ad7816.c
/*
* AD7816 digital temperature sensor driver supporting AD7816/7/8
*
* Copyright 2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
/*
* AD7816 config masks
*/
#define AD7816_FULL 0x1
#define AD7816_PD 0x2
#define AD7816_CS_MASK 0x7
#define AD7816_CS_MAX 0x4
/*
* AD7816 temperature masks
*/
#define AD7816_VALUE_OFFSET 6
#define AD7816_BOUND_VALUE_BASE 0x8
#define AD7816_BOUND_VALUE_MIN -95
#define AD7816_BOUND_VALUE_MAX 152
#define AD7816_TEMP_FLOAT_OFFSET 2
#define AD7816_TEMP_FLOAT_MASK 0x3
/*
* struct ad7816_chip_info - chip specific information
*/
struct ad7816_chip_info {
struct spi_device *spi_dev;
u16 rdwr_pin;
u16 convert_pin;
u16 busy_pin;
u8 oti_data[AD7816_CS_MAX + 1];
u8 channel_id; /* 0 always be temperature */
u8 mode;
};
/*
* ad7816 data access by SPI
*/
static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
{
struct spi_device *spi_dev = chip->spi_dev;
int ret = 0;
__be16 buf;
gpio_set_value(chip->rdwr_pin, 1);
gpio_set_value(chip->rdwr_pin, 0);
ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
if (ret < 0) {
dev_err(&spi_dev->dev, "SPI channel setting error\n");
return ret;
}
gpio_set_value(chip->rdwr_pin, 1);
if (chip->mode == AD7816_PD) { /* operating mode 2 */
gpio_set_value(chip->convert_pin, 1);
gpio_set_value(chip->convert_pin, 0);
} else { /* operating mode 1 */
gpio_set_value(chip->convert_pin, 0);
gpio_set_value(chip->convert_pin, 1);
}
while (gpio_get_value(chip->busy_pin))
cpu_relax();
gpio_set_value(chip->rdwr_pin, 0);
gpio_set_value(chip->rdwr_pin, 1);
ret = spi_read(spi_dev, &buf, sizeof(*data));
if (ret < 0) {
dev_err(&spi_dev->dev, "SPI data read error\n");
return ret;
}
*data = be16_to_cpu(buf);
return ret;
}
static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
{
struct spi_device *spi_dev = chip->spi_dev;
int ret = 0;
gpio_set_value(chip->rdwr_pin, 1);
gpio_set_value(chip->rdwr_pin, 0);
ret = spi_write(spi_dev, &data, sizeof(data));
if (ret < 0)
dev_err(&spi_dev->dev, "SPI oti data write error\n");
return ret;
}
static ssize_t ad7816_show_mode(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
if (chip->mode)
return sprintf(buf, "power-save\n");
return sprintf(buf, "full\n");
}
static ssize_t ad7816_store_mode(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
if (strcmp(buf, "full")) {
gpio_set_value(chip->rdwr_pin, 1);
chip->mode = AD7816_FULL;
} else {
gpio_set_value(chip->rdwr_pin, 0);
chip->mode = AD7816_PD;
}
return len;
}
static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
ad7816_show_mode,
ad7816_store_mode,
0);
static ssize_t ad7816_show_available_modes(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "full\npower-save\n");
}
static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes,
NULL, 0);
static ssize_t ad7816_show_channel(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
return sprintf(buf, "%d\n", chip->channel_id);
}
static ssize_t ad7816_store_channel(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
unsigned long data;
int ret;
ret = kstrtoul(buf, 10, &data);
if (ret)
return ret;
if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
data, indio_dev->name);
return -EINVAL;
} else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
dev_err(&chip->spi_dev->dev,
"Invalid channel id %lu for ad7818.\n", data);
return -EINVAL;
} else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
dev_err(&chip->spi_dev->dev,
"Invalid channel id %lu for ad7816.\n", data);
return -EINVAL;
}
chip->channel_id = data;
return len;
}
static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
ad7816_show_channel,
ad7816_store_channel,
0);
static ssize_t ad7816_show_value(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
u16 data;
s8 value;
int ret;
ret = ad7816_spi_read(chip, &data);
if (ret)
return -EIO;
data >>= AD7816_VALUE_OFFSET;
if (chip->channel_id == 0) {
value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
data &= AD7816_TEMP_FLOAT_MASK;
if (value < 0)
data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
return sprintf(buf, "%d.%.2d\n", value, data * 25);
}
return sprintf(buf, "%u\n", data);
}
static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
static struct attribute *ad7816_attributes[] = {
&iio_dev_attr_available_modes.dev_attr.attr,
&iio_dev_attr_mode.dev_attr.attr,
&iio_dev_attr_channel.dev_attr.attr,
&iio_dev_attr_value.dev_attr.attr,
NULL,
};
static const struct attribute_group ad7816_attribute_group = {
.attrs = ad7816_attributes,
};
/*
* temperature bound events
*/
#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
0, \
IIO_EV_TYPE_THRESH, \
IIO_EV_DIR_FALLING)
static irqreturn_t ad7816_event_handler(int irq, void *private)
{
iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns());
return IRQ_HANDLED;
}
static ssize_t ad7816_show_oti(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
int value;
if (chip->channel_id > AD7816_CS_MAX) {
dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
return -EINVAL;
} else if (chip->channel_id == 0) {
value = AD7816_BOUND_VALUE_MIN +
(chip->oti_data[chip->channel_id] -
AD7816_BOUND_VALUE_BASE);
return sprintf(buf, "%d\n", value);
}
return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
}
static inline ssize_t ad7816_set_oti(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7816_chip_info *chip = iio_priv(indio_dev);
long value;
u8 data;
int ret;
ret = kstrtol(buf, 10, &value);
if (ret)
return ret;
if (chip->channel_id > AD7816_CS_MAX) {
dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
return -EINVAL;
} else if (chip->channel_id == 0) {
if (ret || value < AD7816_BOUND_VALUE_MIN ||
value > AD7816_BOUND_VALUE_MAX)
return -EINVAL;
data = (u8)(value - AD7816_BOUND_VALUE_MIN +
AD7816_BOUND_VALUE_BASE);
} else {
if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
return -EINVAL;
data = (u8)value;
}
ret = ad7816_spi_write(chip, data);
if (ret)
return -EIO;
chip->oti_data[chip->channel_id] = data;
return len;
}
static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
ad7816_show_oti, ad7816_set_oti, 0);
static struct attribute *ad7816_event_attributes[] = {
&iio_dev_attr_oti.dev_attr.attr,
NULL,
};
static struct attribute_group ad7816_event_attribute_group = {
.attrs = ad7816_event_attributes,
.name = "events",
};
static const struct iio_info ad7816_info = {
.attrs = &ad7816_attribute_group,
.event_attrs = &ad7816_event_attribute_group,
.driver_module = THIS_MODULE,
};
/*
* device probe and remove
*/
static int ad7816_probe(struct spi_device *spi_dev)
{
struct ad7816_chip_info *chip;
struct iio_dev *indio_dev;
unsigned short *pins = dev_get_platdata(&spi_dev->dev);
int ret = 0;
int i;
if (!pins) {
dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
return -EINVAL;
}
indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
if (!indio_dev)
return -ENOMEM;
chip = iio_priv(indio_dev);
/* this is only used for device removal purposes */
dev_set_drvdata(&spi_dev->dev, indio_dev);
chip->spi_dev = spi_dev;
for (i = 0; i <= AD7816_CS_MAX; i++)
chip->oti_data[i] = 203;
chip->rdwr_pin = pins[0];
chip->convert_pin = pins[1];
chip->busy_pin = pins[2];
ret = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin,
spi_get_device_id(spi_dev)->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
chip->rdwr_pin);
return ret;
}
gpio_direction_input(chip->rdwr_pin);
ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin,
spi_get_device_id(spi_dev)->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
chip->convert_pin);
return ret;
}
gpio_direction_input(chip->convert_pin);
ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin,
spi_get_device_id(spi_dev)->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
chip->busy_pin);
return ret;
}
gpio_direction_input(chip->busy_pin);
indio_dev->name = spi_get_device_id(spi_dev)->name;
indio_dev->dev.parent = &spi_dev->dev;
indio_dev->info = &ad7816_info;
indio_dev->modes = INDIO_DIRECT_MODE;
if (spi_dev->irq) {
/* Only low trigger is supported in ad7816/7/8 */
ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
NULL,
&ad7816_event_handler,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
indio_dev->name,
indio_dev);
if (ret)
return ret;
}
ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
if (ret)
return ret;
dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
indio_dev->name);
return 0;
}
static const struct spi_device_id ad7816_id[] = {
{ "ad7816", 0 },
{ "ad7817", 0 },
{ "ad7818", 0 },
{}
};
MODULE_DEVICE_TABLE(spi, ad7816_id);
static struct spi_driver ad7816_driver = {
.driver = {
.name = "ad7816",
},
.probe = ad7816_probe,
.id_table = ad7816_id,
};
module_spi_driver(ad7816_driver);
MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
MODULE_LICENSE("GPL v2");
