drivers/iio/dac/stm32-dac.c - arm/linux - Git at Google

 /*
  * This file is part of STM32 DAC driver
  *
  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
  * Authors: Amelie Delaunay <amelie.delaunay@st.com>
  *	    Fabrice Gasnier <fabrice.gasnier@st.com>
  *
  * License type: GPLv2
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  * or FITNESS FOR A PARTICULAR PURPOSE.
  * See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/iio/iio.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>

 #include "stm32-dac-core.h"

 #define STM32_DAC_CHANNEL_1		1
 #define STM32_DAC_CHANNEL_2		2
 #define STM32_DAC_IS_CHAN_1(ch)		((ch) & STM32_DAC_CHANNEL_1)

 /**
  * struct stm32_dac - private data of DAC driver
  * @common:		reference to DAC common data
  */
 struct stm32_dac {
 	struct stm32_dac_common *common;
 };

 static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
 {
 	struct stm32_dac *dac = iio_priv(indio_dev);
 	u32 en, val;
 	int ret;

 	ret = regmap_read(dac->common->regmap, STM32_DAC_CR, &val);
 	if (ret < 0)
 		return ret;
 	if (STM32_DAC_IS_CHAN_1(channel))
 		en = FIELD_GET(STM32_DAC_CR_EN1, val);
 	else
 		en = FIELD_GET(STM32_DAC_CR_EN2, val);

 	return !!en;
 }

 static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
 				      bool enable)
 {
 	struct stm32_dac *dac = iio_priv(indio_dev);
 	u32 msk = STM32_DAC_IS_CHAN_1(ch) ? STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2;
 	u32 en = enable ? msk : 0;
 	int ret;

 	ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
 	if (ret < 0) {
 		dev_err(&indio_dev->dev, "%s failed\n", en ?
 			"Enable" : "Disable");
 		return ret;
 	}

 	/*
 	 * When HFSEL is set, it is not allowed to write the DHRx register
 	 * during 8 clock cycles after the ENx bit is set. It is not allowed
 	 * to make software/hardware trigger during this period either.
 	 */
 	if (en && dac->common->hfsel)
 		udelay(1);

 	return 0;
 }

 static int stm32_dac_get_value(struct stm32_dac *dac, int channel, int *val)
 {
 	int ret;

 	if (STM32_DAC_IS_CHAN_1(channel))
 		ret = regmap_read(dac->common->regmap, STM32_DAC_DOR1, val);
 	else
 		ret = regmap_read(dac->common->regmap, STM32_DAC_DOR2, val);

 	return ret ? ret : IIO_VAL_INT;
 }

 static int stm32_dac_set_value(struct stm32_dac *dac, int channel, int val)
 {
 	int ret;

 	if (STM32_DAC_IS_CHAN_1(channel))
 		ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R1, val);
 	else
 		ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R2, val);

 	return ret;
 }

 static int stm32_dac_read_raw(struct iio_dev *indio_dev,
 			      struct iio_chan_spec const *chan,
 			      int *val, int *val2, long mask)
 {
 	struct stm32_dac *dac = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		return stm32_dac_get_value(dac, chan->channel, val);
 	case IIO_CHAN_INFO_SCALE:
 		*val = dac->common->vref_mv;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	default:
 		return -EINVAL;
 	}
 }

 static int stm32_dac_write_raw(struct iio_dev *indio_dev,
 			       struct iio_chan_spec const *chan,
 			       int val, int val2, long mask)
 {
 	struct stm32_dac *dac = iio_priv(indio_dev);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		return stm32_dac_set_value(dac, chan->channel, val);
 	default:
 		return -EINVAL;
 	}
 }

 static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev,
 					unsigned reg, unsigned writeval,
 					unsigned *readval)
 {
 	struct stm32_dac *dac = iio_priv(indio_dev);

 	if (!readval)
 		return regmap_write(dac->common->regmap, reg, writeval);
 	else
 		return regmap_read(dac->common->regmap, reg, readval);
 }

 static const struct iio_info stm32_dac_iio_info = {
 	.read_raw = stm32_dac_read_raw,
 	.write_raw = stm32_dac_write_raw,
 	.debugfs_reg_access = stm32_dac_debugfs_reg_access,
 	.driver_module = THIS_MODULE,
 };

 static const char * const stm32_dac_powerdown_modes[] = {
 	"three_state",
 };

 static int stm32_dac_get_powerdown_mode(struct iio_dev *indio_dev,
 					const struct iio_chan_spec *chan)
 {
 	return 0;
 }

 static int stm32_dac_set_powerdown_mode(struct iio_dev *indio_dev,
 					const struct iio_chan_spec *chan,
 					unsigned int type)
 {
 	return 0;
 }

 static ssize_t stm32_dac_read_powerdown(struct iio_dev *indio_dev,
 					uintptr_t private,
 					const struct iio_chan_spec *chan,
 					char *buf)
 {
 	int ret = stm32_dac_is_enabled(indio_dev, chan->channel);

 	if (ret < 0)
 		return ret;

 	return sprintf(buf, "%d\n", ret ? 0 : 1);
 }

 static ssize_t stm32_dac_write_powerdown(struct iio_dev *indio_dev,
 					 uintptr_t private,
 					 const struct iio_chan_spec *chan,
 					 const char *buf, size_t len)
 {
 	bool powerdown;
 	int ret;

 	ret = strtobool(buf, &powerdown);
 	if (ret)
 		return ret;

 	ret = stm32_dac_set_enable_state(indio_dev, chan->channel, !powerdown);
 	if (ret)
 		return ret;

 	return len;
 }

 static const struct iio_enum stm32_dac_powerdown_mode_en = {
 	.items = stm32_dac_powerdown_modes,
 	.num_items = ARRAY_SIZE(stm32_dac_powerdown_modes),
 	.get = stm32_dac_get_powerdown_mode,
 	.set = stm32_dac_set_powerdown_mode,
 };

 static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = {
 	{
 		.name = "powerdown",
 		.read = stm32_dac_read_powerdown,
 		.write = stm32_dac_write_powerdown,
 		.shared = IIO_SEPARATE,
 	},
 	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &stm32_dac_powerdown_mode_en),
 	IIO_ENUM_AVAILABLE("powerdown_mode", &stm32_dac_powerdown_mode_en),
 	{},
 };

 #define STM32_DAC_CHANNEL(chan, name) {			\
 	.type = IIO_VOLTAGE,				\
 	.indexed = 1,					\
 	.output = 1,					\
 	.channel = chan,				\
 	.info_mask_separate =				\
 		BIT(IIO_CHAN_INFO_RAW) |		\
 		BIT(IIO_CHAN_INFO_SCALE),		\
 	/* scan_index is always 0 as num_channels is 1 */ \
 	.scan_type = {					\
 		.sign = 'u',				\
 		.realbits = 12,				\
 		.storagebits = 16,			\
 	},						\
 	.datasheet_name = name,				\
 	.ext_info = stm32_dac_ext_info			\
 }

 static const struct iio_chan_spec stm32_dac_channels[] = {
 	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_1, "out1"),
 	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_2, "out2"),
 };

 static int stm32_dac_chan_of_init(struct iio_dev *indio_dev)
 {
 	struct device_node *np = indio_dev->dev.of_node;
 	unsigned int i;
 	u32 channel;
 	int ret;

 	ret = of_property_read_u32(np, "reg", &channel);
 	if (ret) {
 		dev_err(&indio_dev->dev, "Failed to read reg property\n");
 		return ret;
 	}

 	for (i = 0; i < ARRAY_SIZE(stm32_dac_channels); i++) {
 		if (stm32_dac_channels[i].channel == channel)
 			break;
 	}
 	if (i >= ARRAY_SIZE(stm32_dac_channels)) {
 		dev_err(&indio_dev->dev, "Invalid reg property\n");
 		return -EINVAL;
 	}

 	indio_dev->channels = &stm32_dac_channels[i];
 	/*
 	 * Expose only one channel here, as they can be used independently,
 	 * with separate trigger. Then separate IIO devices are instantiated
 	 * to manage this.
 	 */
 	indio_dev->num_channels = 1;

 	return 0;
 };

 static int stm32_dac_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct iio_dev *indio_dev;
 	struct stm32_dac *dac;
 	int ret;

 	if (!np)
 		return -ENODEV;

 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
 	if (!indio_dev)
 		return -ENOMEM;
 	platform_set_drvdata(pdev, indio_dev);

 	dac = iio_priv(indio_dev);
 	dac->common = dev_get_drvdata(pdev->dev.parent);
 	indio_dev->name = dev_name(&pdev->dev);
 	indio_dev->dev.parent = &pdev->dev;
 	indio_dev->dev.of_node = pdev->dev.of_node;
 	indio_dev->info = &stm32_dac_iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	ret = stm32_dac_chan_of_init(indio_dev);
 	if (ret < 0)
 		return ret;

 	return devm_iio_device_register(&pdev->dev, indio_dev);
 }

 static const struct of_device_id stm32_dac_of_match[] = {
 	{ .compatible = "st,stm32-dac", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, stm32_dac_of_match);

 static struct platform_driver stm32_dac_driver = {
 	.probe = stm32_dac_probe,
 	.driver = {
 		.name = "stm32-dac",
 		.of_match_table = stm32_dac_of_match,
 	},
 };
 module_platform_driver(stm32_dac_driver);

 MODULE_ALIAS("platform:stm32-dac");
 MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
 MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* This file is part of STM32 DAC driver
	*
	* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
	* Authors: Amelie Delaunay <amelie.delaunay@st.com>
	* Fabrice Gasnier <fabrice.gasnier@st.com>
	*
	* License type: GPLv2
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
	* or FITNESS FOR A PARTICULAR PURPOSE.
	* See the GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/bitfield.h>
	#include <linux/delay.h>
	#include <linux/iio/iio.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>

	#include "stm32-dac-core.h"

	#define STM32_DAC_CHANNEL_1 1
	#define STM32_DAC_CHANNEL_2 2
	#define STM32_DAC_IS_CHAN_1(ch) ((ch) & STM32_DAC_CHANNEL_1)

	/**
	* struct stm32_dac - private data of DAC driver
	* @common: reference to DAC common data
	*/
	struct stm32_dac {
	struct stm32_dac_common *common;
	};

	static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
	{
	struct stm32_dac *dac = iio_priv(indio_dev);
	u32 en, val;
	int ret;

	ret = regmap_read(dac->common->regmap, STM32_DAC_CR, &val);
	if (ret < 0)
	return ret;
	if (STM32_DAC_IS_CHAN_1(channel))
	en = FIELD_GET(STM32_DAC_CR_EN1, val);
	else
	en = FIELD_GET(STM32_DAC_CR_EN2, val);

	return !!en;
	}

	static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
	bool enable)
	{
	struct stm32_dac *dac = iio_priv(indio_dev);
	u32 msk = STM32_DAC_IS_CHAN_1(ch) ? STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2;
	u32 en = enable ? msk : 0;
	int ret;

	ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
	if (ret < 0) {
	dev_err(&indio_dev->dev, "%s failed\n", en ?
	"Enable" : "Disable");
	return ret;
	}

	/*
	* When HFSEL is set, it is not allowed to write the DHRx register
	* during 8 clock cycles after the ENx bit is set. It is not allowed
	* to make software/hardware trigger during this period either.
	*/
	if (en && dac->common->hfsel)
	udelay(1);

	return 0;
	}

	static int stm32_dac_get_value(struct stm32_dac dac, int channel, int val)
	{
	int ret;

	if (STM32_DAC_IS_CHAN_1(channel))
	ret = regmap_read(dac->common->regmap, STM32_DAC_DOR1, val);
	else
	ret = regmap_read(dac->common->regmap, STM32_DAC_DOR2, val);

	return ret ? ret : IIO_VAL_INT;
	}

	static int stm32_dac_set_value(struct stm32_dac *dac, int channel, int val)
	{
	int ret;

	if (STM32_DAC_IS_CHAN_1(channel))
	ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R1, val);
	else
	ret = regmap_write(dac->common->regmap, STM32_DAC_DHR12R2, val);

	return ret;
	}

	static int stm32_dac_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct stm32_dac *dac = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	return stm32_dac_get_value(dac, chan->channel, val);
	case IIO_CHAN_INFO_SCALE:
	*val = dac->common->vref_mv;
	*val2 = chan->scan_type.realbits;
	return IIO_VAL_FRACTIONAL_LOG2;
	default:
	return -EINVAL;
	}
	}

	static int stm32_dac_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int val, int val2, long mask)
	{
	struct stm32_dac *dac = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	return stm32_dac_set_value(dac, chan->channel, val);
	default:
	return -EINVAL;
	}
	}

	static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev,
	unsigned reg, unsigned writeval,
	unsigned *readval)
	{
	struct stm32_dac *dac = iio_priv(indio_dev);

	if (!readval)
	return regmap_write(dac->common->regmap, reg, writeval);
	else
	return regmap_read(dac->common->regmap, reg, readval);
	}

	static const struct iio_info stm32_dac_iio_info = {
	.read_raw = stm32_dac_read_raw,
	.write_raw = stm32_dac_write_raw,
	.debugfs_reg_access = stm32_dac_debugfs_reg_access,
	.driver_module = THIS_MODULE,
	};

	static const char * const stm32_dac_powerdown_modes[] = {
	"three_state",
	};

	static int stm32_dac_get_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan)
	{
	return 0;
	}

	static int stm32_dac_set_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan,
	unsigned int type)
	{
	return 0;
	}

	static ssize_t stm32_dac_read_powerdown(struct iio_dev *indio_dev,
	uintptr_t private,
	const struct iio_chan_spec *chan,
	char *buf)
	{
	int ret = stm32_dac_is_enabled(indio_dev, chan->channel);

	if (ret < 0)
	return ret;

	return sprintf(buf, "%d\n", ret ? 0 : 1);
	}

	static ssize_t stm32_dac_write_powerdown(struct iio_dev *indio_dev,
	uintptr_t private,
	const struct iio_chan_spec *chan,
	const char *buf, size_t len)
	{
	bool powerdown;
	int ret;

	ret = strtobool(buf, &powerdown);
	if (ret)
	return ret;

	ret = stm32_dac_set_enable_state(indio_dev, chan->channel, !powerdown);
	if (ret)
	return ret;

	return len;
	}

	static const struct iio_enum stm32_dac_powerdown_mode_en = {
	.items = stm32_dac_powerdown_modes,
	.num_items = ARRAY_SIZE(stm32_dac_powerdown_modes),
	.get = stm32_dac_get_powerdown_mode,
	.set = stm32_dac_set_powerdown_mode,
	};

	static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = {
	{
	.name = "powerdown",
	.read = stm32_dac_read_powerdown,
	.write = stm32_dac_write_powerdown,
	.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &stm32_dac_powerdown_mode_en),
	IIO_ENUM_AVAILABLE("powerdown_mode", &stm32_dac_powerdown_mode_en),
	{},
	};

	#define STM32_DAC_CHANNEL(chan, name) { \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.output = 1, \
	.channel = chan, \
	.info_mask_separate = \
	BIT(IIO_CHAN_INFO_RAW) \| \
	BIT(IIO_CHAN_INFO_SCALE), \
	/* scan_index is always 0 as num_channels is 1 */ \
	.scan_type = { \
	.sign = 'u', \
	.realbits = 12, \
	.storagebits = 16, \
	}, \
	.datasheet_name = name, \
	.ext_info = stm32_dac_ext_info \
	}

	static const struct iio_chan_spec stm32_dac_channels[] = {
	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_1, "out1"),
	STM32_DAC_CHANNEL(STM32_DAC_CHANNEL_2, "out2"),
	};

	static int stm32_dac_chan_of_init(struct iio_dev *indio_dev)
	{
	struct device_node *np = indio_dev->dev.of_node;
	unsigned int i;
	u32 channel;
	int ret;

	ret = of_property_read_u32(np, "reg", &channel);
	if (ret) {
	dev_err(&indio_dev->dev, "Failed to read reg property\n");
	return ret;
	}

	for (i = 0; i < ARRAY_SIZE(stm32_dac_channels); i++) {
	if (stm32_dac_channels[i].channel == channel)
	break;
	}
	if (i >= ARRAY_SIZE(stm32_dac_channels)) {
	dev_err(&indio_dev->dev, "Invalid reg property\n");
	return -EINVAL;
	}

	indio_dev->channels = &stm32_dac_channels[i];
	/*
	* Expose only one channel here, as they can be used independently,
	* with separate trigger. Then separate IIO devices are instantiated
	* to manage this.
	*/
	indio_dev->num_channels = 1;

	return 0;
	};

	static int stm32_dac_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct iio_dev *indio_dev;
	struct stm32_dac *dac;
	int ret;

	if (!np)
	return -ENODEV;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
	if (!indio_dev)
	return -ENOMEM;
	platform_set_drvdata(pdev, indio_dev);

	dac = iio_priv(indio_dev);
	dac->common = dev_get_drvdata(pdev->dev.parent);
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->dev.parent = &pdev->dev;
	indio_dev->dev.of_node = pdev->dev.of_node;
	indio_dev->info = &stm32_dac_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = stm32_dac_chan_of_init(indio_dev);
	if (ret < 0)
	return ret;

	return devm_iio_device_register(&pdev->dev, indio_dev);
	}

	static const struct of_device_id stm32_dac_of_match[] = {
	{ .compatible = "st,stm32-dac", },
	{},
	};
	MODULE_DEVICE_TABLE(of, stm32_dac_of_match);

	static struct platform_driver stm32_dac_driver = {
	.probe = stm32_dac_probe,
	.driver = {
	.name = "stm32-dac",
	.of_match_table = stm32_dac_of_match,
	},
	};
	module_platform_driver(stm32_dac_driver);

	MODULE_ALIAS("platform:stm32-dac");
	MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
	MODULE_DESCRIPTION("STMicroelectronics STM32 DAC driver");
	MODULE_LICENSE("GPL v2");