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/*
* max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI
* digital thermometer and thermostats.
*
* Copyright (c) 2016, Intel Corporation.
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*/
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
#define MAX31722_REG_CFG 0x00
#define MAX31722_REG_TEMP_LSB 0x01
#define MAX31722_MODE_CONTINUOUS 0x00
#define MAX31722_MODE_STANDBY 0x01
#define MAX31722_MODE_MASK 0xFE
#define MAX31722_RESOLUTION_12BIT 0x06
#define MAX31722_WRITE_MASK 0x80
struct max31722_data {
struct device *hwmon_dev;
struct spi_device *spi_device;
u8 mode;
};
static int max31722_set_mode(struct max31722_data *data, u8 mode)
{
int ret;
struct spi_device *spi = data->spi_device;
u8 buf[2] = {
MAX31722_REG_CFG | MAX31722_WRITE_MASK,
(data->mode & MAX31722_MODE_MASK) | mode
};
ret = spi_write(spi, &buf, sizeof(buf));
if (ret < 0) {
dev_err(&spi->dev, "failed to set sensor mode.\n");
return ret;
}
data->mode = (data->mode & MAX31722_MODE_MASK) | mode;
return 0;
}
static ssize_t max31722_show_temp(struct device *dev,
struct device_attribute *attr,
char *buf)
{
ssize_t ret;
struct max31722_data *data = dev_get_drvdata(dev);
ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);
if (ret < 0)
return ret;
/* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */
return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
max31722_show_temp, NULL, 0);
static struct attribute *max31722_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(max31722);
static int max31722_probe(struct spi_device *spi)
{
int ret;
struct max31722_data *data;
data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
spi_set_drvdata(spi, data);
data->spi_device = spi;
/*
* Set SD bit to 0 so we can have continuous measurements.
* Set resolution to 12 bits for maximum precision.
*/
data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;
ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
if (ret < 0)
return ret;
data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,
spi->modalias,
data,
max31722_groups);
if (IS_ERR(data->hwmon_dev)) {
max31722_set_mode(data, MAX31722_MODE_STANDBY);
return PTR_ERR(data->hwmon_dev);
}
return 0;
}
static int max31722_remove(struct spi_device *spi)
{
struct max31722_data *data = spi_get_drvdata(spi);
hwmon_device_unregister(data->hwmon_dev);
return max31722_set_mode(data, MAX31722_MODE_STANDBY);
}
static int __maybe_unused max31722_suspend(struct device *dev)
{
struct spi_device *spi_device = to_spi_device(dev);
struct max31722_data *data = spi_get_drvdata(spi_device);
return max31722_set_mode(data, MAX31722_MODE_STANDBY);
}
static int __maybe_unused max31722_resume(struct device *dev)
{
struct spi_device *spi_device = to_spi_device(dev);
struct max31722_data *data = spi_get_drvdata(spi_device);
return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
}
static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);
static const struct spi_device_id max31722_spi_id[] = {
{"max31722", 0},
{"max31723", 0},
{}
};
MODULE_DEVICE_TABLE(spi, max31722_spi_id);
static struct spi_driver max31722_driver = {
.driver = {
.name = "max31722",
.pm = &max31722_pm_ops,
},
.probe = max31722_probe,
.remove = max31722_remove,
.id_table = max31722_spi_id,
};
module_spi_driver(max31722_driver);
MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
MODULE_DESCRIPTION("max31722 sensor driver");
MODULE_LICENSE("GPL v2");
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