drivers/staging/iio/adc/ad7745.c - nest-cam/v179/linux - Git at Google

 /*
  * AD774X capacitive sensor driver supporting AD7745/6/7
  *
  * 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/i2c.h>
 #include <linux/rtc.h>

 #include "../iio.h"
 #include "../sysfs.h"

 /*
  * AD774X registers definition
  */

 #define AD774X_STATUS		0
 #define AD774X_STATUS_RDY	(1 << 2)
 #define AD774X_STATUS_RDYVT	(1 << 1)
 #define AD774X_STATUS_RDYCAP	(1 << 0)
 #define AD774X_CAP_DATA_HIGH	1
 #define AD774X_CAP_DATA_MID	2
 #define AD774X_CAP_DATA_LOW	3
 #define AD774X_VT_DATA_HIGH	4
 #define AD774X_VT_DATA_MID	5
 #define AD774X_VT_DATA_LOW	6
 #define AD774X_CAP_SETUP	7
 #define AD774X_VT_SETUP		8
 #define AD774X_EXEC_SETUP	9
 #define AD774X_CFG		10
 #define AD774X_CAPDACA		11
 #define AD774X_CAPDACB		12
 #define AD774X_CAPDAC_EN	(1 << 7)
 #define AD774X_CAP_OFFH		13
 #define AD774X_CAP_OFFL		14
 #define AD774X_CAP_GAINH	15
 #define AD774X_CAP_GAINL	16
 #define AD774X_VOLT_GAINH	17
 #define AD774X_VOLT_GAINL	18

 #define AD774X_MAX_CONV_MODE	6

 /*
  * struct ad774x_chip_info - chip specifc information
  */

 struct ad774x_chip_info {
 	const char *name;
 	struct i2c_client *client;
 	struct iio_dev *indio_dev;
 	struct work_struct thresh_work;
 	bool inter;
 	s64 last_timestamp;
 	u16 cap_offs;                   /* Capacitive offset */
 	u16 cap_gain;                   /* Capacitive gain calibration */
 	u16 volt_gain;                  /* Voltage gain calibration */
 	u8  cap_setup;
 	u8  vt_setup;
 	u8  exec_setup;

 	char *conversion_mode;
 };

 struct ad774x_conversion_mode {
 	char *name;
 	u8 reg_cfg;
 };

 struct ad774x_conversion_mode ad774x_conv_mode_table[AD774X_MAX_CONV_MODE] = {
 	{ "idle", 0 },
 	{ "continuous-conversion", 1 },
 	{ "single-conversion", 2 },
 	{ "power-down", 3 },
 	{ "offset-calibration", 5 },
 	{ "gain-calibration", 6 },
 };

 /*
  * ad774x register access by I2C
  */

 static int ad774x_i2c_read(struct ad774x_chip_info *chip, u8 reg, u8 *data, int len)
 {
 	struct i2c_client *client = chip->client;
 	int ret;

 	ret = i2c_master_send(client, &reg, 1);
 	if (ret < 0) {
 		dev_err(&client->dev, "I2C write error\n");
 		return ret;
 	}

 	ret = i2c_master_recv(client, data, len);
 	if (ret < 0) {
 		dev_err(&client->dev, "I2C read error\n");
 		return ret;
 	}

 	return ret;
 }

 static int ad774x_i2c_write(struct ad774x_chip_info *chip, u8 reg, u8 data)
 {
 	struct i2c_client *client = chip->client;
 	int ret;

 	u8 tx[2] = {
 		reg,
 		data,
 	};

 	ret = i2c_master_send(client, tx, 2);
 	if (ret < 0)
 		dev_err(&client->dev, "I2C write error\n");

 	return ret;
 }

 /*
  * sysfs nodes
  */

 #define IIO_DEV_ATTR_AVAIL_CONVERSION_MODES(_show)				\
 	IIO_DEVICE_ATTR(available_conversion_modes, S_IRUGO, _show, NULL, 0)
 #define IIO_DEV_ATTR_CONVERSION_MODE(_mode, _show, _store)              \
 	IIO_DEVICE_ATTR(conversion_mode, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_CAP_SETUP(_mode, _show, _store)		\
 	IIO_DEVICE_ATTR(cap_setup, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_VT_SETUP(_mode, _show, _store)              \
 	IIO_DEVICE_ATTR(in0_setup, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_EXEC_SETUP(_mode, _show, _store)              \
 	IIO_DEVICE_ATTR(exec_setup, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_VOLT_GAIN(_mode, _show, _store)		\
 	IIO_DEVICE_ATTR(in0_gain, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_CAP_OFFS(_mode, _show, _store)		\
 	IIO_DEVICE_ATTR(cap_offs, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_CAP_GAIN(_mode, _show, _store)		\
 	IIO_DEVICE_ATTR(cap_gain, _mode, _show, _store, 0)
 #define IIO_DEV_ATTR_CAP_DATA(_show)		\
 	IIO_DEVICE_ATTR(cap0_raw, S_IRUGO, _show, NULL, 0)
 #define IIO_DEV_ATTR_VT_DATA(_show)		\
 	IIO_DEVICE_ATTR(in0_raw, S_IRUGO, _show, NULL, 0)

 static ssize_t ad774x_show_conversion_modes(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	int i;
 	int len = 0;

 	for (i = 0; i < AD774X_MAX_CONV_MODE; i++)
 		len += sprintf(buf + len, "%s ", ad774x_conv_mode_table[i].name);

 	len += sprintf(buf + len, "\n");

 	return len;
 }

 static IIO_DEV_ATTR_AVAIL_CONVERSION_MODES(ad774x_show_conversion_modes);

 static ssize_t ad774x_show_conversion_mode(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "%s\n", chip->conversion_mode);
 }

 static ssize_t ad774x_store_conversion_mode(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	u8 cfg;
 	int i;

 	ad774x_i2c_read(chip, AD774X_CFG, &cfg, 1);

 	for (i = 0; i < AD774X_MAX_CONV_MODE; i++) {
 		if (strncmp(buf, ad774x_conv_mode_table[i].name,
 				strlen(ad774x_conv_mode_table[i].name) - 1) == 0) {
 			chip->conversion_mode = ad774x_conv_mode_table[i].name;
 			cfg |= 0x18 | ad774x_conv_mode_table[i].reg_cfg;
 			ad774x_i2c_write(chip, AD774X_CFG, cfg);
 			return len;
 		}
 	}

 	dev_err(dev, "not supported conversion mode\n");

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_CONVERSION_MODE(S_IRUGO | S_IWUSR,
 		ad774x_show_conversion_mode,
 		ad774x_store_conversion_mode);

 static ssize_t ad774x_show_dac_value(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 	u8 data;

 	ad774x_i2c_read(chip, this_attr->address, &data, 1);

 	return sprintf(buf, "%02x\n", data & 0x7F);
 }

 static ssize_t ad774x_store_dac_value(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if (!ret) {
 		ad774x_i2c_write(chip, this_attr->address,
 			(data ? AD774X_CAPDAC_EN : 0) | (data & 0x7F));
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEVICE_ATTR(capdac0_raw, S_IRUGO | S_IWUSR,
 			ad774x_show_dac_value,
 			ad774x_store_dac_value,
 			AD774X_CAPDACA);

 static IIO_DEVICE_ATTR(capdac1_raw, S_IRUGO | S_IWUSR,
 			ad774x_show_dac_value,
 			ad774x_store_dac_value,
 			AD774X_CAPDACB);

 static ssize_t ad774x_show_cap_setup(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "0x%02x\n", chip->cap_setup);
 }

 static ssize_t ad774x_store_cap_setup(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x100)) {
 		ad774x_i2c_write(chip, AD774X_CAP_SETUP, data);
 		chip->cap_setup = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_CAP_SETUP(S_IRUGO | S_IWUSR,
 		ad774x_show_cap_setup,
 		ad774x_store_cap_setup);

 static ssize_t ad774x_show_vt_setup(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "0x%02x\n", chip->vt_setup);
 }

 static ssize_t ad774x_store_vt_setup(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x100)) {
 		ad774x_i2c_write(chip, AD774X_VT_SETUP, data);
 		chip->vt_setup = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_VT_SETUP(S_IRUGO | S_IWUSR,
 		ad774x_show_vt_setup,
 		ad774x_store_vt_setup);

 static ssize_t ad774x_show_exec_setup(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "0x%02x\n", chip->exec_setup);
 }

 static ssize_t ad774x_store_exec_setup(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x100)) {
 		ad774x_i2c_write(chip, AD774X_EXEC_SETUP, data);
 		chip->exec_setup = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_EXEC_SETUP(S_IRUGO | S_IWUSR,
 		ad774x_show_exec_setup,
 		ad774x_store_exec_setup);

 static ssize_t ad774x_show_volt_gain(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "%d\n", chip->volt_gain);
 }

 static ssize_t ad774x_store_volt_gain(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x10000)) {
 		ad774x_i2c_write(chip, AD774X_VOLT_GAINH, data >> 8);
 		ad774x_i2c_write(chip, AD774X_VOLT_GAINL, data);
 		chip->volt_gain = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_VOLT_GAIN(S_IRUGO | S_IWUSR,
 		ad774x_show_volt_gain,
 		ad774x_store_volt_gain);

 static ssize_t ad774x_show_cap_data(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	char tmp[3];

 	ad774x_i2c_read(chip, AD774X_CAP_DATA_HIGH, tmp, 3);
 	data = ((int)tmp[0] << 16) | ((int)tmp[1] << 8) | (int)tmp[2];

 	return sprintf(buf, "%ld\n", data);
 }

 static IIO_DEV_ATTR_CAP_DATA(ad774x_show_cap_data);

 static ssize_t ad774x_show_vt_data(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	char tmp[3];

 	ad774x_i2c_read(chip, AD774X_VT_DATA_HIGH, tmp, 3);
 	data = ((int)tmp[0] << 16) | ((int)tmp[1] << 8) | (int)tmp[2];

 	return sprintf(buf, "%ld\n", data);
 }

 static IIO_DEV_ATTR_VT_DATA(ad774x_show_vt_data);

 static ssize_t ad774x_show_cap_offs(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "%d\n", chip->cap_offs);
 }

 static ssize_t ad774x_store_cap_offs(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x10000)) {
 		ad774x_i2c_write(chip, AD774X_CAP_OFFH, data >> 8);
 		ad774x_i2c_write(chip, AD774X_CAP_OFFL, data);
 		chip->cap_offs = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_CAP_OFFS(S_IRUGO | S_IWUSR,
 		ad774x_show_cap_offs,
 		ad774x_store_cap_offs);

 static ssize_t ad774x_show_cap_gain(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;

 	return sprintf(buf, "%d\n", chip->cap_gain);
 }

 static ssize_t ad774x_store_cap_gain(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	unsigned long data;
 	int ret;

 	ret = strict_strtoul(buf, 10, &data);

 	if ((!ret) && (data < 0x10000)) {
 		ad774x_i2c_write(chip, AD774X_CAP_GAINH, data >> 8);
 		ad774x_i2c_write(chip, AD774X_CAP_GAINL, data);
 		chip->cap_gain = data;
 		return len;
 	}

 	return -EINVAL;
 }

 static IIO_DEV_ATTR_CAP_GAIN(S_IRUGO | S_IWUSR,
 		ad774x_show_cap_gain,
 		ad774x_store_cap_gain);

 static ssize_t ad774x_show_name(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	struct iio_dev *dev_info = dev_get_drvdata(dev);
 	struct ad774x_chip_info *chip = dev_info->dev_data;
 	return sprintf(buf, "%s\n", chip->name);
 }

 static IIO_DEVICE_ATTR(name, S_IRUGO, ad774x_show_name, NULL, 0);

 static struct attribute *ad774x_attributes[] = {
 	&iio_dev_attr_available_conversion_modes.dev_attr.attr,
 	&iio_dev_attr_conversion_mode.dev_attr.attr,
 	&iio_dev_attr_cap_setup.dev_attr.attr,
 	&iio_dev_attr_in0_setup.dev_attr.attr,
 	&iio_dev_attr_exec_setup.dev_attr.attr,
 	&iio_dev_attr_cap_offs.dev_attr.attr,
 	&iio_dev_attr_cap_gain.dev_attr.attr,
 	&iio_dev_attr_in0_gain.dev_attr.attr,
 	&iio_dev_attr_in0_raw.dev_attr.attr,
 	&iio_dev_attr_cap0_raw.dev_attr.attr,
 	&iio_dev_attr_capdac0_raw.dev_attr.attr,
 	&iio_dev_attr_capdac1_raw.dev_attr.attr,
 	&iio_dev_attr_name.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group ad774x_attribute_group = {
 	.attrs = ad774x_attributes,
 };

 /*
  * data ready events
  */

 #define IIO_EVENT_CODE_CAP_RDY     IIO_BUFFER_EVENT_CODE(0)
 #define IIO_EVENT_CODE_VT_RDY      IIO_BUFFER_EVENT_CODE(1)

 #define IIO_EVENT_ATTR_CAP_RDY_SH(_evlist, _show, _store, _mask)	\
 	IIO_EVENT_ATTR_SH(cap_rdy, _evlist, _show, _store, _mask)

 #define IIO_EVENT_ATTR_VT_RDY_SH(_evlist, _show, _store, _mask)	\
 	IIO_EVENT_ATTR_SH(vt_rdy, _evlist, _show, _store, _mask)

 static void ad774x_interrupt_handler_bh(struct work_struct *work_s)
 {
 	struct ad774x_chip_info *chip =
 		container_of(work_s, struct ad774x_chip_info, thresh_work);
 	u8 int_status;

 	enable_irq(chip->client->irq);

 	ad774x_i2c_read(chip, AD774X_STATUS, &int_status, 1);

 	if (int_status & AD774X_STATUS_RDYCAP)
 		iio_push_event(chip->indio_dev, 0,
 				IIO_EVENT_CODE_CAP_RDY,
 				chip->last_timestamp);

 	if (int_status & AD774X_STATUS_RDYVT)
 		iio_push_event(chip->indio_dev, 0,
 				IIO_EVENT_CODE_VT_RDY,
 				chip->last_timestamp);
 }

 static int ad774x_interrupt_handler_th(struct iio_dev *dev_info,
 		int index,
 		s64 timestamp,
 		int no_test)
 {
 	struct ad774x_chip_info *chip = dev_info->dev_data;

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

 	return 0;
 }

 IIO_EVENT_SH(data_rdy, &ad774x_interrupt_handler_th);

 static ssize_t ad774x_query_out_mode(struct device *dev,
 		struct device_attribute *attr,
 		char *buf)
 {
 	/*
 	 * AD774X provides one /RDY pin, which can be used as interrupt
 	 * but the pin is not configurable
 	 */
 	return sprintf(buf, "1\n");
 }

 static ssize_t ad774x_set_out_mode(struct device *dev,
 		struct device_attribute *attr,
 		const char *buf,
 		size_t len)
 {
 	return len;
 }

 IIO_EVENT_ATTR_CAP_RDY_SH(iio_event_data_rdy, ad774x_query_out_mode, ad774x_set_out_mode, 0);
 IIO_EVENT_ATTR_VT_RDY_SH(iio_event_data_rdy, ad774x_query_out_mode, ad774x_set_out_mode, 0);

 static struct attribute *ad774x_event_attributes[] = {
 	&iio_event_attr_cap_rdy.dev_attr.attr,
 	&iio_event_attr_vt_rdy.dev_attr.attr,
 	NULL,
 };

 static struct attribute_group ad774x_event_attribute_group = {
 	.attrs = ad774x_event_attributes,
 };

 /*
  * device probe and remove
  */

 static int __devinit ad774x_probe(struct i2c_client *client,
 		const struct i2c_device_id *id)
 {
 	int ret = 0, regdone = 0;
 	struct ad774x_chip_info *chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 	if (chip == NULL) {
 		ret = -ENOMEM;
 		goto error_ret;
 	}

 	/* this is only used for device removal purposes */
 	i2c_set_clientdata(client, chip);

 	chip->client = client;
 	chip->name = id->name;

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

 	/* Establish that the iio_dev is a child of the i2c device */
 	chip->indio_dev->dev.parent = &client->dev;
 	chip->indio_dev->attrs = &ad774x_attribute_group;
 	chip->indio_dev->event_attrs = &ad774x_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;
 	regdone = 1;

 	if (client->irq) {
 		ret = iio_register_interrupt_line(client->irq,
 				chip->indio_dev,
 				0,
 				IRQF_TRIGGER_FALLING,
 				"ad774x");
 		if (ret)
 			goto error_free_dev;

 		iio_add_event_to_list(iio_event_attr_cap_rdy.listel,
 				&chip->indio_dev->interrupts[0]->ev_list);

 		INIT_WORK(&chip->thresh_work, ad774x_interrupt_handler_bh);
 	}

 	dev_err(&client->dev, "%s capacitive sensor registered, irq: %d\n", id->name, client->irq);

 	return 0;

 error_free_dev:
 	if (regdone)
 		iio_device_unregister(chip->indio_dev);
 	else
 		iio_free_device(chip->indio_dev);
 error_free_chip:
 	kfree(chip);
 error_ret:
 	return ret;
 }

 static int __devexit ad774x_remove(struct i2c_client *client)
 {
 	struct ad774x_chip_info *chip = i2c_get_clientdata(client);
 	struct iio_dev *indio_dev = chip->indio_dev;

 	if (client->irq)
 		iio_unregister_interrupt_line(indio_dev, 0);
 	iio_device_unregister(indio_dev);
 	kfree(chip);

 	return 0;
 }

 static const struct i2c_device_id ad774x_id[] = {
 	{ "ad7745", 0 },
 	{ "ad7746", 0 },
 	{ "ad7747", 0 },
 	{}
 };

 MODULE_DEVICE_TABLE(i2c, ad774x_id);

 static struct i2c_driver ad774x_driver = {
 	.driver = {
 		.name = "ad774x",
 	},
 	.probe = ad774x_probe,
 	.remove = __devexit_p(ad774x_remove),
 	.id_table = ad774x_id,
 };

 static __init int ad774x_init(void)
 {
 	return i2c_add_driver(&ad774x_driver);
 }

 static __exit void ad774x_exit(void)
 {
 	i2c_del_driver(&ad774x_driver);
 }

 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 MODULE_DESCRIPTION("Analog Devices ad7745/6/7 capacitive sensor driver");
 MODULE_LICENSE("GPL v2");

 module_init(ad774x_init);
 module_exit(ad774x_exit);
	/*
	* AD774X capacitive sensor driver supporting AD7745/6/7
	*
	* 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/i2c.h>
	#include <linux/rtc.h>

	#include "../iio.h"
	#include "../sysfs.h"

	/*
	* AD774X registers definition
	*/

	#define AD774X_STATUS 0
	#define AD774X_STATUS_RDY (1 << 2)
	#define AD774X_STATUS_RDYVT (1 << 1)
	#define AD774X_STATUS_RDYCAP (1 << 0)
	#define AD774X_CAP_DATA_HIGH 1
	#define AD774X_CAP_DATA_MID 2
	#define AD774X_CAP_DATA_LOW 3
	#define AD774X_VT_DATA_HIGH 4
	#define AD774X_VT_DATA_MID 5
	#define AD774X_VT_DATA_LOW 6
	#define AD774X_CAP_SETUP 7
	#define AD774X_VT_SETUP 8
	#define AD774X_EXEC_SETUP 9
	#define AD774X_CFG 10
	#define AD774X_CAPDACA 11
	#define AD774X_CAPDACB 12
	#define AD774X_CAPDAC_EN (1 << 7)
	#define AD774X_CAP_OFFH 13
	#define AD774X_CAP_OFFL 14
	#define AD774X_CAP_GAINH 15
	#define AD774X_CAP_GAINL 16
	#define AD774X_VOLT_GAINH 17
	#define AD774X_VOLT_GAINL 18

	#define AD774X_MAX_CONV_MODE 6

	/*
	* struct ad774x_chip_info - chip specifc information
	*/

	struct ad774x_chip_info {
	const char *name;
	struct i2c_client *client;
	struct iio_dev *indio_dev;
	struct work_struct thresh_work;
	bool inter;
	s64 last_timestamp;
	u16 cap_offs; /* Capacitive offset */
	u16 cap_gain; /* Capacitive gain calibration */
	u16 volt_gain; /* Voltage gain calibration */
	u8 cap_setup;
	u8 vt_setup;
	u8 exec_setup;

	char *conversion_mode;
	};

	struct ad774x_conversion_mode {
	char *name;
	u8 reg_cfg;
	};

	struct ad774x_conversion_mode ad774x_conv_mode_table[AD774X_MAX_CONV_MODE] = {
	{ "idle", 0 },
	{ "continuous-conversion", 1 },
	{ "single-conversion", 2 },
	{ "power-down", 3 },
	{ "offset-calibration", 5 },
	{ "gain-calibration", 6 },
	};

	/*
	* ad774x register access by I2C
	*/

	static int ad774x_i2c_read(struct ad774x_chip_info chip, u8 reg, u8 data, int len)
	{
	struct i2c_client *client = chip->client;
	int ret;

	ret = i2c_master_send(client, &reg, 1);
	if (ret < 0) {
	dev_err(&client->dev, "I2C write error\n");
	return ret;
	}

	ret = i2c_master_recv(client, data, len);
	if (ret < 0) {
	dev_err(&client->dev, "I2C read error\n");
	return ret;
	}

	return ret;
	}

	static int ad774x_i2c_write(struct ad774x_chip_info *chip, u8 reg, u8 data)
	{
	struct i2c_client *client = chip->client;
	int ret;

	u8 tx[2] = {
	reg,
	data,
	};

	ret = i2c_master_send(client, tx, 2);
	if (ret < 0)
	dev_err(&client->dev, "I2C write error\n");

	return ret;
	}

	/*
	* sysfs nodes
	*/

	#define IIO_DEV_ATTR_AVAIL_CONVERSION_MODES(_show) \
	IIO_DEVICE_ATTR(available_conversion_modes, S_IRUGO, _show, NULL, 0)
	#define IIO_DEV_ATTR_CONVERSION_MODE(_mode, _show, _store) \
	IIO_DEVICE_ATTR(conversion_mode, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_CAP_SETUP(_mode, _show, _store) \
	IIO_DEVICE_ATTR(cap_setup, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_VT_SETUP(_mode, _show, _store) \
	IIO_DEVICE_ATTR(in0_setup, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_EXEC_SETUP(_mode, _show, _store) \
	IIO_DEVICE_ATTR(exec_setup, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_VOLT_GAIN(_mode, _show, _store) \
	IIO_DEVICE_ATTR(in0_gain, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_CAP_OFFS(_mode, _show, _store) \
	IIO_DEVICE_ATTR(cap_offs, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_CAP_GAIN(_mode, _show, _store) \
	IIO_DEVICE_ATTR(cap_gain, _mode, _show, _store, 0)
	#define IIO_DEV_ATTR_CAP_DATA(_show) \
	IIO_DEVICE_ATTR(cap0_raw, S_IRUGO, _show, NULL, 0)
	#define IIO_DEV_ATTR_VT_DATA(_show) \
	IIO_DEVICE_ATTR(in0_raw, S_IRUGO, _show, NULL, 0)

	static ssize_t ad774x_show_conversion_modes(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	int i;
	int len = 0;

	for (i = 0; i < AD774X_MAX_CONV_MODE; i++)
	len += sprintf(buf + len, "%s ", ad774x_conv_mode_table[i].name);

	len += sprintf(buf + len, "\n");

	return len;
	}

	static IIO_DEV_ATTR_AVAIL_CONVERSION_MODES(ad774x_show_conversion_modes);

	static ssize_t ad774x_show_conversion_mode(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "%s\n", chip->conversion_mode);
	}

	static ssize_t ad774x_store_conversion_mode(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	u8 cfg;
	int i;

	ad774x_i2c_read(chip, AD774X_CFG, &cfg, 1);

	for (i = 0; i < AD774X_MAX_CONV_MODE; i++) {
	if (strncmp(buf, ad774x_conv_mode_table[i].name,
	strlen(ad774x_conv_mode_table[i].name) - 1) == 0) {
	chip->conversion_mode = ad774x_conv_mode_table[i].name;
	cfg \|= 0x18 \| ad774x_conv_mode_table[i].reg_cfg;
	ad774x_i2c_write(chip, AD774X_CFG, cfg);
	return len;
	}
	}

	dev_err(dev, "not supported conversion mode\n");

	return -EINVAL;
	}

	static IIO_DEV_ATTR_CONVERSION_MODE(S_IRUGO \| S_IWUSR,
	ad774x_show_conversion_mode,
	ad774x_store_conversion_mode);

	static ssize_t ad774x_show_dac_value(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	u8 data;

	ad774x_i2c_read(chip, this_attr->address, &data, 1);

	return sprintf(buf, "%02x\n", data & 0x7F);
	}

	static ssize_t ad774x_store_dac_value(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if (!ret) {
	ad774x_i2c_write(chip, this_attr->address,
	(data ? AD774X_CAPDAC_EN : 0) \| (data & 0x7F));
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEVICE_ATTR(capdac0_raw, S_IRUGO \| S_IWUSR,
	ad774x_show_dac_value,
	ad774x_store_dac_value,
	AD774X_CAPDACA);

	static IIO_DEVICE_ATTR(capdac1_raw, S_IRUGO \| S_IWUSR,
	ad774x_show_dac_value,
	ad774x_store_dac_value,
	AD774X_CAPDACB);

	static ssize_t ad774x_show_cap_setup(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "0x%02x\n", chip->cap_setup);
	}

	static ssize_t ad774x_store_cap_setup(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x100)) {
	ad774x_i2c_write(chip, AD774X_CAP_SETUP, data);
	chip->cap_setup = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_CAP_SETUP(S_IRUGO \| S_IWUSR,
	ad774x_show_cap_setup,
	ad774x_store_cap_setup);

	static ssize_t ad774x_show_vt_setup(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "0x%02x\n", chip->vt_setup);
	}

	static ssize_t ad774x_store_vt_setup(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x100)) {
	ad774x_i2c_write(chip, AD774X_VT_SETUP, data);
	chip->vt_setup = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_VT_SETUP(S_IRUGO \| S_IWUSR,
	ad774x_show_vt_setup,
	ad774x_store_vt_setup);

	static ssize_t ad774x_show_exec_setup(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "0x%02x\n", chip->exec_setup);
	}

	static ssize_t ad774x_store_exec_setup(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x100)) {
	ad774x_i2c_write(chip, AD774X_EXEC_SETUP, data);
	chip->exec_setup = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_EXEC_SETUP(S_IRUGO \| S_IWUSR,
	ad774x_show_exec_setup,
	ad774x_store_exec_setup);

	static ssize_t ad774x_show_volt_gain(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "%d\n", chip->volt_gain);
	}

	static ssize_t ad774x_store_volt_gain(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x10000)) {
	ad774x_i2c_write(chip, AD774X_VOLT_GAINH, data >> 8);
	ad774x_i2c_write(chip, AD774X_VOLT_GAINL, data);
	chip->volt_gain = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_VOLT_GAIN(S_IRUGO \| S_IWUSR,
	ad774x_show_volt_gain,
	ad774x_store_volt_gain);

	static ssize_t ad774x_show_cap_data(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	char tmp[3];

	ad774x_i2c_read(chip, AD774X_CAP_DATA_HIGH, tmp, 3);
	data = ((int)tmp[0] << 16) \| ((int)tmp[1] << 8) \| (int)tmp[2];

	return sprintf(buf, "%ld\n", data);
	}

	static IIO_DEV_ATTR_CAP_DATA(ad774x_show_cap_data);

	static ssize_t ad774x_show_vt_data(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	char tmp[3];

	ad774x_i2c_read(chip, AD774X_VT_DATA_HIGH, tmp, 3);
	data = ((int)tmp[0] << 16) \| ((int)tmp[1] << 8) \| (int)tmp[2];

	return sprintf(buf, "%ld\n", data);
	}

	static IIO_DEV_ATTR_VT_DATA(ad774x_show_vt_data);

	static ssize_t ad774x_show_cap_offs(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "%d\n", chip->cap_offs);
	}

	static ssize_t ad774x_store_cap_offs(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x10000)) {
	ad774x_i2c_write(chip, AD774X_CAP_OFFH, data >> 8);
	ad774x_i2c_write(chip, AD774X_CAP_OFFL, data);
	chip->cap_offs = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_CAP_OFFS(S_IRUGO \| S_IWUSR,
	ad774x_show_cap_offs,
	ad774x_store_cap_offs);

	static ssize_t ad774x_show_cap_gain(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;

	return sprintf(buf, "%d\n", chip->cap_gain);
	}

	static ssize_t ad774x_store_cap_gain(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	unsigned long data;
	int ret;

	ret = strict_strtoul(buf, 10, &data);

	if ((!ret) && (data < 0x10000)) {
	ad774x_i2c_write(chip, AD774X_CAP_GAINH, data >> 8);
	ad774x_i2c_write(chip, AD774X_CAP_GAINL, data);
	chip->cap_gain = data;
	return len;
	}

	return -EINVAL;
	}

	static IIO_DEV_ATTR_CAP_GAIN(S_IRUGO \| S_IWUSR,
	ad774x_show_cap_gain,
	ad774x_store_cap_gain);

	static ssize_t ad774x_show_name(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	struct iio_dev *dev_info = dev_get_drvdata(dev);
	struct ad774x_chip_info *chip = dev_info->dev_data;
	return sprintf(buf, "%s\n", chip->name);
	}

	static IIO_DEVICE_ATTR(name, S_IRUGO, ad774x_show_name, NULL, 0);

	static struct attribute *ad774x_attributes[] = {
	&iio_dev_attr_available_conversion_modes.dev_attr.attr,
	&iio_dev_attr_conversion_mode.dev_attr.attr,
	&iio_dev_attr_cap_setup.dev_attr.attr,
	&iio_dev_attr_in0_setup.dev_attr.attr,
	&iio_dev_attr_exec_setup.dev_attr.attr,
	&iio_dev_attr_cap_offs.dev_attr.attr,
	&iio_dev_attr_cap_gain.dev_attr.attr,
	&iio_dev_attr_in0_gain.dev_attr.attr,
	&iio_dev_attr_in0_raw.dev_attr.attr,
	&iio_dev_attr_cap0_raw.dev_attr.attr,
	&iio_dev_attr_capdac0_raw.dev_attr.attr,
	&iio_dev_attr_capdac1_raw.dev_attr.attr,
	&iio_dev_attr_name.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group ad774x_attribute_group = {
	.attrs = ad774x_attributes,
	};

	/*
	* data ready events
	*/

	#define IIO_EVENT_CODE_CAP_RDY IIO_BUFFER_EVENT_CODE(0)
	#define IIO_EVENT_CODE_VT_RDY IIO_BUFFER_EVENT_CODE(1)

	#define IIO_EVENT_ATTR_CAP_RDY_SH(_evlist, _show, _store, _mask) \
	IIO_EVENT_ATTR_SH(cap_rdy, _evlist, _show, _store, _mask)

	#define IIO_EVENT_ATTR_VT_RDY_SH(_evlist, _show, _store, _mask) \
	IIO_EVENT_ATTR_SH(vt_rdy, _evlist, _show, _store, _mask)

	static void ad774x_interrupt_handler_bh(struct work_struct *work_s)
	{
	struct ad774x_chip_info *chip =
	container_of(work_s, struct ad774x_chip_info, thresh_work);
	u8 int_status;

	enable_irq(chip->client->irq);

	ad774x_i2c_read(chip, AD774X_STATUS, &int_status, 1);

	if (int_status & AD774X_STATUS_RDYCAP)
	iio_push_event(chip->indio_dev, 0,
	IIO_EVENT_CODE_CAP_RDY,
	chip->last_timestamp);

	if (int_status & AD774X_STATUS_RDYVT)
	iio_push_event(chip->indio_dev, 0,
	IIO_EVENT_CODE_VT_RDY,
	chip->last_timestamp);
	}

	static int ad774x_interrupt_handler_th(struct iio_dev *dev_info,
	int index,
	s64 timestamp,
	int no_test)
	{
	struct ad774x_chip_info *chip = dev_info->dev_data;

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

	return 0;
	}

	IIO_EVENT_SH(data_rdy, &ad774x_interrupt_handler_th);

	static ssize_t ad774x_query_out_mode(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	/*
	* AD774X provides one /RDY pin, which can be used as interrupt
	* but the pin is not configurable
	*/
	return sprintf(buf, "1\n");
	}

	static ssize_t ad774x_set_out_mode(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	return len;
	}

	IIO_EVENT_ATTR_CAP_RDY_SH(iio_event_data_rdy, ad774x_query_out_mode, ad774x_set_out_mode, 0);
	IIO_EVENT_ATTR_VT_RDY_SH(iio_event_data_rdy, ad774x_query_out_mode, ad774x_set_out_mode, 0);

	static struct attribute *ad774x_event_attributes[] = {
	&iio_event_attr_cap_rdy.dev_attr.attr,
	&iio_event_attr_vt_rdy.dev_attr.attr,
	NULL,
	};

	static struct attribute_group ad774x_event_attribute_group = {
	.attrs = ad774x_event_attributes,
	};

	/*
	* device probe and remove
	*/

	static int __devinit ad774x_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	int ret = 0, regdone = 0;
	struct ad774x_chip_info chip = kzalloc(sizeof(chip), GFP_KERNEL);
	if (chip == NULL) {
	ret = -ENOMEM;
	goto error_ret;
	}

	/* this is only used for device removal purposes */
	i2c_set_clientdata(client, chip);

	chip->client = client;
	chip->name = id->name;

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

	/* Establish that the iio_dev is a child of the i2c device */
	chip->indio_dev->dev.parent = &client->dev;
	chip->indio_dev->attrs = &ad774x_attribute_group;
	chip->indio_dev->event_attrs = &ad774x_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;
	regdone = 1;

	if (client->irq) {
	ret = iio_register_interrupt_line(client->irq,
	chip->indio_dev,
	0,
	IRQF_TRIGGER_FALLING,
	"ad774x");
	if (ret)
	goto error_free_dev;

	iio_add_event_to_list(iio_event_attr_cap_rdy.listel,
	&chip->indio_dev->interrupts[0]->ev_list);

	INIT_WORK(&chip->thresh_work, ad774x_interrupt_handler_bh);
	}

	dev_err(&client->dev, "%s capacitive sensor registered, irq: %d\n", id->name, client->irq);

	return 0;

	error_free_dev:
	if (regdone)
	iio_device_unregister(chip->indio_dev);
	else
	iio_free_device(chip->indio_dev);
	error_free_chip:
	kfree(chip);
	error_ret:
	return ret;
	}

	static int __devexit ad774x_remove(struct i2c_client *client)
	{
	struct ad774x_chip_info *chip = i2c_get_clientdata(client);
	struct iio_dev *indio_dev = chip->indio_dev;

	if (client->irq)
	iio_unregister_interrupt_line(indio_dev, 0);
	iio_device_unregister(indio_dev);
	kfree(chip);

	return 0;
	}

	static const struct i2c_device_id ad774x_id[] = {
	{ "ad7745", 0 },
	{ "ad7746", 0 },
	{ "ad7747", 0 },
	{}
	};

	MODULE_DEVICE_TABLE(i2c, ad774x_id);

	static struct i2c_driver ad774x_driver = {
	.driver = {
	.name = "ad774x",
	},
	.probe = ad774x_probe,
	.remove = __devexit_p(ad774x_remove),
	.id_table = ad774x_id,
	};

	static __init int ad774x_init(void)
	{
	return i2c_add_driver(&ad774x_driver);
	}

	static __exit void ad774x_exit(void)
	{
	i2c_del_driver(&ad774x_driver);
	}

	MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
	MODULE_DESCRIPTION("Analog Devices ad7745/6/7 capacitive sensor driver");
	MODULE_LICENSE("GPL v2");

	module_init(ad774x_init);
	module_exit(ad774x_exit);