[PATCH v2 0/3] Interrupt and Continuous mode support for VL6180

[PATCH v2 0/3] Interrupt and Continuous mode support for VL6180

[Abhash Jha]

Hello,

The first patch adds support for configuring the Sampling frequency
(inter-measurement period) of the sensor. The values must be provided
in miliseconds. The default value for the inter-measurement period for
ALS is 10ms and for Range is 50ms.

The second patch adds support for interrupt based single shot reading.
We registered an irq_handler that fires everytime the data is ready.
And then we read the appropriate value in the `vl6180_measure` routine.

The third patch adds support for continuous mode in the sensor by using
buffers. We enable the sensor's continuous mode in the buffer_postenable
function depending on the `active_scan_mask`.
The continuous mode can be disabled by disabling the buffer.
Added a trigger to the device for the continuous mode. Also validating that
the device uses the internal trigger provided by us.

Changes in v2:
- Fixed `label followed by a declaration is a C23 extension [-Wc23-extensions]`
  by moving the guard(mutex)(&data->lock) above the switch statement.

- The above error was pointed out during testing by kernel-test-robot

Thanks,
Abhash Jha


Abhash Jha (3):
  iio: light: vl6180: Add configurable inter-measurement period support
  iio: light: vl6180: Added Interrupt support for single shot access
  iio: light: vl6180: Add support for Continuous Mode

 drivers/iio/light/vl6180.c | 266 ++++++++++++++++++++++++++++++++++---
 1 file changed, 249 insertions(+), 17 deletions(-)

-- 
2.43.0

[PATCH v2 1/3] iio: light: vl6180: Add configurable inter-measurement period support

[Abhash Jha]

Expose the IIO_CHAN_INFO_SAMP_FREQ attribute as a way to configure the
inter-measurement period for both the IIO_DISTANCE and IIO_LIGHT
channels. The inter-measurement period must be given in miliseconds.

Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com>
---
 drivers/iio/light/vl6180.c | 66 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index a1b2b3c0b..401f13411 100644
--- a/drivers/iio/light/vl6180.c
+++ b/drivers/iio/light/vl6180.c
@@ -38,7 +38,9 @@
 #define VL6180_OUT_OF_RESET 0x016
 #define VL6180_HOLD 0x017
 #define VL6180_RANGE_START 0x018
+#define VL6180_RANGE_INTER_MEAS_TIME 0x01b
 #define VL6180_ALS_START 0x038
+#define VL6180_ALS_INTER_MEAS_TIME 0x03e
 #define VL6180_ALS_GAIN 0x03f
 #define VL6180_ALS_IT 0x040
 
@@ -86,6 +88,8 @@ struct vl6180_data {
 	struct mutex lock;
 	unsigned int als_gain_milli;
 	unsigned int als_it_ms;
+	unsigned int als_meas_rate;
+	unsigned int range_meas_rate;
 };
 
 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
@@ -261,12 +265,14 @@ static const struct iio_chan_spec vl6180_channels[] = {
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_INT_TIME) |
 			BIT(IIO_CHAN_INFO_SCALE) |
-			BIT(IIO_CHAN_INFO_HARDWAREGAIN),
+			BIT(IIO_CHAN_INFO_HARDWAREGAIN) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_DISTANCE,
 		.address = VL6180_RANGE,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
-			BIT(IIO_CHAN_INFO_SCALE),
+			BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_PROXIMITY,
 		.address = VL6180_PROX,
@@ -333,6 +339,18 @@ static int vl6180_read_raw(struct iio_dev *indio_dev,
 
 		return IIO_VAL_FRACTIONAL;
 
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_DISTANCE:
+			*val = data->range_meas_rate;
+			return IIO_VAL_INT;
+		case IIO_LIGHT:
+			*val = data->als_meas_rate;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+
 	default:
 		return -EINVAL;
 	}
@@ -412,12 +430,24 @@ static int vl6180_set_it(struct vl6180_data *data, int val, int val2)
 	return ret;
 }
 
+static int vl6180_meas_reg_val_from_ms(unsigned int period)
+{
+	unsigned int reg_val = 0;
+
+	if (period > 10)
+		reg_val = period < 2550 ? (DIV_ROUND_CLOSEST(period, 10) - 1) : 254;
+
+	return reg_val;
+}
+
 static int vl6180_write_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int val, int val2, long mask)
 {
 	struct vl6180_data *data = iio_priv(indio_dev);
+	unsigned int reg_val;
 
+	guard(mutex)(&data->lock);
 	switch (mask) {
 	case IIO_CHAN_INFO_INT_TIME:
 		return vl6180_set_it(data, val, val2);
@@ -427,6 +457,22 @@ static int vl6180_write_raw(struct iio_dev *indio_dev,
 			return -EINVAL;
 
 		return vl6180_set_als_gain(data, val, val2);
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		switch (chan->type) {
+		case IIO_DISTANCE:
+			data->range_meas_rate = val;
+			reg_val = vl6180_meas_reg_val_from_ms(val);
+			return vl6180_write_byte(data->client,
+				VL6180_RANGE_INTER_MEAS_TIME, reg_val);
+
+		case IIO_LIGHT:
+			data->als_meas_rate = val;
+			reg_val = vl6180_meas_reg_val_from_ms(val);
+			return vl6180_write_byte(data->client,
+				VL6180_ALS_INTER_MEAS_TIME, reg_val);
+		}
+
 	default:
 		return -EINVAL;
 	}
@@ -473,6 +519,22 @@ static int vl6180_init(struct vl6180_data *data)
 	if (ret < 0)
 		return ret;
 
+	/* Default Range inter-measurement time: 50ms
+	 * reg_val = (50 / 10 - 1) = 4
+	 */
+	ret = vl6180_write_byte(client, VL6180_RANGE_INTER_MEAS_TIME, 4);
+	if (ret < 0)
+		return ret;
+	data->range_meas_rate = 50;
+
+	/* Default ALS inter-measurement time: 10ms
+	 * reg_val = (10 / 10 - 1) = 0
+	 */
+	ret = vl6180_write_byte(client, VL6180_ALS_INTER_MEAS_TIME, 0);
+	if (ret < 0)
+		return ret;
+	data->als_meas_rate = 10;
+
 	/* ALS integration time: 100ms */
 	data->als_it_ms = 100;
 	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
-- 
2.43.0

[PATCH v2 2/3] iio: light: vl6180: Added Interrupt support for single shot access

[Abhash Jha]

Configured the GPIO1 pin to provide output interrupts. And then the
interrupts are serviced in the `vl6180_measure` function when the
irq_handler signals that the reading is complete.

Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com>
---
 drivers/iio/light/vl6180.c | 64 +++++++++++++++++++++++++++++++-------
 1 file changed, 52 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index 401f13411..7630a7503 100644
--- a/drivers/iio/light/vl6180.c
+++ b/drivers/iio/light/vl6180.c
@@ -33,6 +33,7 @@
 #define VL6180_MODEL_ID_VAL 0xb4
 
 /* Configuration registers */
+#define VL6180_MODE_GPIO1 0x011
 #define VL6180_INTR_CONFIG 0x014
 #define VL6180_INTR_CLEAR 0x015
 #define VL6180_OUT_OF_RESET 0x016
@@ -70,6 +71,9 @@
 /* bits of the HOLD register */
 #define VL6180_HOLD_ON BIT(0)
 
+/* bit for enabling GPIO1 Interrupt Output */
+#define VL6180_GPIO1_INTR_OUT BIT(4)
+
 /* default value for the ALS_IT register */
 #define VL6180_ALS_IT_100 0x63 /* 100 ms */
 
@@ -86,6 +90,7 @@
 struct vl6180_data {
 	struct i2c_client *client;
 	struct mutex lock;
+	struct completion completion;
 	unsigned int als_gain_milli;
 	unsigned int als_it_ms;
 	unsigned int als_meas_rate;
@@ -211,6 +216,7 @@ static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
 static int vl6180_measure(struct vl6180_data *data, int addr)
 {
 	struct i2c_client *client = data->client;
+	unsigned long time_left;
 	int tries = 20, ret;
 	u16 value;
 
@@ -221,19 +227,26 @@ static int vl6180_measure(struct vl6180_data *data, int addr)
 	if (ret < 0)
 		goto fail;
 
-	while (tries--) {
-		ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
-		if (ret < 0)
-			goto fail;
-
-		if (ret & vl6180_chan_regs_table[addr].drdy_mask)
-			break;
-		msleep(20);
-	}
+	if (client->irq) {
+		reinit_completion(&data->completion);
+		time_left = wait_for_completion_timeout(&data->completion, HZ / 10);
+		if (time_left == 0)
+			return -ETIMEDOUT;
+	} else {
+		while (tries--) {
+			ret = vl6180_read_byte(client, VL6180_INTR_STATUS);
+			if (ret < 0)
+				goto fail;
+
+			if (ret & vl6180_chan_regs_table[addr].drdy_mask)
+				break;
+			msleep(20);
+		}
 
-	if (tries < 0) {
-		ret = -EIO;
-		goto fail;
+		if (tries < 0) {
+			ret = -EIO;
+			goto fail;
+		}
 	}
 
 	/* Read result value from appropriate registers */
@@ -478,6 +491,15 @@ static int vl6180_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
+static irqreturn_t vl6180_threaded_irq(int irq, void *priv)
+{
+	struct iio_dev *indio_dev = priv;
+	struct vl6180_data *data = iio_priv(indio_dev);
+
+	complete(&data->completion);
+	return IRQ_HANDLED;
+}
+
 static const struct iio_info vl6180_info = {
 	.read_raw = vl6180_read_raw,
 	.write_raw = vl6180_write_raw,
@@ -513,6 +535,11 @@ static int vl6180_init(struct vl6180_data *data)
 	if (ret != 0x01)
 		dev_info(&client->dev, "device is not fresh out of reset\n");
 
+	ret = vl6180_write_byte(client, VL6180_MODE_GPIO1,
+				VL6180_GPIO1_INTR_OUT);
+	if (ret < 0)
+		return ret;
+
 	/* Enable ALS and Range ready interrupts */
 	ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
 				VL6180_ALS_READY | VL6180_RANGE_READY);
@@ -579,6 +606,19 @@ static int vl6180_probe(struct i2c_client *client)
 	if (ret < 0)
 		return ret;
 
+	if (client->irq) {
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						NULL, vl6180_threaded_irq,
+						IRQF_ONESHOT,
+						indio_dev->name, indio_dev);
+		if (ret) {
+			dev_err(&client->dev, "devm_request_irq error: %d\n", ret);
+			return ret;
+		}
+
+		init_completion(&data->completion);
+	}
+
 	return devm_iio_device_register(&client->dev, indio_dev);
 }
 
-- 
2.43.0

[PATCH v2 3/3] iio: light: vl6180: Add support for Continuous Mode

[Abhash Jha]

Added support for getting continuous readings from vl6180 using
triggered buffer approach. The continuous mode can be enabled by
enabling the buffer.
Also added a trigger and appropriate checks to see that it is used
with this device.

Signed-off-by: Abhash Jha <abhashkumarjha123@gmail.com>
---
 drivers/iio/light/vl6180.c | 138 +++++++++++++++++++++++++++++++++++--
 1 file changed, 134 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index 7630a7503..74be3e6dc 100644
--- a/drivers/iio/light/vl6180.c
+++ b/drivers/iio/light/vl6180.c
@@ -25,6 +25,10 @@
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
 
 #define VL6180_DRV_NAME "vl6180"
 
@@ -91,10 +95,16 @@ struct vl6180_data {
 	struct i2c_client *client;
 	struct mutex lock;
 	struct completion completion;
+	struct iio_trigger *trig;
 	unsigned int als_gain_milli;
 	unsigned int als_it_ms;
 	unsigned int als_meas_rate;
 	unsigned int range_meas_rate;
+
+	struct {
+		u16 chan;
+		aligned_u64 timestamp;
+	} scan;
 };
 
 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
@@ -275,6 +285,12 @@ static const struct iio_chan_spec vl6180_channels[] = {
 	{
 		.type = IIO_LIGHT,
 		.address = VL6180_ALS,
+		.scan_index = VL6180_ALS,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+		},
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_INT_TIME) |
 			BIT(IIO_CHAN_INFO_SCALE) |
@@ -283,14 +299,27 @@ static const struct iio_chan_spec vl6180_channels[] = {
 	}, {
 		.type = IIO_DISTANCE,
 		.address = VL6180_RANGE,
+		.scan_index = VL6180_RANGE,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 8,
+			.storagebits = 8,
+		},
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 			BIT(IIO_CHAN_INFO_SCALE) |
 			BIT(IIO_CHAN_INFO_SAMP_FREQ),
 	}, {
 		.type = IIO_PROXIMITY,
 		.address = VL6180_PROX,
+		.scan_index = VL6180_PROX,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+		},
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-	}
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
 /*
@@ -496,17 +525,99 @@ static irqreturn_t vl6180_threaded_irq(int irq, void *priv)
 	struct iio_dev *indio_dev = priv;
 	struct vl6180_data *data = iio_priv(indio_dev);
 
-	complete(&data->completion);
+	if (iio_buffer_enabled(indio_dev))
+		iio_trigger_poll_nested(indio_dev->trig);
+	else
+		complete(&data->completion);
+
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t vl6180_trigger_handler(int irq, void *priv)
+{
+	struct iio_poll_func *pf = priv;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct vl6180_data *data = iio_priv(indio_dev);
+	int ret;
+
+	for (int i = 0; i < indio_dev->masklength; i++) {
+		if (test_bit(i, indio_dev->active_scan_mask)) {
+
+		ret = vl6180_chan_regs_table[i].word ?
+			vl6180_read_word(data->client, vl6180_chan_regs_table[i].value_reg) :
+			vl6180_read_byte(data->client, vl6180_chan_regs_table[i].value_reg);
+		if (ret < 0)
+			dev_err(&data->client->dev, "failed to read from value regs: %d\n", ret);
+
+		data->scan.chan = ret;
+		iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
+						iio_get_time_ns(indio_dev));
+		}
+	}
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	/* Clear the interrupt flag after data read */
+	ret = vl6180_write_byte(data->client, VL6180_INTR_CLEAR,
+		VL6180_CLEAR_ERROR | VL6180_CLEAR_ALS | VL6180_CLEAR_RANGE);
+	if (ret < 0)
+		dev_err(&data->client->dev, "failed to clear irq: %d\n", ret);
+
+	return IRQ_HANDLED;
+}
+
+static int vl6180_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
+{
+	struct vl6180_data *data = iio_priv(indio_dev);
+
+	return data->trig == trig ? 0 : -EINVAL;
+}
+
 static const struct iio_info vl6180_info = {
 	.read_raw = vl6180_read_raw,
 	.write_raw = vl6180_write_raw,
 	.attrs = &vl6180_attribute_group,
+	.validate_trigger = vl6180_validate_trigger,
 };
 
-static int vl6180_init(struct vl6180_data *data)
+static int vl6180_buffer_postenable(struct iio_dev *indio_dev)
+{
+	struct vl6180_data *data = iio_priv(indio_dev);
+
+	for (int i = 0; i < indio_dev->masklength; i++) {
+		if (test_bit(i, indio_dev->active_scan_mask))
+			return vl6180_write_byte(data->client,
+				vl6180_chan_regs_table[i].start_reg,
+				VL6180_MODE_CONT | VL6180_STARTSTOP);
+	}
+
+	return -EINVAL;
+}
+
+static int vl6180_buffer_postdisable(struct iio_dev *indio_dev)
+{
+	struct vl6180_data *data = iio_priv(indio_dev);
+
+	for (int i = 0; i < indio_dev->masklength; i++) {
+		if (test_bit(i, indio_dev->active_scan_mask))
+			return vl6180_write_byte(data->client,
+				vl6180_chan_regs_table[i].start_reg,
+				VL6180_STARTSTOP);
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
+	.postenable = &vl6180_buffer_postenable,
+	.postdisable = &vl6180_buffer_postdisable,
+};
+
+static const struct iio_trigger_ops vl6180_trigger_ops = {
+	.validate_device = iio_trigger_validate_own_device,
+};
+
+static int vl6180_init(struct vl6180_data *data, struct iio_dev *indio_dev)
 {
 	struct i2c_client *client = data->client;
 	int ret;
@@ -546,6 +657,12 @@ static int vl6180_init(struct vl6180_data *data)
 	if (ret < 0)
 		return ret;
 
+	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
+						&vl6180_trigger_handler,
+						&iio_triggered_buffer_setup_ops);
+	if (ret)
+		return ret;
+
 	/* Default Range inter-measurement time: 50ms
 	 * reg_val = (50 / 10 - 1) = 4
 	 */
@@ -602,7 +719,7 @@ static int vl6180_probe(struct i2c_client *client)
 	indio_dev->name = VL6180_DRV_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
-	ret = vl6180_init(data);
+	ret = vl6180_init(data, indio_dev);
 	if (ret < 0)
 		return ret;
 
@@ -617,6 +734,19 @@ static int vl6180_probe(struct i2c_client *client)
 		}
 
 		init_completion(&data->completion);
+
+		data->trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
+						indio_dev->name, iio_device_id(indio_dev));
+		if (!data->trig)
+			return -ENOMEM;
+
+		data->trig->ops = &vl6180_trigger_ops;
+		iio_trigger_set_drvdata(data->trig, indio_dev);
+		ret = devm_iio_trigger_register(&client->dev, data->trig);
+		if (ret)
+			return ret;
+
+		indio_dev->trig = iio_trigger_get(data->trig);
 	}
 
 	return devm_iio_device_register(&client->dev, indio_dev);
-- 
2.43.0

Re: [PATCH v2 0/3] Interrupt and Continuous mode support for VL6180

[Jonathan Cameron]

On Sat,  5 Oct 2024 21:22:22 +0530
Abhash Jha <abhashkumarjha123@gmail.com> wrote:

> Hello,
> 
> The first patch adds support for configuring the Sampling frequency
> (inter-measurement period) of the sensor. The values must be provided
> in miliseconds. The default value for the inter-measurement period for
> ALS is 10ms and for Range is 50ms.
> 
> The second patch adds support for interrupt based single shot reading.
> We registered an irq_handler that fires everytime the data is ready.
> And then we read the appropriate value in the `vl6180_measure` routine.
> 
> The third patch adds support for continuous mode in the sensor by using
> buffers. We enable the sensor's continuous mode in the buffer_postenable
> function depending on the `active_scan_mask`.
> The continuous mode can be disabled by disabling the buffer.
> Added a trigger to the device for the continuous mode. Also validating that
> the device uses the internal trigger provided by us.
> 
> Changes in v2:
> - Fixed `label followed by a declaration is a C23 extension [-Wc23-extensions]`
>   by moving the guard(mutex)(&data->lock) above the switch statement.
> 
> - The above error was pointed out during testing by kernel-test-robot
> 
> Thanks,
> Abhash Jha
Hi Abhash,

I left comments on v1.  Even for a compile issue like this one, maybe just
a quick reply to the earlier posting saying what you will change is more
appropriate than sending a new version just one day after the first.

Not a bit thing, so just check those reviews on v1.

Thanks,

Jonathan

> 
> 
> Abhash Jha (3):
>   iio: light: vl6180: Add configurable inter-measurement period support
>   iio: light: vl6180: Added Interrupt support for single shot access
>   iio: light: vl6180: Add support for Continuous Mode
> 
>  drivers/iio/light/vl6180.c | 266 ++++++++++++++++++++++++++++++++++---
>  1 file changed, 249 insertions(+), 17 deletions(-)
>