Re: [PATCH] iio:light: Add support for STMicro VL6180 sensor

[Jonathan Cameron <jic23@kernel.org>]

On 05/03/17 13:46, Mani Sadhasivam wrote:
> On Sat, Mar 04, 2017 at 05:53:14PM +0000, Jonathan Cameron wrote:
>> On 02/03/17 18:40, Manivannan Sadhasivam wrote:
>>> This patch adds support for STMicro VL6180 - ALS and proximity sensor. Sensor is capable of measuring the light
>>> intensity as well as object distance using TOF(Time of Flight) technology.
>>>
>>> Signed-off-by: Manivannan Sadhasivam <manivannanece23@gmail.com>
>> Few more comments from me.
>>
> Thanks Jonathan for your review.
>> Jonathan
>>> ---
>>>  .../devicetree/bindings/iio/light/vl6180.txt       |  16 +
>>>  drivers/iio/light/Kconfig                          |  10 +
>>>  drivers/iio/light/Makefile                         |   1 +
>>>  drivers/iio/light/vl6180.c                         | 544 +++++++++++++++++++++
>>>  4 files changed, 571 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/iio/light/vl6180.txt
>>>  create mode 100644 drivers/iio/light/vl6180.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/iio/light/vl6180.txt b/Documentation/devicetree/bindings/iio/light/vl6180.txt
>>> new file mode 100644
>>> index 0000000..bc1820a
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/iio/light/vl6180.txt
>>> @@ -0,0 +1,16 @@
>>> +STMicro VL6180 -  ALS and proximity sensor
>>> +
>>> +Link to datasheet: http://www.st.com/resource/en/datasheet/vl6180x.pdf
>>> +
>>> +Required properties:
>>> +
>>> +	-compatible: should be "st,vl6180"
>>> +	-reg: the I2C address of the sensor
>>> +
>>> +Example:
>>> +
>>> +vl6180@29 {
>>> +	compatible = "st,vl6180";
>>> +	reg = <0x29>;
>>> +};
>>> +	
>>> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
>>> index 7c566f5..c26113a 100644
>>> --- a/drivers/iio/light/Kconfig
>>> +++ b/drivers/iio/light/Kconfig
>>> @@ -352,4 +352,14 @@ config VEML6070
>>>  	 To compile this driver as a module, choose M here: the
>>>  	 module will be called veml6070.
>>>  
>>> +config VL6180
>>> +	tristate "VL6180 ALS and proximity sensor"
>>> +	depends on I2C
>>> +	help
>>> +	 Say Y here if you want to build a driver for the STMicroelectronics
>>> +	 VL6180 combined ambient light and proximity sensor.
>>> +
>>> +	 To compile this driver as a module, choose M here: the
>>> +	 module will be called vl6180.
>>> +
>>>  endmenu
>>> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
>>> index 6f2a3c6..24a8d72 100644
>>> --- a/drivers/iio/light/Makefile
>>> +++ b/drivers/iio/light/Makefile
>>> @@ -33,3 +33,4 @@ obj-$(CONFIG_TSL4531)		+= tsl4531.o
>>>  obj-$(CONFIG_US5182D)		+= us5182d.o
>>>  obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
>>>  obj-$(CONFIG_VEML6070)		+= veml6070.o
>>> +obj-$(CONFIG_VL6180)		+= vl6180.o
>>> diff --git a/drivers/iio/light/vl6180.c b/drivers/iio/light/vl6180.c
>>> new file mode 100644
>>> index 0000000..de80d96
>>> --- /dev/null
>>> +++ b/drivers/iio/light/vl6180.c
>>> @@ -0,0 +1,544 @@
>>> +/*
>>> + * vl6180.c - Support for STMicroelectronics VL6180 ALS and proximity sensor
>>> + *
>>> + * Copyright 2017 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
>>> + * Copyright 2017 Manivannan Sadhasivam <manivannanece23@gmail.com>
>>> + *
>>> + * This file is subject to the terms and conditions of version 2 of
>>> + * the GNU General Public License.  See the file COPYING in the main
>>> + * directory of this archive for more details.
>>> + *
>>> + * IIO driver for VL6180 (7-bit I2C slave addresses 0x29)
>>> + *
>>> + * Range: 0 to 100mm
>>> + * ALS: < 1 Lux up to 100 kLux
>>> + * IR: 850nm
>>> + *
>>> + * TODO: irq, threshold events, continuous mode, hardware buffer
>>> + */
>>> +
>>> +#include <linux/module.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/mutex.h>
>>> +#include <linux/err.h>
>>> +#include <linux/of.h>
>>> +#include <linux/delay.h>
>>> +
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/sysfs.h>
>>> +
>>> +#define VL6180_DRV_NAME "vl6180"
>>> +
>>> +/* Device identification register and value */
>>> +#define VL6180_MODEL_ID	0x000
>>> +#define VL6180_MODEL_ID_VAL 0xb4
>>> +
>>> +/* Configuration registers */
>>> +#define VL6180_INTR_CONFIG 0x014
>>> +#define VL6180_INTR_CLEAR 0x015
>>> +#define VL6180_OUT_OF_RESET 0x016
>>> +#define VL6180_HOLD 0x017
>>> +#define VL6180_RANGE_START 0x018
>>> +#define VL6180_ALS_START 0x038
>>> +#define VL6180_ALS_GAIN 0x03f
>>> +#define VL6180_ALS_IT 0x040
>>> +
>>> +/* Status registers */
>>> +#define VL6180_RANGE_STATUS 0x04d
>>> +#define VL6180_ALS_STATUS 0x04e
>>> +#define VL6180_INTR_STATUS 0x04f
>>> +
>>> +/* Result value registers */
>>> +#define VL6180_ALS_VALUE 0x050
>>> +#define VL6180_RANGE_VALUE 0x062
>>> +#define VL6180_RANGE_RATE 0x066
>>> +
>>> +/* bits of the RANGE_START and ALS_START register */
>>> +#define VL6180_MODE_CONT BIT(1) /* continuous mode */
>>> +#define VL6180_STARTSTOP BIT(0) /* start measurement, auto-reset */
>>> +
>>> +/* bits of the INTR_STATUS and INTR_CONFIG register */
>>> +#define VL6180_ALS_READY BIT(5)
>>> +#define VL6180_RANGE_READY BIT(2)
>>> +
>>> +/* bits of the INTR_CLEAR register */
>>> +#define VL6180_CLEAR_ERROR BIT(2)
>>> +#define VL6180_CLEAR_ALS BIT(1)
>>> +#define VL6180_CLEAR_RANGE BIT(0)
>>> +
>>> +/* bits of the HOLD register */
>>> +#define VL6180_HOLD_ON BIT(0)
>>> +
>>> +/* default value for the ALS_IT register */
>>> +#define VL6180_ALS_IT_100 0x063 /* 100 ms */
>>> +
>>> +/* values for the ALS_GAIN register */
>>> +#define VL6180_ALS_GAIN_1 0x46
>>> +#define VL6180_ALS_GAIN_1_25 0x45
>>> +#define VL6180_ALS_GAIN_1_67 0x44
>>> +#define VL6180_ALS_GAIN_2_5 0x43
>>> +#define VL6180_ALS_GAIN_5 0x42
>>> +#define VL6180_ALS_GAIN_10 0x41
>>> +#define VL6180_ALS_GAIN_20 0x40
>>> +#define VL6180_ALS_GAIN_40 0x47
>>> +
>>> +struct vl6180_data {
>>> +	struct i2c_client *client;
>>> +	struct mutex lock;
>>> +};
>>> +
>>> +enum { VL6180_ALS, VL6180_RANGE, VL6180_PROX };
>>> +
>>> +/**
>>> + * struct vl6180_chan_regs - Registers for accessing channels
>>> + * @drdy_mask:			Data ready bits in status register
>>> + * @start_reg:			Conversion start registeir
>>> + * @value_reg:			Result value register
>>> + */
>>> +struct vl6180_chan_regs {
>>> +	u8 drdy_mask;
>>> +	u16 start_reg, value_reg;
>>> +	bool word;
>>> +};
>>> +
>>> +static const struct vl6180_chan_regs vl6180_chan_regs_table[] = {
>>> +	[VL6180_ALS] = {
>>> +		.drdy_mask = VL6180_ALS_READY,
>>> +		.start_reg = VL6180_ALS_START,
>>> +		.value_reg = VL6180_ALS_VALUE,
>>> +		.word = true,
>>> +	},
>>> +	[VL6180_RANGE] = {
>>> +		.drdy_mask = VL6180_RANGE_READY,
>>> +		.start_reg = VL6180_RANGE_START,
>>> +		.value_reg = VL6180_RANGE_VALUE,
>>> +		.word = false,
>>> +	},
>>> +	[VL6180_PROX] = {
>>> +		.drdy_mask = VL6180_RANGE_READY,
>>> +		.start_reg = VL6180_RANGE_START,
>>> +		.value_reg = VL6180_RANGE_RATE,
>>> +		.word = true,
>>> +	},
>>> +};
>>> +
>>> +static int vl6180_read(struct i2c_client *client, u16 cmd, void *databuf,
>>> +		       u8 len)
>>> +{
>>> +	u16 cmdbuf = cpu_to_be16(cmd);
>>> +	struct i2c_msg msgs[2] = {
>>> +		{ .addr = client->addr, .len = 2, .buf = (u8 *) &cmdbuf },
>>> +		{ .addr = client->addr, .len = len, .buf = databuf,
>>> +		  .flags = I2C_M_RD } };
>>> +	int ret;
>> Hmm. could wrap this up in regmap rather neatly I think, but fair enough
>> to keep it all obvious here if you prefer.
> I'd prefer to keep regmap away here as we're not caching any register and this 
> way seems to be more efficient to me!
>>> +
>>> +	ret = i2c_transfer(client->adapter, msgs, 2);
>>> +	if (ret < 0)
>>> +		dev_err(&client->dev, "failed reading register 0x%04x\n", cmd);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static int vl6180_read_byte(struct i2c_client *client, u16 cmd)
>>> +{
>>> +	u8 data;
>>> +	int ret;
>>> +
>>> +	ret = vl6180_read(client, cmd, &data, sizeof(data));
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return data;
>>> +}
>>> +
>>> +static int vl6180_read_word(struct i2c_client *client, u16 cmd)
>>> +{
>>> +	__be16 data;
>>> +	int ret;
>>> +
>>> +	ret = vl6180_read(client, cmd, &data, sizeof(data));
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return be16_to_cpu(data);
>>> +}
>>> +
>>> +static int vl6180_write_byte(struct i2c_client *client, u16 cmd, u8 val)
>>> +{
>>> +	u8 buf[3];
>>> +	struct i2c_msg msgs[1] = {
>>> +		{ .addr = client->addr, .len = 3, .buf = buf } };
>>> +	int ret;
>>> +
>>> +	buf[0] = cmd >> 8;
>>> +	buf[1] = cmd & 0xff;
>> Here you end up with a mix that makes it harder to force the endianness than
>> below, but it can still be done by using cpu_to_be16p and again makes
>> that conversion explicit.
> Ack
>>> +	buf[2] = val;
>>> +
>>> +	ret = i2c_transfer(client->adapter, msgs, 1);
>>> +	if (ret < 0) {
>>> +		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
>>> +		return ret;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int vl6180_write_word(struct i2c_client *client, u16 cmd, u16 val)
>>> +{
>>> +	u8 buf[4];
>>> +	struct i2c_msg msgs[1] = {
>>> +		{ .addr = client->addr, .len = 4, .buf = buf } };
>>> +	int ret;
>>> +
>>> +	buf[0] = cmd >> 8;
>>> +	buf[1] = cmd & 0xff;
>> Could be done 'slightly' more efficiently by using the fact these are clearly
>> u16s.  Then in the case where the system is of the same endianness these
>> become simple copies.  cpu_to_be16 should do the trick (assuming I've got
>> the write one;)
>>
>> Make buf __be16 and this becomes explicit in the code which is always a
>> nice bonus.
> True. Like Peter also suggested, use of cpu_to_be16 is more efficient here.
> I'll incorporate in the next version.
>>> +	buf[2] = val >> 8;
>>> +	buf[3] = val & 0xff;
>>> +
>>> +	ret = i2c_transfer(client->adapter, msgs, 1);
>>> +	if (ret < 0) {
>>> +		dev_err(&client->dev, "failed writing register 0x%04x\n", cmd);
>>> +		return ret;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int vl6180_measure(struct vl6180_data *data, int addr)
>>> +{
>>> +	struct i2c_client *client = data->client;
>>> +	int tries = 20, ret;
>>> +	u16 value;
>>> +
>>> +	mutex_lock(&data->lock);
>>> +	/* Start single shot measurement */
>>> +	ret = vl6180_write_byte(client,
>>> +		vl6180_chan_regs_table[addr].start_reg, VL6180_STARTSTOP);
>>> +	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);
>> Presumably we can know approximately how long this is going to take depending
>> on state and perhaps reduce the bus traffic by guessing 'about' right.
> Sensor update rate is 40 to 60Hz. Hence, 20ms seems to be good enough.
>>> +	}
>>> +
>>> +	if (tries < 0) {
>>> +		ret = -EIO;
>>> +		goto fail;
>>> +	}
>>> +
>>> +	/* Read result value from appropriate registers */
>>> +	ret = vl6180_chan_regs_table[addr].word ?
>>> +		vl6180_read_word(client, vl6180_chan_regs_table[addr].value_reg) :
>>> +		vl6180_read_byte(client, vl6180_chan_regs_table[addr].value_reg);
>>> +	if (ret < 0)
>>> +		goto fail;
>>> +	value = ret;
>>> +
>>> +	/* Clear the interrupt flag after data read */
>>> +	ret = vl6180_write_byte(client, VL6180_INTR_CLEAR,
>>> +		VL6180_CLEAR_ERROR | VL6180_CLEAR_ALS | VL6180_CLEAR_RANGE);
>>> +	if (ret < 0)
>>> +		goto fail;
>>> +
>>> +	ret = value;
>>> +
>>> +fail:
>>> +	mutex_unlock(&data->lock);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static const struct iio_chan_spec vl6180_channels[] = {
>>> +	{
>>> +		.type = IIO_LIGHT,
>>> +		.address = VL6180_ALS,
>>> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>>> +			BIT(IIO_CHAN_INFO_INT_TIME) |
>>> +			BIT(IIO_CHAN_INFO_SCALE) |
>>> +			BIT(IIO_CHAN_INFO_HARDWAREGAIN),
>>> +	}, {
>>> +		.type = IIO_DISTANCE,
>>> +		.address = VL6180_RANGE,
>>> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>>> +			BIT(IIO_CHAN_INFO_SCALE),
>>> +	}, {
>>> +		.type = IIO_PROXIMITY,
>>> +		.address = VL6180_PROX,
>>> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>>> +	}
>>> +};
>>> +
>> As Peter raised, not that obvious what these are. Please add a comment
>> explaining.
> Ack
>>> +static const int vl6180_als_gain[8][4] = {
>>> +	{ 1,	0,	70,	VL6180_ALS_GAIN_1 },
>>> +	{ 1,    250000, 69,	VL6180_ALS_GAIN_1_25 },
>>> +	{ 1,    670000, 68,	VL6180_ALS_GAIN_1_67 },
>>> +	{ 2,    500000, 67,	VL6180_ALS_GAIN_2_5 },
>>> +	{ 5,    0,      66,	VL6180_ALS_GAIN_5 },
>>> +	{ 10,   0,      65,	VL6180_ALS_GAIN_10 },
>>> +	{ 20,   0,      64,	VL6180_ALS_GAIN_20 },
>>> +	{ 40,   0,      71,	VL6180_ALS_GAIN_40 }
>>> +};
>>> +
>>> +
>>> +static int vl6180_read_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);
>>> +	int ret, i;
>>> +
>>> +	switch (mask) {
>>> +	case IIO_CHAN_INFO_RAW:
>>> +		ret = vl6180_measure(data, chan->address);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		*val = ret;
>>> +
>>> +		return IIO_VAL_INT;
>>> +	case IIO_CHAN_INFO_INT_TIME:
>>> +		ret = vl6180_read_word(data->client, VL6180_ALS_IT);
>>> +		if (ret < 0)
>>> +			return ret;
>>> +		*val = 0; /* 1 count = 1ms (0 = 1ms) */
>>> +		*val2 = (ret + 1) * 1000; /* convert to seconds */
>>> +
>>> +		return IIO_VAL_INT_PLUS_MICRO;
>>> +	case IIO_CHAN_INFO_SCALE:
>>> +		switch (chan->type) {
>>> +		case IIO_LIGHT:
>>> +			*val = 0; /* one ALS count is 0.32 Lux */
>>> +			*val2 = 320000;
>>> +			break;
>>> +		case IIO_DISTANCE:
>>> +			*val = 0; /* sensor reports mm, scale to meter */
>>> +			*val2 = 1000;
>>> +			break;
>>> +		default:
>>> +			return -EINVAL;
>>> +		}
>>> +
>>> +		return IIO_VAL_INT_PLUS_MICRO;
>>> +	case IIO_CHAN_INFO_HARDWAREGAIN:
>>> +		ret = vl6180_read_byte(data->client, VL6180_ALS_GAIN);
>>> +		if (ret < 0)
>>> +			return -EINVAL;
>>> +		for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) {
>>> +			if (ret == vl6180_als_gain[i][2]) {
>>> +				*val = vl6180_als_gain[i][0];
>>> +				*val2 = vl6180_als_gain[i][1];
>>> +			}
>>> +		}
>>> +
>>> +		return IIO_VAL_INT_PLUS_MICRO;
>>> +	default:
>>> +		return -EINVAL;
>>> +	}
>>> +}
>>> +
>>> +static IIO_CONST_ATTR(als_gain_available, "1 1.25 1.67 2.5 5 10 20 40");
>>> +
>>> +static struct attribute *vl6180_attributes[] = {
>>> +	&iio_const_attr_als_gain_available.dev_attr.attr,
>>> +	NULL
>>> +};
>>> +
>>> +static const struct attribute_group vl6180_attribute_group = {
>>> +	.attrs = vl6180_attributes,
>>> +};
>>> +
>>> +/* HOLD is needed before updading any config registers */
>>> +static int vl6180_hold(struct vl6180_data *data, bool hold)
>>> +{
>>> +	return vl6180_write_byte(data->client, VL6180_HOLD,
>>> +		hold ? VL6180_HOLD_ON : 0);
>>> +}
>>> +
>>> +static int vl6180_set_als_gain(struct vl6180_data *data, int val, int val2)
>>> +{
>>> +	int i, ret;
>>> +
>>> +	for (i = 0; i < ARRAY_SIZE(vl6180_als_gain); i++) {
>>> +		if (val == vl6180_als_gain[i][0] &&
>>> +			val2 == vl6180_als_gain[i][1]) {
>>> +			mutex_lock(&data->lock);
>>> +			ret = vl6180_hold(data, true);
>>> +			if (ret < 0)
>>> +				goto fail;
>>> +			ret = vl6180_write_byte(data->client, VL6180_ALS_GAIN,
>>> +				vl6180_als_gain[i][3]);
>>> +fail:
>>> +			vl6180_hold(data, false);
>>> +			mutex_unlock(&data->lock);
>>> +			return ret;
>>> +		}
>>> +	}
>>> +
>>> +	return -EINVAL;
>>> +}
>>> +
>>> +static int vl6180_set_it(struct vl6180_data *data, int val2)
>>> +{
>>> +	int ret;
>>> +
>>> +	mutex_lock(&data->lock);
>>> +	ret = vl6180_hold(data, true);
>>> +	if (ret < 0)
>>> +		goto fail;
>>> +	ret = vl6180_write_word(data->client, VL6180_ALS_IT,
>>> +		(val2 - 500) / 1000); /* write value in ms */
>>> +fail:
>>> +	vl6180_hold(data, false);
>>> +	mutex_unlock(&data->lock);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +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);
>>> +
>>> +	switch (mask) {
>>> +	case IIO_CHAN_INFO_INT_TIME:
>>> +		if (val != 0 || val2 < 500 || val2 >= 512500)
>>> +			return -EINVAL;
>>> +
>>> +		return vl6180_set_it(data, val2);
>>> +	case IIO_CHAN_INFO_HARDWAREGAIN:
>>> +		if (chan->type != IIO_LIGHT)
>>> +			return -EINVAL;
>>> +
>>> +		return vl6180_set_als_gain(data, val, val2);
>>> +	default:
>>> +		return -EINVAL;
>>> +	}
>>> +}
>>> +
>>> +static const struct iio_info vl6180_info = {
>>> +	.read_raw = vl6180_read_raw,
>>> +	.write_raw = vl6180_write_raw,
>>> +	.attrs = &vl6180_attribute_group,
>>> +	.driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +/**
>>> + * Following settings are enabled:
>>> + * 1. ALS and Range ready interrupts
>> I'd prefer to see these comments next to the place they are implemented.
>> Much less likely to end up out of date there.
> Ack
>>> + * 2. ALS integration time: 100ms
>>> + * 3. ALS gain: 1
>>> + */
>>> +static int vl6180_init(struct vl6180_data *data)
>>> +{
>>> +	struct i2c_client *client = data->client;
>>> +	int ret;
>>> +
>>> +	ret = vl6180_read_byte(client, VL6180_MODEL_ID);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	if (ret != VL6180_MODEL_ID_VAL) {
>>> +		dev_err(&client->dev, "invalid model ID %02x\n", ret);
>>> +		return -ENODEV;
>>> +	}
>>> +
>>> +	ret = vl6180_hold(data, true);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = vl6180_read_byte(client, VL6180_OUT_OF_RESET);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	if (ret != 0x01) {
>>> +		dev_err(&client->dev, "device is not fresh out of reset\n");
>>> +		return -EINVAL;
>>> +	}
>> Why would it necessarily be fresh out of reset? If it is in some fashion
>> supposed to be guaranteed here, please add a comment explaining why.
> Device sometimes suffers from false reset condition. Hence, this check ensures that
> the device always starts up in the fresh reset condition.
> Will add a comment here.
Ensures it or checks that it is the case?

What about a module remove and reprobe?  Should work in that case as well.
>>> +
>>> +	ret = vl6180_write_byte(client, VL6180_INTR_CONFIG,
>>> +				VL6180_ALS_READY | VL6180_RANGE_READY);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = vl6180_write_word(client, VL6180_ALS_IT, VL6180_ALS_IT_100);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = vl6180_write_byte(client, VL6180_ALS_GAIN, VL6180_ALS_GAIN_1);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = vl6180_write_byte(client, VL6180_OUT_OF_RESET, 0x00);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return vl6180_hold(data, false);
>>> +}
>>> +
>>> +static int vl6180_probe(struct i2c_client *client,
>>> +			  const struct i2c_device_id *id)
>>> +{
>>> +	struct vl6180_data *data;
>>> +	struct iio_dev *indio_dev;
>>> +	int ret;
>>> +
>>> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>> +	if (!indio_dev)
>>> +		return -ENOMEM;
>>> +
>>> +	data = iio_priv(indio_dev);
>>> +	i2c_set_clientdata(client, indio_dev);
>>> +	data->client = client;
>>> +	mutex_init(&data->lock);
>>> +
>>> +	indio_dev->dev.parent = &client->dev;
>>> +	indio_dev->info = &vl6180_info;
>>> +	indio_dev->channels = vl6180_channels;
>>> +	indio_dev->num_channels = ARRAY_SIZE(vl6180_channels);
>>> +	indio_dev->name = VL6180_DRV_NAME;
>>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>>> +
>>> +	ret = vl6180_init(data);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	ret = devm_iio_device_register(&client->dev, indio_dev);
>>> +	if (ret < 0)
>>> +		return ret;
>> return devm_iio_device_register directly.
>>
>> The static checkers will fire on this anyway, but best to fix
>> it now.
> Ack
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static const struct of_device_id vl6180_of_match[] = {
>>> +	{ .compatible = "st,vl6180", },
>>> +	{ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, vl6180_of_match);
>>> +
>>> +static const struct i2c_device_id vl6180_id[] = {
>>> +	{ "vl6180", 0 },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, vl6180_id);
>>> +
>>> +static struct i2c_driver vl6180_driver = {
>>> +	.driver = {
>>> +		.name   = VL6180_DRV_NAME,
>>> +		.of_match_table = of_match_ptr(vl6180_of_match),
>>> +	},
>>> +	.probe  = vl6180_probe,
>>> +	.id_table = vl6180_id,
>>> +};
>>> +
>>> +module_i2c_driver(vl6180_driver);
>>> +
>>> +MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
>>> +MODULE_AUTHOR("Manivannan Sadhasivam <manivannanece23@gmail.com>");
>>> +MODULE_DESCRIPTION("STMicro VL6180 ALS and proximity sensor driver");
>>> +MODULE_LICENSE("GPL");
>>>
>>