iio: adc: Add support for AD7091R5 ADC

AD7091R5 is 4-Channel, I2C, Ultra Low Power,12-Bit ADC.

This driver will also support AD7091R2/4/8 in the future.

Datasheet:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7091r-5.pdfSigned-off-by: Paul Cercueil <paul.cercueil@analog.com>
Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -32,6 +32,13 @@ config AD7124
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad7124.
 
+config AD7091R5
+	tristate "Analog Devices AD7091R5 ADC Driver"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say yes here to build support for Analog Devices AD7091R-5 ADC.
+
 config AD7266
 	tristate "Analog Devices AD7265/AD7266 ADC driver"
 	depends on SPI_MASTER

drivers/iio/adc/Makefile

@@ -7,6 +7,7 @@
 obj-$(CONFIG_AB8500_GPADC) += ab8500-gpadc.o
 obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD7124) += ad7124.o
+obj-$(CONFIG_AD7091R5) += ad7091r5.o ad7091r-base.o
 obj-$(CONFIG_AD7266) += ad7266.o
 obj-$(CONFIG_AD7291) += ad7291.o
 obj-$(CONFIG_AD7292) += ad7292.o

drivers/iio/adc/ad7091r-base.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD7091RX Analog to Digital converter driver
+ *
+ * Copyright 2014-2019 Analog Devices Inc.
+ */
+
+#include <linux/bitops.h>
+#include <linux/iio/events.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "ad7091r-base.h"
+
+#define AD7091R_REG_RESULT  0
+#define AD7091R_REG_CHANNEL 1
+#define AD7091R_REG_CONF    2
+#define AD7091R_REG_ALERT   3
+#define AD7091R_REG_CH_LOW_LIMIT(ch) ((ch) * 3 + 4)
+#define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5)
+#define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
+
+/* AD7091R_REG_RESULT */
+#define AD7091R_REG_RESULT_CH_ID(x)	    (((x) >> 13) & 0x3)
+#define AD7091R_REG_RESULT_CONV_RESULT(x)   ((x) & 0xfff)
+
+/* AD7091R_REG_CONF */
+#define AD7091R_REG_CONF_AUTO   BIT(8)
+#define AD7091R_REG_CONF_CMD    BIT(10)
+
+#define AD7091R_REG_CONF_MODE_MASK  \
+	(AD7091R_REG_CONF_AUTO | AD7091R_REG_CONF_CMD)
+
+enum ad7091r_mode {
+	AD7091R_MODE_SAMPLE,
+	AD7091R_MODE_COMMAND,
+	AD7091R_MODE_AUTOCYCLE,
+};
+
+struct ad7091r_state {
+	struct device *dev;
+	struct regmap *map;
+	const struct ad7091r_chip_info *chip_info;
+	enum ad7091r_mode mode;
+	struct mutex lock; /*lock to prevent concurent reads */
+};
+
+static int ad7091r_set_mode(struct ad7091r_state *st, enum ad7091r_mode mode)
+{
+	int ret, conf;
+
+	switch (mode) {
+	case AD7091R_MODE_SAMPLE:
+		conf = 0;
+		break;
+	case AD7091R_MODE_COMMAND:
+		conf = AD7091R_REG_CONF_CMD;
+		break;
+	case AD7091R_MODE_AUTOCYCLE:
+		conf = AD7091R_REG_CONF_AUTO;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
+				 AD7091R_REG_CONF_MODE_MASK, conf);
+	if (ret)
+		return ret;
+
+	st->mode = mode;
+
+	return 0;
+}
+
+static int ad7091r_set_channel(struct ad7091r_state *st, unsigned int channel)
+{
+	unsigned int dummy;
+	int ret;
+
+	/* AD7091R_REG_CHANNEL specified which channels to be converted */
+	ret = regmap_write(st->map, AD7091R_REG_CHANNEL,
+			BIT(channel) | (BIT(channel) << 8));
+	if (ret)
+		return ret;
+
+	/*
+	 * There is a latency of one conversion before the channel conversion
+	 * sequence is updated
+	 */
+	return regmap_read(st->map, AD7091R_REG_RESULT, &dummy);
+}
+
+static int ad7091r_read_one(struct iio_dev *iio_dev,
+		unsigned int channel, unsigned int *read_val)
+{
+	struct ad7091r_state *st = iio_priv(iio_dev);
+	unsigned int val;
+	int ret;
+
+	ret = ad7091r_set_channel(st, channel);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->map, AD7091R_REG_RESULT, &val);
+	if (ret)
+		return ret;
+
+	if (AD7091R_REG_RESULT_CH_ID(val) != channel)
+		return -EIO;
+
+	*read_val = AD7091R_REG_RESULT_CONV_RESULT(val);
+
+	return 0;
+}
+
+static int ad7091r_read_raw(struct iio_dev *iio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long m)
+{
+	struct ad7091r_state *st = iio_priv(iio_dev);
+	unsigned int read_val;
+	int ret;
+
+	mutex_lock(&st->lock);
+
+	switch (m) {
+	case IIO_CHAN_INFO_RAW:
+		if (st->mode != AD7091R_MODE_COMMAND) {
+			ret = -EBUSY;
+			goto unlock;
+		}
+
+		ret = ad7091r_read_one(iio_dev, chan->channel, &read_val);
+		if (ret)
+			goto unlock;
+
+		*val = read_val;
+		ret = IIO_VAL_INT;
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+unlock:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+static const struct iio_info ad7091r_info = {
+	.read_raw = ad7091r_read_raw,
+};
+
+static irqreturn_t ad7091r_event_handler(int irq, void *private)
+{
+	struct ad7091r_state *st = (struct ad7091r_state *) private;
+	struct iio_dev *iio_dev = dev_get_drvdata(st->dev);
+	unsigned int i, read_val;
+	int ret;
+	s64 timestamp = iio_get_time_ns(iio_dev);
+
+	ret = regmap_read(st->map, AD7091R_REG_ALERT, &read_val);
+	if (ret)
+		return IRQ_HANDLED;
+
+	for (i = 0; i < st->chip_info->num_channels; i++) {
+		if (read_val & BIT(i * 2))
+			iio_push_event(iio_dev,
+					IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
+						IIO_EV_TYPE_THRESH,
+						IIO_EV_DIR_RISING), timestamp);
+		if (read_val & BIT(i * 2 + 1))
+			iio_push_event(iio_dev,
+					IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
+						IIO_EV_TYPE_THRESH,
+						IIO_EV_DIR_FALLING), timestamp);
+	}
+
+	return IRQ_HANDLED;
+}
+
+int ad7091r_probe(struct device *dev, const char *name,
+		const struct ad7091r_chip_info *chip_info,
+		struct regmap *map, int irq)
+{
+	struct iio_dev *iio_dev;
+	struct ad7091r_state *st;
+	int ret;
+
+	iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!iio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(iio_dev);
+	st->dev = dev;
+	st->chip_info = chip_info;
+	st->map = map;
+
+	iio_dev->dev.parent = dev;
+	iio_dev->name = name;
+	iio_dev->info = &ad7091r_info;
+	iio_dev->modes = INDIO_DIRECT_MODE;
+
+	iio_dev->num_channels = chip_info->num_channels;
+	iio_dev->channels = chip_info->channels;
+
+	if (irq) {
+		ret = devm_request_threaded_irq(dev, irq, NULL,
+				ad7091r_event_handler,
+				IRQF_TRIGGER_FALLING | IRQF_ONESHOT, name, st);
+		if (ret)
+			return ret;
+	}
+
+	/* Use command mode by default to convert only desired channels*/
+	ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, iio_dev);
+}
+EXPORT_SYMBOL_GPL(ad7091r_probe);
+
+static bool ad7091r_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case AD7091R_REG_RESULT:
+	case AD7091R_REG_ALERT:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool ad7091r_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case AD7091R_REG_RESULT:
+	case AD7091R_REG_ALERT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+const struct regmap_config ad7091r_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.writeable_reg = ad7091r_writeable_reg,
+	.volatile_reg = ad7091r_volatile_reg,
+};
+EXPORT_SYMBOL_GPL(ad7091r_regmap_config);
+
+MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7091Rx multi-channel converters");
+MODULE_LICENSE("GPL v2");

drivers/iio/adc/ad7091r-base.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * AD7091RX Analog to Digital converter driver
+ *
+ * Copyright 2014-2019 Analog Devices Inc.
+ */
+
+#ifndef __DRIVERS_IIO_ADC_AD7091R_BASE_H__
+#define __DRIVERS_IIO_ADC_AD7091R_BASE_H__
+
+struct device;
+struct ad7091r_state;
+
+struct ad7091r_chip_info {
+	unsigned int num_channels;
+	const struct iio_chan_spec *channels;
+};
+
+extern const struct regmap_config ad7091r_regmap_config;
+
+int ad7091r_probe(struct device *dev, const char *name,
+		const struct ad7091r_chip_info *chip_info,
+		struct regmap *map, int irq);
+
+#endif /* __DRIVERS_IIO_ADC_AD7091R_BASE_H__ */

drivers/iio/adc/ad7091r5.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AD7091R5 Analog to Digital converter driver
+ *
+ * Copyright 2014-2019 Analog Devices Inc.
+ */
+
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "ad7091r-base.h"
+
+static const struct iio_event_spec ad7091r5_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
+				 BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+};
+
+#define AD7091R_CHANNEL(idx, bits, ev, num_ev) { \
+	.type = IIO_VOLTAGE, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.indexed = 1, \
+	.channel = idx, \
+	.event_spec = ev, \
+	.num_event_specs = num_ev, \
+}
+static const struct iio_chan_spec ad7091r5_channels_irq[] = {
+	AD7091R_CHANNEL(0, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
+	AD7091R_CHANNEL(1, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
+	AD7091R_CHANNEL(2, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
+	AD7091R_CHANNEL(3, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
+};
+
+static const struct iio_chan_spec ad7091r5_channels_noirq[] = {
+	AD7091R_CHANNEL(0, 12, NULL, 0),
+	AD7091R_CHANNEL(1, 12, NULL, 0),
+	AD7091R_CHANNEL(2, 12, NULL, 0),
+	AD7091R_CHANNEL(3, 12, NULL, 0),
+};
+
+static const struct ad7091r_chip_info ad7091r5_chip_info_irq = {
+	.channels = ad7091r5_channels_irq,
+	.num_channels = ARRAY_SIZE(ad7091r5_channels_irq),
+};
+
+static const struct ad7091r_chip_info ad7091r5_chip_info_noirq = {
+	.channels = ad7091r5_channels_noirq,
+	.num_channels = ARRAY_SIZE(ad7091r5_channels_noirq),
+};
+
+static int ad7091r5_i2c_probe(struct i2c_client *i2c,
+		const struct i2c_device_id *id)
+{
+	const struct ad7091r_chip_info *chip_info;
+	struct regmap *map = devm_regmap_init_i2c(i2c, &ad7091r_regmap_config);
+
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	if (i2c->irq)
+		chip_info = &ad7091r5_chip_info_irq;
+	else
+		chip_info = &ad7091r5_chip_info_noirq;
+
+	return ad7091r_probe(&i2c->dev, id->name, chip_info, map, i2c->irq);
+}
+
+static const struct of_device_id ad7091r5_dt_ids[] = {
+	{ .compatible = "adi,ad7091r5" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ad7091r5_dt_ids);
+
+static const struct i2c_device_id ad7091r5_i2c_ids[] = {
+	{"ad7091r5", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ad7091r5_i2c_ids);
+
+static struct i2c_driver ad7091r5_driver = {
+	.driver = {
+		.name = "ad7091r5",
+		.of_match_table = ad7091r5_dt_ids,
+	},
+	.probe = ad7091r5_i2c_probe,
+	.id_table = ad7091r5_i2c_ids,
+};
+module_i2c_driver(ad7091r5_driver);
+
+MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7091R5 multi-channel ADC driver");
+MODULE_LICENSE("GPL v2");