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 | 133 +++++++++++++++++++++++++++++++++++--
 1 file changed, 129 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
index a747501b0..f0c7a13a0 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"
 
@@ -87,10 +91,16 @@ 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[2];
+		aligned_s64 timestamp;
+	} scan;
 };
 
 enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
@@ -272,6 +282,12 @@ 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) |
@@ -280,14 +296,27 @@ 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),
 };
 
 /*
@@ -499,7 +528,48 @@ 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);
+	s64 time_ns = iio_get_time_ns(indio_dev);
+	int ret, bit, i = 0;
+
+	iio_for_each_active_channel(indio_dev, bit) {
+		if (vl6180_chan_regs_table[bit].word)
+			ret = vl6180_read_word(data->client,
+				vl6180_chan_regs_table[bit].value_reg);
+		else
+			ret = vl6180_read_byte(data->client,
+				vl6180_chan_regs_table[bit].value_reg);
+
+		if (ret < 0) {
+			dev_err(&data->client->dev,
+				"failed to read from value regs: %d\n", ret);
+			return IRQ_HANDLED;
+		}
+
+		data->scan.chan[i++] = ret;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, time_ns);
+	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;
 }
 
@@ -507,9 +577,45 @@ static const struct iio_info vl6180_info = {
 	.read_raw = vl6180_read_raw,
 	.write_raw = vl6180_write_raw,
 	.attrs = &vl6180_attribute_group,
+	.validate_trigger = iio_validate_own_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);
+	int bit;
+
+	iio_for_each_active_channel(indio_dev, bit)
+		return vl6180_write_byte(data->client,
+			vl6180_chan_regs_table[bit].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);
+	int bit;
+
+	iio_for_each_active_channel(indio_dev, bit)
+		return vl6180_write_byte(data->client,
+			vl6180_chan_regs_table[bit].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;
@@ -544,6 +650,12 @@ 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 or 20000 mHz */
 	ret = vl6180_write_byte(client, VL6180_RANGE_INTER_MEAS_TIME,
 				vl6180_meas_reg_val_from_mhz(20000));
@@ -598,7 +710,7 @@ 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;
 
@@ -611,6 +723,19 @@ static int vl6180_probe(struct i2c_client *client)
 			return dev_err_probe(&client->dev, ret, "devm_request_irq error \n");
 
 		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