iio: ltr501: Add interrupt support

This patch adds interrupt support for Liteon 501 chip.

Interrupt will be generated whenever ALS or proximity
data exceeds values given in upper and lower threshold
register settings.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/ltr501.c

@@ -9,7 +9,7 @@
  *
  * 7-bit I2C slave address 0x23
  *
- * TODO: interrupt, threshold, measurement rate, IR LED characteristics
+ * TODO: measurement rate, IR LED characteristics
  */
 
 #include <linux/module.h>
@@ -19,6 +19,7 @@
 #include <linux/regmap.h>
 
 #include <linux/iio/iio.h>
+#include <linux/iio/events.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/buffer.h>
@@ -35,6 +36,11 @@
 #define LTR501_ALS_DATA0 0x8a /* 16-bit, little endian */
 #define LTR501_ALS_PS_STATUS 0x8c
 #define LTR501_PS_DATA 0x8d /* 16-bit, little endian */
+#define LTR501_INTR 0x8f /* output mode, polarity, mode */
+#define LTR501_PS_THRESH_UP 0x90 /* 11 bit, ps upper threshold */
+#define LTR501_PS_THRESH_LOW 0x92 /* 11 bit, ps lower threshold */
+#define LTR501_ALS_THRESH_UP 0x97 /* 16 bit, ALS upper threshold */
+#define LTR501_ALS_THRESH_LOW 0x99 /* 16 bit, ALS lower threshold */
 #define LTR501_MAX_REG 0x9f
 
 #define LTR501_ALS_CONTR_SW_RESET BIT(2)
@@ -43,10 +49,14 @@
 #define LTR501_CONTR_ALS_GAIN_MASK BIT(3)
 #define LTR501_CONTR_ACTIVE BIT(1)
 
+#define LTR501_STATUS_ALS_INTR BIT(3)
 #define LTR501_STATUS_ALS_RDY BIT(2)
+#define LTR501_STATUS_PS_INTR BIT(1)
 #define LTR501_STATUS_PS_RDY BIT(0)
 
 #define LTR501_PS_DATA_MASK 0x7ff
+#define LTR501_PS_THRESH_MASK 0x7ff
+#define LTR501_ALS_THRESH_MASK 0xffff
 
 #define LTR501_REGMAP_NAME "ltr501_regmap"
 
@@ -54,6 +64,10 @@ static const int int_time_mapping[] = {100000, 50000, 200000, 400000};
 
 static const struct reg_field reg_field_it =
 				REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
+static const struct reg_field reg_field_als_intr =
+				REG_FIELD(LTR501_INTR, 0, 0);
+static const struct reg_field reg_field_ps_intr =
+				REG_FIELD(LTR501_INTR, 1, 1);
 
 struct ltr501_data {
 	struct i2c_client *client;
@@ -61,6 +75,8 @@ struct ltr501_data {
 	u8 als_contr, ps_contr;
 	struct regmap *regmap;
 	struct regmap_field *reg_it;
+	struct regmap_field *reg_als_intr;
+	struct regmap_field *reg_ps_intr;
 };
 
 static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
@@ -161,7 +177,41 @@ static int ltr501_read_ps(struct ltr501_data *data)
 	return status;
 }
 
-#define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared) { \
+static const struct iio_event_spec ltr501_als_event_spec[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+
+};
+
+static const struct iio_event_spec ltr501_pxs_event_spec[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	},
+};
+
+#define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared, \
+				 _evspec, _evsize) { \
 	.type = IIO_INTENSITY, \
 	.modified = 1, \
 	.address = (_addr), \
@@ -174,14 +224,19 @@ static int ltr501_read_ps(struct ltr501_data *data)
 		.realbits = 16, \
 		.storagebits = 16, \
 		.endianness = IIO_CPU, \
-	} \
+	}, \
+	.event_spec = _evspec,\
+	.num_event_specs = _evsize,\
 }
 
 static const struct iio_chan_spec ltr501_channels[] = {
-	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
+	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
+				 ltr501_als_event_spec,
+				 ARRAY_SIZE(ltr501_als_event_spec)),
 	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
 				 BIT(IIO_CHAN_INFO_SCALE) |
-				 BIT(IIO_CHAN_INFO_INT_TIME)),
+				 BIT(IIO_CHAN_INFO_INT_TIME),
+				 NULL, 0),
 	{
 		.type = IIO_PROXIMITY,
 		.address = LTR501_PS_DATA,
@@ -194,6 +249,8 @@ static const struct iio_chan_spec ltr501_channels[] = {
 			.storagebits = 16,
 			.endianness = IIO_CPU,
 		},
+		.event_spec = ltr501_pxs_event_spec,
+		.num_event_specs = ARRAY_SIZE(ltr501_pxs_event_spec),
 	},
 	IIO_CHAN_SOFT_TIMESTAMP(3),
 };
@@ -329,6 +386,185 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int ltr501_read_thresh(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 ltr501_data *data = iio_priv(indio_dev);
+	int ret, thresh_data;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			ret = regmap_bulk_read(data->regmap,
+					       LTR501_ALS_THRESH_UP,
+					       &thresh_data, 2);
+			if (ret < 0)
+				return ret;
+			*val = thresh_data & LTR501_ALS_THRESH_MASK;
+			return IIO_VAL_INT;
+		case IIO_EV_DIR_FALLING:
+			ret = regmap_bulk_read(data->regmap,
+					       LTR501_ALS_THRESH_LOW,
+					       &thresh_data, 2);
+			if (ret < 0)
+				return ret;
+			*val = thresh_data & LTR501_ALS_THRESH_MASK;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_PROXIMITY:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			ret = regmap_bulk_read(data->regmap,
+					       LTR501_PS_THRESH_UP,
+					       &thresh_data, 2);
+			if (ret < 0)
+				return ret;
+			*val = thresh_data & LTR501_PS_THRESH_MASK;
+			return IIO_VAL_INT;
+		case IIO_EV_DIR_FALLING:
+			ret = regmap_bulk_read(data->regmap,
+					       LTR501_PS_THRESH_LOW,
+					       &thresh_data, 2);
+			if (ret < 0)
+				return ret;
+			*val = thresh_data & LTR501_PS_THRESH_MASK;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_write_thresh(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 ltr501_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (val < 0)
+		return -EINVAL;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		if (val > LTR501_ALS_THRESH_MASK)
+			return -EINVAL;
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			mutex_lock(&data->lock_als);
+			ret = regmap_bulk_write(data->regmap,
+						LTR501_ALS_THRESH_UP,
+						&val, 2);
+			mutex_unlock(&data->lock_als);
+			return ret;
+		case IIO_EV_DIR_FALLING:
+			mutex_lock(&data->lock_als);
+			ret = regmap_bulk_write(data->regmap,
+						LTR501_ALS_THRESH_LOW,
+						&val, 2);
+			mutex_unlock(&data->lock_als);
+			return ret;
+		default:
+			return -EINVAL;
+		}
+	case IIO_PROXIMITY:
+		switch (dir) {
+		if (val > LTR501_PS_THRESH_MASK)
+			return -EINVAL;
+		case IIO_EV_DIR_RISING:
+			mutex_lock(&data->lock_ps);
+			ret = regmap_bulk_write(data->regmap,
+						LTR501_PS_THRESH_UP,
+						&val, 2);
+			mutex_unlock(&data->lock_ps);
+			return ret;
+		case IIO_EV_DIR_FALLING:
+			mutex_lock(&data->lock_ps);
+			ret = regmap_bulk_write(data->regmap,
+						LTR501_PS_THRESH_LOW,
+						&val, 2);
+			mutex_unlock(&data->lock_ps);
+			return ret;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_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 ltr501_data *data = iio_priv(indio_dev);
+	int ret, status;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		ret = regmap_field_read(data->reg_als_intr, &status);
+		if (ret < 0)
+			return ret;
+		return status;
+	case IIO_PROXIMITY:
+		ret = regmap_field_read(data->reg_ps_intr, &status);
+		if (ret < 0)
+			return ret;
+		return status;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_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)
+{
+	struct ltr501_data *data = iio_priv(indio_dev);
+	int ret;
+
+	/* only 1 and 0 are valid inputs */
+	if (state != 1  || state != 0)
+		return -EINVAL;
+
+	switch (chan->type) {
+	case IIO_INTENSITY:
+		mutex_lock(&data->lock_als);
+		ret = regmap_field_write(data->reg_als_intr, state);
+		mutex_unlock(&data->lock_als);
+		return ret;
+	case IIO_PROXIMITY:
+		mutex_lock(&data->lock_ps);
+		ret = regmap_field_write(data->reg_ps_intr, state);
+		mutex_unlock(&data->lock_ps);
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
 static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
 static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
 static IIO_CONST_ATTR_INT_TIME_AVAIL("0.05 0.1 0.2 0.4");
@@ -344,10 +580,21 @@ static const struct attribute_group ltr501_attribute_group = {
 	.attrs = ltr501_attributes,
 };
 
+static const struct iio_info ltr501_info_no_irq = {
+	.read_raw = ltr501_read_raw,
+	.write_raw = ltr501_write_raw,
+	.attrs = &ltr501_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
 static const struct iio_info ltr501_info = {
 	.read_raw = ltr501_read_raw,
 	.write_raw = ltr501_write_raw,
 	.attrs = &ltr501_attribute_group,
+	.read_event_value	= &ltr501_read_thresh,
+	.write_event_value	= &ltr501_write_thresh,
+	.read_event_config	= &ltr501_read_event_config,
+	.write_event_config	= &ltr501_write_event_config,
 	.driver_module = THIS_MODULE,
 };
 
@@ -413,6 +660,36 @@ done:
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t ltr501_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct ltr501_data *data = iio_priv(indio_dev);
+	int ret, status;
+
+	ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"irq read int reg failed\n");
+		return IRQ_HANDLED;
+	}
+
+	if (status & LTR501_STATUS_ALS_INTR)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_EITHER),
+			       iio_get_time_ns());
+
+	if (status & LTR501_STATUS_PS_INTR)
+		iio_push_event(indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_EITHER),
+			       iio_get_time_ns());
+
+	return IRQ_HANDLED;
+}
+
 static int ltr501_init(struct ltr501_data *data)
 {
 	int ret, status;
@@ -492,6 +769,20 @@ static int ltr501_probe(struct i2c_client *client,
 		return PTR_ERR(data->reg_it);
 	}
 
+	data->reg_als_intr = devm_regmap_field_alloc(&client->dev, regmap,
+						     reg_field_als_intr);
+	if (IS_ERR(data->reg_als_intr)) {
+		dev_err(&client->dev, "ALS intr mode reg field init failed\n");
+		return PTR_ERR(data->reg_als_intr);
+	}
+
+	data->reg_ps_intr = devm_regmap_field_alloc(&client->dev, regmap,
+						    reg_field_ps_intr);
+	if (IS_ERR(data->reg_ps_intr)) {
+		dev_err(&client->dev, "PS intr mode reg field init failed.\n");
+		return PTR_ERR(data->reg_ps_intr);
+	}
+
 	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
 	if (ret < 0)
 		return ret;
@@ -499,7 +790,6 @@ static int ltr501_probe(struct i2c_client *client,
 		return -ENODEV;
 
 	indio_dev->dev.parent = &client->dev;
-	indio_dev->info = &ltr501_info;
 	indio_dev->channels = ltr501_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ltr501_channels);
 	indio_dev->name = LTR501_DRV_NAME;
@@ -509,6 +799,23 @@ static int ltr501_probe(struct i2c_client *client,
 	if (ret < 0)
 		return ret;
 
+	if (client->irq > 0) {
+		indio_dev->info = &ltr501_info;
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, ltr501_interrupt_handler,
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						"ltr501_thresh_event",
+						indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "request irq (%d) failed\n",
+				client->irq);
+			return ret;
+		}
+	} else {
+		indio_dev->info = &ltr501_info_no_irq;
+	}
+
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 					 ltr501_trigger_handler, NULL);
 	if (ret)