struct i2c_driver g760a_driver = {
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.driver = {
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.name = "g760a",
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},
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.probe = g760a_probe,
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.remove = g760a_remove,
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.id_table = g760a_id,
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};
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/* read/write wrappers */
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static int g760a_read_value(struct i2c_client *client, enum g760a_regs reg)
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{
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return i2c_smbus_read_byte_data(client, reg);
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}
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static int g760a_write_value(struct i2c_client *client, enum g760a_regs reg,
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u16 value)
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{
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return i2c_smbus_write_byte_data(client, reg, value);
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}
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/*
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* sysfs attributes
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*/
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static struct g760a_data *g760a_update_client(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct g760a_data *data = i2c_get_clientdata(client);
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + G760A_UPDATE_INTERVAL)
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|| !data->valid) {
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dev_dbg(&client->dev, "Starting g760a update\n");
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data->set_cnt = g760a_read_value(client, G760A_REG_SET_CNT);
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data->act_cnt = g760a_read_value(client, G760A_REG_ACT_CNT);
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data->fan_sta = g760a_read_value(client, G760A_REG_FAN_STA);
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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_fan(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct g760a_data *data = g760a_update_client(dev);
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unsigned int rpm = 0;
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mutex_lock(&data->update_lock);
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if (!(data->fan_sta & G760A_REG_FAN_STA_RPM_LOW))
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rpm = rpm_from_cnt(data->act_cnt, data->clk, data->fan_div);
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mutex_unlock(&data->update_lock);
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return sprintf(buf, "%d\n", rpm);
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}
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static ssize_t show_fan_alarm(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct g760a_data *data = g760a_update_client(dev);
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int fan_alarm = (data->fan_sta & G760A_REG_FAN_STA_RPM_OFF) ? 1 : 0;
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return sprintf(buf, "%d\n", fan_alarm);
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}
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static ssize_t get_pwm(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct g760a_data *data = g760a_update_client(dev);
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return sprintf(buf, "%d\n", PWM_FROM_CNT(data->set_cnt));
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}
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static ssize_t set_pwm(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 i2c_client *client = to_i2c_client(dev);
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struct g760a_data *data = g760a_update_client(dev);
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unsigned long val;
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if (kstrtoul(buf, 10, &val))
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return -EINVAL;
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mutex_lock(&data->update_lock);
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data->set_cnt = PWM_TO_CNT(SENSORS_LIMIT(val, 0, 255));
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g760a_write_value(client, G760A_REG_SET_CNT, data->set_cnt);
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mutex_unlock(&data->update_lock);
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return count;
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}
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static DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm);
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static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
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static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
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static struct attribute *g760a_attributes[] = {
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&dev_attr_pwm1.attr,
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&dev_attr_fan1_input.attr,
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&dev_attr_fan1_alarm.attr,
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NULL
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};
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static const struct attribute_group g760a_group = {
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.attrs = g760a_attributes,
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};
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/*
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* new-style driver model code
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*/
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static int g760a_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct g760a_data *data;
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int err;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_BYTE_DATA))
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return -EIO;
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data = kzalloc(sizeof(struct g760a_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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data->client = client;
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mutex_init(&data->update_lock);
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/* setup default configuration for now */
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data->fan_div = G760A_DEFAULT_FAN_DIV;
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data->clk = G760A_DEFAULT_CLK;
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/* Register sysfs hooks */
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err = sysfs_create_group(&client->dev.kobj, &g760a_group);
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if (err)
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goto error_sysfs_create_group;
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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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goto error_hwmon_device_register;
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}
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return 0;
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error_hwmon_device_register:
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sysfs_remove_group(&client->dev.kobj, &g760a_group);
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error_sysfs_create_group:
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kfree(data);
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return err;
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}
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static int g760a_remove(struct i2c_client *client)
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{
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struct g760a_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, &g760a_group);
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kfree(data);
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return 0;
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}
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module_i2c_driver(g760a_driver);
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MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
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MODULE_DESCRIPTION("GMT G760A driver");
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MODULE_LICENSE("GPL");
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