Commit ba56b46d authored by Angelo Dureghello's avatar Angelo Dureghello Committed by Jonathan Cameron
Browse files

iio: dac: add support for max5522 



Add initial support for DAC max5522.

Tested writing DAC A and B with some values,
from 0 to 1023, measured output voltages, driver works properly.

Additions for max5523/24/25 will follow.

Signed-off-by: default avatarAngelo Dureghello <angelo.dureghello@timesys.com>
Link: https://lore.kernel.org/r/20221106165928.223318-1-angelo.dureghello@timesys.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent f2edf0c8

drivers/iio/dac/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -357,6 +357,19 @@ config MAX517 
	  This driver can also be built as a module.  If so, the module

	  will be called max517.



config MAX5522

	tristate "Maxim MAX5522 DAC driver"

	depends on SPI_MASTER

	select REGMAP_SPI

	help

	  Say Y here if you want to build a driver for the Maxim MAX5522.



	  MAX5522 is a dual, ultra-low-power, 10-Bit, voltage-output

	  digital to analog converter (DAC) offering rail-to-rail buffered

	  voltage outputs.



	  If compiled as a module, it will be called max5522.



config MAX5821

	tristate "Maxim MAX5821 DAC driver"

	depends on I2C

drivers/iio/dac/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ obj-$(CONFIG_LTC2632) += ltc2632.o 
obj-$(CONFIG_LTC2688) += ltc2688.o

obj-$(CONFIG_M62332) += m62332.o

obj-$(CONFIG_MAX517) += max517.o

obj-$(CONFIG_MAX5522) += max5522.o

obj-$(CONFIG_MAX5821) += max5821.o

obj-$(CONFIG_MCP4725) += mcp4725.o

obj-$(CONFIG_MCP4922) += mcp4922.o

drivers/iio/dac/max5522.c

0 → 100644
+207 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Maxim MAX5522

 * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs

 *

 * Copyright 2022 Timesys Corp.

 */



#include <linux/device.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/regmap.h>

#include <linux/regulator/consumer.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>



#include <linux/iio/iio.h>



#define MAX5522_MAX_ADDR	15

#define MAX5522_CTRL_NONE	0

#define MAX5522_CTRL_LOAD_IN_A	9

#define MAX5522_CTRL_LOAD_IN_B	10



#define MAX5522_REG_DATA(x)	((x) + MAX5522_CTRL_LOAD_IN_A)



struct max5522_chip_info {

	const char *name;

	const struct iio_chan_spec *channels;

	unsigned int num_channels;

};



struct max5522_state {

	struct regmap *regmap;

	const struct max5522_chip_info *chip_info;

	unsigned short dac_cache[2];

	struct regulator *vrefin_reg;

};



#define MAX5522_CHANNEL(chan) {	\

	.type = IIO_VOLTAGE, \

	.indexed = 1, \

	.output = 1, \

	.channel = chan, \

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \

			      BIT(IIO_CHAN_INFO_SCALE), \

	.scan_type = { \

		.sign = 'u', \

		.realbits = 10, \

		.storagebits = 16, \

		.shift = 2, \

	} \

}



const struct iio_chan_spec max5522_channels[] = {

	MAX5522_CHANNEL(0),

	MAX5522_CHANNEL(1),

};



enum max5522_type {

	ID_MAX5522,

};



static const struct max5522_chip_info max5522_chip_info_tbl[] = {

	[ID_MAX5522] = {

		.name = "max5522",

		.channels = max5522_channels,

		.num_channels = 2,

	},

};



static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)

{

	return MAX5522_REG_DATA(chan->channel);

}



static int max5522_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long info)

{

	struct max5522_state *state = iio_priv(indio_dev);

	int ret;



	switch (info) {

	case IIO_CHAN_INFO_RAW:

		*val = state->dac_cache[chan->channel];

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		ret = regulator_get_voltage(state->vrefin_reg);

		if (ret < 0)

			return -EINVAL;

		*val = ret / 1000;

		*val2 = 10;

		return IIO_VAL_FRACTIONAL_LOG2;

	default:

		return -EINVAL;

	}



	return -EINVAL;

}



static int max5522_write_raw(struct iio_dev *indio_dev,

			     struct iio_chan_spec const *chan,

			     int val, int val2, long info)

{

	struct max5522_state *state = iio_priv(indio_dev);

	int rval;



	if (val > 1023 || val < 0)

		return -EINVAL;



	rval = regmap_write(state->regmap, max5522_info_to_reg(chan),

			    val << chan->scan_type.shift);

	if (rval < 0)

		return rval;



	state->dac_cache[chan->channel] = val;



	return 0;

}



static const struct iio_info max5522_info = {

	.read_raw = max5522_read_raw,

	.write_raw = max5522_write_raw,

};



static const struct regmap_config max5522_regmap_config = {

	.reg_bits = 4,

	.val_bits = 12,

	.max_register = MAX5522_MAX_ADDR,

};



static int max5522_spi_probe(struct spi_device *spi)

{

	const struct spi_device_id *id = spi_get_device_id(spi);

	struct iio_dev *indio_dev;

	struct max5522_state *state;

	int ret;



	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));

	if (indio_dev == NULL) {

		dev_err(&spi->dev, "failed to allocate iio device\n");

		return  -ENOMEM;

	}



	state = iio_priv(indio_dev);

	state->chip_info = device_get_match_data(&spi->dev);

	if (!state->chip_info) {

		state->chip_info =

			(struct max5522_chip_info *)(id->driver_data);

		if (!state->chip_info)

			return -EINVAL;

	}



	state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");

	if (IS_ERR(state->vrefin_reg))

		return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),

				     "Vrefin regulator not specified\n");



	ret = regulator_enable(state->vrefin_reg);

	if (ret) {

		return dev_err_probe(&spi->dev, ret,

				     "Failed to enable vref regulators\n");

	}



	state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);



	if (IS_ERR(state->regmap))

		return PTR_ERR(state->regmap);



	indio_dev->info = &max5522_info;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = max5522_channels;

	indio_dev->num_channels = ARRAY_SIZE(max5522_channels);

	indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;



	return devm_iio_device_register(&spi->dev, indio_dev);

}



static const struct spi_device_id max5522_ids[] = {

	{ "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },

	{}

};

MODULE_DEVICE_TABLE(spi, max5522_ids);



static const struct of_device_id max5522_of_match[] = {

	{

		.compatible = "maxim,max5522",

		.data = &max5522_chip_info_tbl[ID_MAX5522],

	},

	{}

};

MODULE_DEVICE_TABLE(of, max5522_of_match);



static struct spi_driver max5522_spi_driver = {

	.driver = {

		.name = "max5522",

		.of_match_table = max5522_of_match,

	},

	.probe = max5522_spi_probe,

	.id_table = max5522_ids,

};

module_spi_driver(max5522_spi_driver);



MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com");

MODULE_DESCRIPTION("MAX5522 DAC driver");

MODULE_LICENSE("GPL");