drivers/iio/adc/max34408.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * IIO driver for Maxim MAX34409/34408 ADC, 4-Channels/2-Channels, 8bits, I2C
  *
  * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf
  *
  * TODO: ALERT interrupt, Overcurrent delay, Shutdown delay
  */

 #include <linux/bitfield.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/property.h>
 #include <linux/regmap.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/types.h>

 #define MAX34408_STATUS_REG		0x0
 #define MAX34408_CONTROL_REG		0x1
 #define MAX34408_OCDELAY_REG		0x2
 #define MAX34408_SDDELAY_REG		0x3

 #define MAX34408_ADC1_REG		0x4
 #define MAX34408_ADC2_REG		0x5
 /* ADC3 & ADC4 always returns 0x0 on 34408 */
 #define MAX34409_ADC3_REG		0x6
 #define MAX34409_ADC4_REG		0x7

 #define MAX34408_OCT1_REG		0x8
 #define MAX34408_OCT2_REG		0x9
 #define MAX34409_OCT3_REG		0xA
 #define MAX34409_OCT4_REG		0xB

 #define MAX34408_DID_REG		0xC
 #define MAX34408_DCYY_REG		0xD
 #define MAX34408_DCWW_REG		0xE

 /* Bit masks for status register */
 #define MAX34408_STATUS_OC_MSK		GENMASK(1, 0)
 #define MAX34409_STATUS_OC_MSK		GENMASK(3, 0)
 #define MAX34408_STATUS_SHTDN		BIT(4)
 #define MAX34408_STATUS_ENA		BIT(5)

 /* Bit masks for control register */
 #define MAX34408_CONTROL_AVG0		BIT(0)
 #define MAX34408_CONTROL_AVG1		BIT(1)
 #define MAX34408_CONTROL_AVG2		BIT(2)
 #define MAX34408_CONTROL_ALERT		BIT(3)

 #define MAX34408_DEFAULT_AVG		0x4

 /* Bit masks for over current delay */
 #define MAX34408_OCDELAY_OCD_MSK	GENMASK(6, 0)
 #define MAX34408_OCDELAY_RESET		BIT(7)

 /* Bit masks for shutdown delay */
 #define MAX34408_SDDELAY_SHD_MSK	GENMASK(6, 0)
 #define MAX34408_SDDELAY_RESET		BIT(7)

 #define MAX34408_DEFAULT_RSENSE		1000

 /**
  * struct max34408_data - max34408/max34409 specific data.
  * @regmap:	device register map.
  * @dev:	max34408 device.
  * @lock:	lock for protecting access to device hardware registers, mostly
  *		for read modify write cycles for control registers.
  * @input_rsense:	Rsense values in uOhm, will be overwritten by
  *			values from channel nodes.
  */
 struct max34408_data {
 	struct regmap *regmap;
 	struct device *dev;
 	struct mutex lock;
 	u32 input_rsense[4];
 };

 static const struct regmap_config max34408_regmap_config = {
 	.reg_bits	= 8,
 	.val_bits	= 8,
 	.max_register	= MAX34408_DCWW_REG,
 };

 struct max34408_adc_model_data {
 	const char *model_name;
 	const struct iio_chan_spec *channels;
 	const int num_channels;
 };

 #define MAX34008_CHANNEL(_index, _address)			\
 	{							\
 		.type = IIO_CURRENT,				\
 		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) | \
 					  BIT(IIO_CHAN_INFO_SCALE) | \
 					  BIT(IIO_CHAN_INFO_OFFSET), \
 		.channel = (_index),				\
 		.address = (_address),				\
 		.indexed = 1,					\
 	}

 static const struct iio_chan_spec max34408_channels[] = {
 	MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
 	MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
 };

 static const struct iio_chan_spec max34409_channels[] = {
 	MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
 	MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
 	MAX34008_CHANNEL(2, MAX34409_ADC3_REG),
 	MAX34008_CHANNEL(3, MAX34409_ADC4_REG),
 };

 static int max34408_read_adc_avg(struct max34408_data *max34408,
 				 const struct iio_chan_spec *chan, int *val)
 {
 	unsigned int ctrl;
 	int rc;

 	guard(mutex)(&max34408->lock);
 	rc = regmap_read(max34408->regmap, MAX34408_CONTROL_REG, (u32 *)&ctrl);
 	if (rc)
 		return rc;

 	/* set averaging (0b100) default values*/
 	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG,
 			  MAX34408_DEFAULT_AVG);
 	if (rc) {
 		dev_err(max34408->dev,
 			"Error (%d) writing control register\n", rc);
 		return rc;
 	}

 	rc = regmap_read(max34408->regmap, chan->address, val);
 	if (rc)
 		return rc;

 	/* back to old values */
 	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, ctrl);
 	if (rc)
 		dev_err(max34408->dev,
 			"Error (%d) writing control register\n", rc);

 	return rc;
 }

 static int max34408_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val, int *val2, long mask)
 {
 	struct max34408_data *max34408 = iio_priv(indio_dev);
 	int rc;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		rc = max34408_read_adc_avg(max34408, chan, val);
 		if (rc)
 			return rc;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		/*
 		 * calcluate current for 8bit ADC with Rsense
 		 * value.
 		 * 10 mV * 1000 / Rsense uOhm = max current
 		 * (max current * adc val * 1000) / (2^8 - 1) mA
 		 */
 		*val = 10000 / max34408->input_rsense[chan->channel];
 		*val2 = 8;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	default:
 		return -EINVAL;
 	}
 }

 static const struct iio_info max34408_info = {
 	.read_raw	= max34408_read_raw,
 };

 static const struct max34408_adc_model_data max34408_model_data = {
 	.model_name = "max34408",
 	.channels = max34408_channels,
 	.num_channels = 2,
 };

 static const struct max34408_adc_model_data max34409_model_data = {
 	.model_name = "max34409",
 	.channels = max34409_channels,
 	.num_channels = 4,
 };

 static int max34408_probe(struct i2c_client *client)
 {
 	const struct max34408_adc_model_data *model_data;
 	struct device *dev = &client->dev;
 	struct max34408_data *max34408;
 	struct fwnode_handle *node;
 	struct iio_dev *indio_dev;
 	struct regmap *regmap;
 	int rc, i = 0;

 	model_data = i2c_get_match_data(client);
 	if (!model_data)
 		return -EINVAL;

 	regmap = devm_regmap_init_i2c(client, &max34408_regmap_config);
 	if (IS_ERR(regmap)) {
 		dev_err_probe(dev, PTR_ERR(regmap),
 			      "regmap_init failed\n");
 		return PTR_ERR(regmap);
 	}

 	indio_dev = devm_iio_device_alloc(dev, sizeof(*max34408));
 	if (!indio_dev)
 		return -ENOMEM;

 	max34408 = iio_priv(indio_dev);
 	max34408->regmap = regmap;
 	max34408->dev = dev;
 	mutex_init(&max34408->lock);

 	device_for_each_child_node(dev, node) {
 		fwnode_property_read_u32(node, "maxim,rsense-val-micro-ohms",
 					 &max34408->input_rsense[i]);
 		i++;
 	}

 	/* disable ALERT and averaging */
 	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, 0x0);
 	if (rc)
 		return rc;

 	indio_dev->channels = model_data->channels;
 	indio_dev->num_channels = model_data->num_channels;
 	indio_dev->name = model_data->model_name;

 	indio_dev->info = &max34408_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	return devm_iio_device_register(dev, indio_dev);
 }

 static const struct of_device_id max34408_of_match[] = {
 	{
 		.compatible = "maxim,max34408",
 		.data = &max34408_model_data,
 	},
 	{
 		.compatible = "maxim,max34409",
 		.data = &max34409_model_data,
 	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, max34408_of_match);

 static const struct i2c_device_id max34408_id[] = {
 	{ "max34408", (kernel_ulong_t)&max34408_model_data },
 	{ "max34409", (kernel_ulong_t)&max34409_model_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max34408_id);

 static struct i2c_driver max34408_driver = {
 	.driver = {
 		.name   = "max34408",
 		.of_match_table = max34408_of_match,
 	},
 	.probe = max34408_probe,
 	.id_table = max34408_id,
 };
 module_i2c_driver(max34408_driver);

 MODULE_AUTHOR("Ivan Mikhaylov <fr0st61te@gmail.com>");
 MODULE_DESCRIPTION("Maxim MAX34408/34409 ADC driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* IIO driver for Maxim MAX34409/34408 ADC, 4-Channels/2-Channels, 8bits, I2C
	*
	* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf
	*
	* TODO: ALERT interrupt, Overcurrent delay, Shutdown delay
	*/

	#include <linux/bitfield.h>
	#include <linux/init.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/property.h>
	#include <linux/regmap.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/types.h>

	#define MAX34408_STATUS_REG 0x0
	#define MAX34408_CONTROL_REG 0x1
	#define MAX34408_OCDELAY_REG 0x2
	#define MAX34408_SDDELAY_REG 0x3

	#define MAX34408_ADC1_REG 0x4
	#define MAX34408_ADC2_REG 0x5
	/* ADC3 & ADC4 always returns 0x0 on 34408 */
	#define MAX34409_ADC3_REG 0x6
	#define MAX34409_ADC4_REG 0x7

	#define MAX34408_OCT1_REG 0x8
	#define MAX34408_OCT2_REG 0x9
	#define MAX34409_OCT3_REG 0xA
	#define MAX34409_OCT4_REG 0xB

	#define MAX34408_DID_REG 0xC
	#define MAX34408_DCYY_REG 0xD
	#define MAX34408_DCWW_REG 0xE

	/* Bit masks for status register */
	#define MAX34408_STATUS_OC_MSK GENMASK(1, 0)
	#define MAX34409_STATUS_OC_MSK GENMASK(3, 0)
	#define MAX34408_STATUS_SHTDN BIT(4)
	#define MAX34408_STATUS_ENA BIT(5)

	/* Bit masks for control register */
	#define MAX34408_CONTROL_AVG0 BIT(0)
	#define MAX34408_CONTROL_AVG1 BIT(1)
	#define MAX34408_CONTROL_AVG2 BIT(2)
	#define MAX34408_CONTROL_ALERT BIT(3)

	#define MAX34408_DEFAULT_AVG 0x4

	/* Bit masks for over current delay */
	#define MAX34408_OCDELAY_OCD_MSK GENMASK(6, 0)
	#define MAX34408_OCDELAY_RESET BIT(7)

	/* Bit masks for shutdown delay */
	#define MAX34408_SDDELAY_SHD_MSK GENMASK(6, 0)
	#define MAX34408_SDDELAY_RESET BIT(7)

	#define MAX34408_DEFAULT_RSENSE 1000

	/**
	* struct max34408_data - max34408/max34409 specific data.
	* @regmap: device register map.
	* @dev: max34408 device.
	* @lock: lock for protecting access to device hardware registers, mostly
	* for read modify write cycles for control registers.
	* @input_rsense: Rsense values in uOhm, will be overwritten by
	* values from channel nodes.
	*/
	struct max34408_data {
	struct regmap *regmap;
	struct device *dev;
	struct mutex lock;
	u32 input_rsense[4];
	};

	static const struct regmap_config max34408_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = MAX34408_DCWW_REG,
	};

	struct max34408_adc_model_data {
	const char *model_name;
	const struct iio_chan_spec *channels;
	const int num_channels;
	};

	#define MAX34008_CHANNEL(_index, _address) \
	{ \
	.type = IIO_CURRENT, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \| \
	BIT(IIO_CHAN_INFO_SCALE) \| \
	BIT(IIO_CHAN_INFO_OFFSET), \
	.channel = (_index), \
	.address = (_address), \
	.indexed = 1, \
	}

	static const struct iio_chan_spec max34408_channels[] = {
	MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
	MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
	};

	static const struct iio_chan_spec max34409_channels[] = {
	MAX34008_CHANNEL(0, MAX34408_ADC1_REG),
	MAX34008_CHANNEL(1, MAX34408_ADC2_REG),
	MAX34008_CHANNEL(2, MAX34409_ADC3_REG),
	MAX34008_CHANNEL(3, MAX34409_ADC4_REG),
	};

	static int max34408_read_adc_avg(struct max34408_data *max34408,
	const struct iio_chan_spec chan, int val)
	{
	unsigned int ctrl;
	int rc;

	guard(mutex)(&max34408->lock);
	rc = regmap_read(max34408->regmap, MAX34408_CONTROL_REG, (u32 *)&ctrl);
	if (rc)
	return rc;

	/* set averaging (0b100) default values*/
	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG,
	MAX34408_DEFAULT_AVG);
	if (rc) {
	dev_err(max34408->dev,
	"Error (%d) writing control register\n", rc);
	return rc;
	}

	rc = regmap_read(max34408->regmap, chan->address, val);
	if (rc)
	return rc;

	/* back to old values */
	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, ctrl);
	if (rc)
	dev_err(max34408->dev,
	"Error (%d) writing control register\n", rc);

	return rc;
	}

	static int max34408_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct max34408_data *max34408 = iio_priv(indio_dev);
	int rc;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	rc = max34408_read_adc_avg(max34408, chan, val);
	if (rc)
	return rc;
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	/*
	* calcluate current for 8bit ADC with Rsense
	* value.
	* 10 mV * 1000 / Rsense uOhm = max current
	* (max current * adc val * 1000) / (2^8 - 1) mA
	*/
	*val = 10000 / max34408->input_rsense[chan->channel];
	*val2 = 8;
	return IIO_VAL_FRACTIONAL_LOG2;
	default:
	return -EINVAL;
	}
	}

	static const struct iio_info max34408_info = {
	.read_raw = max34408_read_raw,
	};

	static const struct max34408_adc_model_data max34408_model_data = {
	.model_name = "max34408",
	.channels = max34408_channels,
	.num_channels = 2,
	};

	static const struct max34408_adc_model_data max34409_model_data = {
	.model_name = "max34409",
	.channels = max34409_channels,
	.num_channels = 4,
	};

	static int max34408_probe(struct i2c_client *client)
	{
	const struct max34408_adc_model_data *model_data;
	struct device *dev = &client->dev;
	struct max34408_data *max34408;
	struct fwnode_handle *node;
	struct iio_dev *indio_dev;
	struct regmap *regmap;
	int rc, i = 0;

	model_data = i2c_get_match_data(client);
	if (!model_data)
	return -EINVAL;

	regmap = devm_regmap_init_i2c(client, &max34408_regmap_config);
	if (IS_ERR(regmap)) {
	dev_err_probe(dev, PTR_ERR(regmap),
	"regmap_init failed\n");
	return PTR_ERR(regmap);
	}

	indio_dev = devm_iio_device_alloc(dev, sizeof(*max34408));
	if (!indio_dev)
	return -ENOMEM;

	max34408 = iio_priv(indio_dev);
	max34408->regmap = regmap;
	max34408->dev = dev;
	mutex_init(&max34408->lock);

	device_for_each_child_node(dev, node) {
	fwnode_property_read_u32(node, "maxim,rsense-val-micro-ohms",
	&max34408->input_rsense[i]);
	i++;
	}

	/* disable ALERT and averaging */
	rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, 0x0);
	if (rc)
	return rc;

	indio_dev->channels = model_data->channels;
	indio_dev->num_channels = model_data->num_channels;
	indio_dev->name = model_data->model_name;

	indio_dev->info = &max34408_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	return devm_iio_device_register(dev, indio_dev);
	}

	static const struct of_device_id max34408_of_match[] = {
	{
	.compatible = "maxim,max34408",
	.data = &max34408_model_data,
	},
	{
	.compatible = "maxim,max34409",
	.data = &max34409_model_data,
	},
	{ }
	};
	MODULE_DEVICE_TABLE(of, max34408_of_match);

	static const struct i2c_device_id max34408_id[] = {
	{ "max34408", (kernel_ulong_t)&max34408_model_data },
	{ "max34409", (kernel_ulong_t)&max34409_model_data },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, max34408_id);

	static struct i2c_driver max34408_driver = {
	.driver = {
	.name = "max34408",
	.of_match_table = max34408_of_match,
	},
	.probe = max34408_probe,
	.id_table = max34408_id,
	};
	module_i2c_driver(max34408_driver);

	MODULE_AUTHOR("Ivan Mikhaylov <fr0st61te@gmail.com>");
	MODULE_DESCRIPTION("Maxim MAX34408/34409 ADC driver");
	MODULE_LICENSE("GPL");