Commit 761c1770 authored by Maciej S. Szmigiero's avatar Maciej S. Szmigiero Committed by Guenter Roeck
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hwmon: add driver for Microchip TC74



Add hwmon driver for the Microchip TC74.

The TC74 is a single-input 8-bit I2C temperature sensor,
with +-2 degrees centigrade accuracy.
Signed-off-by: default avatarMaciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent f6725ae2
Kernel driver tc74
====================
Supported chips:
* Microchip TC74
Prefix: 'tc74'
Datasheet: Publicly available at Microchip website.
Description
-----------
Driver supports the above part.
The tc74 has an 8-bit sensor, with 1 degree centigrade resolution
and +- 2 degrees centigrade accuracy.
Notes
-----
Currently entering low power standby mode is not supported.
......@@ -1452,6 +1452,16 @@ config SENSORS_INA2XX
This driver can also be built as a module. If so, the module
will be called ina2xx.
config SENSORS_TC74
tristate "Microchip TC74"
depends on I2C
help
If you say yes here you get support for Microchip TC74 single
input temperature sensor chips.
This driver can also be built as a module. If so, the module
will be called tc74.
config SENSORS_THMC50
tristate "Texas Instruments THMC50 / Analog Devices ADM1022"
depends on I2C
......
......@@ -140,6 +140,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
obj-$(CONFIG_SENSORS_TC74) += tc74.o
obj-$(CONFIG_SENSORS_THMC50) += thmc50.o
obj-$(CONFIG_SENSORS_TMP102) += tmp102.o
obj-$(CONFIG_SENSORS_TMP103) += tmp103.o
......
/*
* An hwmon driver for the Microchip TC74
*
* Copyright 2015 Maciej Szmigiero <mail@maciej.szmigiero.name>
*
* Based on ad7414.c:
* Copyright 2006 Stefan Roese, DENX Software Engineering
* Copyright 2008 Sean MacLennan, PIKA Technologies
* Copyright 2008 Frank Edelhaeuser, Spansion Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/i2c.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
/* TC74 registers */
#define TC74_REG_TEMP 0x00
#define TC74_REG_CONFIG 0x01
struct tc74_data {
struct i2c_client *client;
struct mutex lock; /* atomic read data updates */
bool valid; /* validity of fields below */
unsigned long next_update; /* In jiffies */
s8 temp_input; /* Temp value in dC */
};
static int tc74_update_device(struct device *dev)
{
struct tc74_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int ret;
ret = mutex_lock_interruptible(&data->lock);
if (ret)
return ret;
if (time_after(jiffies, data->next_update) || !data->valid) {
s32 value;
value = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG);
if (value < 0) {
dev_dbg(&client->dev, "TC74_REG_CONFIG read err %d\n",
(int)value);
ret = value;
goto ret_unlock;
}
if (!(value & BIT(6))) {
/* not ready yet */
ret = -EAGAIN;
goto ret_unlock;
}
value = i2c_smbus_read_byte_data(client, TC74_REG_TEMP);
if (value < 0) {
dev_dbg(&client->dev, "TC74_REG_TEMP read err %d\n",
(int)value);
ret = value;
goto ret_unlock;
}
data->temp_input = value;
data->next_update = jiffies + HZ / 4;
data->valid = true;
}
ret_unlock:
mutex_unlock(&data->lock);
return ret;
}
static ssize_t show_temp_input(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct tc74_data *data = dev_get_drvdata(dev);
int ret;
ret = tc74_update_device(dev);
if (ret)
return ret;
return sprintf(buf, "%d\n", data->temp_input * 1000);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
static struct attribute *tc74_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(tc74);
static int tc74_probe(struct i2c_client *client,
const struct i2c_device_id *dev_id)
{
struct device *dev = &client->dev;
struct tc74_data *data;
struct device *hwmon_dev;
s32 conf;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -EOPNOTSUPP;
data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->lock);
/* Make sure the chip is powered up. */
conf = i2c_smbus_read_byte_data(client, TC74_REG_CONFIG);
if (conf < 0) {
dev_err(dev, "unable to read config register\n");
return conf;
}
if (conf & 0x3f) {
dev_err(dev, "invalid config register value\n");
return -ENODEV;
}
if (conf & BIT(7)) {
s32 ret;
conf &= ~BIT(7);
ret = i2c_smbus_write_byte_data(client, TC74_REG_CONFIG, conf);
if (ret)
dev_warn(dev, "unable to disable STANDBY\n");
}
hwmon_dev = devm_hwmon_device_register_with_groups(dev,
client->name,
data, tc74_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id tc74_id[] = {
{ "tc74", 0 },
{}
};
MODULE_DEVICE_TABLE(i2c, tc74_id);
static struct i2c_driver tc74_driver = {
.driver = {
.name = "tc74",
},
.probe = tc74_probe,
.id_table = tc74_id,
};
module_i2c_driver(tc74_driver);
MODULE_AUTHOR("Maciej Szmigiero <mail@maciej.szmigiero.name>");
MODULE_DESCRIPTION("TC74 driver");
MODULE_LICENSE("GPL");
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