[PATCH v4 0/5] Added LTR501 Interrupt support

[PATCH v4 0/5] Added LTR501 Interrupt support

[Kuppuswamy Sathyanarayanan]

This patchset adds Integration time, sampling frequency, interrupt
and acpi enumeration support for LTR-501 chip.

Please let me know your review comments.

v1:
1. Added support to enable ALS & PS intterupts based 
   on threshold settings.
2. Added support to control intrrupt rate.
3. Added acpi enumeration support.

v2:
1. Removed persistance attribute from ext_channel and
   added support for IIO_EV_INFO_PERIOD.
2. Rebased my patches on top of Daniel's alignment fix.

v3:
1. Added a new ABI to define threshold interrupt persistence
   filter value.
2. Added Documentation for persistence filter iio ABI
3. Used IIO_EV_INFO_PERSISTENCE instead of IIO_EV_INFO_PERIOD
   in ltr501 driver.

v4:
1. Added regmap support to handle register bitwise updates easily.
2. Added support to change integration time from user code.
3. Modified threshold interrupt persistence code to use IIO_EV_INFO_PERIOD
   values.
4. Added support to change sampling frequency from user code
5. Addressed Jonathan's comments

Kuppuswamy Sathyanarayanan (5):
  iio: ltr501: Add regmap support.
  iio: ltr501: Add integration time support
  iio: ltr501: Add interrupt support
  iio: ltr501: Add interrupt rate control support
  iio: ltr501: Add ACPI enumeration support

 drivers/iio/light/ltr501.c | 894 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 853 insertions(+), 41 deletions(-)

-- 
1.9.1

[PATCH v4 1/5] iio: ltr501: Add regmap support.

[Kuppuswamy Sathyanarayanan]

Added regmap support. It will be useful to handle
bitwise updates to als & ps control registers.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/iio/light/ltr501.c | 114 +++++++++++++++++++++++++++++++--------------
 1 file changed, 80 insertions(+), 34 deletions(-)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 62b7072..84ee2b3 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -16,6 +16,7 @@
 #include <linux/i2c.h>
 #include <linux/err.h>
 #include <linux/delay.h>
+#include <linux/regmap.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -33,6 +34,7 @@
 #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_MAX_REG 0x9f
 
 #define LTR501_ALS_CONTR_SW_RESET BIT(2)
 #define LTR501_CONTR_PS_GAIN_MASK (BIT(3) | BIT(2))
@@ -45,23 +47,25 @@
 
 #define LTR501_PS_DATA_MASK 0x7ff
 
+#define LTR501_REGMAP_NAME "ltr501_regmap"
+
 struct ltr501_data {
 	struct i2c_client *client;
 	struct mutex lock_als, lock_ps;
 	u8 als_contr, ps_contr;
+	struct regmap *regmap;
 };
 
 static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
 {
 	int tries = 100;
-	int ret;
+	int ret, status;
 
 	while (tries--) {
-		ret = i2c_smbus_read_byte_data(data->client,
-			LTR501_ALS_PS_STATUS);
+		ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
 		if (ret < 0)
 			return ret;
-		if ((ret & drdy_mask) == drdy_mask)
+		if ((status & drdy_mask) == drdy_mask)
 			return 0;
 		msleep(25);
 	}
@@ -76,16 +80,24 @@ static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
 	if (ret < 0)
 		return ret;
 	/* always read both ALS channels in given order */
-	return i2c_smbus_read_i2c_block_data(data->client,
-		LTR501_ALS_DATA1, 2 * sizeof(__le16), (u8 *) buf);
+	return regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
+				buf, 2 * sizeof(__le16));
 }
 
 static int ltr501_read_ps(struct ltr501_data *data)
 {
-	int ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
+	int ret, status;
+
+	ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
+				&status, 2);
 	if (ret < 0)
 		return ret;
-	return i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
+
+	return status;
 }
 
 #define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared) { \
@@ -218,16 +230,18 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 				data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
 			else
 				return -EINVAL;
-			return i2c_smbus_write_byte_data(data->client,
-				LTR501_ALS_CONTR, data->als_contr);
+
+			return regmap_write(data->regmap, LTR501_ALS_CONTR,
+					    data->als_contr);
 		case IIO_PROXIMITY:
 			i = ltr501_get_ps_gain_index(val, val2);
 			if (i < 0)
 				return -EINVAL;
 			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
 			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;
-			return i2c_smbus_write_byte_data(data->client,
-				LTR501_PS_CONTR, data->ps_contr);
+
+			return regmap_write(data->regmap, LTR501_PS_CONTR,
+					    data->ps_contr);
 		default:
 			return -EINVAL;
 		}
@@ -255,13 +269,13 @@ static const struct iio_info ltr501_info = {
 	.driver_module = THIS_MODULE,
 };
 
-static int ltr501_write_contr(struct i2c_client *client, u8 als_val, u8 ps_val)
+static int ltr501_write_contr(struct ltr501_data *data, u8 als_val, u8 ps_val)
 {
-	int ret = i2c_smbus_write_byte_data(client, LTR501_ALS_CONTR, als_val);
+	int ret = regmap_write(data->regmap, LTR501_ALS_CONTR, als_val);
 	if (ret < 0)
 		return ret;
 
-	return i2c_smbus_write_byte_data(client, LTR501_PS_CONTR, ps_val);
+	return regmap_write(data->regmap, LTR501_PS_CONTR, ps_val);
 }
 
 static irqreturn_t ltr501_trigger_handler(int irq, void *p)
@@ -273,7 +287,7 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
 	__le16 als_buf[2];
 	u8 mask = 0;
 	int j = 0;
-	int ret;
+	int ret, psdata;
 
 	memset(buf, 0, sizeof(buf));
 
@@ -289,8 +303,8 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
 		goto done;
 
 	if (mask & LTR501_STATUS_ALS_RDY) {
-		ret = i2c_smbus_read_i2c_block_data(data->client,
-			LTR501_ALS_DATA1, sizeof(als_buf), (u8 *) als_buf);
+		ret = regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
+				       (u8 *) als_buf, sizeof(als_buf));
 		if (ret < 0)
 			return ret;
 		if (test_bit(0, indio_dev->active_scan_mask))
@@ -300,10 +314,11 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
 	}
 
 	if (mask & LTR501_STATUS_PS_RDY) {
-		ret = i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
+		ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
+				       &psdata, 2);
 		if (ret < 0)
 			goto done;
-		buf[j++] = ret & LTR501_PS_DATA_MASK;
+		buf[j++] = psdata & LTR501_PS_DATA_MASK;
 	}
 
 	iio_push_to_buffers_with_timestamp(indio_dev, buf,
@@ -317,43 +332,75 @@ done:
 
 static int ltr501_init(struct ltr501_data *data)
 {
-	int ret;
+	int ret, status;
 
-	ret = i2c_smbus_read_byte_data(data->client, LTR501_ALS_CONTR);
+	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
 	if (ret < 0)
 		return ret;
-	data->als_contr = ret | LTR501_CONTR_ACTIVE;
 
-	ret = i2c_smbus_read_byte_data(data->client, LTR501_PS_CONTR);
+	data->als_contr = status | LTR501_CONTR_ACTIVE;
+
+	ret = regmap_read(data->regmap, LTR501_PS_CONTR, &status);
 	if (ret < 0)
 		return ret;
-	data->ps_contr = ret | LTR501_CONTR_ACTIVE;
 
-	return ltr501_write_contr(data->client, data->als_contr,
-		data->ps_contr);
+	data->ps_contr = status | LTR501_CONTR_ACTIVE;
+
+	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
+}
+
+static bool ltr501_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case LTR501_ALS_DATA1:
+	case LTR501_ALS_DATA0:
+	case LTR501_ALS_PS_STATUS:
+	case LTR501_PS_DATA:
+		return true;
+	default:
+		return false;
+	}
 }
 
+static struct regmap_config ltr501_regmap_config = {
+	.name =  LTR501_REGMAP_NAME,
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = LTR501_MAX_REG,
+	.cache_type = REGCACHE_RBTREE,
+	.volatile_reg = ltr501_is_volatile_reg,
+};
+
 static int ltr501_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	struct ltr501_data *data;
 	struct iio_dev *indio_dev;
-	int ret;
+	struct regmap *regmap;
+	int ret, partid;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
 
+	regmap = devm_regmap_init_i2c(client, &ltr501_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(&client->dev, "Regmap initialization failed.\n");
+		return PTR_ERR(regmap);
+	}
+
 	data = iio_priv(indio_dev);
 	i2c_set_clientdata(client, indio_dev);
 	data->client = client;
+	data->regmap = regmap;
 	mutex_init(&data->lock_als);
 	mutex_init(&data->lock_ps);
 
-	ret = i2c_smbus_read_byte_data(data->client, LTR501_PART_ID);
+	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
 	if (ret < 0)
 		return ret;
-	if ((ret >> 4) != 0x8)
+
+	if ((partid >> 4) != 0x8)
 		return -ENODEV;
 
 	indio_dev->dev.parent = &client->dev;
@@ -385,9 +432,8 @@ error_unreg_buffer:
 
 static int ltr501_powerdown(struct ltr501_data *data)
 {
-	return ltr501_write_contr(data->client,
-		data->als_contr & ~LTR501_CONTR_ACTIVE,
-		data->ps_contr & ~LTR501_CONTR_ACTIVE);
+	return ltr501_write_contr(data, data->als_contr & ~LTR501_CONTR_ACTIVE,
+				  data->ps_contr & ~LTR501_CONTR_ACTIVE);
 }
 
 static int ltr501_remove(struct i2c_client *client)
@@ -414,7 +460,7 @@ static int ltr501_resume(struct device *dev)
 	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
 		to_i2c_client(dev)));
 
-	return ltr501_write_contr(data->client, data->als_contr,
+	return ltr501_write_contr(data, data->als_contr,
 		data->ps_contr);
 }
 #endif
-- 
1.9.1

[PATCH v4 2/5] iio: ltr501: Add integration time support

[Kuppuswamy Sathyanarayanan]

Added support to modify and read ALS integration time.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/iio/light/ltr501.c | 87 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 86 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 84ee2b3..22769c8 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -28,6 +28,7 @@
 
 #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
 #define LTR501_PS_CONTR 0x81 /* PS operation mode */
+#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
 #define LTR501_PART_ID 0x86
 #define LTR501_MANUFAC_ID 0x87
 #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
@@ -49,11 +50,16 @@
 
 #define LTR501_REGMAP_NAME "ltr501_regmap"
 
+static int int_time_mapping[] = {100000, 50000, 200000, 400000};
+
+static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
+
 struct ltr501_data {
 	struct i2c_client *client;
 	struct mutex lock_als, lock_ps;
 	u8 als_contr, ps_contr;
 	struct regmap *regmap;
+	struct regmap_field *reg_it;
 };
 
 static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
@@ -74,6 +80,58 @@ static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
 	return -EIO;
 }
 
+static int ltr501_set_it_time(struct ltr501_data *data, int it)
+{
+	int ret, i, index = -1, status;
+
+	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
+		if (int_time_mapping[i] == it) {
+			index = i;
+			break;
+		}
+	}
+	/* Make sure integ time index is valid */
+	if (index < 0)
+		return -EINVAL;
+
+	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
+	if (ret < 0)
+		return ret;
+
+	if (status & LTR501_CONTR_ALS_GAIN_MASK) {
+		/*
+		 * 200 ms and 400 ms integ time can only be
+		 * used in dynamic range 1
+		 */
+		if (index > 1)
+			return -EINVAL;
+	} else
+		/* 50 ms integ time can only be used in dynamic range 2 */
+		if (index == 1)
+			return -EINVAL;
+
+	return regmap_field_write(data->reg_it, index);
+}
+
+/* read int time in micro seconds */
+static int ltr501_read_it_time(struct ltr501_data *data, int *val, int *val2)
+{
+	int ret, index;
+
+	ret = regmap_field_read(data->reg_it, &index);
+	if (ret < 0)
+		return ret;
+
+	/* Make sure integ time index is valid */
+	if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
+		return -EINVAL;
+
+	*val2 = int_time_mapping[index];
+	*val = 0;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
 static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
 {
 	int ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
@@ -119,7 +177,7 @@ static int ltr501_read_ps(struct ltr501_data *data)
 static const struct iio_chan_spec ltr501_channels[] = {
 	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
 	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
-		BIT(IIO_CHAN_INFO_SCALE)),
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME)),
 	{
 		.type = IIO_PROXIMITY,
 		.address = LTR501_PS_DATA,
@@ -195,6 +253,13 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
+	case IIO_CHAN_INFO_INT_TIME:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			return ltr501_read_it_time(data, val, val2);
+		default:
+			return -EINVAL;
+		}
 	}
 	return -EINVAL;
 }
@@ -245,16 +310,30 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
+	case IIO_CHAN_INFO_INT_TIME:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			if (val != 0)
+				return -EINVAL;
+			mutex_lock(&data->lock_als);
+			i = ltr501_set_it_time(data, val2);
+			mutex_unlock(&data->lock_als);
+			return i;
+		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");
 
 static struct attribute *ltr501_attributes[] = {
 	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
 	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
+	&iio_const_attr_integration_time_available.dev_attr.attr,
 	NULL
 };
 
@@ -396,6 +475,12 @@ static int ltr501_probe(struct i2c_client *client,
 	mutex_init(&data->lock_als);
 	mutex_init(&data->lock_ps);
 
+	data->reg_it = devm_regmap_field_alloc(&client->dev, regmap, reg_it);
+	if (IS_ERR(data->reg_it)) {
+		dev_err(&client->dev, "Integ time reg field init failed.\n");
+		return PTR_ERR(data->reg_it);
+	}
+
 	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
 	if (ret < 0)
 		return ret;
-- 
1.9.1

[PATCH v4 3/5] iio: ltr501: Add interrupt support

[Kuppuswamy Sathyanarayanan]

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>
---
 drivers/iio/light/ltr501.c | 310 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 304 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 22769c8..8ead137 100644
--- a/drivers/iio/light/ltr501.c
+++ b/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)
@@ -43,16 +49,22 @@
 #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"
 
 static int int_time_mapping[] = {100000, 50000, 200000, 400000};
 
 static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
+static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
+static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
 
 struct ltr501_data {
 	struct i2c_client *client;
@@ -60,6 +72,8 @@ 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)
@@ -158,7 +172,41 @@ 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), \
@@ -171,13 +219,17 @@ 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_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME),
+		NULL, 0),
 	{
 		.type = IIO_PROXIMITY,
 		.address = LTR501_PS_DATA,
@@ -190,6 +242,8 @@ 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),
 };
@@ -326,6 +380,180 @@ 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");
@@ -341,10 +569,21 @@ 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,
 };
 
@@ -409,6 +648,36 @@ 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;
@@ -481,6 +750,20 @@ 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_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_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;
@@ -489,7 +772,6 @@ 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;
@@ -499,6 +781,22 @@ 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)
-- 
1.9.1

[PATCH v4 4/5] iio: ltr501: Add interrupt rate control support

[Kuppuswamy Sathyanarayanan]

Added rate control support for ALS and proximity
threshold interrupts.Also, Added support to modify
and read ALS & proximity sensor sampling frequency.

LTR-501 supports interrupt rate control using persistence
register settings. Writing <n> to persistence register
would generate interrupt only if there are <n> consecutive
data values outside the threshold range.

Since we don't have any existing ABI's to directly
control the persistence register count, we have implemented
the rate control using IIO_EV_INFO_PERIOD. _period event
attribute represents the amount of time in seconds an
event should be true for the device to generate the
interrupt. So using _period value and device frequency,
persistence count is calculated in driver using following
logic.

count =  period / measurement_rate

If the given period is not a multiple of measurement rate then
we round up the value to next multiple.

This patch also handles change to persistence count whenever
there is change in frequency.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/iio/light/ltr501.c | 389 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 382 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index 8ead137..d635ff4 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -9,7 +9,7 @@
  *
  * 7-bit I2C slave address 0x23
  *
- * TODO: measurement rate, IR LED characteristics
+ * TODO: IR LED characteristics
  */
 
 #include <linux/module.h>
@@ -29,6 +29,7 @@
 
 #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
 #define LTR501_PS_CONTR 0x81 /* PS operation mode */
+#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
 #define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
 #define LTR501_PART_ID 0x86
 #define LTR501_MANUFAC_ID 0x87
@@ -41,6 +42,7 @@
 #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_INTR_PRST 0x9e /* ps thresh, als thresh */
 #define LTR501_MAX_REG 0x9f
 
 #define LTR501_ALS_CONTR_SW_RESET BIT(2)
@@ -58,6 +60,9 @@
 #define LTR501_PS_THRESH_MASK 0x7ff
 #define LTR501_ALS_THRESH_MASK 0xffff
 
+#define LTR501_ALS_DEF_PERIOD 500000
+#define LTR501_PS_DEF_PERIOD 100000
+
 #define LTR501_REGMAP_NAME "ltr501_regmap"
 
 static int int_time_mapping[] = {100000, 50000, 200000, 400000};
@@ -65,17 +70,119 @@ static int int_time_mapping[] = {100000, 50000, 200000, 400000};
 static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
 static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
 static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
+static struct reg_field reg_als_rate = REG_FIELD(LTR501_ALS_MEAS_RATE, 0, 2);
+static struct reg_field reg_ps_rate = REG_FIELD(LTR501_PS_MEAS_RATE, 0, 3);
+static struct reg_field reg_als_prst = REG_FIELD(LTR501_INTR_PRST, 0, 3);
+static struct reg_field reg_ps_prst = REG_FIELD(LTR501_INTR_PRST, 4, 7);
+
+struct ltr501_samp_table {
+	int freq_val;  /* repetition frequency in micro HZ*/
+	int time_val; /* repetition rate in micro seconds */
+};
 
 struct ltr501_data {
 	struct i2c_client *client;
 	struct mutex lock_als, lock_ps;
 	u8 als_contr, ps_contr;
+	int als_period, ps_period; /* period in micro seconds */
 	struct regmap *regmap;
 	struct regmap_field *reg_it;
 	struct regmap_field *reg_als_intr;
 	struct regmap_field *reg_ps_intr;
+	struct regmap_field *reg_als_rate;
+	struct regmap_field *reg_ps_rate;
+	struct regmap_field *reg_als_prst;
+	struct regmap_field *reg_ps_prst;
+};
+
+static struct ltr501_samp_table als_sampling_table[] = {
+			{20000000, 50000}, {10000000, 100000},
+			{5000000, 200000}, {2000000, 500000},
+			{1000000, 1000000}, {500000, 2000000},
+			{500000, 2000000}, {500000, 2000000}
+};
+
+static struct ltr501_samp_table ps_sampling_table[] = {
+			{20000000, 50000}, {14285714, 70000},
+			{10000000, 100000}, {5000000, 200000},
+			{2000000, 500000}, {1000000, 1000000},
+			{500000, 2000000}, {500000, 2000000},
+			{500000, 2000000}
 };
 
+static unsigned int ltr501_match_samp_freq(struct ltr501_samp_table *table,
+					   int len, int val, int val2)
+{
+	int i, freq;
+
+	freq = val * 1000000 + val2;
+
+	for (i = 0; i < len; i++) {
+		if (table[i].freq_val == freq)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_read_samp_freq(struct regmap_field *field,
+			   struct ltr501_samp_table *freq,
+			   int len, int *val, int *val2)
+{
+	int ret, i;
+
+	ret = regmap_field_read(field, &i);
+	if (ret < 0)
+		return ret;
+
+	if (i < 0 || i >= len)
+		return -EINVAL;
+
+	*val = freq[i].freq_val / 1000000;
+	*val2 = freq[i].freq_val % 1000000;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ltr501_write_samp_freq(struct ltr501_data *data,
+				struct regmap_field *field,
+				struct ltr501_samp_table *freq,
+				int len, int val, int val2)
+{
+	int i, ret;
+
+	i = ltr501_match_samp_freq(als_sampling_table,
+				   ARRAY_SIZE(als_sampling_table),
+				   val, val2);
+
+	if (i < 0)
+		return i;
+
+	mutex_lock(&data->lock_als);
+	ret = regmap_field_write(data->reg_als_rate, i);
+	mutex_unlock(&data->lock_als);
+
+	return ret;
+}
+
+static int ltr501_read_samp_rate(struct regmap_field *field,
+			   struct ltr501_samp_table *table,
+			   int len, int *val)
+{
+	int ret, i;
+
+	ret = regmap_field_read(field, &i);
+	if (ret < 0)
+		return ret;
+
+	if (i < 0 || i >= len)
+		return -EINVAL;
+
+	*val = table[i].time_val;
+
+	return IIO_VAL_INT;
+}
+
 static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
 {
 	int tries = 100;
@@ -172,6 +279,116 @@ static int ltr501_read_ps(struct ltr501_data *data)
 	return status;
 }
 
+static int ltr501_read_intr_prst(struct ltr501_data *data,
+				 enum iio_chan_type type,
+				 int *val2)
+{
+	int ret, rate, prst;
+
+	switch (type) {
+	case IIO_INTENSITY:
+		ret = regmap_field_read(data->reg_als_prst, &prst);
+		if (ret < 0)
+			return ret;
+
+		ret = ltr501_read_samp_rate(data->reg_als_rate,
+					    als_sampling_table,
+					    ARRAY_SIZE(als_sampling_table),
+					    &rate);
+
+		if (ret < 0)
+			return ret;
+		*val2 = rate * prst;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_PROXIMITY:
+		ret = regmap_field_read(data->reg_ps_prst, &prst);
+		if (ret < 0)
+			return ret;
+
+		ret = ltr501_read_samp_rate(data->reg_ps_rate,
+					    ps_sampling_table,
+					    ARRAY_SIZE(ps_sampling_table),
+					    &rate);
+
+		if (ret < 0)
+			return ret;
+
+		*val2 = rate * prst;
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_write_intr_prst(struct ltr501_data *data,
+				 enum iio_chan_type type,
+				  int val, int val2)
+{
+	int ret, rate, new_val;
+	unsigned long period;
+
+	if (val < 0 || val2 < 0)
+		return -EINVAL;
+
+	/* period in microseconds */
+	period = ((val * 1000000) + val2);
+
+	switch (type) {
+	case IIO_INTENSITY:
+		ret = ltr501_read_samp_rate(data->reg_als_rate,
+					    als_sampling_table,
+					    ARRAY_SIZE(als_sampling_table),
+					    &rate);
+		if (ret < 0)
+			return ret;
+
+		/* period should be atleast equal to rate */
+		if (period < rate)
+			return -EINVAL;
+
+		new_val = DIV_ROUND_UP(period, rate);
+		if (new_val < 0 || new_val > 0x0f)
+			return -EINVAL;
+
+		mutex_lock(&data->lock_als);
+		ret = regmap_field_write(data->reg_als_prst, new_val);
+		mutex_unlock(&data->lock_als);
+		if (ret >= 0)
+			data->als_period = period;
+
+		return ret;
+	case IIO_PROXIMITY:
+		ret = ltr501_read_samp_rate(data->reg_ps_rate,
+					    ps_sampling_table,
+					    ARRAY_SIZE(ps_sampling_table),
+					    &rate);
+		if (ret < 0)
+			return ret;
+
+		/* period should be atleast equal to rate */
+		if (period < rate)
+			return -EINVAL;
+
+		new_val = DIV_ROUND_UP(period, rate);
+		if (new_val < 0 || new_val > 0x0f)
+			return -EINVAL;
+
+		mutex_lock(&data->lock_ps);
+		ret = regmap_field_write(data->reg_ps_prst, new_val);
+		mutex_unlock(&data->lock_ps);
+		if (ret >= 0)
+			data->ps_period = period;
+
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
 static const struct iio_event_spec ltr501_als_event_spec[] = {
 	{
 		.type = IIO_EV_TYPE_THRESH,
@@ -184,7 +401,8 @@ static const struct iio_event_spec ltr501_als_event_spec[] = {
 	}, {
 		.type = IIO_EV_TYPE_THRESH,
 		.dir = IIO_EV_DIR_EITHER,
-		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+				 BIT(IIO_EV_INFO_PERIOD),
 	},
 
 };
@@ -201,7 +419,8 @@ static const struct iio_event_spec ltr501_pxs_event_spec[] = {
 	}, {
 		.type = IIO_EV_TYPE_THRESH,
 		.dir = IIO_EV_DIR_EITHER,
-		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+				 BIT(IIO_EV_INFO_PERIOD),
 	},
 };
 
@@ -228,7 +447,8 @@ static const struct iio_chan_spec ltr501_channels[] = {
 	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_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME) |
+		BIT(IIO_CHAN_INFO_SAMP_FREQ),
 		NULL, 0),
 	{
 		.type = IIO_PROXIMITY,
@@ -314,6 +534,23 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			ret = ltr501_read_samp_freq(data->reg_als_rate,
+						als_sampling_table,
+						ARRAY_SIZE(als_sampling_table),
+						val, val2);
+			return ret;
+		case IIO_PROXIMITY:
+			ret = ltr501_read_samp_freq(data->reg_ps_rate,
+						ps_sampling_table,
+						ARRAY_SIZE(ps_sampling_table),
+						val, val2);
+			return ret;
+		default:
+			return -EINVAL;
+		}
 	}
 	return -EINVAL;
 }
@@ -334,7 +571,7 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 			       int val, int val2, long mask)
 {
 	struct ltr501_data *data = iio_priv(indio_dev);
-	int i;
+	int i, ret, freq_val, freq_val2;
 
 	if (iio_buffer_enabled(indio_dev))
 		return -EBUSY;
@@ -376,6 +613,57 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
 		default:
 			return -EINVAL;
 		}
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_INTENSITY:
+			ret = ltr501_read_samp_freq(data->reg_als_rate,
+						als_sampling_table,
+						ARRAY_SIZE(als_sampling_table),
+						&freq_val, &freq_val2);
+			ret = ltr501_write_samp_freq(data, data->reg_als_rate,
+						als_sampling_table,
+						ARRAY_SIZE(als_sampling_table),
+						val, val2);
+			if (ret < 0)
+				return ret;
+
+			/* update persistence count when changing frequency */
+			ret = ltr501_write_intr_prst(data, chan->type,
+						     0, data->als_period);
+
+			if (ret < 0)
+				return ltr501_write_samp_freq(data,
+						data->reg_als_rate,
+						als_sampling_table,
+						ARRAY_SIZE(als_sampling_table),
+						freq_val, freq_val2);
+			return ret;
+		case IIO_PROXIMITY:
+			ret = ltr501_read_samp_freq(data->reg_ps_rate,
+						ps_sampling_table,
+						ARRAY_SIZE(ps_sampling_table),
+						&freq_val, &freq_val2);
+			ret = ltr501_write_samp_freq(data, data->reg_ps_rate,
+						ps_sampling_table,
+						ARRAY_SIZE(ps_sampling_table),
+						val, val2);
+			if (ret < 0)
+				return ret;
+
+			/* update persistence count when changing frequency */
+			ret = ltr501_write_intr_prst(data, chan->type,
+						     0, data->ps_period);
+
+			if (ret < 0)
+				return ltr501_write_samp_freq(data,
+						data->reg_ps_rate,
+						ps_sampling_table,
+						ARRAY_SIZE(ps_sampling_table),
+						freq_val, freq_val2);
+			return ret;
+		default:
+			return -EINVAL;
+		}
 	}
 	return -EINVAL;
 }
@@ -499,6 +787,55 @@ static int ltr501_write_thresh(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
+static int ltr501_read_event(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)
+{
+	int ret;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		return ltr501_read_thresh(indio_dev, chan, type, dir,
+					  info, val, val2);
+	case IIO_EV_INFO_PERIOD:
+		ret = ltr501_read_intr_prst(iio_priv(indio_dev),
+					    chan->type, val2);
+		*val = *val2 / 1000000;
+		*val2 = *val2 % 1000000;
+		return ret;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ltr501_write_event(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)
+{
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		if (val2 != 0)
+			return -EINVAL;
+		return ltr501_write_thresh(indio_dev, chan, type, dir,
+					   info, val, val2);
+	case IIO_EV_INFO_PERIOD:
+		return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
+					      val, val2);
+	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,
@@ -557,11 +894,13 @@ static int ltr501_write_event_config(struct iio_dev *indio_dev,
 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");
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
 
 static struct attribute *ltr501_attributes[] = {
 	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
 	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
 	&iio_const_attr_integration_time_available.dev_attr.attr,
+	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	NULL
 };
 
@@ -580,8 +919,8 @@ 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_value	= &ltr501_read_event,
+	.write_event_value	= &ltr501_write_event,
 	.read_event_config	= &ltr501_read_event_config,
 	.write_event_config	= &ltr501_write_event_config,
 	.driver_module = THIS_MODULE,
@@ -694,6 +1033,14 @@ static int ltr501_init(struct ltr501_data *data)
 
 	data->ps_contr = status | LTR501_CONTR_ACTIVE;
 
+	ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
+	if (ret < 0)
+		return ret;
+
+	ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
+	if (ret < 0)
+		return ret;
+
 	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
 }
 
@@ -764,6 +1111,34 @@ static int ltr501_probe(struct i2c_client *client,
 		return PTR_ERR(data->reg_ps_intr);
 	}
 
+	data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
+						      reg_als_rate);
+	if (IS_ERR(data->reg_als_rate)) {
+		dev_err(&client->dev, "ALS samp rate field init failed.\n");
+		return PTR_ERR(data->reg_als_rate);
+	}
+
+	data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
+						      reg_ps_rate);
+	if (IS_ERR(data->reg_ps_rate)) {
+		dev_err(&client->dev, "PS samp rate field init failed.\n");
+		return PTR_ERR(data->reg_ps_rate);
+	}
+
+	data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
+						      reg_als_prst);
+	if (IS_ERR(data->reg_als_prst)) {
+		dev_err(&client->dev, "ALS prst reg field init failed\n");
+		return PTR_ERR(data->reg_als_prst);
+	}
+
+	data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
+						      reg_ps_prst);
+	if (IS_ERR(data->reg_ps_prst)) {
+		dev_err(&client->dev, "PS prst reg field init failed.\n");
+		return PTR_ERR(data->reg_ps_prst);
+	}
+
 	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
 	if (ret < 0)
 		return ret;
-- 
1.9.1

[PATCH v4 5/5] iio: ltr501: Add ACPI enumeration support

[Kuppuswamy Sathyanarayanan]

Added ACPI enumeration support for LTR501 chip.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 drivers/iio/light/ltr501.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
index d635ff4..214fb95 100644
--- a/drivers/iio/light/ltr501.c
+++ b/drivers/iio/light/ltr501.c
@@ -17,6 +17,7 @@
 #include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/regmap.h>
+#include <linux/acpi.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/events.h>
@@ -1225,6 +1226,12 @@ static int ltr501_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(ltr501_pm_ops, ltr501_suspend, ltr501_resume);
 
+static const struct acpi_device_id ltr_acpi_match[] = {
+	{"LTER0501", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, ltr_acpi_match);
+
 static const struct i2c_device_id ltr501_id[] = {
 	{ "ltr501", 0 },
 	{ }
@@ -1235,6 +1242,7 @@ static struct i2c_driver ltr501_driver = {
 	.driver = {
 		.name   = LTR501_DRV_NAME,
 		.pm	= &ltr501_pm_ops,
+		.acpi_match_table = ACPI_PTR(ltr_acpi_match),
 		.owner  = THIS_MODULE,
 	},
 	.probe  = ltr501_probe,
-- 
1.9.1

Re: [PATCH v4 1/5] iio: ltr501: Add regmap support.

[Jonathan Cameron]

On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
> Added regmap support. It will be useful to handle
> bitwise updates to als & ps control registers.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Looks good.  Applied to the togreg branch of iio.git
Initially pushed out as testign for the autobuilders to play with it.

Note I hand applied this as there was a lot of realignment stuff in
a recent patch from Daniel.

As he'd gone to the effort to make checkpatch.pl --strict pass it I
did the same and cleaned up a few corners (nothing remotely significant!)

If you could take a look at the result and check I didn't do anything silly
that would be great!

Thanks,

Jonathan
> ---
>  drivers/iio/light/ltr501.c | 114 +++++++++++++++++++++++++++++++--------------
>  1 file changed, 80 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 62b7072..84ee2b3 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -16,6 +16,7 @@
>  #include <linux/i2c.h>
>  #include <linux/err.h>
>  #include <linux/delay.h>
> +#include <linux/regmap.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> @@ -33,6 +34,7 @@
>  #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_MAX_REG 0x9f
>  
>  #define LTR501_ALS_CONTR_SW_RESET BIT(2)
>  #define LTR501_CONTR_PS_GAIN_MASK (BIT(3) | BIT(2))
> @@ -45,23 +47,25 @@
>  
>  #define LTR501_PS_DATA_MASK 0x7ff
>  
> +#define LTR501_REGMAP_NAME "ltr501_regmap"
> +
>  struct ltr501_data {
>  	struct i2c_client *client;
>  	struct mutex lock_als, lock_ps;
>  	u8 als_contr, ps_contr;
> +	struct regmap *regmap;
>  };
>  
>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>  {
>  	int tries = 100;
> -	int ret;
> +	int ret, status;
>  
>  	while (tries--) {
> -		ret = i2c_smbus_read_byte_data(data->client,
> -			LTR501_ALS_PS_STATUS);
> +		ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
>  		if (ret < 0)
>  			return ret;
> -		if ((ret & drdy_mask) == drdy_mask)
> +		if ((status & drdy_mask) == drdy_mask)
>  			return 0;
>  		msleep(25);
>  	}
> @@ -76,16 +80,24 @@ static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
>  	if (ret < 0)
>  		return ret;
>  	/* always read both ALS channels in given order */
> -	return i2c_smbus_read_i2c_block_data(data->client,
> -		LTR501_ALS_DATA1, 2 * sizeof(__le16), (u8 *) buf);
> +	return regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
> +				buf, 2 * sizeof(__le16));
>  }
>  
>  static int ltr501_read_ps(struct ltr501_data *data)
>  {
> -	int ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
> +	int ret, status;
> +
> +	ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
> +				&status, 2);
>  	if (ret < 0)
>  		return ret;
> -	return i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
> +
> +	return status;
>  }
>  
>  #define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared) { \
> @@ -218,16 +230,18 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  				data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
>  			else
>  				return -EINVAL;
> -			return i2c_smbus_write_byte_data(data->client,
> -				LTR501_ALS_CONTR, data->als_contr);
> +
> +			return regmap_write(data->regmap, LTR501_ALS_CONTR,
> +					    data->als_contr);
>  		case IIO_PROXIMITY:
>  			i = ltr501_get_ps_gain_index(val, val2);
>  			if (i < 0)
>  				return -EINVAL;
>  			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
>  			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;
> -			return i2c_smbus_write_byte_data(data->client,
> -				LTR501_PS_CONTR, data->ps_contr);
> +
> +			return regmap_write(data->regmap, LTR501_PS_CONTR,
> +					    data->ps_contr);
>  		default:
>  			return -EINVAL;
>  		}
> @@ -255,13 +269,13 @@ static const struct iio_info ltr501_info = {
>  	.driver_module = THIS_MODULE,
>  };
>  
> -static int ltr501_write_contr(struct i2c_client *client, u8 als_val, u8 ps_val)
> +static int ltr501_write_contr(struct ltr501_data *data, u8 als_val, u8 ps_val)
>  {
> -	int ret = i2c_smbus_write_byte_data(client, LTR501_ALS_CONTR, als_val);
> +	int ret = regmap_write(data->regmap, LTR501_ALS_CONTR, als_val);
>  	if (ret < 0)
>  		return ret;
>  
> -	return i2c_smbus_write_byte_data(client, LTR501_PS_CONTR, ps_val);
> +	return regmap_write(data->regmap, LTR501_PS_CONTR, ps_val);
>  }
>  
>  static irqreturn_t ltr501_trigger_handler(int irq, void *p)
> @@ -273,7 +287,7 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
>  	__le16 als_buf[2];
>  	u8 mask = 0;
>  	int j = 0;
> -	int ret;
> +	int ret, psdata;
>  
>  	memset(buf, 0, sizeof(buf));
>  
> @@ -289,8 +303,8 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
>  		goto done;
>  
>  	if (mask & LTR501_STATUS_ALS_RDY) {
> -		ret = i2c_smbus_read_i2c_block_data(data->client,
> -			LTR501_ALS_DATA1, sizeof(als_buf), (u8 *) als_buf);
> +		ret = regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
> +				       (u8 *) als_buf, sizeof(als_buf));
>  		if (ret < 0)
>  			return ret;
>  		if (test_bit(0, indio_dev->active_scan_mask))
> @@ -300,10 +314,11 @@ static irqreturn_t ltr501_trigger_handler(int irq, void *p)
>  	}
>  
>  	if (mask & LTR501_STATUS_PS_RDY) {
> -		ret = i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
> +		ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
> +				       &psdata, 2);
>  		if (ret < 0)
>  			goto done;
> -		buf[j++] = ret & LTR501_PS_DATA_MASK;
> +		buf[j++] = psdata & LTR501_PS_DATA_MASK;
>  	}
>  
>  	iio_push_to_buffers_with_timestamp(indio_dev, buf,
> @@ -317,43 +332,75 @@ done:
>  
>  static int ltr501_init(struct ltr501_data *data)
>  {
> -	int ret;
> +	int ret, status;
>  
> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_ALS_CONTR);
> +	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
>  	if (ret < 0)
>  		return ret;
> -	data->als_contr = ret | LTR501_CONTR_ACTIVE;
>  
> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_PS_CONTR);
> +	data->als_contr = status | LTR501_CONTR_ACTIVE;
> +
> +	ret = regmap_read(data->regmap, LTR501_PS_CONTR, &status);
>  	if (ret < 0)
>  		return ret;
> -	data->ps_contr = ret | LTR501_CONTR_ACTIVE;
>  
> -	return ltr501_write_contr(data->client, data->als_contr,
> -		data->ps_contr);
> +	data->ps_contr = status | LTR501_CONTR_ACTIVE;
> +
> +	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
> +}
> +
> +static bool ltr501_is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case LTR501_ALS_DATA1:
> +	case LTR501_ALS_DATA0:
> +	case LTR501_ALS_PS_STATUS:
> +	case LTR501_PS_DATA:
> +		return true;
> +	default:
> +		return false;
> +	}
>  }
>  
> +static struct regmap_config ltr501_regmap_config = {
> +	.name =  LTR501_REGMAP_NAME,
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = LTR501_MAX_REG,
> +	.cache_type = REGCACHE_RBTREE,
> +	.volatile_reg = ltr501_is_volatile_reg,
> +};
> +
>  static int ltr501_probe(struct i2c_client *client,
>  			  const struct i2c_device_id *id)
>  {
>  	struct ltr501_data *data;
>  	struct iio_dev *indio_dev;
> -	int ret;
> +	struct regmap *regmap;
> +	int ret, partid;
>  
>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>  	if (!indio_dev)
>  		return -ENOMEM;
>  
> +	regmap = devm_regmap_init_i2c(client, &ltr501_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(&client->dev, "Regmap initialization failed.\n");
> +		return PTR_ERR(regmap);
> +	}
> +
>  	data = iio_priv(indio_dev);
>  	i2c_set_clientdata(client, indio_dev);
>  	data->client = client;
> +	data->regmap = regmap;
>  	mutex_init(&data->lock_als);
>  	mutex_init(&data->lock_ps);
>  
> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_PART_ID);
> +	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>  	if (ret < 0)
>  		return ret;
> -	if ((ret >> 4) != 0x8)
> +
> +	if ((partid >> 4) != 0x8)
>  		return -ENODEV;
>  
>  	indio_dev->dev.parent = &client->dev;
> @@ -385,9 +432,8 @@ error_unreg_buffer:
>  
>  static int ltr501_powerdown(struct ltr501_data *data)
>  {
> -	return ltr501_write_contr(data->client,
> -		data->als_contr & ~LTR501_CONTR_ACTIVE,
> -		data->ps_contr & ~LTR501_CONTR_ACTIVE);
> +	return ltr501_write_contr(data, data->als_contr & ~LTR501_CONTR_ACTIVE,
> +				  data->ps_contr & ~LTR501_CONTR_ACTIVE);
>  }
>  
>  static int ltr501_remove(struct i2c_client *client)
> @@ -414,7 +460,7 @@ static int ltr501_resume(struct device *dev)
>  	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
>  		to_i2c_client(dev)));
>  
> -	return ltr501_write_contr(data->client, data->als_contr,
> +	return ltr501_write_contr(data, data->als_contr,
>  		data->ps_contr);
>  }
>  #endif
> 

Re: [PATCH v4 2/5] iio: ltr501: Add integration time support

[Jonathan Cameron]

On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
> Added support to modify and read ALS integration time.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

Cool, didn't know about this regmap field stuff before.  Not exactly heavily
used but looks helpful!

A few questions inline..

1) A spot where a variable name change would make it easier to follow.
2) Why are the struct reg_field not defined as const in the regmap_field
allocators?  Here it gives the impression we are restricting ourselves to
one instance of this chip, but in reality they seem to actually be const
so we aren't.

messy :(

> ---
>  drivers/iio/light/ltr501.c | 87 +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 86 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 84ee2b3..22769c8 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -28,6 +28,7 @@
>  
>  #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
>  #define LTR501_PS_CONTR 0x81 /* PS operation mode */
> +#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
>  #define LTR501_PART_ID 0x86
>  #define LTR501_MANUFAC_ID 0x87
>  #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
> @@ -49,11 +50,16 @@
>  
>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>  
> +static int int_time_mapping[] = {100000, 50000, 200000, 400000};
> +
> +static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
Naming could be clearer.  The reg_it here and the regmap_field below
are different structures, but their name doesn't make this clear.

Also, why is the above not const?  Obviously regmap doesn't take a const
but I can't see why not... Mark?

It is only used to initialize elements (by copying) in the regmap_field
that allocator of which it is passed to.  
> +
>  struct ltr501_data {
>  	struct i2c_client *client;
>  	struct mutex lock_als, lock_ps;
>  	u8 als_contr, ps_contr;
>  	struct regmap *regmap;
> +	struct regmap_field *reg_it;
>  };
>  
>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
> @@ -74,6 +80,58 @@ static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>  	return -EIO;
>  }
>  
> +static int ltr501_set_it_time(struct ltr501_data *data, int it)
> +{
> +	int ret, i, index = -1, status;
> +
> +	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
> +		if (int_time_mapping[i] == it) {
> +			index = i;
> +			break;
> +		}
> +	}
> +	/* Make sure integ time index is valid */
> +	if (index < 0)
> +		return -EINVAL;
> +
> +	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (status & LTR501_CONTR_ALS_GAIN_MASK) {
> +		/*
> +		 * 200 ms and 400 ms integ time can only be
> +		 * used in dynamic range 1
> +		 */
> +		if (index > 1)
> +			return -EINVAL;
> +	} else
> +		/* 50 ms integ time can only be used in dynamic range 2 */
> +		if (index == 1)
> +			return -EINVAL;
> +
> +	return regmap_field_write(data->reg_it, index);
> +}
> +
> +/* read int time in micro seconds */
> +static int ltr501_read_it_time(struct ltr501_data *data, int *val, int *val2)
> +{
> +	int ret, index;
> +
> +	ret = regmap_field_read(data->reg_it, &index);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Make sure integ time index is valid */
> +	if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
> +		return -EINVAL;
> +
> +	*val2 = int_time_mapping[index];
> +	*val = 0;
> +
> +	return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
>  static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
>  {
>  	int ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
> @@ -119,7 +177,7 @@ static int ltr501_read_ps(struct ltr501_data *data)
>  static const struct iio_chan_spec ltr501_channels[] = {
>  	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
>  	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
> -		BIT(IIO_CHAN_INFO_SCALE)),
> +		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME)),
>  	{
>  		.type = IIO_PROXIMITY,
>  		.address = LTR501_PS_DATA,
> @@ -195,6 +253,13 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_INT_TIME:
> +		switch (chan->type) {
> +		case IIO_INTENSITY:
> +			return ltr501_read_it_time(data, val, val2);
> +		default:
> +			return -EINVAL;
> +		}
>  	}
>  	return -EINVAL;
>  }
> @@ -245,16 +310,30 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_INT_TIME:
> +		switch (chan->type) {
> +		case IIO_INTENSITY:
> +			if (val != 0)
> +				return -EINVAL;
> +			mutex_lock(&data->lock_als);
> +			i = ltr501_set_it_time(data, val2);
> +			mutex_unlock(&data->lock_als);
> +			return i;
> +		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");
>  
>  static struct attribute *ltr501_attributes[] = {
>  	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
>  	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
> +	&iio_const_attr_integration_time_available.dev_attr.attr,
>  	NULL
>  };
>  
> @@ -396,6 +475,12 @@ static int ltr501_probe(struct i2c_client *client,
>  	mutex_init(&data->lock_als);
>  	mutex_init(&data->lock_ps);
>  
> +	data->reg_it = devm_regmap_field_alloc(&client->dev, regmap, reg_it);
> +	if (IS_ERR(data->reg_it)) {
> +		dev_err(&client->dev, "Integ time reg field init failed.\n");
> +		return PTR_ERR(data->reg_it);
> +	}
> +
>  	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>  	if (ret < 0)
>  		return ret;
> 

Re: [PATCH v4 3/5] iio: ltr501: Add interrupt support

[Jonathan Cameron]

On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
> 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>
Looks good.  Will pick this one up once we've addressed those little bits
in patch 2.

Thanks,
> ---
>  drivers/iio/light/ltr501.c | 310 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 304 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 22769c8..8ead137 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/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)
> @@ -43,16 +49,22 @@
>  #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"
>  
>  static int int_time_mapping[] = {100000, 50000, 200000, 400000};
>  
>  static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
> +static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
> +static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
>  
>  struct ltr501_data {
>  	struct i2c_client *client;
> @@ -60,6 +72,8 @@ 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)
> @@ -158,7 +172,41 @@ 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), \
> @@ -171,13 +219,17 @@ 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_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME),
> +		NULL, 0),
>  	{
>  		.type = IIO_PROXIMITY,
>  		.address = LTR501_PS_DATA,
> @@ -190,6 +242,8 @@ 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),
>  };
> @@ -326,6 +380,180 @@ 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");
> @@ -341,10 +569,21 @@ 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,
>  };
>  
> @@ -409,6 +648,36 @@ 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;
> @@ -481,6 +750,20 @@ 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_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_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;
> @@ -489,7 +772,6 @@ 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;
> @@ -499,6 +781,22 @@ 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)
> 

Re: [PATCH v4 4/5] iio: ltr501: Add interrupt rate control support

[Jonathan Cameron]

On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
> Added rate control support for ALS and proximity
> threshold interrupts.Also, Added support to modify
> and read ALS & proximity sensor sampling frequency.
> 
> LTR-501 supports interrupt rate control using persistence
> register settings. Writing <n> to persistence register
> would generate interrupt only if there are <n> consecutive
> data values outside the threshold range.
> 
> Since we don't have any existing ABI's to directly
> control the persistence register count, we have implemented
> the rate control using IIO_EV_INFO_PERIOD. _period event
> attribute represents the amount of time in seconds an
> event should be true for the device to generate the
> interrupt. So using _period value and device frequency,
> persistence count is calculated in driver using following
> logic.
> 
> count =  period / measurement_rate
> 
> If the given period is not a multiple of measurement rate then
> we round up the value to next multiple.
> 
> This patch also handles change to persistence count whenever
> there is change in frequency.

Thanks for your continued hard work on this!

Anyhow, mostly this is stalled on the patch 2 questions, but I have
made a few little suggestions inline.

Note that the term 'rate' is somewhat ambiguous so I'd use sampling_period
which is better defined.  Rate is often a frequency measurement.

Also, a few arrays that should be const + the places they are used should
also have the parameters as const.

Thanks,

Jonathan
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> ---
>  drivers/iio/light/ltr501.c | 389 ++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 382 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 8ead137..d635ff4 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -9,7 +9,7 @@
>   *
>   * 7-bit I2C slave address 0x23
>   *
> - * TODO: measurement rate, IR LED characteristics
> + * TODO: IR LED characteristics
>   */
>  
>  #include <linux/module.h>
> @@ -29,6 +29,7 @@
>  
>  #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
>  #define LTR501_PS_CONTR 0x81 /* PS operation mode */
> +#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
>  #define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
>  #define LTR501_PART_ID 0x86
>  #define LTR501_MANUFAC_ID 0x87
> @@ -41,6 +42,7 @@
>  #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_INTR_PRST 0x9e /* ps thresh, als thresh */
>  #define LTR501_MAX_REG 0x9f
>  
>  #define LTR501_ALS_CONTR_SW_RESET BIT(2)
> @@ -58,6 +60,9 @@
>  #define LTR501_PS_THRESH_MASK 0x7ff
>  #define LTR501_ALS_THRESH_MASK 0xffff
>  
> +#define LTR501_ALS_DEF_PERIOD 500000
> +#define LTR501_PS_DEF_PERIOD 100000
> +
>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>  
>  static int int_time_mapping[] = {100000, 50000, 200000, 400000};
> @@ -65,17 +70,119 @@ static int int_time_mapping[] = {100000, 50000, 200000, 400000};
>  static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
>  static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
>  static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
> +static struct reg_field reg_als_rate = REG_FIELD(LTR501_ALS_MEAS_RATE, 0, 2);
> +static struct reg_field reg_ps_rate = REG_FIELD(LTR501_PS_MEAS_RATE, 0, 3);
> +static struct reg_field reg_als_prst = REG_FIELD(LTR501_INTR_PRST, 0, 3);
> +static struct reg_field reg_ps_prst = REG_FIELD(LTR501_INTR_PRST, 4, 7);
> +
> +struct ltr501_samp_table {
> +	int freq_val;  /* repetition frequency in micro HZ*/
> +	int time_val; /* repetition rate in micro seconds */
> +};
>  
>  struct ltr501_data {
>  	struct i2c_client *client;
>  	struct mutex lock_als, lock_ps;
>  	u8 als_contr, ps_contr;
> +	int als_period, ps_period; /* period in micro seconds */
>  	struct regmap *regmap;
>  	struct regmap_field *reg_it;
>  	struct regmap_field *reg_als_intr;
>  	struct regmap_field *reg_ps_intr;
> +	struct regmap_field *reg_als_rate;
> +	struct regmap_field *reg_ps_rate;
> +	struct regmap_field *reg_als_prst;
> +	struct regmap_field *reg_ps_prst;
> +};
> +
const. Also ideally prefix the name. More that plausible
that als_sampling_table might turn up in a header at some
point in the future.

> +static struct ltr501_samp_table als_sampling_table[] = {
> +			{20000000, 50000}, {10000000, 100000},
> +			{5000000, 200000}, {2000000, 500000},
> +			{1000000, 1000000}, {500000, 2000000},
> +			{500000, 2000000}, {500000, 2000000}
> +};
> +
const
> +static struct ltr501_samp_table ps_sampling_table[] = {
> +			{20000000, 50000}, {14285714, 70000},
> +			{10000000, 100000}, {5000000, 200000},
> +			{2000000, 500000}, {1000000, 1000000},
> +			{500000, 2000000}, {500000, 2000000},
> +			{500000, 2000000}
>  };
>  
> +static unsigned int ltr501_match_samp_freq(struct ltr501_samp_table *table,
> +					   int len, int val, int val2)
> +{
> +	int i, freq;
> +
> +	freq = val * 1000000 + val2;
> +
> +	for (i = 0; i < len; i++) {
> +		if (table[i].freq_val == freq)
> +			return i;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ltr501_read_samp_freq(struct regmap_field *field,
> +			   struct ltr501_samp_table *freq,
> +			   int len, int *val, int *val2)
> +{
> +	int ret, i;
> +
> +	ret = regmap_field_read(field, &i);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (i < 0 || i >= len)
> +		return -EINVAL;
> +
> +	*val = freq[i].freq_val / 1000000;
> +	*val2 = freq[i].freq_val % 1000000;
> +
> +	return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static int ltr501_write_samp_freq(struct ltr501_data *data,
> +				struct regmap_field *field,
> +				struct ltr501_samp_table *freq,
> +				int len, int val, int val2)
> +{
> +	int i, ret;
> +
> +	i = ltr501_match_samp_freq(als_sampling_table,
> +				   ARRAY_SIZE(als_sampling_table),
> +				   val, val2);
> +
> +	if (i < 0)
> +		return i;
> +
> +	mutex_lock(&data->lock_als);
> +	ret = regmap_field_write(data->reg_als_rate, i);
> +	mutex_unlock(&data->lock_als);
> +
> +	return ret;
> +}
> +
read_samp_period.
Rate is normally used to mean a frequency.

I wonder if the code would be shorter and simpler if you
define a utility function here and then do two specific
versions for als and ps? Would allow dropping a lot of
parameters elsewhere for a couple of extra lines here.

> +static int ltr501_read_samp_rate(struct regmap_field *field,
> +			   struct ltr501_samp_table *table,
> +			   int len, int *val)
> +{
> +	int ret, i;
> +
> +	ret = regmap_field_read(field, &i);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (i < 0 || i >= len)
> +		return -EINVAL;
> +
> +	*val = table[i].time_val;
> +
> +	return IIO_VAL_INT;
> +}
> +
>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>  {
>  	int tries = 100;
> @@ -172,6 +279,116 @@ static int ltr501_read_ps(struct ltr501_data *data)
>  	return status;
>  }
>  
> +static int ltr501_read_intr_prst(struct ltr501_data *data,
> +				 enum iio_chan_type type,
> +				 int *val2)
> +{
> +	int ret, rate, prst;
> +
> +	switch (type) {
> +	case IIO_INTENSITY:
> +		ret = regmap_field_read(data->reg_als_prst, &prst);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = ltr501_read_samp_rate(data->reg_als_rate,
> +					    als_sampling_table,
> +					    ARRAY_SIZE(als_sampling_table),
> +					    &rate);
> +
> +		if (ret < 0)
> +			return ret;
> +		*val2 = rate * prst;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_PROXIMITY:
> +		ret = regmap_field_read(data->reg_ps_prst, &prst);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = ltr501_read_samp_rate(data->reg_ps_rate,
> +					    ps_sampling_table,
> +					    ARRAY_SIZE(ps_sampling_table),
> +					    &rate);
> +
> +		if (ret < 0)
> +			return ret;
> +
> +		*val2 = rate * prst;
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ltr501_write_intr_prst(struct ltr501_data *data,
> +				 enum iio_chan_type type,
> +				  int val, int val2)
> +{
> +	int ret, rate, new_val;
> +	unsigned long period;
> +
> +	if (val < 0 || val2 < 0)
> +		return -EINVAL;
> +
> +	/* period in microseconds */
> +	period = ((val * 1000000) + val2);
> +
> +	switch (type) {
> +	case IIO_INTENSITY:
> +		ret = ltr501_read_samp_rate(data->reg_als_rate,
> +					    als_sampling_table,
> +					    ARRAY_SIZE(als_sampling_table),
> +					    &rate);
> +		if (ret < 0)
> +			return ret;
> +
> +		/* period should be atleast equal to rate */
Event period should be at least equal to sampling period (not rate which
is a term used indicate how often per second - e.g. a frequency).

> +		if (period < rate)
> +			return -EINVAL;
> +
> +		new_val = DIV_ROUND_UP(period, rate);
> +		if (new_val < 0 || new_val > 0x0f)
> +			return -EINVAL;
> +
> +		mutex_lock(&data->lock_als);
> +		ret = regmap_field_write(data->reg_als_prst, new_val);
> +		mutex_unlock(&data->lock_als);
> +		if (ret >= 0)
> +			data->als_period = period;
> +
> +		return ret;
> +	case IIO_PROXIMITY:
> +		ret = ltr501_read_samp_rate(data->reg_ps_rate,
> +					    ps_sampling_table,
> +					    ARRAY_SIZE(ps_sampling_table),
> +					    &rate);
> +		if (ret < 0)
> +			return ret;
> +
> +		/* period should be atleast equal to rate */
> +		if (period < rate)
> +			return -EINVAL;
> +
> +		new_val = DIV_ROUND_UP(period, rate);
> +		if (new_val < 0 || new_val > 0x0f)
> +			return -EINVAL;
> +
> +		mutex_lock(&data->lock_ps);
> +		ret = regmap_field_write(data->reg_ps_prst, new_val);
> +		mutex_unlock(&data->lock_ps);
> +		if (ret >= 0)
> +			data->ps_period = period;
> +
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +}
> +
>  static const struct iio_event_spec ltr501_als_event_spec[] = {
>  	{
>  		.type = IIO_EV_TYPE_THRESH,
> @@ -184,7 +401,8 @@ static const struct iio_event_spec ltr501_als_event_spec[] = {
>  	}, {
>  		.type = IIO_EV_TYPE_THRESH,
>  		.dir = IIO_EV_DIR_EITHER,
> -		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> +				 BIT(IIO_EV_INFO_PERIOD),
>  	},
>  
>  };
> @@ -201,7 +419,8 @@ static const struct iio_event_spec ltr501_pxs_event_spec[] = {
>  	}, {
>  		.type = IIO_EV_TYPE_THRESH,
>  		.dir = IIO_EV_DIR_EITHER,
> -		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> +				 BIT(IIO_EV_INFO_PERIOD),
>  	},
>  };
>  
> @@ -228,7 +447,8 @@ static const struct iio_chan_spec ltr501_channels[] = {
>  	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_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME) |
> +		BIT(IIO_CHAN_INFO_SAMP_FREQ),
>  		NULL, 0),
>  	{
>  		.type = IIO_PROXIMITY,
> @@ -314,6 +534,23 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		switch (chan->type) {
> +		case IIO_INTENSITY:
> +			ret = ltr501_read_samp_freq(data->reg_als_rate,
> +						als_sampling_table,
> +						ARRAY_SIZE(als_sampling_table),
> +						val, val2);
> +			return ret;
> +		case IIO_PROXIMITY:
> +			ret = ltr501_read_samp_freq(data->reg_ps_rate,
> +						ps_sampling_table,
> +						ARRAY_SIZE(ps_sampling_table),
> +						val, val2);
> +			return ret;
> +		default:
> +			return -EINVAL;
> +		}
>  	}
>  	return -EINVAL;
>  }
> @@ -334,7 +571,7 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  			       int val, int val2, long mask)
>  {
>  	struct ltr501_data *data = iio_priv(indio_dev);
> -	int i;
> +	int i, ret, freq_val, freq_val2;
>  
>  	if (iio_buffer_enabled(indio_dev))
>  		return -EBUSY;
> @@ -376,6 +613,57 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		switch (chan->type) {
> +		case IIO_INTENSITY:
> +			ret = ltr501_read_samp_freq(data->reg_als_rate,
> +						als_sampling_table,
> +						ARRAY_SIZE(als_sampling_table),
> +						&freq_val, &freq_val2);
> +			ret = ltr501_write_samp_freq(data, data->reg_als_rate,
> +						als_sampling_table,
> +						ARRAY_SIZE(als_sampling_table),
> +						val, val2);
> +			if (ret < 0)
> +				return ret;
> +
> +			/* update persistence count when changing frequency */
> +			ret = ltr501_write_intr_prst(data, chan->type,
> +						     0, data->als_period);
> +
> +			if (ret < 0)
> +				return ltr501_write_samp_freq(data,
> +						data->reg_als_rate,
> +						als_sampling_table,
> +						ARRAY_SIZE(als_sampling_table),
> +						freq_val, freq_val2);
> +			return ret;
> +		case IIO_PROXIMITY:
> +			ret = ltr501_read_samp_freq(data->reg_ps_rate,
> +						ps_sampling_table,
> +						ARRAY_SIZE(ps_sampling_table),
> +						&freq_val, &freq_val2);
> +			ret = ltr501_write_samp_freq(data, data->reg_ps_rate,
> +						ps_sampling_table,
> +						ARRAY_SIZE(ps_sampling_table),
> +						val, val2);
> +			if (ret < 0)
> +				return ret;
> +
> +			/* update persistence count when changing frequency */
> +			ret = ltr501_write_intr_prst(data, chan->type,
> +						     0, data->ps_period);
> +
> +			if (ret < 0)
> +				return ltr501_write_samp_freq(data,
> +						data->reg_ps_rate,
> +						ps_sampling_table,
> +						ARRAY_SIZE(ps_sampling_table),
> +						freq_val, freq_val2);
> +			return ret;
> +		default:
> +			return -EINVAL;
> +		}
>  	}
>  	return -EINVAL;
>  }
> @@ -499,6 +787,55 @@ static int ltr501_write_thresh(struct iio_dev *indio_dev,
>  	return -EINVAL;
>  }
>  
> +static int ltr501_read_event(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)
> +{
> +	int ret;
> +
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE:
> +		return ltr501_read_thresh(indio_dev, chan, type, dir,
> +					  info, val, val2);
> +	case IIO_EV_INFO_PERIOD:
> +		ret = ltr501_read_intr_prst(iio_priv(indio_dev),
> +					    chan->type, val2);
> +		*val = *val2 / 1000000;
> +		*val2 = *val2 % 1000000;
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ltr501_write_event(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)
> +{
> +	switch (info) {
> +	case IIO_EV_INFO_VALUE:
> +		if (val2 != 0)
> +			return -EINVAL;
> +		return ltr501_write_thresh(indio_dev, chan, type, dir,
> +					   info, val, val2);
> +	case IIO_EV_INFO_PERIOD:
> +		return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
> +					      val, val2);
> +	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,
> @@ -557,11 +894,13 @@ static int ltr501_write_event_config(struct iio_dev *indio_dev,
>  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");
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
>  
>  static struct attribute *ltr501_attributes[] = {
>  	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
>  	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
>  	&iio_const_attr_integration_time_available.dev_attr.attr,
> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>  	NULL
>  };
>  
> @@ -580,8 +919,8 @@ 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_value	= &ltr501_read_event,
> +	.write_event_value	= &ltr501_write_event,
>  	.read_event_config	= &ltr501_read_event_config,
>  	.write_event_config	= &ltr501_write_event_config,
>  	.driver_module = THIS_MODULE,
> @@ -694,6 +1033,14 @@ static int ltr501_init(struct ltr501_data *data)
>  
>  	data->ps_contr = status | LTR501_CONTR_ACTIVE;
>  
> +	ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
> +	if (ret < 0)
> +		return ret;
> +
>  	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
>  }
>  
> @@ -764,6 +1111,34 @@ static int ltr501_probe(struct i2c_client *client,
>  		return PTR_ERR(data->reg_ps_intr);
>  	}
>  
> +	data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
> +						      reg_als_rate);
> +	if (IS_ERR(data->reg_als_rate)) {
> +		dev_err(&client->dev, "ALS samp rate field init failed.\n");
> +		return PTR_ERR(data->reg_als_rate);
> +	}
> +
> +	data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
> +						      reg_ps_rate);
> +	if (IS_ERR(data->reg_ps_rate)) {
> +		dev_err(&client->dev, "PS samp rate field init failed.\n");
> +		return PTR_ERR(data->reg_ps_rate);
> +	}
> +
> +	data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
> +						      reg_als_prst);
> +	if (IS_ERR(data->reg_als_prst)) {
> +		dev_err(&client->dev, "ALS prst reg field init failed\n");
> +		return PTR_ERR(data->reg_als_prst);
> +	}
> +
> +	data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
> +						      reg_ps_prst);
> +	if (IS_ERR(data->reg_ps_prst)) {
> +		dev_err(&client->dev, "PS prst reg field init failed.\n");
> +		return PTR_ERR(data->reg_ps_prst);
> +	}
> +
>  	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>  	if (ret < 0)
>  		return ret;
> 

Re: [PATCH v4 1/5] iio: ltr501: Add regmap support.

[sathyanarayanan.kuppuswamy]

Hi Jonathan,

> On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
>> Added regmap support. It will be useful to handle
>> bitwise updates to als & ps control registers.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan
>> <sathyanarayanan.kuppuswamy@linux.intel.com>
> Looks good.  Applied to the togreg branch of iio.git
> Initially pushed out as testign for the autobuilders to play with it.
>
> Note I hand applied this as there was a lot of realignment stuff in
> a recent patch from Daniel.
>
> As he'd gone to the effort to make checkpatch.pl --strict pass it I
> did the same and cleaned up a few corners (nothing remotely significant!)
>
> If you could take a look at the result and check I didn't do anything
> silly
> that would be great!
Thanks for fixing it. Just reviewed the patch in testing branch. It looks
fine. I have cherry-picked it and sent it along with my next set.
>
> Thanks,
>
> Jonathan
>> ---
>>  drivers/iio/light/ltr501.c | 114
>> +++++++++++++++++++++++++++++++--------------
>>  1 file changed, 80 insertions(+), 34 deletions(-)
>>
>> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
>> index 62b7072..84ee2b3 100644
>> --- a/drivers/iio/light/ltr501.c
>> +++ b/drivers/iio/light/ltr501.c
>> @@ -16,6 +16,7 @@
>>  #include <linux/i2c.h>
>>  #include <linux/err.h>
>>  #include <linux/delay.h>
>> +#include <linux/regmap.h>
>>
>>  #include <linux/iio/iio.h>
>>  #include <linux/iio/sysfs.h>
>> @@ -33,6 +34,7 @@
>>  #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_MAX_REG 0x9f
>>
>>  #define LTR501_ALS_CONTR_SW_RESET BIT(2)
>>  #define LTR501_CONTR_PS_GAIN_MASK (BIT(3) | BIT(2))
>> @@ -45,23 +47,25 @@
>>
>>  #define LTR501_PS_DATA_MASK 0x7ff
>>
>> +#define LTR501_REGMAP_NAME "ltr501_regmap"
>> +
>>  struct ltr501_data {
>>  	struct i2c_client *client;
>>  	struct mutex lock_als, lock_ps;
>>  	u8 als_contr, ps_contr;
>> +	struct regmap *regmap;
>>  };
>>
>>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>>  {
>>  	int tries = 100;
>> -	int ret;
>> +	int ret, status;
>>
>>  	while (tries--) {
>> -		ret = i2c_smbus_read_byte_data(data->client,
>> -			LTR501_ALS_PS_STATUS);
>> +		ret = regmap_read(data->regmap, LTR501_ALS_PS_STATUS, &status);
>>  		if (ret < 0)
>>  			return ret;
>> -		if ((ret & drdy_mask) == drdy_mask)
>> +		if ((status & drdy_mask) == drdy_mask)
>>  			return 0;
>>  		msleep(25);
>>  	}
>> @@ -76,16 +80,24 @@ static int ltr501_read_als(struct ltr501_data *data,
>> __le16 buf[2])
>>  	if (ret < 0)
>>  		return ret;
>>  	/* always read both ALS channels in given order */
>> -	return i2c_smbus_read_i2c_block_data(data->client,
>> -		LTR501_ALS_DATA1, 2 * sizeof(__le16), (u8 *) buf);
>> +	return regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
>> +				buf, 2 * sizeof(__le16));
>>  }
>>
>>  static int ltr501_read_ps(struct ltr501_data *data)
>>  {
>> -	int ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
>> +	int ret, status;
>> +
>> +	ret = ltr501_drdy(data, LTR501_STATUS_PS_RDY);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
>> +				&status, 2);
>>  	if (ret < 0)
>>  		return ret;
>> -	return i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
>> +
>> +	return status;
>>  }
>>
>>  #define LTR501_INTENSITY_CHANNEL(_idx, _addr, _mod, _shared) { \
>> @@ -218,16 +230,18 @@ static int ltr501_write_raw(struct iio_dev
>> *indio_dev,
>>  				data->als_contr &= ~LTR501_CONTR_ALS_GAIN_MASK;
>>  			else
>>  				return -EINVAL;
>> -			return i2c_smbus_write_byte_data(data->client,
>> -				LTR501_ALS_CONTR, data->als_contr);
>> +
>> +			return regmap_write(data->regmap, LTR501_ALS_CONTR,
>> +					    data->als_contr);
>>  		case IIO_PROXIMITY:
>>  			i = ltr501_get_ps_gain_index(val, val2);
>>  			if (i < 0)
>>  				return -EINVAL;
>>  			data->ps_contr &= ~LTR501_CONTR_PS_GAIN_MASK;
>>  			data->ps_contr |= i << LTR501_CONTR_PS_GAIN_SHIFT;
>> -			return i2c_smbus_write_byte_data(data->client,
>> -				LTR501_PS_CONTR, data->ps_contr);
>> +
>> +			return regmap_write(data->regmap, LTR501_PS_CONTR,
>> +					    data->ps_contr);
>>  		default:
>>  			return -EINVAL;
>>  		}
>> @@ -255,13 +269,13 @@ static const struct iio_info ltr501_info = {
>>  	.driver_module = THIS_MODULE,
>>  };
>>
>> -static int ltr501_write_contr(struct i2c_client *client, u8 als_val, u8
>> ps_val)
>> +static int ltr501_write_contr(struct ltr501_data *data, u8 als_val, u8
>> ps_val)
>>  {
>> -	int ret = i2c_smbus_write_byte_data(client, LTR501_ALS_CONTR,
>> als_val);
>> +	int ret = regmap_write(data->regmap, LTR501_ALS_CONTR, als_val);
>>  	if (ret < 0)
>>  		return ret;
>>
>> -	return i2c_smbus_write_byte_data(client, LTR501_PS_CONTR, ps_val);
>> +	return regmap_write(data->regmap, LTR501_PS_CONTR, ps_val);
>>  }
>>
>>  static irqreturn_t ltr501_trigger_handler(int irq, void *p)
>> @@ -273,7 +287,7 @@ static irqreturn_t ltr501_trigger_handler(int irq,
>> void *p)
>>  	__le16 als_buf[2];
>>  	u8 mask = 0;
>>  	int j = 0;
>> -	int ret;
>> +	int ret, psdata;
>>
>>  	memset(buf, 0, sizeof(buf));
>>
>> @@ -289,8 +303,8 @@ static irqreturn_t ltr501_trigger_handler(int irq,
>> void *p)
>>  		goto done;
>>
>>  	if (mask & LTR501_STATUS_ALS_RDY) {
>> -		ret = i2c_smbus_read_i2c_block_data(data->client,
>> -			LTR501_ALS_DATA1, sizeof(als_buf), (u8 *) als_buf);
>> +		ret = regmap_bulk_read(data->regmap, LTR501_ALS_DATA1,
>> +				       (u8 *) als_buf, sizeof(als_buf));
>>  		if (ret < 0)
>>  			return ret;
>>  		if (test_bit(0, indio_dev->active_scan_mask))
>> @@ -300,10 +314,11 @@ static irqreturn_t ltr501_trigger_handler(int irq,
>> void *p)
>>  	}
>>
>>  	if (mask & LTR501_STATUS_PS_RDY) {
>> -		ret = i2c_smbus_read_word_data(data->client, LTR501_PS_DATA);
>> +		ret = regmap_bulk_read(data->regmap, LTR501_PS_DATA,
>> +				       &psdata, 2);
>>  		if (ret < 0)
>>  			goto done;
>> -		buf[j++] = ret & LTR501_PS_DATA_MASK;
>> +		buf[j++] = psdata & LTR501_PS_DATA_MASK;
>>  	}
>>
>>  	iio_push_to_buffers_with_timestamp(indio_dev, buf,
>> @@ -317,43 +332,75 @@ done:
>>
>>  static int ltr501_init(struct ltr501_data *data)
>>  {
>> -	int ret;
>> +	int ret, status;
>>
>> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_ALS_CONTR);
>> +	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
>>  	if (ret < 0)
>>  		return ret;
>> -	data->als_contr = ret | LTR501_CONTR_ACTIVE;
>>
>> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_PS_CONTR);
>> +	data->als_contr = status | LTR501_CONTR_ACTIVE;
>> +
>> +	ret = regmap_read(data->regmap, LTR501_PS_CONTR, &status);
>>  	if (ret < 0)
>>  		return ret;
>> -	data->ps_contr = ret | LTR501_CONTR_ACTIVE;
>>
>> -	return ltr501_write_contr(data->client, data->als_contr,
>> -		data->ps_contr);
>> +	data->ps_contr = status | LTR501_CONTR_ACTIVE;
>> +
>> +	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
>> +}
>> +
>> +static bool ltr501_is_volatile_reg(struct device *dev, unsigned int
>> reg)
>> +{
>> +	switch (reg) {
>> +	case LTR501_ALS_DATA1:
>> +	case LTR501_ALS_DATA0:
>> +	case LTR501_ALS_PS_STATUS:
>> +	case LTR501_PS_DATA:
>> +		return true;
>> +	default:
>> +		return false;
>> +	}
>>  }
>>
>> +static struct regmap_config ltr501_regmap_config = {
>> +	.name =  LTR501_REGMAP_NAME,
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +	.max_register = LTR501_MAX_REG,
>> +	.cache_type = REGCACHE_RBTREE,
>> +	.volatile_reg = ltr501_is_volatile_reg,
>> +};
>> +
>>  static int ltr501_probe(struct i2c_client *client,
>>  			  const struct i2c_device_id *id)
>>  {
>>  	struct ltr501_data *data;
>>  	struct iio_dev *indio_dev;
>> -	int ret;
>> +	struct regmap *regmap;
>> +	int ret, partid;
>>
>>  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>  	if (!indio_dev)
>>  		return -ENOMEM;
>>
>> +	regmap = devm_regmap_init_i2c(client, &ltr501_regmap_config);
>> +	if (IS_ERR(regmap)) {
>> +		dev_err(&client->dev, "Regmap initialization failed.\n");
>> +		return PTR_ERR(regmap);
>> +	}
>> +
>>  	data = iio_priv(indio_dev);
>>  	i2c_set_clientdata(client, indio_dev);
>>  	data->client = client;
>> +	data->regmap = regmap;
>>  	mutex_init(&data->lock_als);
>>  	mutex_init(&data->lock_ps);
>>
>> -	ret = i2c_smbus_read_byte_data(data->client, LTR501_PART_ID);
>> +	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>>  	if (ret < 0)
>>  		return ret;
>> -	if ((ret >> 4) != 0x8)
>> +
>> +	if ((partid >> 4) != 0x8)
>>  		return -ENODEV;
>>
>>  	indio_dev->dev.parent = &client->dev;
>> @@ -385,9 +432,8 @@ error_unreg_buffer:
>>
>>  static int ltr501_powerdown(struct ltr501_data *data)
>>  {
>> -	return ltr501_write_contr(data->client,
>> -		data->als_contr & ~LTR501_CONTR_ACTIVE,
>> -		data->ps_contr & ~LTR501_CONTR_ACTIVE);
>> +	return ltr501_write_contr(data, data->als_contr &
>> ~LTR501_CONTR_ACTIVE,
>> +				  data->ps_contr & ~LTR501_CONTR_ACTIVE);
>>  }
>>
>>  static int ltr501_remove(struct i2c_client *client)
>> @@ -414,7 +460,7 @@ static int ltr501_resume(struct device *dev)
>>  	struct ltr501_data *data = iio_priv(i2c_get_clientdata(
>>  		to_i2c_client(dev)));
>>
>> -	return ltr501_write_contr(data->client, data->als_contr,
>> +	return ltr501_write_contr(data, data->als_contr,
>>  		data->ps_contr);
>>  }
>>  #endif
>>
>
>

Re: [PATCH v4 4/5] iio: ltr501: Add interrupt rate control support

[sathyanarayanan.kuppuswamy]

Hi Jonathan,

Thanks for the review. Please check my reply inline.

> On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
>> Added rate control support for ALS and proximity
>> threshold interrupts.Also, Added support to modify
>> and read ALS & proximity sensor sampling frequency.
>>
>> LTR-501 supports interrupt rate control using persistence
>> register settings. Writing <n> to persistence register
>> would generate interrupt only if there are <n> consecutive
>> data values outside the threshold range.
>>
>> Since we don't have any existing ABI's to directly
>> control the persistence register count, we have implemented
>> the rate control using IIO_EV_INFO_PERIOD. _period event
>> attribute represents the amount of time in seconds an
>> event should be true for the device to generate the
>> interrupt. So using _period value and device frequency,
>> persistence count is calculated in driver using following
>> logic.
>>
>> count =  period / measurement_rate
>>
>> If the given period is not a multiple of measurement rate then
>> we round up the value to next multiple.
>>
>> This patch also handles change to persistence count whenever
>> there is change in frequency.
>
> Thanks for your continued hard work on this!
>
> Anyhow, mostly this is stalled on the patch 2 questions, but I have
> made a few little suggestions inline.
>
> Note that the term 'rate' is somewhat ambiguous so I'd use sampling_period
> which is better defined.  Rate is often a frequency measurement.

Agreed. Fixed it in next set.

>
> Also, a few arrays that should be const + the places they are used should
> also have the parameters as const.

Fixed it in next set.
>
> Thanks,
>
> Jonathan
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan
>> <sathyanarayanan.kuppuswamy@linux.intel.com>
>> ---
>>  drivers/iio/light/ltr501.c | 389
>> ++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 382 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
>> index 8ead137..d635ff4 100644
>> --- a/drivers/iio/light/ltr501.c
>> +++ b/drivers/iio/light/ltr501.c
>> @@ -9,7 +9,7 @@
>>   *
>>   * 7-bit I2C slave address 0x23
>>   *
>> - * TODO: measurement rate, IR LED characteristics
>> + * TODO: IR LED characteristics
>>   */
>>
>>  #include <linux/module.h>
>> @@ -29,6 +29,7 @@
>>
>>  #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
>>  #define LTR501_PS_CONTR 0x81 /* PS operation mode */
>> +#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
>>  #define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
>>  #define LTR501_PART_ID 0x86
>>  #define LTR501_MANUFAC_ID 0x87
>> @@ -41,6 +42,7 @@
>>  #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_INTR_PRST 0x9e /* ps thresh, als thresh */
>>  #define LTR501_MAX_REG 0x9f
>>
>>  #define LTR501_ALS_CONTR_SW_RESET BIT(2)
>> @@ -58,6 +60,9 @@
>>  #define LTR501_PS_THRESH_MASK 0x7ff
>>  #define LTR501_ALS_THRESH_MASK 0xffff
>>
>> +#define LTR501_ALS_DEF_PERIOD 500000
>> +#define LTR501_PS_DEF_PERIOD 100000
>> +
>>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>>
>>  static int int_time_mapping[] = {100000, 50000, 200000, 400000};
>> @@ -65,17 +70,119 @@ static int int_time_mapping[] = {100000, 50000,
>> 200000, 400000};
>>  static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
>>  static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
>>  static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
>> +static struct reg_field reg_als_rate = REG_FIELD(LTR501_ALS_MEAS_RATE,
>> 0, 2);
>> +static struct reg_field reg_ps_rate = REG_FIELD(LTR501_PS_MEAS_RATE, 0,
>> 3);
>> +static struct reg_field reg_als_prst = REG_FIELD(LTR501_INTR_PRST, 0,
>> 3);
>> +static struct reg_field reg_ps_prst = REG_FIELD(LTR501_INTR_PRST, 4,
>> 7);
>> +
>> +struct ltr501_samp_table {
>> +	int freq_val;  /* repetition frequency in micro HZ*/
>> +	int time_val; /* repetition rate in micro seconds */
>> +};
>>
>>  struct ltr501_data {
>>  	struct i2c_client *client;
>>  	struct mutex lock_als, lock_ps;
>>  	u8 als_contr, ps_contr;
>> +	int als_period, ps_period; /* period in micro seconds */
>>  	struct regmap *regmap;
>>  	struct regmap_field *reg_it;
>>  	struct regmap_field *reg_als_intr;
>>  	struct regmap_field *reg_ps_intr;
>> +	struct regmap_field *reg_als_rate;
>> +	struct regmap_field *reg_ps_rate;
>> +	struct regmap_field *reg_als_prst;
>> +	struct regmap_field *reg_ps_prst;
>> +};
>> +
> const. Also ideally prefix the name. More that plausible
> that als_sampling_table might turn up in a header at some
> point in the future.
>
>> +static struct ltr501_samp_table als_sampling_table[] = {
>> +			{20000000, 50000}, {10000000, 100000},
>> +			{5000000, 200000}, {2000000, 500000},
>> +			{1000000, 1000000}, {500000, 2000000},
>> +			{500000, 2000000}, {500000, 2000000}
>> +};
>> +
> const
>> +static struct ltr501_samp_table ps_sampling_table[] = {
>> +			{20000000, 50000}, {14285714, 70000},
>> +			{10000000, 100000}, {5000000, 200000},
>> +			{2000000, 500000}, {1000000, 1000000},
>> +			{500000, 2000000}, {500000, 2000000},
>> +			{500000, 2000000}
>>  };
>>
>> +static unsigned int ltr501_match_samp_freq(struct ltr501_samp_table
>> *table,
>> +					   int len, int val, int val2)
>> +{
>> +	int i, freq;
>> +
>> +	freq = val * 1000000 + val2;
>> +
>> +	for (i = 0; i < len; i++) {
>> +		if (table[i].freq_val == freq)
>> +			return i;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int ltr501_read_samp_freq(struct regmap_field *field,
>> +			   struct ltr501_samp_table *freq,
>> +			   int len, int *val, int *val2)
>> +{
>> +	int ret, i;
>> +
>> +	ret = regmap_field_read(field, &i);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (i < 0 || i >= len)
>> +		return -EINVAL;
>> +
>> +	*val = freq[i].freq_val / 1000000;
>> +	*val2 = freq[i].freq_val % 1000000;
>> +
>> +	return IIO_VAL_INT_PLUS_MICRO;
>> +}
>> +
>> +static int ltr501_write_samp_freq(struct ltr501_data *data,
>> +				struct regmap_field *field,
>> +				struct ltr501_samp_table *freq,
>> +				int len, int val, int val2)
>> +{
>> +	int i, ret;
>> +
>> +	i = ltr501_match_samp_freq(als_sampling_table,
>> +				   ARRAY_SIZE(als_sampling_table),
>> +				   val, val2);
>> +
>> +	if (i < 0)
>> +		return i;
>> +
>> +	mutex_lock(&data->lock_als);
>> +	ret = regmap_field_write(data->reg_als_rate, i);
>> +	mutex_unlock(&data->lock_als);
>> +
>> +	return ret;
>> +}
>> +
> read_samp_period.
> Rate is normally used to mean a frequency.
>
> I wonder if the code would be shorter and simpler if you
> define a utility function here and then do two specific
> versions for als and ps? Would allow dropping a lot of
> parameters elsewhere for a couple of extra lines here.

I agree. It will make it clean and simple. I fixed it in next set.

>
>> +static int ltr501_read_samp_rate(struct regmap_field *field,
>> +			   struct ltr501_samp_table *table,
>> +			   int len, int *val)
>> +{
>> +	int ret, i;
>> +
>> +	ret = regmap_field_read(field, &i);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (i < 0 || i >= len)
>> +		return -EINVAL;
>> +
>> +	*val = table[i].time_val;
>> +
>> +	return IIO_VAL_INT;
>> +}
>> +
>>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>>  {
>>  	int tries = 100;
>> @@ -172,6 +279,116 @@ static int ltr501_read_ps(struct ltr501_data
>> *data)
>>  	return status;
>>  }
>>
>> +static int ltr501_read_intr_prst(struct ltr501_data *data,
>> +				 enum iio_chan_type type,
>> +				 int *val2)
>> +{
>> +	int ret, rate, prst;
>> +
>> +	switch (type) {
>> +	case IIO_INTENSITY:
>> +		ret = regmap_field_read(data->reg_als_prst, &prst);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = ltr501_read_samp_rate(data->reg_als_rate,
>> +					    als_sampling_table,
>> +					    ARRAY_SIZE(als_sampling_table),
>> +					    &rate);
>> +
>> +		if (ret < 0)
>> +			return ret;
>> +		*val2 = rate * prst;
>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +	case IIO_PROXIMITY:
>> +		ret = regmap_field_read(data->reg_ps_prst, &prst);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = ltr501_read_samp_rate(data->reg_ps_rate,
>> +					    ps_sampling_table,
>> +					    ARRAY_SIZE(ps_sampling_table),
>> +					    &rate);
>> +
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		*val2 = rate * prst;
>> +		return IIO_VAL_INT_PLUS_MICRO;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int ltr501_write_intr_prst(struct ltr501_data *data,
>> +				 enum iio_chan_type type,
>> +				  int val, int val2)
>> +{
>> +	int ret, rate, new_val;
>> +	unsigned long period;
>> +
>> +	if (val < 0 || val2 < 0)
>> +		return -EINVAL;
>> +
>> +	/* period in microseconds */
>> +	period = ((val * 1000000) + val2);
>> +
>> +	switch (type) {
>> +	case IIO_INTENSITY:
>> +		ret = ltr501_read_samp_rate(data->reg_als_rate,
>> +					    als_sampling_table,
>> +					    ARRAY_SIZE(als_sampling_table),
>> +					    &rate);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		/* period should be atleast equal to rate */
> Event period should be at least equal to sampling period (not rate which
> is a term used indicate how often per second - e.g. a frequency).
>
>> +		if (period < rate)
>> +			return -EINVAL;
>> +
>> +		new_val = DIV_ROUND_UP(period, rate);
>> +		if (new_val < 0 || new_val > 0x0f)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&data->lock_als);
>> +		ret = regmap_field_write(data->reg_als_prst, new_val);
>> +		mutex_unlock(&data->lock_als);
>> +		if (ret >= 0)
>> +			data->als_period = period;
>> +
>> +		return ret;
>> +	case IIO_PROXIMITY:
>> +		ret = ltr501_read_samp_rate(data->reg_ps_rate,
>> +					    ps_sampling_table,
>> +					    ARRAY_SIZE(ps_sampling_table),
>> +					    &rate);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		/* period should be atleast equal to rate */
>> +		if (period < rate)
>> +			return -EINVAL;
>> +
>> +		new_val = DIV_ROUND_UP(period, rate);
>> +		if (new_val < 0 || new_val > 0x0f)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&data->lock_ps);
>> +		ret = regmap_field_write(data->reg_ps_prst, new_val);
>> +		mutex_unlock(&data->lock_ps);
>> +		if (ret >= 0)
>> +			data->ps_period = period;
>> +
>> +		return ret;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>>  static const struct iio_event_spec ltr501_als_event_spec[] = {
>>  	{
>>  		.type = IIO_EV_TYPE_THRESH,
>> @@ -184,7 +401,8 @@ static const struct iio_event_spec
>> ltr501_als_event_spec[] = {
>>  	}, {
>>  		.type = IIO_EV_TYPE_THRESH,
>>  		.dir = IIO_EV_DIR_EITHER,
>> -		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
>> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
>> +				 BIT(IIO_EV_INFO_PERIOD),
>>  	},
>>
>>  };
>> @@ -201,7 +419,8 @@ static const struct iio_event_spec
>> ltr501_pxs_event_spec[] = {
>>  	}, {
>>  		.type = IIO_EV_TYPE_THRESH,
>>  		.dir = IIO_EV_DIR_EITHER,
>> -		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
>> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
>> +				 BIT(IIO_EV_INFO_PERIOD),
>>  	},
>>  };
>>
>> @@ -228,7 +447,8 @@ static const struct iio_chan_spec ltr501_channels[]
>> = {
>>  	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_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME) |
>> +		BIT(IIO_CHAN_INFO_SAMP_FREQ),
>>  		NULL, 0),
>>  	{
>>  		.type = IIO_PROXIMITY,
>> @@ -314,6 +534,23 @@ static int ltr501_read_raw(struct iio_dev
>> *indio_dev,
>>  		default:
>>  			return -EINVAL;
>>  		}
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		switch (chan->type) {
>> +		case IIO_INTENSITY:
>> +			ret = ltr501_read_samp_freq(data->reg_als_rate,
>> +						als_sampling_table,
>> +						ARRAY_SIZE(als_sampling_table),
>> +						val, val2);
>> +			return ret;
>> +		case IIO_PROXIMITY:
>> +			ret = ltr501_read_samp_freq(data->reg_ps_rate,
>> +						ps_sampling_table,
>> +						ARRAY_SIZE(ps_sampling_table),
>> +						val, val2);
>> +			return ret;
>> +		default:
>> +			return -EINVAL;
>> +		}
>>  	}
>>  	return -EINVAL;
>>  }
>> @@ -334,7 +571,7 @@ static int ltr501_write_raw(struct iio_dev
>> *indio_dev,
>>  			       int val, int val2, long mask)
>>  {
>>  	struct ltr501_data *data = iio_priv(indio_dev);
>> -	int i;
>> +	int i, ret, freq_val, freq_val2;
>>
>>  	if (iio_buffer_enabled(indio_dev))
>>  		return -EBUSY;
>> @@ -376,6 +613,57 @@ static int ltr501_write_raw(struct iio_dev
>> *indio_dev,
>>  		default:
>>  			return -EINVAL;
>>  		}
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		switch (chan->type) {
>> +		case IIO_INTENSITY:
>> +			ret = ltr501_read_samp_freq(data->reg_als_rate,
>> +						als_sampling_table,
>> +						ARRAY_SIZE(als_sampling_table),
>> +						&freq_val, &freq_val2);
>> +			ret = ltr501_write_samp_freq(data, data->reg_als_rate,
>> +						als_sampling_table,
>> +						ARRAY_SIZE(als_sampling_table),
>> +						val, val2);
>> +			if (ret < 0)
>> +				return ret;
>> +
>> +			/* update persistence count when changing frequency */
>> +			ret = ltr501_write_intr_prst(data, chan->type,
>> +						     0, data->als_period);
>> +
>> +			if (ret < 0)
>> +				return ltr501_write_samp_freq(data,
>> +						data->reg_als_rate,
>> +						als_sampling_table,
>> +						ARRAY_SIZE(als_sampling_table),
>> +						freq_val, freq_val2);
>> +			return ret;
>> +		case IIO_PROXIMITY:
>> +			ret = ltr501_read_samp_freq(data->reg_ps_rate,
>> +						ps_sampling_table,
>> +						ARRAY_SIZE(ps_sampling_table),
>> +						&freq_val, &freq_val2);
>> +			ret = ltr501_write_samp_freq(data, data->reg_ps_rate,
>> +						ps_sampling_table,
>> +						ARRAY_SIZE(ps_sampling_table),
>> +						val, val2);
>> +			if (ret < 0)
>> +				return ret;
>> +
>> +			/* update persistence count when changing frequency */
>> +			ret = ltr501_write_intr_prst(data, chan->type,
>> +						     0, data->ps_period);
>> +
>> +			if (ret < 0)
>> +				return ltr501_write_samp_freq(data,
>> +						data->reg_ps_rate,
>> +						ps_sampling_table,
>> +						ARRAY_SIZE(ps_sampling_table),
>> +						freq_val, freq_val2);
>> +			return ret;
>> +		default:
>> +			return -EINVAL;
>> +		}
>>  	}
>>  	return -EINVAL;
>>  }
>> @@ -499,6 +787,55 @@ static int ltr501_write_thresh(struct iio_dev
>> *indio_dev,
>>  	return -EINVAL;
>>  }
>>
>> +static int ltr501_read_event(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)
>> +{
>> +	int ret;
>> +
>> +	switch (info) {
>> +	case IIO_EV_INFO_VALUE:
>> +		return ltr501_read_thresh(indio_dev, chan, type, dir,
>> +					  info, val, val2);
>> +	case IIO_EV_INFO_PERIOD:
>> +		ret = ltr501_read_intr_prst(iio_priv(indio_dev),
>> +					    chan->type, val2);
>> +		*val = *val2 / 1000000;
>> +		*val2 = *val2 % 1000000;
>> +		return ret;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int ltr501_write_event(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)
>> +{
>> +	switch (info) {
>> +	case IIO_EV_INFO_VALUE:
>> +		if (val2 != 0)
>> +			return -EINVAL;
>> +		return ltr501_write_thresh(indio_dev, chan, type, dir,
>> +					   info, val, val2);
>> +	case IIO_EV_INFO_PERIOD:
>> +		return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
>> +					      val, val2);
>> +	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,
>> @@ -557,11 +894,13 @@ static int ltr501_write_event_config(struct
>> iio_dev *indio_dev,
>>  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");
>> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
>>
>>  static struct attribute *ltr501_attributes[] = {
>>  	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
>>  	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
>>  	&iio_const_attr_integration_time_available.dev_attr.attr,
>> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>>  	NULL
>>  };
>>
>> @@ -580,8 +919,8 @@ 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_value	= &ltr501_read_event,
>> +	.write_event_value	= &ltr501_write_event,
>>  	.read_event_config	= &ltr501_read_event_config,
>>  	.write_event_config	= &ltr501_write_event_config,
>>  	.driver_module = THIS_MODULE,
>> @@ -694,6 +1033,14 @@ static int ltr501_init(struct ltr501_data *data)
>>
>>  	data->ps_contr = status | LTR501_CONTR_ACTIVE;
>>
>> +	ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
>> +	if (ret < 0)
>> +		return ret;
>> +
>>  	return ltr501_write_contr(data, data->als_contr, data->ps_contr);
>>  }
>>
>> @@ -764,6 +1111,34 @@ static int ltr501_probe(struct i2c_client *client,
>>  		return PTR_ERR(data->reg_ps_intr);
>>  	}
>>
>> +	data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
>> +						      reg_als_rate);
>> +	if (IS_ERR(data->reg_als_rate)) {
>> +		dev_err(&client->dev, "ALS samp rate field init failed.\n");
>> +		return PTR_ERR(data->reg_als_rate);
>> +	}
>> +
>> +	data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
>> +						      reg_ps_rate);
>> +	if (IS_ERR(data->reg_ps_rate)) {
>> +		dev_err(&client->dev, "PS samp rate field init failed.\n");
>> +		return PTR_ERR(data->reg_ps_rate);
>> +	}
>> +
>> +	data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
>> +						      reg_als_prst);
>> +	if (IS_ERR(data->reg_als_prst)) {
>> +		dev_err(&client->dev, "ALS prst reg field init failed\n");
>> +		return PTR_ERR(data->reg_als_prst);
>> +	}
>> +
>> +	data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
>> +						      reg_ps_prst);
>> +	if (IS_ERR(data->reg_ps_prst)) {
>> +		dev_err(&client->dev, "PS prst reg field init failed.\n");
>> +		return PTR_ERR(data->reg_ps_prst);
>> +	}
>> +
>>  	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>>  	if (ret < 0)
>>  		return ret;
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH v4 2/5] iio: ltr501: Add integration time support

[sathyanarayanan.kuppuswamy]

Hi Jonathan,

> On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
>> Added support to modify and read ALS integration time.
>>
>> Signed-off-by: Kuppuswamy Sathyanarayanan
>> <sathyanarayanan.kuppuswamy@linux.intel.com>
>
> Cool, didn't know about this regmap field stuff before.  Not exactly
> heavily
> used but looks helpful!
yes. It simplifies the bit wise manipulations and makes it more readable.
Avoids use of masks and logical operations.
>
> A few questions inline..
>
> 1) A spot where a variable name change would make it easier to follow.
Fixed it in next set.
> 2) Why are the struct reg_field not defined as const in the regmap_field
> allocators?  Here it gives the impression we are restricting ourselves to
> one instance of this chip, but in reality they seem to actually be const
> so we aren't.
There are few use cases in kernel where they allocate the reg_map fields
in an array. In these cases same reg_field can be used with few index
manipulations. Add const to allocators would restrict users in doing that.
>
> messy :(
>
>> ---
>>  drivers/iio/light/ltr501.c | 87
>> +++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 86 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
>> index 84ee2b3..22769c8 100644
>> --- a/drivers/iio/light/ltr501.c
>> +++ b/drivers/iio/light/ltr501.c
>> @@ -28,6 +28,7 @@
>>
>>  #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
>>  #define LTR501_PS_CONTR 0x81 /* PS operation mode */
>> +#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
>>  #define LTR501_PART_ID 0x86
>>  #define LTR501_MANUFAC_ID 0x87
>>  #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
>> @@ -49,11 +50,16 @@
>>
>>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>>
>> +static int int_time_mapping[] = {100000, 50000, 200000, 400000};
>> +
>> +static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
> Naming could be clearer.  The reg_it here and the regmap_field below
> are different structures, but their name doesn't make this clear.
Fixed it in next set.
>
> Also, why is the above not const?  Obviously regmap doesn't take a const
> but I can't see why not... Mark?
I agree. Fixed it in next set.
>
> It is only used to initialize elements (by copying) in the regmap_field
> that allocator of which it is passed to.
>> +
>>  struct ltr501_data {
>>  	struct i2c_client *client;
>>  	struct mutex lock_als, lock_ps;
>>  	u8 als_contr, ps_contr;
>>  	struct regmap *regmap;
>> +	struct regmap_field *reg_it;
>>  };
>>
>>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>> @@ -74,6 +80,58 @@ static int ltr501_drdy(struct ltr501_data *data, u8
>> drdy_mask)
>>  	return -EIO;
>>  }
>>
>> +static int ltr501_set_it_time(struct ltr501_data *data, int it)
>> +{
>> +	int ret, i, index = -1, status;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
>> +		if (int_time_mapping[i] == it) {
>> +			index = i;
>> +			break;
>> +		}
>> +	}
>> +	/* Make sure integ time index is valid */
>> +	if (index < 0)
>> +		return -EINVAL;
>> +
>> +	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (status & LTR501_CONTR_ALS_GAIN_MASK) {
>> +		/*
>> +		 * 200 ms and 400 ms integ time can only be
>> +		 * used in dynamic range 1
>> +		 */
>> +		if (index > 1)
>> +			return -EINVAL;
>> +	} else
>> +		/* 50 ms integ time can only be used in dynamic range 2 */
>> +		if (index == 1)
>> +			return -EINVAL;
>> +
>> +	return regmap_field_write(data->reg_it, index);
>> +}
>> +
>> +/* read int time in micro seconds */
>> +static int ltr501_read_it_time(struct ltr501_data *data, int *val, int
>> *val2)
>> +{
>> +	int ret, index;
>> +
>> +	ret = regmap_field_read(data->reg_it, &index);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/* Make sure integ time index is valid */
>> +	if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
>> +		return -EINVAL;
>> +
>> +	*val2 = int_time_mapping[index];
>> +	*val = 0;
>> +
>> +	return IIO_VAL_INT_PLUS_MICRO;
>> +}
>> +
>>  static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
>>  {
>>  	int ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
>> @@ -119,7 +177,7 @@ static int ltr501_read_ps(struct ltr501_data *data)
>>  static const struct iio_chan_spec ltr501_channels[] = {
>>  	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
>>  	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
>> -		BIT(IIO_CHAN_INFO_SCALE)),
>> +		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME)),
>>  	{
>>  		.type = IIO_PROXIMITY,
>>  		.address = LTR501_PS_DATA,
>> @@ -195,6 +253,13 @@ static int ltr501_read_raw(struct iio_dev
>> *indio_dev,
>>  		default:
>>  			return -EINVAL;
>>  		}
>> +	case IIO_CHAN_INFO_INT_TIME:
>> +		switch (chan->type) {
>> +		case IIO_INTENSITY:
>> +			return ltr501_read_it_time(data, val, val2);
>> +		default:
>> +			return -EINVAL;
>> +		}
>>  	}
>>  	return -EINVAL;
>>  }
>> @@ -245,16 +310,30 @@ static int ltr501_write_raw(struct iio_dev
>> *indio_dev,
>>  		default:
>>  			return -EINVAL;
>>  		}
>> +	case IIO_CHAN_INFO_INT_TIME:
>> +		switch (chan->type) {
>> +		case IIO_INTENSITY:
>> +			if (val != 0)
>> +				return -EINVAL;
>> +			mutex_lock(&data->lock_als);
>> +			i = ltr501_set_it_time(data, val2);
>> +			mutex_unlock(&data->lock_als);
>> +			return i;
>> +		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");
>>
>>  static struct attribute *ltr501_attributes[] = {
>>  	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
>>  	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
>> +	&iio_const_attr_integration_time_available.dev_attr.attr,
>>  	NULL
>>  };
>>
>> @@ -396,6 +475,12 @@ static int ltr501_probe(struct i2c_client *client,
>>  	mutex_init(&data->lock_als);
>>  	mutex_init(&data->lock_ps);
>>
>> +	data->reg_it = devm_regmap_field_alloc(&client->dev, regmap, reg_it);
>> +	if (IS_ERR(data->reg_it)) {
>> +		dev_err(&client->dev, "Integ time reg field init failed.\n");
>> +		return PTR_ERR(data->reg_it);
>> +	}
>> +
>>  	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>>  	if (ret < 0)
>>  		return ret;
>>
>
> --
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> the body of a message to majordomo@vger.kernel.org
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>

Re: [PATCH v4 2/5] iio: ltr501: Add integration time support

[Jonathan Cameron]

On 19/04/15 10:36, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> Hi Jonathan,
> 
>> On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
>>> Added support to modify and read ALS integration time.
>>>
>>> Signed-off-by: Kuppuswamy Sathyanarayanan
>>> <sathyanarayanan.kuppuswamy@linux.intel.com>
>>
>> Cool, didn't know about this regmap field stuff before.  Not exactly
>> heavily
>> used but looks helpful!
> yes. It simplifies the bit wise manipulations and makes it more readable.
> Avoids use of masks and logical operations.
>>
>> A few questions inline..
>>
>> 1) A spot where a variable name change would make it easier to follow.
> Fixed it in next set.
>> 2) Why are the struct reg_field not defined as const in the regmap_field
>> allocators?  Here it gives the impression we are restricting ourselves to
>> one instance of this chip, but in reality they seem to actually be const
>> so we aren't.
> There are few use cases in kernel where they allocate the reg_map fields
> in an array. In these cases same reg_field can be used with few index
> manipulations. Add const to allocators would restrict users in doing that.
I may be half asleep today but....

No it wouldn't.  You can quite happily pass non constant variables to
functions taking a const.  All you are guaranteeing is the function
won't do anything to it and hence you can pass a constant variable to
it if you like.  The current lack of const specifier means that will be
an error.  The other way around should be unaffected.
>>
>> messy :(
>>
>>> ---
>>>  drivers/iio/light/ltr501.c | 87
>>> +++++++++++++++++++++++++++++++++++++++++++++-
>>>  1 file changed, 86 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
>>> index 84ee2b3..22769c8 100644
>>> --- a/drivers/iio/light/ltr501.c
>>> +++ b/drivers/iio/light/ltr501.c
>>> @@ -28,6 +28,7 @@
>>>
>>>  #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
>>>  #define LTR501_PS_CONTR 0x81 /* PS operation mode */
>>> +#define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
>>>  #define LTR501_PART_ID 0x86
>>>  #define LTR501_MANUFAC_ID 0x87
>>>  #define LTR501_ALS_DATA1 0x88 /* 16-bit, little endian */
>>> @@ -49,11 +50,16 @@
>>>
>>>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>>>
>>> +static int int_time_mapping[] = {100000, 50000, 200000, 400000};
>>> +
>>> +static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
>> Naming could be clearer.  The reg_it here and the regmap_field below
>> are different structures, but their name doesn't make this clear.
> Fixed it in next set.
>>
>> Also, why is the above not const?  Obviously regmap doesn't take a const
>> but I can't see why not... Mark?
> I agree. Fixed it in next set.
>>
>> It is only used to initialize elements (by copying) in the regmap_field
>> that allocator of which it is passed to.
>>> +
>>>  struct ltr501_data {
>>>  	struct i2c_client *client;
>>>  	struct mutex lock_als, lock_ps;
>>>  	u8 als_contr, ps_contr;
>>>  	struct regmap *regmap;
>>> +	struct regmap_field *reg_it;
>>>  };
>>>
>>>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>>> @@ -74,6 +80,58 @@ static int ltr501_drdy(struct ltr501_data *data, u8
>>> drdy_mask)
>>>  	return -EIO;
>>>  }
>>>
>>> +static int ltr501_set_it_time(struct ltr501_data *data, int it)
>>> +{
>>> +	int ret, i, index = -1, status;
>>> +
>>> +	for (i = 0; i < ARRAY_SIZE(int_time_mapping); i++) {
>>> +		if (int_time_mapping[i] == it) {
>>> +			index = i;
>>> +			break;
>>> +		}
>>> +	}
>>> +	/* Make sure integ time index is valid */
>>> +	if (index < 0)
>>> +		return -EINVAL;
>>> +
>>> +	ret = regmap_read(data->regmap, LTR501_ALS_CONTR, &status);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	if (status & LTR501_CONTR_ALS_GAIN_MASK) {
>>> +		/*
>>> +		 * 200 ms and 400 ms integ time can only be
>>> +		 * used in dynamic range 1
>>> +		 */
>>> +		if (index > 1)
>>> +			return -EINVAL;
>>> +	} else
>>> +		/* 50 ms integ time can only be used in dynamic range 2 */
>>> +		if (index == 1)
>>> +			return -EINVAL;
>>> +
>>> +	return regmap_field_write(data->reg_it, index);
>>> +}
>>> +
>>> +/* read int time in micro seconds */
>>> +static int ltr501_read_it_time(struct ltr501_data *data, int *val, int
>>> *val2)
>>> +{
>>> +	int ret, index;
>>> +
>>> +	ret = regmap_field_read(data->reg_it, &index);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	/* Make sure integ time index is valid */
>>> +	if (index < 0 || index >= ARRAY_SIZE(int_time_mapping))
>>> +		return -EINVAL;
>>> +
>>> +	*val2 = int_time_mapping[index];
>>> +	*val = 0;
>>> +
>>> +	return IIO_VAL_INT_PLUS_MICRO;
>>> +}
>>> +
>>>  static int ltr501_read_als(struct ltr501_data *data, __le16 buf[2])
>>>  {
>>>  	int ret = ltr501_drdy(data, LTR501_STATUS_ALS_RDY);
>>> @@ -119,7 +177,7 @@ static int ltr501_read_ps(struct ltr501_data *data)
>>>  static const struct iio_chan_spec ltr501_channels[] = {
>>>  	LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0),
>>>  	LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
>>> -		BIT(IIO_CHAN_INFO_SCALE)),
>>> +		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME)),
>>>  	{
>>>  		.type = IIO_PROXIMITY,
>>>  		.address = LTR501_PS_DATA,
>>> @@ -195,6 +253,13 @@ static int ltr501_read_raw(struct iio_dev
>>> *indio_dev,
>>>  		default:
>>>  			return -EINVAL;
>>>  		}
>>> +	case IIO_CHAN_INFO_INT_TIME:
>>> +		switch (chan->type) {
>>> +		case IIO_INTENSITY:
>>> +			return ltr501_read_it_time(data, val, val2);
>>> +		default:
>>> +			return -EINVAL;
>>> +		}
>>>  	}
>>>  	return -EINVAL;
>>>  }
>>> @@ -245,16 +310,30 @@ static int ltr501_write_raw(struct iio_dev
>>> *indio_dev,
>>>  		default:
>>>  			return -EINVAL;
>>>  		}
>>> +	case IIO_CHAN_INFO_INT_TIME:
>>> +		switch (chan->type) {
>>> +		case IIO_INTENSITY:
>>> +			if (val != 0)
>>> +				return -EINVAL;
>>> +			mutex_lock(&data->lock_als);
>>> +			i = ltr501_set_it_time(data, val2);
>>> +			mutex_unlock(&data->lock_als);
>>> +			return i;
>>> +		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");
>>>
>>>  static struct attribute *ltr501_attributes[] = {
>>>  	&iio_const_attr_in_proximity_scale_available.dev_attr.attr,
>>>  	&iio_const_attr_in_intensity_scale_available.dev_attr.attr,
>>> +	&iio_const_attr_integration_time_available.dev_attr.attr,
>>>  	NULL
>>>  };
>>>
>>> @@ -396,6 +475,12 @@ static int ltr501_probe(struct i2c_client *client,
>>>  	mutex_init(&data->lock_als);
>>>  	mutex_init(&data->lock_ps);
>>>
>>> +	data->reg_it = devm_regmap_field_alloc(&client->dev, regmap, reg_it);
>>> +	if (IS_ERR(data->reg_it)) {
>>> +		dev_err(&client->dev, "Integ time reg field init failed.\n");
>>> +		return PTR_ERR(data->reg_it);
>>> +	}
>>> +
>>>  	ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
>>>  	if (ret < 0)
>>>  		return ret;
>>>
>>
>> --
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>>
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