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/*
* AD7314 digital temperature sensor driver for AD7314, ADT7301 and ADT7302
*
* Copyright 2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*
* Conversion to hwmon from IIO done by Jonathan Cameron <jic23@cam.ac.uk>
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/bitops.h>
/*
* AD7314 temperature masks
*/
#define AD7314_TEMP_MASK 0x7FE0
#define AD7314_TEMP_SHIFT 5
/*
* ADT7301 and ADT7302 temperature masks
*/
#define ADT7301_TEMP_MASK 0x3FFF
enum ad7314_variant {
adt7301,
adt7302,
ad7314,
};
struct ad7314_data {
struct spi_device *spi_dev;
u16 rx ____cacheline_aligned;
};
static int ad7314_spi_read(struct ad7314_data *chip)
{
int ret;
ret = spi_read(chip->spi_dev, (u8 *)&chip->rx, sizeof(chip->rx));
if (ret < 0) {
dev_err(&chip->spi_dev->dev, "SPI read error\n");
return ret;
}
return be16_to_cpu(chip->rx);
}
static ssize_t ad7314_show_temperature(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct ad7314_data *chip = dev_get_drvdata(dev);
s16 data;
int ret;
ret = ad7314_spi_read(chip);
if (ret < 0)
return ret;
switch (spi_get_device_id(chip->spi_dev)->driver_data) {
case ad7314:
data = (ret & AD7314_TEMP_MASK) >> AD7314_TEMP_SHIFT;
data = sign_extend32(data, 9);
return sprintf(buf, "%d\n", 250 * data);
case adt7301:
case adt7302:
/*
* Documented as a 13 bit twos complement register
* with a sign bit - which is a 14 bit 2's complement
* register. 1lsb - 31.25 milli degrees centigrade
*/
data = ret & ADT7301_TEMP_MASK;
data = sign_extend32(data, 13);
return sprintf(buf, "%d\n",
DIV_ROUND_CLOSEST(data * 3125, 100));
default:
return -EINVAL;
}
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
ad7314_show_temperature, NULL, 0);
static struct attribute *ad7314_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ad7314);
static int ad7314_probe(struct spi_device *spi_dev)
{
struct ad7314_data *chip;
struct device *hwmon_dev;
chip = devm_kzalloc(&spi_dev->dev, sizeof(*chip), GFP_KERNEL);
if (chip == NULL)
return -ENOMEM;
chip->spi_dev = spi_dev;
hwmon_dev = devm_hwmon_device_register_with_groups(&spi_dev->dev,
spi_dev->modalias,
chip, ad7314_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct spi_device_id ad7314_id[] = {
{ "adt7301", adt7301 },
{ "adt7302", adt7302 },
{ "ad7314", ad7314 },
{ }
};
MODULE_DEVICE_TABLE(spi, ad7314_id);
static struct spi_driver ad7314_driver = {
.driver = {
.name = "ad7314",
},
.probe = ad7314_probe,
.id_table = ad7314_id,
};
module_spi_driver(ad7314_driver);
MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital temperature sensor driver");
MODULE_LICENSE("GPL v2");
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