315 lines
8.2 KiB
C
315 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
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* with Overtemperature Alarm
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*
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* Copyright (C) 2011 AppearTV AS
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*
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* Derived from:
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*
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* Based on the max1619 driver.
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* Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
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* Jean Delvare <jdelvare@suse.de>
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*
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* The MAX6642 is a sensor chip made by Maxim.
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* It reports up to two temperatures (its own plus up to
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* one external one). Complete datasheet can be
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* obtained from Maxim's website at:
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* http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
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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 unsigned short normal_i2c[] = {
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0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
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/*
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* The MAX6642 registers
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*/
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#define MAX6642_REG_R_MAN_ID 0xFE
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#define MAX6642_REG_R_CONFIG 0x03
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#define MAX6642_REG_W_CONFIG 0x09
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#define MAX6642_REG_R_STATUS 0x02
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#define MAX6642_REG_R_LOCAL_TEMP 0x00
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#define MAX6642_REG_R_LOCAL_TEMPL 0x11
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#define MAX6642_REG_R_LOCAL_HIGH 0x05
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#define MAX6642_REG_W_LOCAL_HIGH 0x0B
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#define MAX6642_REG_R_REMOTE_TEMP 0x01
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#define MAX6642_REG_R_REMOTE_TEMPL 0x10
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#define MAX6642_REG_R_REMOTE_HIGH 0x07
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#define MAX6642_REG_W_REMOTE_HIGH 0x0D
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/*
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* Conversions
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*/
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static int temp_from_reg10(int val)
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{
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return val * 250;
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}
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static int temp_from_reg(int val)
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{
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return val * 1000;
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}
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static int temp_to_reg(int val)
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{
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return val / 1000;
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}
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/*
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* Client data (each client gets its own)
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*/
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struct max6642_data {
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struct i2c_client *client;
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struct mutex update_lock;
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bool valid; /* zero until following fields are valid */
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unsigned long last_updated; /* in jiffies */
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/* registers values */
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u16 temp_input[2]; /* local/remote */
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u16 temp_high[2]; /* local/remote */
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u8 alarms;
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};
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/*
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* Real code
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*/
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static void max6642_init_client(struct max6642_data *data,
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struct i2c_client *client)
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{
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u8 config;
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/*
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* Start the conversions.
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*/
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config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
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if (config & 0x40)
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i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
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config & 0xBF); /* run */
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data->temp_high[0] = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_LOCAL_HIGH);
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data->temp_high[1] = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_REMOTE_HIGH);
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}
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/* Return 0 if detection is successful, -ENODEV otherwise */
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static int max6642_detect(struct i2c_client *client,
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struct i2c_board_info *info)
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{
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struct i2c_adapter *adapter = client->adapter;
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u8 reg_config, reg_status, man_id;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
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return -ENODEV;
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/* identification */
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man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
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if (man_id != 0x4D)
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return -ENODEV;
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/* sanity check */
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if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
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|| i2c_smbus_read_byte_data(client, 0x06) != 0x4D
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|| i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
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return -ENODEV;
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/*
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* We read the config and status register, the 4 lower bits in the
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* config register should be zero and bit 5, 3, 1 and 0 should be
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* zero in the status register.
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*/
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reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
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if ((reg_config & 0x0f) != 0x00)
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return -ENODEV;
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/* in between, another round of sanity checks */
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if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
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|| i2c_smbus_read_byte_data(client, 0x06) != reg_config
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|| i2c_smbus_read_byte_data(client, 0xff) != reg_config)
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return -ENODEV;
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reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
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if ((reg_status & 0x2b) != 0x00)
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return -ENODEV;
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strscpy(info->type, "max6642", I2C_NAME_SIZE);
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return 0;
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}
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static struct max6642_data *max6642_update_device(struct device *dev)
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{
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struct max6642_data *data = dev_get_drvdata(dev);
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struct i2c_client *client = data->client;
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u16 val, tmp;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
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dev_dbg(dev, "Updating max6642 data.\n");
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val = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_LOCAL_TEMPL);
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tmp = (val >> 6) & 3;
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val = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_LOCAL_TEMP);
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val = (val << 2) | tmp;
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data->temp_input[0] = val;
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val = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_REMOTE_TEMPL);
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tmp = (val >> 6) & 3;
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val = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_REMOTE_TEMP);
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val = (val << 2) | tmp;
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data->temp_input[1] = val;
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data->alarms = i2c_smbus_read_byte_data(client,
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MAX6642_REG_R_STATUS);
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data->last_updated = jiffies;
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data->valid = true;
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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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/*
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* Sysfs stuff
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*/
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static ssize_t temp_max10_show(struct device *dev,
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struct device_attribute *dev_attr, char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
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struct max6642_data *data = max6642_update_device(dev);
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return sprintf(buf, "%d\n",
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temp_from_reg10(data->temp_input[attr->index]));
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}
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static ssize_t temp_max_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
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struct max6642_data *data = max6642_update_device(dev);
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return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
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}
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static ssize_t temp_max_store(struct device *dev,
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struct device_attribute *attr, const char *buf,
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size_t count)
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{
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struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
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struct max6642_data *data = dev_get_drvdata(dev);
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unsigned long val;
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int err;
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err = kstrtoul(buf, 10, &val);
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if (err < 0)
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return err;
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mutex_lock(&data->update_lock);
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data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
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i2c_smbus_write_byte_data(data->client, attr2->index,
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data->temp_high[attr2->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 ssize_t alarm_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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int bitnr = to_sensor_dev_attr(attr)->index;
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struct max6642_data *data = max6642_update_device(dev);
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return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
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}
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static SENSOR_DEVICE_ATTR_RO(temp1_input, temp_max10, 0);
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static SENSOR_DEVICE_ATTR_RO(temp2_input, temp_max10, 1);
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static SENSOR_DEVICE_ATTR_2_RW(temp1_max, temp_max, 0,
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MAX6642_REG_W_LOCAL_HIGH);
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static SENSOR_DEVICE_ATTR_2_RW(temp2_max, temp_max, 1,
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MAX6642_REG_W_REMOTE_HIGH);
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static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 2);
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static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6);
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static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 4);
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static struct attribute *max6642_attrs[] = {
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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_temp1_max.dev_attr.attr,
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&sensor_dev_attr_temp2_max.dev_attr.attr,
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&sensor_dev_attr_temp2_fault.dev_attr.attr,
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&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
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&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
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NULL
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};
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ATTRIBUTE_GROUPS(max6642);
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static int max6642_probe(struct i2c_client *client)
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{
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struct device *dev = &client->dev;
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struct max6642_data *data;
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struct device *hwmon_dev;
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data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->client = client;
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mutex_init(&data->update_lock);
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/* Initialize the MAX6642 chip */
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max6642_init_client(data, client);
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hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
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client->name, data,
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max6642_groups);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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/*
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* Driver data (common to all clients)
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*/
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static const struct i2c_device_id max6642_id[] = {
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{ "max6642" },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, max6642_id);
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static struct i2c_driver max6642_driver = {
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.class = I2C_CLASS_HWMON,
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.driver = {
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.name = "max6642",
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},
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.probe = max6642_probe,
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.id_table = max6642_id,
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.detect = max6642_detect,
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.address_list = normal_i2c,
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};
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module_i2c_driver(max6642_driver);
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MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
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MODULE_DESCRIPTION("MAX6642 sensor driver");
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MODULE_LICENSE("GPL");
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