Initial import

1 files changed, 585 insertions, 0 deletions

diff --git a/drivers/iio/adc/ad7291.c b/drivers/iio/adc/ad7291.c
new file mode 100644
index 000000000..c0eabf156
--- /dev/null
+++ b/drivers/iio/adc/ad7291.c
@@ -0,0 +1,585 @@
+/*
+ * AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor
+ *
+ * Copyright 2010-2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+#include <linux/platform_data/ad7291.h>
+
+/*
+ * Simplified handling
+ *
+ * If no events enabled - single polled channel read
+ * If event enabled direct reads disable unless channel
+ * is in the read mask.
+ *
+ * The noise-delayed bit as per datasheet suggestion is always enabled.
+ */
+
+/*
+ * AD7291 registers definition
+ */
+#define AD7291_COMMAND			0x00
+#define AD7291_VOLTAGE			0x01
+#define AD7291_T_SENSE			0x02
+#define AD7291_T_AVERAGE		0x03
+#define AD7291_DATA_HIGH(x)		((x) * 3 + 0x4)
+#define AD7291_DATA_LOW(x)		((x) * 3 + 0x5)
+#define AD7291_HYST(x)			((x) * 3 + 0x6)
+#define AD7291_VOLTAGE_ALERT_STATUS	0x1F
+#define AD7291_T_ALERT_STATUS		0x20
+
+#define AD7291_BITS			12
+#define AD7291_VOLTAGE_LIMIT_COUNT	8
+
+
+/*
+ * AD7291 command
+ */
+#define AD7291_AUTOCYCLE		BIT(0)
+#define AD7291_RESET			BIT(1)
+#define AD7291_ALERT_CLEAR		BIT(2)
+#define AD7291_ALERT_POLARITY		BIT(3)
+#define AD7291_EXT_REF			BIT(4)
+#define AD7291_NOISE_DELAY		BIT(5)
+#define AD7291_T_SENSE_MASK		BIT(7)
+#define AD7291_VOLTAGE_MASK		GENMASK(15, 8)
+#define AD7291_VOLTAGE_OFFSET		8
+
+/*
+ * AD7291 value masks
+ */
+#define AD7291_VALUE_MASK		GENMASK(11, 0)
+
+/*
+ * AD7291 alert register bits
+ */
+#define AD7291_T_LOW			BIT(0)
+#define AD7291_T_HIGH			BIT(1)
+#define AD7291_T_AVG_LOW		BIT(2)
+#define AD7291_T_AVG_HIGH		BIT(3)
+#define AD7291_V_LOW(x)			BIT((x) * 2)
+#define AD7291_V_HIGH(x)		BIT((x) * 2 + 1)
+
+
+struct ad7291_chip_info {
+	struct i2c_client	*client;
+	struct regulator	*reg;
+	u16			command;
+	u16			c_mask;	/* Active voltage channels for events */
+	struct mutex		state_lock;
+};
+
+static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data)
+{
+	struct i2c_client *client = chip->client;
+	int ret = 0;
+
+	ret = i2c_smbus_read_word_swapped(client, reg);
+	if (ret < 0) {
+		dev_err(&client->dev, "I2C read error\n");
+		return ret;
+	}
+
+	*data = ret;
+
+	return 0;
+}
+
+static int ad7291_i2c_write(struct ad7291_chip_info *chip, u8 reg, u16 data)
+{
+	return i2c_smbus_write_word_swapped(chip->client, reg, data);
+}
+
+static irqreturn_t ad7291_event_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct ad7291_chip_info *chip = iio_priv(private);
+	u16 t_status, v_status;
+	u16 command;
+	int i;
+	s64 timestamp = iio_get_time_ns();
+
+	if (ad7291_i2c_read(chip, AD7291_T_ALERT_STATUS, &t_status))
+		return IRQ_HANDLED;
+
+	if (ad7291_i2c_read(chip, AD7291_VOLTAGE_ALERT_STATUS, &v_status))
+		return IRQ_HANDLED;
+
+	if (!(t_status || v_status))
+		return IRQ_HANDLED;
+
+	command = chip->command | AD7291_ALERT_CLEAR;
+	ad7291_i2c_write(chip, AD7291_COMMAND, command);
+
+	command = chip->command & ~AD7291_ALERT_CLEAR;
+	ad7291_i2c_write(chip, AD7291_COMMAND, command);
+
+	/* For now treat t_sense and t_sense_average the same */
+	if ((t_status & AD7291_T_LOW) || (t_status & AD7291_T_AVG_LOW))
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_TEMP,
+						    0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_FALLING),
+			       timestamp);
+	if ((t_status & AD7291_T_HIGH) || (t_status & AD7291_T_AVG_HIGH))
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_TEMP,
+						    0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_RISING),
+			       timestamp);
+
+	for (i = 0; i < AD7291_VOLTAGE_LIMIT_COUNT; i++) {
+		if (v_status & AD7291_V_LOW(i))
+			iio_push_event(indio_dev,
+				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+							    i,
+							    IIO_EV_TYPE_THRESH,
+							    IIO_EV_DIR_FALLING),
+				       timestamp);
+		if (v_status & AD7291_V_HIGH(i))
+			iio_push_event(indio_dev,
+				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+							    i,
+							    IIO_EV_TYPE_THRESH,
+							    IIO_EV_DIR_RISING),
+				       timestamp);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static unsigned int ad7291_threshold_reg(const struct iio_chan_spec *chan,
+					 enum iio_event_direction dir,
+					 enum iio_event_info info)
+{
+	unsigned int offset;
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		offset = chan->channel;
+		break;
+	case IIO_TEMP:
+		offset = AD7291_VOLTAGE_OFFSET;
+		break;
+	default:
+	    return 0;
+	}
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		if (dir == IIO_EV_DIR_FALLING)
+			return AD7291_DATA_HIGH(offset);
+		else
+			return AD7291_DATA_LOW(offset);
+	case IIO_EV_INFO_HYSTERESIS:
+		return AD7291_HYST(offset);
+	default:
+		break;
+	}
+	return 0;
+}
+
+static int ad7291_read_event_value(struct iio_dev *indio_dev,
+				   const struct iio_chan_spec *chan,
+				   enum iio_event_type type,
+				   enum iio_event_direction dir,
+				   enum iio_event_info info,
+				   int *val, int *val2)
+{
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+	int ret;
+	u16 uval;
+
+	ret = ad7291_i2c_read(chip, ad7291_threshold_reg(chan, dir, info),
+			      &uval);
+	if (ret < 0)
+		return ret;
+
+	if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE)
+		*val = uval & AD7291_VALUE_MASK;
+
+	else
+		*val = sign_extend32(uval, 11);
+
+	return IIO_VAL_INT;
+}
+
+static int ad7291_write_event_value(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir,
+				    enum iio_event_info info,
+				    int val, int val2)
+{
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+
+	if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) {
+		if (val > AD7291_VALUE_MASK || val < 0)
+			return -EINVAL;
+	} else {
+		if (val > 2047 || val < -2048)
+			return -EINVAL;
+	}
+
+	return ad7291_i2c_write(chip, ad7291_threshold_reg(chan, dir, info),
+				val);
+}
+
+static int ad7291_read_event_config(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir)
+{
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+	/*
+	 * To be enabled the channel must simply be on. If any are enabled
+	 * we are in continuous sampling mode
+	 */
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		return !!(chip->c_mask & BIT(15 - chan->channel));
+	case IIO_TEMP:
+		/* always on */
+		return 1;
+	default:
+		return -EINVAL;
+	}
+
+}
+
+static int ad7291_write_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir,
+				     int state)
+{
+	int ret = 0;
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+	unsigned int mask;
+	u16 regval;
+
+	mutex_lock(&chip->state_lock);
+	regval = chip->command;
+	/*
+	 * To be enabled the channel must simply be on. If any are enabled
+	 * use continuous sampling mode.
+	 * Possible to disable temp as well but that makes single read tricky.
+	 */
+
+	mask = BIT(15 - chan->channel);
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		if ((!state) && (chip->c_mask & mask))
+			chip->c_mask &= ~mask;
+		else if (state && (!(chip->c_mask & mask)))
+			chip->c_mask |= mask;
+		else
+			break;
+
+		regval &= ~AD7291_AUTOCYCLE;
+		regval |= chip->c_mask;
+		if (chip->c_mask) /* Enable autocycle? */
+			regval |= AD7291_AUTOCYCLE;
+
+		ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
+		if (ret < 0)
+			goto error_ret;
+
+		chip->command = regval;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+error_ret:
+	mutex_unlock(&chip->state_lock);
+	return ret;
+}
+
+static int ad7291_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long mask)
+{
+	int ret;
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+	u16 regval;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			mutex_lock(&chip->state_lock);
+			/* If in autocycle mode drop through */
+			if (chip->command & AD7291_AUTOCYCLE) {
+				mutex_unlock(&chip->state_lock);
+				return -EBUSY;
+			}
+			/* Enable this channel alone */
+			regval = chip->command & (~AD7291_VOLTAGE_MASK);
+			regval |= BIT(15 - chan->channel);
+			ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
+			if (ret < 0) {
+				mutex_unlock(&chip->state_lock);
+				return ret;
+			}
+			/* Read voltage */
+			ret = i2c_smbus_read_word_swapped(chip->client,
+							  AD7291_VOLTAGE);
+			if (ret < 0) {
+				mutex_unlock(&chip->state_lock);
+				return ret;
+			}
+			*val = ret & AD7291_VALUE_MASK;
+			mutex_unlock(&chip->state_lock);
+			return IIO_VAL_INT;
+		case IIO_TEMP:
+			/* Assumes tsense bit of command register always set */
+			ret = i2c_smbus_read_word_swapped(chip->client,
+							  AD7291_T_SENSE);
+			if (ret < 0)
+				return ret;
+			*val = sign_extend32(ret, 11);
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_AVERAGE_RAW:
+		ret = i2c_smbus_read_word_swapped(chip->client,
+						  AD7291_T_AVERAGE);
+			if (ret < 0)
+				return ret;
+			*val = sign_extend32(ret, 11);
+			return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chip->reg) {
+				int vref;
+
+				vref = regulator_get_voltage(chip->reg);
+				if (vref < 0)
+					return vref;
+				*val = vref / 1000;
+			} else {
+				*val = 2500;
+			}
+			*val2 = AD7291_BITS;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		case IIO_TEMP:
+			/*
+			 * One LSB of the ADC corresponds to 0.25 deg C.
+			 * The temperature reading is in 12-bit twos
+			 * complement format
+			 */
+			*val = 250;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_event_spec ad7291_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 AD7291_VOLTAGE_CHAN(_chan)					\
+{									\
+	.type = IIO_VOLTAGE,						\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\
+	.indexed = 1,							\
+	.channel = _chan,						\
+	.event_spec = ad7291_events,					\
+	.num_event_specs = ARRAY_SIZE(ad7291_events),			\
+}
+
+static const struct iio_chan_spec ad7291_channels[] = {
+	AD7291_VOLTAGE_CHAN(0),
+	AD7291_VOLTAGE_CHAN(1),
+	AD7291_VOLTAGE_CHAN(2),
+	AD7291_VOLTAGE_CHAN(3),
+	AD7291_VOLTAGE_CHAN(4),
+	AD7291_VOLTAGE_CHAN(5),
+	AD7291_VOLTAGE_CHAN(6),
+	AD7291_VOLTAGE_CHAN(7),
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				BIT(IIO_CHAN_INFO_AVERAGE_RAW) |
+				BIT(IIO_CHAN_INFO_SCALE),
+		.indexed = 1,
+		.channel = 0,
+		.event_spec = ad7291_events,
+		.num_event_specs = ARRAY_SIZE(ad7291_events),
+	}
+};
+
+static const struct iio_info ad7291_info = {
+	.read_raw = &ad7291_read_raw,
+	.read_event_config = &ad7291_read_event_config,
+	.write_event_config = &ad7291_write_event_config,
+	.read_event_value = &ad7291_read_event_value,
+	.write_event_value = &ad7291_write_event_value,
+	.driver_module = THIS_MODULE,
+};
+
+static int ad7291_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ad7291_platform_data *pdata = client->dev.platform_data;
+	struct ad7291_chip_info *chip;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+	if (!indio_dev)
+		return -ENOMEM;
+	chip = iio_priv(indio_dev);
+
+	if (pdata && pdata->use_external_ref) {
+		chip->reg = devm_regulator_get(&client->dev, "vref");
+		if (IS_ERR(chip->reg))
+			return PTR_ERR(chip->reg);
+
+		ret = regulator_enable(chip->reg);
+		if (ret)
+			return ret;
+	}
+
+	mutex_init(&chip->state_lock);
+	/* this is only used for device removal purposes */
+	i2c_set_clientdata(client, indio_dev);
+
+	chip->client = client;
+
+	chip->command = AD7291_NOISE_DELAY |
+			AD7291_T_SENSE_MASK | /* Tsense always enabled */
+			AD7291_ALERT_POLARITY; /* set irq polarity low level */
+
+	if (pdata && pdata->use_external_ref)
+		chip->command |= AD7291_EXT_REF;
+
+	indio_dev->name = id->name;
+	indio_dev->channels = ad7291_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ad7291_channels);
+
+	indio_dev->dev.parent = &client->dev;
+	indio_dev->info = &ad7291_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = ad7291_i2c_write(chip, AD7291_COMMAND, AD7291_RESET);
+	if (ret) {
+		ret = -EIO;
+		goto error_disable_reg;
+	}
+
+	ret = ad7291_i2c_write(chip, AD7291_COMMAND, chip->command);
+	if (ret) {
+		ret = -EIO;
+		goto error_disable_reg;
+	}
+
+	if (client->irq > 0) {
+		ret = request_threaded_irq(client->irq,
+					   NULL,
+					   &ad7291_event_handler,
+					   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					   id->name,
+					   indio_dev);
+		if (ret)
+			goto error_disable_reg;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_unreg_irq;
+
+	return 0;
+
+error_unreg_irq:
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
+error_disable_reg:
+	if (chip->reg)
+		regulator_disable(chip->reg);
+
+	return ret;
+}
+
+static int ad7291_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct ad7291_chip_info *chip = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	if (client->irq)
+		free_irq(client->irq, indio_dev);
+
+	if (chip->reg)
+		regulator_disable(chip->reg);
+
+	return 0;
+}
+
+static const struct i2c_device_id ad7291_id[] = {
+	{ "ad7291", 0 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, ad7291_id);
+
+static struct i2c_driver ad7291_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+	},
+	.probe = ad7291_probe,
+	.remove = ad7291_remove,
+	.id_table = ad7291_id,
+};
+module_i2c_driver(ad7291_driver);
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7291 ADC driver");
+MODULE_LICENSE("GPL v2");