drivers/iio/adc/mcp3911.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Driver for Microchip MCP3911, Two-channel Analog Front End
  *
  * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
  * Copyright (C) 2018 Kent Gustavsson <kent@minoris.se>
  */
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/iio/iio.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>

 #define MCP3911_REG_CHANNEL0		0x00
 #define MCP3911_REG_CHANNEL1		0x03
 #define MCP3911_REG_MOD			0x06
 #define MCP3911_REG_PHASE		0x07
 #define MCP3911_REG_GAIN		0x09

 #define MCP3911_REG_STATUSCOM		0x0a
 #define MCP3911_STATUSCOM_CH1_24WIDTH	BIT(4)
 #define MCP3911_STATUSCOM_CH0_24WIDTH	BIT(3)
 #define MCP3911_STATUSCOM_EN_OFFCAL	BIT(2)
 #define MCP3911_STATUSCOM_EN_GAINCAL	BIT(1)

 #define MCP3911_REG_CONFIG		0x0c
 #define MCP3911_CONFIG_CLKEXT		BIT(1)
 #define MCP3911_CONFIG_VREFEXT		BIT(2)

 #define MCP3911_REG_OFFCAL_CH0		0x0e
 #define MCP3911_REG_GAINCAL_CH0		0x11
 #define MCP3911_REG_OFFCAL_CH1		0x14
 #define MCP3911_REG_GAINCAL_CH1		0x17
 #define MCP3911_REG_VREFCAL		0x1a

 #define MCP3911_CHANNEL(x)		(MCP3911_REG_CHANNEL0 + x * 3)
 #define MCP3911_OFFCAL(x)		(MCP3911_REG_OFFCAL_CH0 + x * 6)

 /* Internal voltage reference in uV */
 #define MCP3911_INT_VREF_UV		1200000

 #define MCP3911_REG_READ(reg, id)	((((reg) << 1) | ((id) << 5) | (1 << 0)) & 0xff)
 #define MCP3911_REG_WRITE(reg, id)	((((reg) << 1) | ((id) << 5) | (0 << 0)) & 0xff)

 #define MCP3911_NUM_CHANNELS		2

 struct mcp3911 {
 	struct spi_device *spi;
 	struct mutex lock;
 	struct regulator *vref;
 	struct clk *clki;
 	u32 dev_addr;
 };

 static int mcp3911_read(struct mcp3911 *adc, u8 reg, u32 *val, u8 len)
 {
 	int ret;

 	reg = MCP3911_REG_READ(reg, adc->dev_addr);
 	ret = spi_write_then_read(adc->spi, &reg, 1, val, len);
 	if (ret < 0)
 		return ret;

 	be32_to_cpus(val);
 	*val >>= ((4 - len) * 8);
 	dev_dbg(&adc->spi->dev, "reading 0x%x from register 0x%x\n", *val,
 		reg >> 1);
 	return ret;
 }

 static int mcp3911_write(struct mcp3911 *adc, u8 reg, u32 val, u8 len)
 {
 	dev_dbg(&adc->spi->dev, "writing 0x%x to register 0x%x\n", val, reg);

 	val <<= (3 - len) * 8;
 	cpu_to_be32s(&val);
 	val |= MCP3911_REG_WRITE(reg, adc->dev_addr);

 	return spi_write(adc->spi, &val, len + 1);
 }

 static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask,
 		u32 val, u8 len)
 {
 	u32 tmp;
 	int ret;

 	ret = mcp3911_read(adc, reg, &tmp, len);
 	if (ret)
 		return ret;

 	val &= mask;
 	val |= tmp & ~mask;
 	return mcp3911_write(adc, reg, val, len);
 }

 static int mcp3911_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *channel, int *val,
 			    int *val2, long mask)
 {
 	struct mcp3911 *adc = iio_priv(indio_dev);
 	int ret = -EINVAL;

 	mutex_lock(&adc->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = mcp3911_read(adc,
 				   MCP3911_CHANNEL(channel->channel), val, 3);
 		if (ret)
 			goto out;

 		ret = IIO_VAL_INT;
 		break;

 	case IIO_CHAN_INFO_OFFSET:
 		ret = mcp3911_read(adc,
 				   MCP3911_OFFCAL(channel->channel), val, 3);
 		if (ret)
 			goto out;

 		ret = IIO_VAL_INT;
 		break;

 	case IIO_CHAN_INFO_SCALE:
 		if (adc->vref) {
 			ret = regulator_get_voltage(adc->vref);
 			if (ret < 0) {
 				dev_err(indio_dev->dev.parent,
 					"failed to get vref voltage: %d\n",
 				       ret);
 				goto out;
 			}

 			*val = ret / 1000;
 		} else {
 			*val = MCP3911_INT_VREF_UV;
 		}

 		*val2 = 24;
 		ret = IIO_VAL_FRACTIONAL_LOG2;
 		break;
 	}

 out:
 	mutex_unlock(&adc->lock);
 	return ret;
 }

 static int mcp3911_write_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *channel, int val,
 			    int val2, long mask)
 {
 	struct mcp3911 *adc = iio_priv(indio_dev);
 	int ret = -EINVAL;

 	mutex_lock(&adc->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_OFFSET:
 		if (val2 != 0) {
 			ret = -EINVAL;
 			goto out;
 		}

 		/* Write offset */
 		ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val,
 				    3);
 		if (ret)
 			goto out;

 		/* Enable offset*/
 		ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM,
 				MCP3911_STATUSCOM_EN_OFFCAL,
 				MCP3911_STATUSCOM_EN_OFFCAL, 2);
 		break;
 	}

 out:
 	mutex_unlock(&adc->lock);
 	return ret;
 }

 #define MCP3911_CHAN(idx) {					\
 		.type = IIO_VOLTAGE,				\
 		.indexed = 1,					\
 		.channel = idx,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
 			BIT(IIO_CHAN_INFO_OFFSET) |		\
 			BIT(IIO_CHAN_INFO_SCALE),		\
 }

 static const struct iio_chan_spec mcp3911_channels[] = {
 	MCP3911_CHAN(0),
 	MCP3911_CHAN(1),
 };

 static const struct iio_info mcp3911_info = {
 	.read_raw = mcp3911_read_raw,
 	.write_raw = mcp3911_write_raw,
 };

 static int mcp3911_config(struct mcp3911 *adc, struct device_node *of_node)
 {
 	u32 configreg;
 	int ret;

 	of_property_read_u32(of_node, "device-addr", &adc->dev_addr);
 	if (adc->dev_addr > 3) {
 		dev_err(&adc->spi->dev,
 			"invalid device address (%i). Must be in range 0-3.\n",
 			adc->dev_addr);
 		return -EINVAL;
 	}
 	dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);

 	ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2);
 	if (ret)
 		return ret;

 	if (adc->vref) {
 		dev_dbg(&adc->spi->dev, "use external voltage reference\n");
 		configreg |= MCP3911_CONFIG_VREFEXT;
 	} else {
 		dev_dbg(&adc->spi->dev,
 			"use internal voltage reference (1.2V)\n");
 		configreg &= ~MCP3911_CONFIG_VREFEXT;
 	}

 	if (adc->clki) {
 		dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");
 		configreg |= MCP3911_CONFIG_CLKEXT;
 	} else {
 		dev_dbg(&adc->spi->dev,
 			"use crystal oscillator as clocksource\n");
 		configreg &= ~MCP3911_CONFIG_CLKEXT;
 	}

 	return  mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
 }

 static int mcp3911_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
 	struct mcp3911 *adc;
 	int ret;

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

 	adc = iio_priv(indio_dev);
 	adc->spi = spi;

 	adc->vref = devm_regulator_get_optional(&adc->spi->dev, "vref");
 	if (IS_ERR(adc->vref)) {
 		if (PTR_ERR(adc->vref) == -ENODEV) {
 			adc->vref = NULL;
 		} else {
 			dev_err(&adc->spi->dev,
 				"failed to get regulator (%ld)\n",
 				PTR_ERR(adc->vref));
 			return PTR_ERR(adc->vref);
 		}

 	} else {
 		ret = regulator_enable(adc->vref);
 		if (ret)
 			return ret;
 	}

 	adc->clki = devm_clk_get(&adc->spi->dev, NULL);
 	if (IS_ERR(adc->clki)) {
 		if (PTR_ERR(adc->clki) == -ENOENT) {
 			adc->clki = NULL;
 		} else {
 			dev_err(&adc->spi->dev,
 				"failed to get adc clk (%ld)\n",
 				PTR_ERR(adc->clki));
 			ret = PTR_ERR(adc->clki);
 			goto reg_disable;
 		}
 	} else {
 		ret = clk_prepare_enable(adc->clki);
 		if (ret < 0) {
 			dev_err(&adc->spi->dev,
 				"Failed to enable clki: %d\n", ret);
 			goto reg_disable;
 		}
 	}

 	ret = mcp3911_config(adc, spi->dev.of_node);
 	if (ret)
 		goto clk_disable;

 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &mcp3911_info;
 	spi_set_drvdata(spi, indio_dev);

 	indio_dev->channels = mcp3911_channels;
 	indio_dev->num_channels = ARRAY_SIZE(mcp3911_channels);

 	mutex_init(&adc->lock);

 	ret = iio_device_register(indio_dev);
 	if (ret)
 		goto clk_disable;

 	return ret;

 clk_disable:
 	clk_disable_unprepare(adc->clki);
 reg_disable:
 	if (adc->vref)
 		regulator_disable(adc->vref);

 	return ret;
 }

 static int mcp3911_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct mcp3911 *adc = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);

 	clk_disable_unprepare(adc->clki);
 	if (adc->vref)
 		regulator_disable(adc->vref);

 	return 0;
 }

 static const struct of_device_id mcp3911_dt_ids[] = {
 	{ .compatible = "microchip,mcp3911" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, mcp3911_dt_ids);

 static const struct spi_device_id mcp3911_id[] = {
 	{ "mcp3911", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, mcp3911_id);

 static struct spi_driver mcp3911_driver = {
 	.driver = {
 		.name = "mcp3911",
 		.of_match_table = mcp3911_dt_ids,
 	},
 	.probe = mcp3911_probe,
 	.remove = mcp3911_remove,
 	.id_table = mcp3911_id,
 };
 module_spi_driver(mcp3911_driver);

 MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
 MODULE_AUTHOR("Kent Gustavsson <kent@minoris.se>");
 MODULE_DESCRIPTION("Microchip Technology MCP3911");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Driver for Microchip MCP3911, Two-channel Analog Front End
	*
	* Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
	* Copyright (C) 2018 Kent Gustavsson <kent@minoris.se>
	*/
	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/iio/iio.h>
	#include <linux/module.h>
	#include <linux/regulator/consumer.h>
	#include <linux/spi/spi.h>

	#define MCP3911_REG_CHANNEL0 0x00
	#define MCP3911_REG_CHANNEL1 0x03
	#define MCP3911_REG_MOD 0x06
	#define MCP3911_REG_PHASE 0x07
	#define MCP3911_REG_GAIN 0x09

	#define MCP3911_REG_STATUSCOM 0x0a
	#define MCP3911_STATUSCOM_CH1_24WIDTH BIT(4)
	#define MCP3911_STATUSCOM_CH0_24WIDTH BIT(3)
	#define MCP3911_STATUSCOM_EN_OFFCAL BIT(2)
	#define MCP3911_STATUSCOM_EN_GAINCAL BIT(1)

	#define MCP3911_REG_CONFIG 0x0c
	#define MCP3911_CONFIG_CLKEXT BIT(1)
	#define MCP3911_CONFIG_VREFEXT BIT(2)

	#define MCP3911_REG_OFFCAL_CH0 0x0e
	#define MCP3911_REG_GAINCAL_CH0 0x11
	#define MCP3911_REG_OFFCAL_CH1 0x14
	#define MCP3911_REG_GAINCAL_CH1 0x17
	#define MCP3911_REG_VREFCAL 0x1a

	#define MCP3911_CHANNEL(x) (MCP3911_REG_CHANNEL0 + x * 3)
	#define MCP3911_OFFCAL(x) (MCP3911_REG_OFFCAL_CH0 + x * 6)

	/* Internal voltage reference in uV */
	#define MCP3911_INT_VREF_UV 1200000

	#define MCP3911_REG_READ(reg, id) ((((reg) << 1) \| ((id) << 5) \| (1 << 0)) & 0xff)
	#define MCP3911_REG_WRITE(reg, id) ((((reg) << 1) \| ((id) << 5) \| (0 << 0)) & 0xff)

	#define MCP3911_NUM_CHANNELS 2

	struct mcp3911 {
	struct spi_device *spi;
	struct mutex lock;
	struct regulator *vref;
	struct clk *clki;
	u32 dev_addr;
	};

	static int mcp3911_read(struct mcp3911 adc, u8 reg, u32 val, u8 len)
	{
	int ret;

	reg = MCP3911_REG_READ(reg, adc->dev_addr);
	ret = spi_write_then_read(adc->spi, &reg, 1, val, len);
	if (ret < 0)
	return ret;

	be32_to_cpus(val);
	val >>= ((4 - len) 8);
	dev_dbg(&adc->spi->dev, "reading 0x%x from register 0x%x\n", *val,
	reg >> 1);
	return ret;
	}

	static int mcp3911_write(struct mcp3911 *adc, u8 reg, u32 val, u8 len)
	{
	dev_dbg(&adc->spi->dev, "writing 0x%x to register 0x%x\n", val, reg);

	val <<= (3 - len) * 8;
	cpu_to_be32s(&val);
	val \|= MCP3911_REG_WRITE(reg, adc->dev_addr);

	return spi_write(adc->spi, &val, len + 1);
	}

	static int mcp3911_update(struct mcp3911 *adc, u8 reg, u32 mask,
	u32 val, u8 len)
	{
	u32 tmp;
	int ret;

	ret = mcp3911_read(adc, reg, &tmp, len);
	if (ret)
	return ret;

	val &= mask;
	val \|= tmp & ~mask;
	return mcp3911_write(adc, reg, val, len);
	}

	static int mcp3911_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const channel, int val,
	int *val2, long mask)
	{
	struct mcp3911 *adc = iio_priv(indio_dev);
	int ret = -EINVAL;

	mutex_lock(&adc->lock);
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = mcp3911_read(adc,
	MCP3911_CHANNEL(channel->channel), val, 3);
	if (ret)
	goto out;

	ret = IIO_VAL_INT;
	break;

	case IIO_CHAN_INFO_OFFSET:
	ret = mcp3911_read(adc,
	MCP3911_OFFCAL(channel->channel), val, 3);
	if (ret)
	goto out;

	ret = IIO_VAL_INT;
	break;

	case IIO_CHAN_INFO_SCALE:
	if (adc->vref) {
	ret = regulator_get_voltage(adc->vref);
	if (ret < 0) {
	dev_err(indio_dev->dev.parent,
	"failed to get vref voltage: %d\n",
	ret);
	goto out;
	}

	*val = ret / 1000;
	} else {
	*val = MCP3911_INT_VREF_UV;
	}

	*val2 = 24;
	ret = IIO_VAL_FRACTIONAL_LOG2;
	break;
	}

	out:
	mutex_unlock(&adc->lock);
	return ret;
	}

	static int mcp3911_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *channel, int val,
	int val2, long mask)
	{
	struct mcp3911 *adc = iio_priv(indio_dev);
	int ret = -EINVAL;

	mutex_lock(&adc->lock);
	switch (mask) {
	case IIO_CHAN_INFO_OFFSET:
	if (val2 != 0) {
	ret = -EINVAL;
	goto out;
	}

	/* Write offset */
	ret = mcp3911_write(adc, MCP3911_OFFCAL(channel->channel), val,
	3);
	if (ret)
	goto out;

	/* Enable offset*/
	ret = mcp3911_update(adc, MCP3911_REG_STATUSCOM,
	MCP3911_STATUSCOM_EN_OFFCAL,
	MCP3911_STATUSCOM_EN_OFFCAL, 2);
	break;
	}

	out:
	mutex_unlock(&adc->lock);
	return ret;
	}

	#define MCP3911_CHAN(idx) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = idx, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \| \
	BIT(IIO_CHAN_INFO_OFFSET) \| \
	BIT(IIO_CHAN_INFO_SCALE), \
	}

	static const struct iio_chan_spec mcp3911_channels[] = {
	MCP3911_CHAN(0),
	MCP3911_CHAN(1),
	};

	static const struct iio_info mcp3911_info = {
	.read_raw = mcp3911_read_raw,
	.write_raw = mcp3911_write_raw,
	};

	static int mcp3911_config(struct mcp3911 adc, struct device_node of_node)
	{
	u32 configreg;
	int ret;

	of_property_read_u32(of_node, "device-addr", &adc->dev_addr);
	if (adc->dev_addr > 3) {
	dev_err(&adc->spi->dev,
	"invalid device address (%i). Must be in range 0-3.\n",
	adc->dev_addr);
	return -EINVAL;
	}
	dev_dbg(&adc->spi->dev, "use device address %i\n", adc->dev_addr);

	ret = mcp3911_read(adc, MCP3911_REG_CONFIG, &configreg, 2);
	if (ret)
	return ret;

	if (adc->vref) {
	dev_dbg(&adc->spi->dev, "use external voltage reference\n");
	configreg \|= MCP3911_CONFIG_VREFEXT;
	} else {
	dev_dbg(&adc->spi->dev,
	"use internal voltage reference (1.2V)\n");
	configreg &= ~MCP3911_CONFIG_VREFEXT;
	}

	if (adc->clki) {
	dev_dbg(&adc->spi->dev, "use external clock as clocksource\n");
	configreg \|= MCP3911_CONFIG_CLKEXT;
	} else {
	dev_dbg(&adc->spi->dev,
	"use crystal oscillator as clocksource\n");
	configreg &= ~MCP3911_CONFIG_CLKEXT;
	}

	return mcp3911_write(adc, MCP3911_REG_CONFIG, configreg, 2);
	}

	static int mcp3911_probe(struct spi_device *spi)
	{
	struct iio_dev *indio_dev;
	struct mcp3911 *adc;
	int ret;

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

	adc = iio_priv(indio_dev);
	adc->spi = spi;

	adc->vref = devm_regulator_get_optional(&adc->spi->dev, "vref");
	if (IS_ERR(adc->vref)) {
	if (PTR_ERR(adc->vref) == -ENODEV) {
	adc->vref = NULL;
	} else {
	dev_err(&adc->spi->dev,
	"failed to get regulator (%ld)\n",
	PTR_ERR(adc->vref));
	return PTR_ERR(adc->vref);
	}

	} else {
	ret = regulator_enable(adc->vref);
	if (ret)
	return ret;
	}

	adc->clki = devm_clk_get(&adc->spi->dev, NULL);
	if (IS_ERR(adc->clki)) {
	if (PTR_ERR(adc->clki) == -ENOENT) {
	adc->clki = NULL;
	} else {
	dev_err(&adc->spi->dev,
	"failed to get adc clk (%ld)\n",
	PTR_ERR(adc->clki));
	ret = PTR_ERR(adc->clki);
	goto reg_disable;
	}
	} else {
	ret = clk_prepare_enable(adc->clki);
	if (ret < 0) {
	dev_err(&adc->spi->dev,
	"Failed to enable clki: %d\n", ret);
	goto reg_disable;
	}
	}

	ret = mcp3911_config(adc, spi->dev.of_node);
	if (ret)
	goto clk_disable;

	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &mcp3911_info;
	spi_set_drvdata(spi, indio_dev);

	indio_dev->channels = mcp3911_channels;
	indio_dev->num_channels = ARRAY_SIZE(mcp3911_channels);

	mutex_init(&adc->lock);

	ret = iio_device_register(indio_dev);
	if (ret)
	goto clk_disable;

	return ret;

	clk_disable:
	clk_disable_unprepare(adc->clki);
	reg_disable:
	if (adc->vref)
	regulator_disable(adc->vref);

	return ret;
	}

	static int mcp3911_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct mcp3911 *adc = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	clk_disable_unprepare(adc->clki);
	if (adc->vref)
	regulator_disable(adc->vref);

	return 0;
	}

	static const struct of_device_id mcp3911_dt_ids[] = {
	{ .compatible = "microchip,mcp3911" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, mcp3911_dt_ids);

	static const struct spi_device_id mcp3911_id[] = {
	{ "mcp3911", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(spi, mcp3911_id);

	static struct spi_driver mcp3911_driver = {
	.driver = {
	.name = "mcp3911",
	.of_match_table = mcp3911_dt_ids,
	},
	.probe = mcp3911_probe,
	.remove = mcp3911_remove,
	.id_table = mcp3911_id,
	};
	module_spi_driver(mcp3911_driver);

	MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
	MODULE_AUTHOR("Kent Gustavsson <kent@minoris.se>");
	MODULE_DESCRIPTION("Microchip Technology MCP3911");
	MODULE_LICENSE("GPL v2");