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staging: iio: adc: new driver for AD7816 devices
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Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Sonic Zhang authored and Greg Kroah-Hartman committed Nov 9, 2010
1 parent 671d85f commit 7924425
Showing 3 changed files with 543 additions and 0 deletions.
7 changes: 7 additions & 0 deletions drivers/staging/iio/adc/Kconfig
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@@ -106,3 +106,10 @@ config AD7745

To compile this driver as a module, choose M here: the
module will be called ad7745.

config AD7816
tristate "Analog Devices AD7816/7/8 temperature sensor and ADC driver"
depends on SPI
help
Say yes here to build support for Analog Devices AD7816/7/8
temperature sensors and ADC.
1 change: 1 addition & 0 deletions drivers/staging/iio/adc/Makefile
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@@ -21,3 +21,4 @@ obj-$(CONFIG_AD7291) += ad7291.o
obj-$(CONFIG_AD7298) += ad7298.o
obj-$(CONFIG_AD7314) += ad7314.o
obj-$(CONFIG_AD7745) += ad7745.o
obj-$(CONFIG_AD7816) += ad7816.o
535 changes: 535 additions & 0 deletions drivers/staging/iio/adc/ad7816.c
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@@ -0,0 +1,535 @@
/*
* 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/workqueue.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/rtc.h>

#include "../iio.h"
#include "../sysfs.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 specifc information
*/

struct ad7816_chip_info {
const char *name;
struct spi_device *spi_dev;
struct iio_dev *indio_dev;
struct work_struct thresh_work;
s64 last_timestamp;
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;

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, (u8 *)data, sizeof(*data));
if (ret < 0) {
dev_err(&spi_dev->dev, "SPI data read error\n");
return ret;
}

*data = be16_to_cpu(*data);

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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;

if (chip->mode)
return sprintf(buf, "power-save\n");
else
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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;

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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;

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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;
unsigned long data;
int ret;

ret = strict_strtoul(buf, 10, &data);
if (ret)
return -EINVAL;

if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
data, chip->name);
return -EINVAL;
} else if (strcmp(chip->name, "ad7818") == 0 && data > 1) {
dev_err(&chip->spi_dev->dev,
"Invalid channel id %lu for ad7818.\n", data);
return -EINVAL;
} else if (strcmp(chip->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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;
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);
} else
return sprintf(buf, "%u\n", data);
}

static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);

static ssize_t ad7816_show_name(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;
return sprintf(buf, "%s\n", chip->name);
}

static IIO_DEVICE_ATTR(name, S_IRUGO, ad7816_show_name, 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,
&iio_dev_attr_name.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_BUFFER_EVENT_CODE(0)

static void ad7816_interrupt_bh(struct work_struct *work_s)
{
struct ad7816_chip_info *chip =
container_of(work_s, struct ad7816_chip_info, thresh_work);

enable_irq(chip->spi_dev->irq);

iio_push_event(chip->indio_dev, 0,
IIO_EVENT_CODE_AD7816_OTI,
chip->last_timestamp);
}

static int ad7816_interrupt(struct iio_dev *dev_info,
int index,
s64 timestamp,
int no_test)
{
struct ad7816_chip_info *chip = dev_info->dev_data;

chip->last_timestamp = timestamp;
schedule_work(&chip->thresh_work);

return 0;
}

IIO_EVENT_SH(ad7816, &ad7816_interrupt);

static ssize_t ad7816_show_oti(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;
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);
} else
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 *dev_info = dev_get_drvdata(dev);
struct ad7816_chip_info *chip = dev_info->dev_data;
long value;
u8 data;
int ret;

ret = strict_strtol(buf, 10, &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) {
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;
}

IIO_EVENT_ATTR_SH(oti, iio_event_ad7816,
ad7816_show_oti, ad7816_set_oti, 0);

static struct attribute *ad7816_event_attributes[] = {
&iio_event_attr_oti.dev_attr.attr,
NULL,
};

static struct attribute_group ad7816_event_attribute_group = {
.attrs = ad7816_event_attributes,
};

/*
* device probe and remove
*/

static int __devinit ad7816_probe(struct spi_device *spi_dev)
{
struct ad7816_chip_info *chip;
unsigned short *pins = spi_dev->dev.platform_data;
int ret = 0;
int i;

if (!pins) {
dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
return -EINVAL;
}

chip = kzalloc(sizeof(struct ad7816_chip_info), GFP_KERNEL);

if (chip == NULL)
return -ENOMEM;

/* this is only used for device removal purposes */
dev_set_drvdata(&spi_dev->dev, chip);

chip->spi_dev = spi_dev;
chip->name = spi_dev->modalias;
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 = gpio_request(chip->rdwr_pin, chip->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
chip->rdwr_pin);
goto error_free_chip;
}
gpio_direction_input(chip->rdwr_pin);
ret = gpio_request(chip->convert_pin, chip->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
chip->convert_pin);
goto error_free_gpio_rdwr;
}
gpio_direction_input(chip->convert_pin);
ret = gpio_request(chip->busy_pin, chip->name);
if (ret) {
dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
chip->busy_pin);
goto error_free_gpio_convert;
}
gpio_direction_input(chip->busy_pin);

chip->indio_dev = iio_allocate_device();
if (chip->indio_dev == NULL) {
ret = -ENOMEM;
goto error_free_gpio;
}

chip->indio_dev->dev.parent = &spi_dev->dev;
chip->indio_dev->attrs = &ad7816_attribute_group;
chip->indio_dev->event_attrs = &ad7816_event_attribute_group;
chip->indio_dev->dev_data = (void *)chip;
chip->indio_dev->driver_module = THIS_MODULE;
chip->indio_dev->num_interrupt_lines = 1;
chip->indio_dev->modes = INDIO_DIRECT_MODE;

ret = iio_device_register(chip->indio_dev);
if (ret)
goto error_free_dev;

if (spi_dev->irq) {
/* Only low trigger is supported in ad7816/7/8 */
ret = iio_register_interrupt_line(spi_dev->irq,
chip->indio_dev,
0,
IRQF_TRIGGER_LOW,
chip->name);
if (ret)
goto error_unreg_dev;

/*
* The event handler list element refer to iio_event_ad7816.
* All event attributes bind to the same event handler.
* So, only register event handler once.
*/
iio_add_event_to_list(&iio_event_ad7816,
&chip->indio_dev->interrupts[0]->ev_list);

INIT_WORK(&chip->thresh_work, ad7816_interrupt_bh);
}

dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
chip->name);

return 0;

error_unreg_dev:
iio_device_unregister(chip->indio_dev);
error_free_dev:
iio_free_device(chip->indio_dev);
error_free_gpio:
gpio_free(chip->busy_pin);
error_free_gpio_convert:
gpio_free(chip->convert_pin);
error_free_gpio_rdwr:
gpio_free(chip->rdwr_pin);
error_free_chip:
kfree(chip);

return ret;
}

static int __devexit ad7816_remove(struct spi_device *spi_dev)
{
struct ad7816_chip_info *chip = dev_get_drvdata(&spi_dev->dev);
struct iio_dev *indio_dev = chip->indio_dev;

dev_set_drvdata(&spi_dev->dev, NULL);
if (spi_dev->irq)
iio_unregister_interrupt_line(indio_dev, 0);
iio_device_unregister(indio_dev);
iio_free_device(chip->indio_dev);
gpio_free(chip->busy_pin);
gpio_free(chip->convert_pin);
gpio_free(chip->rdwr_pin);
kfree(chip);

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",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = ad7816_probe,
.remove = __devexit_p(ad7816_remove),
.id_table = ad7816_id,
};

static __init int ad7816_init(void)
{
return spi_register_driver(&ad7816_driver);
}

static __exit void ad7816_exit(void)
{
spi_unregister_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");

module_init(ad7816_init);
module_exit(ad7816_exit);

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