drivers/iio/adc/ltc2497.c - third_party/linux - Git at Google

 /*
  * ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC
  *
  * Copyright (C) 2017 Analog Devices Inc.
  *
  * Licensed under the GPL-2.
  *
  * Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
  */

 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/driver.h>
 #include <linux/iio/sysfs.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/regulator/consumer.h>

 #define LTC2497_ENABLE			0xA0
 #define LTC2497_SGL			BIT(4)
 #define LTC2497_DIFF			0
 #define LTC2497_SIGN			BIT(3)
 #define LTC2497_CONFIG_DEFAULT		LTC2497_ENABLE
 #define LTC2497_CONVERSION_TIME_MS	150ULL

 struct ltc2497_st {
 	struct i2c_client *client;
 	struct regulator *ref;
 	ktime_t	time_prev;
 	u8 addr_prev;
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 */
 	__be32 buf ____cacheline_aligned;
 };

 static int ltc2497_wait_conv(struct ltc2497_st *st)
 {
 	s64 time_elapsed;

 	time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev);

 	if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
 		/* delay if conversion time not passed
 		 * since last read or write
 		 */
 		if (msleep_interruptible(
 		    LTC2497_CONVERSION_TIME_MS - time_elapsed))
 			return -ERESTARTSYS;

 		return 0;
 	}

 	if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
 		/* We're in automatic mode -
 		 * so the last reading is stil not outdated
 		 */
 		return 0;
 	}

 	return 1;
 }

 static int ltc2497_read(struct ltc2497_st *st, u8 address, int *val)
 {
 	struct i2c_client *client = st->client;
 	int ret;

 	ret = ltc2497_wait_conv(st);
 	if (ret < 0)
 		return ret;

 	if (ret || st->addr_prev != address) {
 		ret = i2c_smbus_write_byte(st->client,
 					   LTC2497_ENABLE | address);
 		if (ret < 0)
 			return ret;
 		st->addr_prev = address;
 		if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
 			return -ERESTARTSYS;
 	}
 	ret = i2c_master_recv(client, (char *)&st->buf, 3);
 	if (ret < 0)  {
 		dev_err(&client->dev, "i2c_master_recv failed\n");
 		return ret;
 	}
 	st->time_prev = ktime_get();

 	/* convert and shift the result,
 	 * and finally convert from offset binary to signed integer
 	 */
 	*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);

 	return ret;
 }

 static int ltc2497_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long mask)
 {
 	struct ltc2497_st *st = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&indio_dev->mlock);
 		ret = ltc2497_read(st, chan->address, val);
 		mutex_unlock(&indio_dev->mlock);
 		if (ret < 0)
 			return ret;

 		return IIO_VAL_INT;

 	case IIO_CHAN_INFO_SCALE:
 		ret = regulator_get_voltage(st->ref);
 		if (ret < 0)
 			return ret;

 		*val = ret / 1000;
 		*val2 = 17;

 		return IIO_VAL_FRACTIONAL_LOG2;

 	default:
 		return -EINVAL;
 	}
 }

 #define LTC2497_CHAN(_chan, _addr, _ds_name) { \
 	.type = IIO_VOLTAGE, \
 	.indexed = 1, \
 	.channel = (_chan), \
 	.address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 	.datasheet_name = (_ds_name), \
 }

 #define LTC2497_CHAN_DIFF(_chan, _addr) { \
 	.type = IIO_VOLTAGE, \
 	.indexed = 1, \
 	.channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
 	.channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
 	.address = (_addr | _chan), \
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 	.differential = 1, \
 }

 static const struct iio_chan_spec ltc2497_channel[] = {
 	LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
 	LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
 	LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
 	LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
 	LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
 	LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
 	LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
 	LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
 	LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
 	LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
 	LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
 	LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
 	LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
 	LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
 	LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
 	LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
 	LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
 	LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
 	LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
 };

 static const struct iio_info ltc2497_info = {
 	.read_raw = ltc2497_read_raw,
 };

 static int ltc2497_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct iio_dev *indio_dev;
 	struct ltc2497_st *st;
 	struct iio_map *plat_data;
 	int ret;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
 				     I2C_FUNC_SMBUS_WRITE_BYTE))
 		return -EOPNOTSUPP;

 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;

 	st = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 	st->client = client;

 	indio_dev->dev.parent = &client->dev;
 	indio_dev->name = id->name;
 	indio_dev->info = &ltc2497_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = ltc2497_channel;
 	indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel);

 	st->ref = devm_regulator_get(&client->dev, "vref");
 	if (IS_ERR(st->ref))
 		return PTR_ERR(st->ref);

 	ret = regulator_enable(st->ref);
 	if (ret < 0)
 		return ret;

 	if (client->dev.platform_data) {
 		plat_data = ((struct iio_map *)client->dev.platform_data);
 		ret = iio_map_array_register(indio_dev, plat_data);
 		if (ret) {
 			dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
 			goto err_regulator_disable;
 		}
 	}

 	ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT);
 	if (ret < 0)
 		goto err_array_unregister;

 	st->addr_prev = LTC2497_CONFIG_DEFAULT;
 	st->time_prev = ktime_get();

 	ret = iio_device_register(indio_dev);
 	if (ret < 0)
 		goto err_array_unregister;

 	return 0;

 err_array_unregister:
 	iio_map_array_unregister(indio_dev);

 err_regulator_disable:
 	regulator_disable(st->ref);

 	return ret;
 }

 static int ltc2497_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
 	struct ltc2497_st *st = iio_priv(indio_dev);

 	iio_map_array_unregister(indio_dev);
 	iio_device_unregister(indio_dev);
 	regulator_disable(st->ref);

 	return 0;
 }

 static const struct i2c_device_id ltc2497_id[] = {
 	{ "ltc2497", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ltc2497_id);

 static const struct of_device_id ltc2497_of_match[] = {
 	{ .compatible = "lltc,ltc2497", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ltc2497_of_match);

 static struct i2c_driver ltc2497_driver = {
 	.driver = {
 		.name = "ltc2497",
 		.of_match_table = of_match_ptr(ltc2497_of_match),
 	},
 	.probe = ltc2497_probe,
 	.remove = ltc2497_remove,
 	.id_table = ltc2497_id,
 };
 module_i2c_driver(ltc2497_driver);

 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC
	*
	* Copyright (C) 2017 Analog Devices Inc.
	*
	* Licensed under the GPL-2.
	*
	* Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
	*/

	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/driver.h>
	#include <linux/iio/sysfs.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/regulator/consumer.h>

	#define LTC2497_ENABLE 0xA0
	#define LTC2497_SGL BIT(4)
	#define LTC2497_DIFF 0
	#define LTC2497_SIGN BIT(3)
	#define LTC2497_CONFIG_DEFAULT LTC2497_ENABLE
	#define LTC2497_CONVERSION_TIME_MS 150ULL

	struct ltc2497_st {
	struct i2c_client *client;
	struct regulator *ref;
	ktime_t time_prev;
	u8 addr_prev;
	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	*/
	__be32 buf ____cacheline_aligned;
	};

	static int ltc2497_wait_conv(struct ltc2497_st *st)
	{
	s64 time_elapsed;

	time_elapsed = ktime_ms_delta(ktime_get(), st->time_prev);

	if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
	/* delay if conversion time not passed
	* since last read or write
	*/
	if (msleep_interruptible(
	LTC2497_CONVERSION_TIME_MS - time_elapsed))
	return -ERESTARTSYS;

	return 0;
	}

	if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
	/* We're in automatic mode -
	* so the last reading is stil not outdated
	*/
	return 0;
	}

	return 1;
	}

	static int ltc2497_read(struct ltc2497_st st, u8 address, int val)
	{
	struct i2c_client *client = st->client;
	int ret;

	ret = ltc2497_wait_conv(st);
	if (ret < 0)
	return ret;

	if (ret \|\| st->addr_prev != address) {
	ret = i2c_smbus_write_byte(st->client,
	LTC2497_ENABLE \| address);
	if (ret < 0)
	return ret;
	st->addr_prev = address;
	if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
	return -ERESTARTSYS;
	}
	ret = i2c_master_recv(client, (char *)&st->buf, 3);
	if (ret < 0) {
	dev_err(&client->dev, "i2c_master_recv failed\n");
	return ret;
	}
	st->time_prev = ktime_get();

	/* convert and shift the result,
	* and finally convert from offset binary to signed integer
	*/
	*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);

	return ret;
	}

	static int ltc2497_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct ltc2497_st *st = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	mutex_lock(&indio_dev->mlock);
	ret = ltc2497_read(st, chan->address, val);
	mutex_unlock(&indio_dev->mlock);
	if (ret < 0)
	return ret;

	return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
	ret = regulator_get_voltage(st->ref);
	if (ret < 0)
	return ret;

	*val = ret / 1000;
	*val2 = 17;

	return IIO_VAL_FRACTIONAL_LOG2;

	default:
	return -EINVAL;
	}
	}

	#define LTC2497_CHAN(_chan, _addr, _ds_name) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (_chan), \
	.address = (_addr \| (_chan / 2) \| ((_chan & 1) ? LTC2497_SIGN : 0)), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.datasheet_name = (_ds_name), \
	}

	#define LTC2497_CHAN_DIFF(_chan, _addr) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
	.channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
	.address = (_addr \| _chan), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.differential = 1, \
	}

	static const struct iio_chan_spec ltc2497_channel[] = {
	LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
	LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
	LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
	LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
	LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
	LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
	LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
	LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
	LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
	LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
	LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
	LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
	LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
	LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
	LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
	LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
	LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
	LTC2497_CHAN_DIFF(0, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(1, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(2, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(3, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(4, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(5, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(6, LTC2497_DIFF \| LTC2497_SIGN),
	LTC2497_CHAN_DIFF(7, LTC2497_DIFF \| LTC2497_SIGN),
	};

	static const struct iio_info ltc2497_info = {
	.read_raw = ltc2497_read_raw,
	};

	static int ltc2497_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct iio_dev *indio_dev;
	struct ltc2497_st *st;
	struct iio_map *plat_data;
	int ret;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C \|
	I2C_FUNC_SMBUS_WRITE_BYTE))
	return -EOPNOTSUPP;

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
	if (!indio_dev)
	return -ENOMEM;

	st = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	st->client = client;

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = id->name;
	indio_dev->info = &ltc2497_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = ltc2497_channel;
	indio_dev->num_channels = ARRAY_SIZE(ltc2497_channel);

	st->ref = devm_regulator_get(&client->dev, "vref");
	if (IS_ERR(st->ref))
	return PTR_ERR(st->ref);

	ret = regulator_enable(st->ref);
	if (ret < 0)
	return ret;

	if (client->dev.platform_data) {
	plat_data = ((struct iio_map *)client->dev.platform_data);
	ret = iio_map_array_register(indio_dev, plat_data);
	if (ret) {
	dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
	goto err_regulator_disable;
	}
	}

	ret = i2c_smbus_write_byte(st->client, LTC2497_CONFIG_DEFAULT);
	if (ret < 0)
	goto err_array_unregister;

	st->addr_prev = LTC2497_CONFIG_DEFAULT;
	st->time_prev = ktime_get();

	ret = iio_device_register(indio_dev);
	if (ret < 0)
	goto err_array_unregister;

	return 0;

	err_array_unregister:
	iio_map_array_unregister(indio_dev);

	err_regulator_disable:
	regulator_disable(st->ref);

	return ret;
	}

	static int ltc2497_remove(struct i2c_client *client)
	{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct ltc2497_st *st = iio_priv(indio_dev);

	iio_map_array_unregister(indio_dev);
	iio_device_unregister(indio_dev);
	regulator_disable(st->ref);

	return 0;
	}

	static const struct i2c_device_id ltc2497_id[] = {
	{ "ltc2497", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ltc2497_id);

	static const struct of_device_id ltc2497_of_match[] = {
	{ .compatible = "lltc,ltc2497", },
	{},
	};
	MODULE_DEVICE_TABLE(of, ltc2497_of_match);

	static struct i2c_driver ltc2497_driver = {
	.driver = {
	.name = "ltc2497",
	.of_match_table = of_match_ptr(ltc2497_of_match),
	},
	.probe = ltc2497_probe,
	.remove = ltc2497_remove,
	.id_table = ltc2497_id,
	};
	module_i2c_driver(ltc2497_driver);

	MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
	MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
	MODULE_LICENSE("GPL v2");