Commit cf277758 authored by Ivan Mikhaylov's avatar Ivan Mikhaylov Committed by Jonathan Cameron
Browse files

iio: adc: Add driver support for MAX34408/9 

The MAX34408/MAX34409 are two- and four-channel current monitors that are
configured and monitored with a standard I2C/SMBus serial interface. Each
unidirectional current sensor offers precision high-side operation with a
low full-scale sense voltage. The devices automatically sequence through
two or four channels and collect the current-sense samples and average them
to reduce the effect of impulse noise. The raw ADC samples are compared to
user-programmable digital thresholds to indicate overcurrent conditions.
Overcurrent conditions trigger a hardware output to provide an immediate
indication to shut down any necessary external circuitry.

Add as ADC driver which only supports current monitoring for now.

Link: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf



Signed-off-by: default avatarIvan Mikhaylov <fr0st61te@gmail.com>
Link: https://lore.kernel.org/r/20231014211254.16719-3-fr0st61te@gmail.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent f0d1a9b7

drivers/iio/adc/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -745,6 +745,17 @@ config MAX1363 
	  To compile this driver as a module, choose M here: the module will be

	  called max1363.



config MAX34408

	tristate "Maxim max34408/max344089 ADC driver"

	depends on I2C

	help

	  Say yes here to build support for Maxim max34408/max34409 current sense

	  monitor with 8-bits ADC interface with overcurrent delay/threshold and

	  shutdown delay.



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

	  called max34408.



config MAX77541_ADC

	tristate "Analog Devices MAX77541 ADC driver"

	depends on MFD_MAX77541

drivers/iio/adc/Makefile

+1 −0
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@@ -68,6 +68,7 @@ obj-$(CONFIG_MAX11205) += max11205.o 
obj-$(CONFIG_MAX11410) += max11410.o

obj-$(CONFIG_MAX1241) += max1241.o

obj-$(CONFIG_MAX1363) += max1363.o

obj-$(CONFIG_MAX34408) += max34408.o

obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o

obj-$(CONFIG_MAX9611) += max9611.o

obj-$(CONFIG_MCP320X) += mcp320x.o

drivers/iio/adc/max34408.c

0 → 100644
+276 −0
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// 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");