/*
* 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>
/*
* AD7314 power mode
*/
#define AD7314_PD 0x2000
/*
* AD7314 temperature masks
*/
#define AD7314_TEMP_SIGN 0x200
#define AD7314_TEMP_MASK 0x7FE0
#define AD7314_TEMP_OFFSET 5
/*
* ADT7301 and ADT7302 temperature masks
*/
#define ADT7301_TEMP_SIGN 0x2000
#define ADT7301_TEMP_MASK 0x3FFF
enum ad7314_variant {
adt7301,
adt7302,
ad7314,
};
struct ad7314_data {
struct spi_device *spi_dev;
struct device *hwmon_dev;
u16 rx ____cacheline_aligned;
};
static int ad7314_spi_read(struct ad7314_data *chip, s16 *data)
{
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;
}
*data = be16_to_cpu(chip->rx);
return ret;
}
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, &data);
if (ret < 0)
return ret;
switch (spi_get_device_id(chip->spi_dev)->driver_data) {
case ad7314:
data = (data & AD7314_TEMP_MASK) >> AD7314_TEMP_OFFSET;
data = (data << 6) >> 6;
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 &= ADT7301_TEMP_MASK;
data = (data << 2) >> 2;
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_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
NULL,
};
static const struct attribute_group ad7314_group = {
.attrs = ad7314_attributes,
};
static int __devinit ad7314_probe(struct spi_device *spi_dev)
{
int ret;
struct ad7314_data *chip;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (chip == NULL) {
ret = -ENOMEM;
goto error_ret;
}
dev_set_drvdata(&spi_dev->dev, chip);
ret = sysfs_create_group(&spi_dev->dev.kobj, &ad7314_group);
if (ret < 0)
goto error_free_chip;
chip->hwmon_dev = hwmon_device_register(&spi_dev->dev);
if (IS_ERR(chip->hwmon_dev)) {
ret = PTR_ERR(chip->hwmon_dev);
goto error_remove_group;
}
return 0;
error_remove_group:
sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
error_free_chip:
kfree(chip);
error_ret:
return ret;
}
static int __devexit ad7314_remove(struct spi_device *spi_dev)
{
struct ad7314_data *chip = dev_get_drvdata(&spi_dev->dev);
hwmon_device_unregister(chip->hwmon_dev);
sysfs_remove_group(&spi_dev->dev.kobj, &ad7314_group);
kfree(chip);
return 0;
}
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",
.owner = THIS_MODULE,
},
.probe = ad7314_probe,
.remove = __devexit_p(ad7314_remove),
.id_table = ad7314_id,
};
static __init int ad7314_init(void)
{
return spi_register_driver(&ad7314_driver);
}
module_init(ad7314_init);
static __exit void ad7314_exit(void)
{
spi_unregister_driver(&ad7314_driver);
}
module_exit(ad7314_exit);
MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7314, ADT7301 and ADT7302 digital"
" temperature sensor driver");
MODULE_LICENSE("GPL v2");
