[PATCH v6 0/2] iio: proximity: add PulsedLight LIDAR sensor support

[PATCH v6 0/2] iio: proximity: add PulsedLight LIDAR sensor support

[Matt Ranostay]

This patchset adds support for this range finding LIDAR module, and reports
distance back in meters to centimeter resolution with +/- 2.5 CM of accuracy
at ~40 meters.

Changes from v5:
* Use indio_dev->mlock mutex to be sure of buffer enabled state
  and removed data->lock
* Changed CONFIG_LIDAR to CONFIG_LIDAR_LITE_V2
* Changed lidar to lidar-lite-v2 in i2c module lookup table 

Matt Ranostay (2):
  devicetree: add PulsedLight vendor + device docs
  iio: proximity: add support for PulsedLight LIDAR

 .../devicetree/bindings/i2c/trivial-devices.txt    |   1 +
 .../devicetree/bindings/vendor-prefixes.txt        |   1 +
 drivers/iio/proximity/Kconfig                      |  12 +
 drivers/iio/proximity/Makefile                     |   1 +
 drivers/iio/proximity/pulsedlight-lidar-lite-v2.c  | 288 +++++++++++++++++++++
 5 files changed, 303 insertions(+)
 create mode 100644 drivers/iio/proximity/pulsedlight-lidar-lite-v2.c

-- 
1.9.1

[PATCH v6 1/2] devicetree: add PulsedLight vendor + device docs

[Matt Ranostay]

Add pulsedlight vendor to vendor-prefixes.txt, and LIDAR device
documentation to trivial-devices.txt

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
---
 Documentation/devicetree/bindings/i2c/trivial-devices.txt | 1 +
 Documentation/devicetree/bindings/vendor-prefixes.txt     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index d77d412..cecd315 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -80,6 +80,7 @@ oki,ml86v7667		OKI ML86V7667 video decoder
 ovti,ov5642		OV5642: Color CMOS QSXGA (5-megapixel) Image Sensor with OmniBSI and Embedded TrueFocus
 pericom,pt7c4338	Real-time Clock Module
 plx,pex8648		48-Lane, 12-Port PCI Express Gen 2 (5.0 GT/s) Switch
+pulsedlight,lidar-lite-v2	Pulsedlight LIDAR range-finding sensor
 ramtron,24c64		i2c serial eeprom  (24cxx)
 ricoh,r2025sd		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
 ricoh,r2221tl		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 3ac71a8..c220209 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -166,6 +166,7 @@ phytec	PHYTEC Messtechnik GmbH
 picochip	Picochip Ltd
 plathome	Plat'Home Co., Ltd.
 pixcir  PIXCIR MICROELECTRONICS Co., Ltd
+pulsedlight	PulsedLight, Inc
 powervr	PowerVR (deprecated, use img)
 qca	Qualcomm Atheros, Inc.
 qcom	Qualcomm Technologies, Inc
-- 
1.9.1

Re: [PATCH v6 1/2] devicetree: add PulsedLight vendor + device docs

[Jonathan Cameron]

On 18/08/15 15:40, Matt Ranostay wrote:
> Add pulsedlight vendor to vendor-prefixes.txt, and LIDAR device
> documentation to trivial-devices.txt
> 
> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Applied to the togreg branch of iio.git.

Thanks,

Jonathan
> ---
>  Documentation/devicetree/bindings/i2c/trivial-devices.txt | 1 +
>  Documentation/devicetree/bindings/vendor-prefixes.txt     | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index d77d412..cecd315 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -80,6 +80,7 @@ oki,ml86v7667		OKI ML86V7667 video decoder
>  ovti,ov5642		OV5642: Color CMOS QSXGA (5-megapixel) Image Sensor with OmniBSI and Embedded TrueFocus
>  pericom,pt7c4338	Real-time Clock Module
>  plx,pex8648		48-Lane, 12-Port PCI Express Gen 2 (5.0 GT/s) Switch
> +pulsedlight,lidar-lite-v2	Pulsedlight LIDAR range-finding sensor
>  ramtron,24c64		i2c serial eeprom  (24cxx)
>  ricoh,r2025sd		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
>  ricoh,r2221tl		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
> index 3ac71a8..c220209 100644
> --- a/Documentation/devicetree/bindings/vendor-prefixes.txt
> +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
> @@ -166,6 +166,7 @@ phytec	PHYTEC Messtechnik GmbH
>  picochip	Picochip Ltd
>  plathome	Plat'Home Co., Ltd.
>  pixcir  PIXCIR MICROELECTRONICS Co., Ltd
> +pulsedlight	PulsedLight, Inc
>  powervr	PowerVR (deprecated, use img)
>  qca	Qualcomm Atheros, Inc.
>  qcom	Qualcomm Technologies, Inc
> 

[PATCH v6 2/2] iio: proximity: add support for PulsedLight LIDAR

[Matt Ranostay]

Add support for the PulsedLight LIDAR rangefinder sensor which allows
high speed (over 300Hz) distance measurements using Barker Coding within
40 meter range.

Support only tested on the "blue label" rev 2, but may work using low
sample frequencies on the original version.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
---
 drivers/iio/proximity/Kconfig                     |  12 +
 drivers/iio/proximity/Makefile                    |   1 +
 drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 288 ++++++++++++++++++++++
 3 files changed, 301 insertions(+)
 create mode 100644 drivers/iio/proximity/pulsedlight-lidar-lite-v2.c

diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
index 41a8d8f..ef4c73d 100644
--- a/drivers/iio/proximity/Kconfig
+++ b/drivers/iio/proximity/Kconfig
@@ -20,6 +20,18 @@ endmenu
 
 menu "Proximity sensors"
 
+config LIDAR_LITE_V2
+	tristate "PulsedLight LIDAR sensor"
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	depends on I2C
+	help
+	  Say Y to build a driver for PulsedLight LIDAR range finding
+	  sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pulsedlight-lite-v2
+
 config SX9500
 	tristate "SX9500 Semtech proximity sensor"
 	select IIO_BUFFER
diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
index 9818dc5..9aadd9a 100644
--- a/drivers/iio/proximity/Makefile
+++ b/drivers/iio/proximity/Makefile
@@ -4,4 +4,5 @@
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AS3935)		+= as3935.o
+obj-$(CONFIG_LIDAR_LITE_V2)	+= pulsedlight-lidar-lite-v2.o
 obj-$(CONFIG_SX9500)		+= sx9500.o
diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
new file mode 100644
index 0000000..185a7ab
--- /dev/null
+++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
@@ -0,0 +1,288 @@
+/*
+ * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR sensor
+ *
+ * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * TODO: runtime pm, interrupt mode, and signal strength reporting
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+
+#define LIDAR_REG_CONTROL		0x00
+#define LIDAR_REG_CONTROL_ACQUIRE	BIT(2)
+
+#define LIDAR_REG_STATUS		0x01
+#define LIDAR_REG_STATUS_INVALID	BIT(3)
+#define LIDAR_REG_STATUS_READY		BIT(0)
+
+#define LIDAR_REG_DATA_HBYTE	0x0f
+#define LIDAR_REG_DATA_LBYTE	0x10
+
+#define LIDAR_DRV_NAME "lidar"
+
+struct lidar_data {
+	struct iio_dev *indio_dev;
+	struct i2c_client *client;
+
+	u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */
+};
+
+static const struct iio_chan_spec lidar_channels[] = {
+	{
+		.type = IIO_DISTANCE,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static int lidar_read_byte(struct lidar_data *data, int reg)
+{
+	struct i2c_client *client = data->client;
+	int ret;
+
+	/*
+	 * Device needs a STOP condition between address write, and data read
+	 * so in turn i2c_smbus_read_byte_data cannot be used
+	 */
+
+	ret = i2c_smbus_write_byte(client, reg);
+	if (ret < 0) {
+		dev_err(&client->dev, "cannot write addr value");
+		return ret;
+	}
+
+	ret = i2c_smbus_read_byte(client);
+	if (ret < 0)
+		dev_err(&client->dev, "cannot read data value");
+
+	return ret;
+}
+
+static inline int lidar_write_control(struct lidar_data *data, int val)
+{
+	return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
+}
+
+static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
+{
+	int ret;
+	int val;
+
+	ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE);
+	if (ret < 0)
+		return ret;
+	val = ret << 8;
+
+	ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE);
+	if (ret < 0)
+		return ret;
+
+	val |= ret;
+	*reg = val;
+
+	return 0;
+}
+
+static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
+{
+	struct i2c_client *client = data->client;
+	int tries = 10;
+	int ret;
+
+	/* start sample */
+	ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
+	if (ret < 0) {
+		dev_err(&client->dev, "cannot send start measurement command");
+		return ret;
+	}
+
+	while (tries--) {
+		usleep_range(1000, 2000);
+
+		ret = lidar_read_byte(data, LIDAR_REG_STATUS);
+		if (ret < 0)
+			break;
+
+		/* return 0 since laser is likely pointed out of range */
+		if (ret & LIDAR_REG_STATUS_INVALID) {
+			*reg = 0;
+			ret = 0;
+			break;
+		}
+
+		/* sample ready to read */
+		if (!(ret & LIDAR_REG_STATUS_READY)) {
+			ret = lidar_read_measurement(data, reg);
+			break;
+		}
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+static int lidar_read_raw(struct iio_dev *indio_dev,
+			  struct iio_chan_spec const *chan,
+			  int *val, int *val2, long mask)
+{
+	struct lidar_data *data = iio_priv(indio_dev);
+	int ret = -EINVAL;
+
+	mutex_lock(&indio_dev->mlock);
+
+	if (iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW) {
+		ret = -EBUSY;
+		goto error_busy;
+	}
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: {
+		u16 reg;
+
+		ret = lidar_get_measurement(data, &reg);
+		if (!ret) {
+			*val = reg;
+			ret = IIO_VAL_INT;
+		}
+		break;
+	}
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		*val2 = 10000;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	}
+
+error_busy:
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static irqreturn_t lidar_trigger_handler(int irq, void *private)
+{
+	struct iio_poll_func *pf = private;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct lidar_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = lidar_get_measurement(data, data->buffer);
+	if (!ret) {
+		iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+						   iio_get_time_ns());
+	} else {
+		dev_err(&data->client->dev, "cannot read LIDAR measurement");
+	}
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_info lidar_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = lidar_read_raw,
+};
+
+static int lidar_probe(struct i2c_client *client,
+		       const struct i2c_device_id *id)
+{
+	struct lidar_data *data;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	indio_dev->info = &lidar_info;
+	indio_dev->name = LIDAR_DRV_NAME;
+	indio_dev->channels = lidar_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	data = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+
+	data->client = client;
+	data->indio_dev = indio_dev;
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 lidar_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_unreg_buffer;
+
+	return 0;
+
+error_unreg_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return ret;
+}
+
+static int lidar_remove(struct i2c_client *client)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id lidar_id[] = {
+	{"lidar-lite-v2", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, lidar_id);
+
+static const struct of_device_id lidar_dt_ids[] = {
+	{ .compatible = "pulsedlight,lidar-lite-v2" },
+	{ }
+};
+
+static struct i2c_driver lidar_driver = {
+	.driver = {
+		.name	= LIDAR_DRV_NAME,
+		.of_match_table	= of_match_ptr(lidar_dt_ids),
+	},
+	.probe		= lidar_probe,
+	.remove		= lidar_remove,
+	.id_table	= lidar_id,
+};
+module_i2c_driver(lidar_driver);
+
+MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
+MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
+MODULE_LICENSE("GPL");
-- 
1.9.1

Re: [PATCH v6 2/2] iio: proximity: add support for PulsedLight LIDAR

[Jonathan Cameron]

On 18/08/15 15:40, Matt Ranostay wrote:
> Add support for the PulsedLight LIDAR rangefinder sensor which allows
> high speed (over 300Hz) distance measurements using Barker Coding within
> 40 meter range.
> 
> Support only tested on the "blue label" rev 2, but may work using low
> sample frequencies on the original version.
> 
> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Nice diver,

Applied to the togreg branch of iio.git.  Initially pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan
> ---
>  drivers/iio/proximity/Kconfig                     |  12 +
>  drivers/iio/proximity/Makefile                    |   1 +
>  drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 288 ++++++++++++++++++++++
>  3 files changed, 301 insertions(+)
>  create mode 100644 drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> 
> diff --git a/drivers/iio/proximity/Kconfig b/drivers/iio/proximity/Kconfig
> index 41a8d8f..ef4c73d 100644
> --- a/drivers/iio/proximity/Kconfig
> +++ b/drivers/iio/proximity/Kconfig
> @@ -20,6 +20,18 @@ endmenu
>  
>  menu "Proximity sensors"
>  
> +config LIDAR_LITE_V2
> +	tristate "PulsedLight LIDAR sensor"
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	depends on I2C
> +	help
> +	  Say Y to build a driver for PulsedLight LIDAR range finding
> +	  sensor.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called pulsedlight-lite-v2
> +
>  config SX9500
>  	tristate "SX9500 Semtech proximity sensor"
>  	select IIO_BUFFER
> diff --git a/drivers/iio/proximity/Makefile b/drivers/iio/proximity/Makefile
> index 9818dc5..9aadd9a 100644
> --- a/drivers/iio/proximity/Makefile
> +++ b/drivers/iio/proximity/Makefile
> @@ -4,4 +4,5 @@
>  
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_AS3935)		+= as3935.o
> +obj-$(CONFIG_LIDAR_LITE_V2)	+= pulsedlight-lidar-lite-v2.o
>  obj-$(CONFIG_SX9500)		+= sx9500.o
> diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> new file mode 100644
> index 0000000..185a7ab
> --- /dev/null
> +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c
> @@ -0,0 +1,288 @@
> +/*
> + * pulsedlight-lidar-lite-v2.c - Support for PulsedLight LIDAR sensor
> + *
> + * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * TODO: runtime pm, interrupt mode, and signal strength reporting
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +
> +#define LIDAR_REG_CONTROL		0x00
> +#define LIDAR_REG_CONTROL_ACQUIRE	BIT(2)
> +
> +#define LIDAR_REG_STATUS		0x01
> +#define LIDAR_REG_STATUS_INVALID	BIT(3)
> +#define LIDAR_REG_STATUS_READY		BIT(0)
> +
> +#define LIDAR_REG_DATA_HBYTE	0x0f
> +#define LIDAR_REG_DATA_LBYTE	0x10
> +
> +#define LIDAR_DRV_NAME "lidar"
> +
> +struct lidar_data {
> +	struct iio_dev *indio_dev;
> +	struct i2c_client *client;
> +
> +	u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */
> +};
> +
> +static const struct iio_chan_spec lidar_channels[] = {
> +	{
> +		.type = IIO_DISTANCE,
> +		.info_mask_separate =
> +			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = 0,
> +		.scan_type = {
> +			.sign = 'u',
> +			.realbits = 16,
> +			.storagebits = 16,
> +		},
> +	},
> +	IIO_CHAN_SOFT_TIMESTAMP(1),
> +};
> +
> +static int lidar_read_byte(struct lidar_data *data, int reg)
> +{
> +	struct i2c_client *client = data->client;
> +	int ret;
> +
> +	/*
> +	 * Device needs a STOP condition between address write, and data read
> +	 * so in turn i2c_smbus_read_byte_data cannot be used
> +	 */
> +
> +	ret = i2c_smbus_write_byte(client, reg);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "cannot write addr value");
> +		return ret;
> +	}
> +
> +	ret = i2c_smbus_read_byte(client);
> +	if (ret < 0)
> +		dev_err(&client->dev, "cannot read data value");
> +
> +	return ret;
> +}
> +
> +static inline int lidar_write_control(struct lidar_data *data, int val)
> +{
> +	return i2c_smbus_write_byte_data(data->client, LIDAR_REG_CONTROL, val);
> +}
> +
> +static int lidar_read_measurement(struct lidar_data *data, u16 *reg)
> +{
> +	int ret;
> +	int val;
> +
> +	ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE);
> +	if (ret < 0)
> +		return ret;
> +	val = ret << 8;
> +
> +	ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE);
> +	if (ret < 0)
> +		return ret;
> +
> +	val |= ret;
> +	*reg = val;
> +
> +	return 0;
> +}
> +
> +static int lidar_get_measurement(struct lidar_data *data, u16 *reg)
> +{
> +	struct i2c_client *client = data->client;
> +	int tries = 10;
> +	int ret;
> +
> +	/* start sample */
> +	ret = lidar_write_control(data, LIDAR_REG_CONTROL_ACQUIRE);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "cannot send start measurement command");
> +		return ret;
> +	}
> +
> +	while (tries--) {
> +		usleep_range(1000, 2000);
> +
> +		ret = lidar_read_byte(data, LIDAR_REG_STATUS);
> +		if (ret < 0)
> +			break;
> +
> +		/* return 0 since laser is likely pointed out of range */
> +		if (ret & LIDAR_REG_STATUS_INVALID) {
> +			*reg = 0;
> +			ret = 0;
> +			break;
> +		}
> +
> +		/* sample ready to read */
> +		if (!(ret & LIDAR_REG_STATUS_READY)) {
> +			ret = lidar_read_measurement(data, reg);
> +			break;
> +		}
> +		ret = -EIO;
> +	}
> +
> +	return ret;
> +}
> +
> +static int lidar_read_raw(struct iio_dev *indio_dev,
> +			  struct iio_chan_spec const *chan,
> +			  int *val, int *val2, long mask)
> +{
> +	struct lidar_data *data = iio_priv(indio_dev);
> +	int ret = -EINVAL;
> +
> +	mutex_lock(&indio_dev->mlock);
> +
> +	if (iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW) {
> +		ret = -EBUSY;
> +		goto error_busy;
> +	}
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW: {
> +		u16 reg;
> +
> +		ret = lidar_get_measurement(data, &reg);
> +		if (!ret) {
> +			*val = reg;
> +			ret = IIO_VAL_INT;
> +		}
> +		break;
> +	}
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 0;
> +		*val2 = 10000;
> +		ret = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	}
> +
> +error_busy:
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static irqreturn_t lidar_trigger_handler(int irq, void *private)
> +{
> +	struct iio_poll_func *pf = private;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct lidar_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = lidar_get_measurement(data, data->buffer);
> +	if (!ret) {
> +		iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
> +						   iio_get_time_ns());
> +	} else {
> +		dev_err(&data->client->dev, "cannot read LIDAR measurement");
> +	}
> +
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct iio_info lidar_info = {
> +	.driver_module = THIS_MODULE,
> +	.read_raw = lidar_read_raw,
> +};
> +
> +static int lidar_probe(struct i2c_client *client,
> +		       const struct i2c_device_id *id)
> +{
> +	struct lidar_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	indio_dev->info = &lidar_info;
> +	indio_dev->name = LIDAR_DRV_NAME;
> +	indio_dev->channels = lidar_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(lidar_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	data->client = client;
> +	data->indio_dev = indio_dev;
> +
> +	ret = iio_triggered_buffer_setup(indio_dev, NULL,
> +					 lidar_trigger_handler, NULL);
> +	if (ret)
> +		return ret;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret)
> +		goto error_unreg_buffer;
> +
> +	return 0;
> +
> +error_unreg_buffer:
> +	iio_triggered_buffer_cleanup(indio_dev);
> +
> +	return ret;
> +}
> +
> +static int lidar_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id lidar_id[] = {
> +	{"lidar-lite-v2", 0},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(i2c, lidar_id);
> +
> +static const struct of_device_id lidar_dt_ids[] = {
> +	{ .compatible = "pulsedlight,lidar-lite-v2" },
> +	{ }
> +};
> +
> +static struct i2c_driver lidar_driver = {
> +	.driver = {
> +		.name	= LIDAR_DRV_NAME,
> +		.of_match_table	= of_match_ptr(lidar_dt_ids),
> +	},
> +	.probe		= lidar_probe,
> +	.remove		= lidar_remove,
> +	.id_table	= lidar_id,
> +};
> +module_i2c_driver(lidar_driver);
> +
> +MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
> +MODULE_DESCRIPTION("PulsedLight LIDAR sensor");
> +MODULE_LICENSE("GPL");
>