Message-ID: <20191008132744.000047cb@huawei.com>
Date:   Tue, 8 Oct 2019 13:27:44 +0100
From:   Jonathan Cameron <jonathan.cameron@...wei.com>
To:     Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
CC:     <ars@...afoo.de>, <Michael.Hennerich@...log.com>,
        <jic23@...nel.org>, <knaack.h@....de>, <pmeerw@...erw.net>,
        <robh+dt@...nel.org>, <alexandru.Ardelean@...log.com>,
        <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] iio: light: Add support for ADUX1020 sensor

On Mon, 7 Oct 2019 21:09:17 +0530
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org> wrote:

> Add initial support for Analog Devices ADUX1020 Photometric sensor.
> Only proximity mode has been enabled for now.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>

Hi Manivannan,

Various minor comments inline.

Thanks,

Jonathan

> ---
>  drivers/iio/light/Kconfig    |  11 +
>  drivers/iio/light/Makefile   |   1 +
>  drivers/iio/light/adux1020.c | 783 +++++++++++++++++++++++++++++++++++
>  3 files changed, 795 insertions(+)
>  create mode 100644 drivers/iio/light/adux1020.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 08d7e1ef2186..3f8c8689cd89 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -32,6 +32,17 @@ config ADJD_S311
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called adjd_s311.
>  
> +config ADUX1020
> +	tristate "ADUX1020 photometric sensor"
> +	select REGMAP_I2C
> +	depends on I2C
> +	help
> +	 Say Y here if you want to build a driver for the Analog Devices
> +	 ADUX1020 photometric sensor.
> +
> +	 To compile this driver as a module, choose M here: the
> +	 module will be called adux1020.
> +
>  config AL3320A
>  	tristate "AL3320A ambient light sensor"
>  	depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index 00d1f9b98f39..5d650ce46a40 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -6,6 +6,7 @@
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_ACPI_ALS)		+= acpi-als.o
>  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
> +obj-$(CONFIG_ADUX1020)		+= adux1020.o
>  obj-$(CONFIG_AL3320A)		+= al3320a.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
>  obj-$(CONFIG_APDS9960)		+= apds9960.o
> diff --git a/drivers/iio/light/adux1020.c b/drivers/iio/light/adux1020.c
> new file mode 100644
> index 000000000000..d0b76e5b44f1
> --- /dev/null
> +++ b/drivers/iio/light/adux1020.c
> @@ -0,0 +1,783 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * adux1020.c - Support for Analog Devices ADUX1020 photometric sensor
> + *
> + * Copyright (C) 2019 Linaro Ltd.
> + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> + *
> + * TODO: Triggered buffer support
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
> +
> +#define ADUX1020_REGMAP_NAME		"adux1020_regmap"
> +#define ADUX1020_DRV_NAME		"adux1020"
> +
> +/* System registers */
> +#define ADUX1020_REG_CHIP_ID		0x08
> +#define ADUX1020_REG_SLAVE_ADDRESS	0x09
> +
> +#define ADUX1020_REG_SW_RESET		0x0f
> +#define ADUX1020_REG_INT_ENABLE		0x1c
> +#define ADUX1020_REG_INT_POLARITY	0x1d
> +#define ADUX1020_REG_PROX_TH_ON1	0x2a
> +#define ADUX1020_REG_PROX_TH_OFF1	0x2b
> +#define	ADUX1020_REG_PROX_TYPE		0x2f
> +#define	ADUX1020_REG_TEST_MODES_3	0x32
> +#define	ADUX1020_REG_FORCE_MODE		0x33
> +#define	ADUX1020_REG_FREQUENCY		0x40
> +#define ADUX1020_REG_LED_CURRENT	0x41
> +#define	ADUX1020_REG_OP_MODE		0x45
> +#define	ADUX1020_REG_INT_MASK		0x48
> +#define	ADUX1020_REG_INT_STATUS		0x49
> +#define	ADUX1020_REG_DATA_BUFFER	0x60
> +
> +/* Chip ID bits */
> +#define ADUX1020_CHIP_ID_MASK		GENMASK(11, 0)
> +#define ADUX1020_CHIP_ID		0x03fc
> +
> +#define ADUX1020_MODE_OUT_SHIFT		4
> +#define ADUX1020_MODE_OUT_PROX_I	1
> +#define ADUX1020_MODE_OUT_PROX_XY	3
> +
> +#define ADUX1020_SW_RESET		BIT(1)
> +#define ADUX1020_FIFO_FLUSH		BIT(15)
> +#define ADUX1020_OP_MODE_MASK		GENMASK(3, 0)
> +#define ADUX1020_DATA_OUT_MODE_MASK	GENMASK(7, 4)
> +
> +#define ADUX1020_MODE_INT_MASK		GENMASK(7, 0)
> +#define ADUX1020_INT_ENABLE		0x2096
> +#define ADUX1020_INT_DISABLE		0x2090
> +#define ADUX1020_PROX_INT_ENABLE	0x00f0
> +#define ADUX1020_PROX_ON1_INT		BIT(0)
> +#define ADUX1020_PROX_OFF1_INT		BIT(1)
> +#define ADUX1020_FIFO_INT_ENABLE	0x7f
> +#define ADUX1020_MODE_INT_DISABLE	0xff
> +#define ADUX1020_MODE_INT_STATUS_MASK	GENMASK(7, 0)
> +#define ADUX1020_FIFO_STATUS_MASK	GENMASK(15, 8)
> +#define ADUX1020_PROX_TYPE		BIT(15)
> +
> +#define ADUX1020_INT_PROX_ON1		BIT(0)
> +#define ADUX1020_INT_PROX_OFF1		BIT(1)
> +
> +#define	ADUX1020_FORCE_CLOCK_ON		0x0f4f
> +#define	ADUX1020_FORCE_CLOCK_RESET	0x0040
> +#define ADUX1020_ACTIVE_4_STATE		0x0008
> +
> +#define ADUX1020_PROX_FREQ_MASK		GENMASK(7, 4)
> +#define ADUX1020_PROX_FREQ_SHIFT	4
> +
> +#define ADUX1020_LED_CURRENT_MASK	GENMASK(3, 0)
> +#define ADUX1020_LED_PIREF_EN		BIT(12)
> +
> +/* Operating modes */
> +enum adux1020_op_modes {
> +	ADUX1020_MODE_STANDBY,
> +	ADUX1020_MODE_PROX_I,
> +	ADUX1020_MODE_PROX_XY,
> +	ADUX1020_MODE_GEST,
> +	ADUX1020_MODE_SAMPLE,
> +	ADUX1020_MODE_FORCE = 0x0e,
> +	ADUX1020_MODE_IDLE = 0x0f,
> +};
> +
> +struct adux1020_data {
> +	struct i2c_client *client;
> +	struct iio_dev *indio_dev;
> +	struct mutex lock;
> +	struct regmap *regmap;
> +};
> +
> +struct adux1020_mode_data {
> +	u8 bytes;
> +	u8 buf_len;
> +	u16 int_en;
> +};
> +
> +static const struct adux1020_mode_data adux1020_modes[] = {
> +	[ADUX1020_MODE_PROX_I] = {
> +		.bytes = 2,
> +		.buf_len = 1,
> +		.int_en = ADUX1020_PROX_INT_ENABLE,
> +	},
> +};
> +
> +static const struct regmap_config adux1020_regmap_config = {
> +	.name = ADUX1020_REGMAP_NAME,
> +	.reg_bits = 8,
> +	.val_bits = 16,
> +	.max_register = 0x6F,
> +	.cache_type = REGCACHE_NONE,
> +};
> +
> +static const int adux1020_def_conf[][2] = {
> +	{ 0x000c, 0x000f },
> +	{ 0x0010, 0x1010 },
> +	{ 0x0011, 0x004c },
> +	{ 0x0012, 0x5f0c },
> +	{ 0x0013, 0xada5 },
> +	{ 0x0014, 0x0080 },
> +	{ 0x0015, 0x0000 },
> +	{ 0x0016, 0x0600 },
> +	{ 0x0017, 0x0000 },
> +	{ 0x0018, 0x2693 },
> +	{ 0x0019, 0x0004 },
> +	{ 0x001a, 0x4280 },
> +	{ 0x001b, 0x0060 },
> +	{ 0x001c, 0x2094 },
> +	{ 0x001d, 0x0020 },
> +	{ 0x001e, 0x0001 },
> +	{ 0x001f, 0x0100 },
> +	{ 0x0020, 0x0320 },
> +	{ 0x0021, 0x0A13 },
> +	{ 0x0022, 0x0320 },
> +	{ 0x0023, 0x0113 },
> +	{ 0x0024, 0x0000 },
> +	{ 0x0025, 0x2412 },
> +	{ 0x0026, 0x2412 },
> +	{ 0x0027, 0x0022 },
> +	{ 0x0028, 0x0000 },
> +	{ 0x0029, 0x0300 },
> +	{ 0x002a, 0x0700 },
> +	{ 0x002b, 0x0600 },
> +	{ 0x002c, 0x6000 },
> +	{ 0x002d, 0x4000 },
> +	{ 0x002e, 0x0000 },
> +	{ 0x002f, 0x0000 },
> +	{ 0x0030, 0x0000 },
> +	{ 0x0031, 0x0000 },
> +	{ 0x0032, 0x0040 },
> +	{ 0x0033, 0x0008 },
> +	{ 0x0034, 0xE400 },
> +	{ 0x0038, 0x8080 },
> +	{ 0x0039, 0x8080 },
> +	{ 0x003a, 0x2000 },
> +	{ 0x003b, 0x1f00 },
> +	{ 0x003c, 0x2000 },
> +	{ 0x003d, 0x2000 },
> +	{ 0x003e, 0x0000 },
> +	{ 0x0040, 0x8069 },
> +	{ 0x0041, 0x1f2f },
> +	{ 0x0042, 0x4000 },
> +	{ 0x0043, 0x0000 },
> +	{ 0x0044, 0x0008 },
> +	{ 0x0046, 0x0000 },
> +	{ 0x0048, 0x00ef },
> +	{ 0x0049, 0x0000 },
> +	{ 0x0045, 0x0000 },
> +};
> +
> +static const int adux1020_rate[][2] = {
> +	{ 0, 100000 },
> +	{ 0, 200000 },
> +	{ 0, 500000 },
> +	{ 1, 0 },
> +	{ 2, 0 },
> +	{ 5, 0 },
> +	{ 10, 0 },
> +	{ 20, 0 },
> +	{ 50, 0 },
> +	{ 100, 0 },
> +	{ 190, 0 },
> +	{ 450, 0 },
> +	{ 820, 0 },
> +	{ 1400, 0 },
> +};
> +
> +static const int adux1020_led_current[][2] = {
> +	{ 0, 25000 },
> +	{ 0, 40000 },
> +	{ 0, 55000 },
> +	{ 0, 70000 },
> +	{ 0, 85000 },
> +	{ 0, 100000 },
> +	{ 0, 115000 },
> +	{ 0, 130000 },
> +	{ 0, 145000 },
> +	{ 0, 160000 },
> +	{ 0, 175000 },
> +	{ 0, 190000 },
> +	{ 0, 205000 },
> +	{ 0, 220000 },
> +	{ 0, 235000 },
> +	{ 0, 250000 },
> +};
> +
> +static void adux1020_flush_fifo(struct adux1020_data *data)
> +{
> +	/* Force Idle mode */
> +	regmap_write(data->regmap, ADUX1020_REG_FORCE_MODE,
> +		     ADUX1020_ACTIVE_4_STATE);
> +	regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> +			   ADUX1020_OP_MODE_MASK, ADUX1020_MODE_FORCE);
> +	regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> +			   ADUX1020_OP_MODE_MASK, ADUX1020_MODE_IDLE);
> +
> +	/* Flush FIFO */
> +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> +		     ADUX1020_FORCE_CLOCK_ON);
> +	regmap_write(data->regmap, ADUX1020_REG_INT_STATUS,
> +		     ADUX1020_FIFO_FLUSH);
> +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> +		     ADUX1020_FORCE_CLOCK_RESET);
> +}
> +
> +static int adux1020_read_fifo(struct adux1020_data *data, u16 *buf, u8 buf_len)
> +{
> +	int i, ret = -EINVAL;
> +	unsigned int regval;
> +
> +	/* Enable 32MHz clock */
> +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> +		     ADUX1020_FORCE_CLOCK_ON);
> +
> +	for (i = 0; i < buf_len; i++) {
> +		ret = regmap_read(data->regmap, ADUX1020_REG_DATA_BUFFER,
> +				      &regval);
> +		if (ret < 0)
> +			goto err_out;
> +
> +		buf[i] = regval;
> +	}
> +
> +	/* Set 32MHz clock to be controlled by internal state machine */
> +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> +		     ADUX1020_FORCE_CLOCK_RESET);
> +
> +err_out:
> +	return ret;
> +}
> +
> +static void adux1020_set_mode(struct adux1020_data *data,
> +			      enum adux1020_op_modes mode)
> +{
> +	/* Switch to standby mode before changing the mode */
> +	regmap_write(data->regmap, ADUX1020_REG_OP_MODE, ADUX1020_MODE_STANDBY);
> +
> +	/* Set data out and switch to the desired mode */
> +	if (mode == ADUX1020_MODE_PROX_I) {
> +		regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> +			ADUX1020_DATA_OUT_MODE_MASK,
> +			ADUX1020_MODE_OUT_PROX_I << ADUX1020_MODE_OUT_SHIFT);
> +		regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> +			ADUX1020_OP_MODE_MASK, ADUX1020_MODE_PROX_I);
> +	}
> +}
> +
> +static int adux1020_measure(struct adux1020_data *data,
> +			    enum adux1020_op_modes mode,
> +			    u16 *val)
> +{
> +	int ret, tries = 50;
> +	unsigned int status;
> +
> +	mutex_lock(&data->lock);
> +
> +	/* Disable INT pin as polling is going to be used */
> +	regmap_write(data->regmap, ADUX1020_REG_INT_ENABLE,
> +		     ADUX1020_INT_DISABLE);
Error checking.
> +
> +	/* Enable mode interrupt */
> +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> +			   ADUX1020_MODE_INT_MASK,
> +			   adux1020_modes[mode].int_en);
> +
> +	while (tries--) {
> +		ret = regmap_read(data->regmap, ADUX1020_REG_INT_STATUS,
> +				  &status);
> +		if (ret < 0)
> +			goto fail;
> +
> +		status &= ADUX1020_FIFO_STATUS_MASK;
> +		if (status >= adux1020_modes[mode].bytes)
> +			break;
> +		msleep(20);
> +	}
> +
> +	if (tries < 0) {
> +		ret = -EIO;
> +		goto fail;
> +	}
> +
> +	ret = adux1020_read_fifo(data, val, adux1020_modes[mode].buf_len);
> +	if (ret < 0)
> +		goto fail;
> +
> +	/* Clear mode interrupt */
> +	regmap_write(data->regmap, ADUX1020_REG_INT_STATUS,
> +			   (~adux1020_modes[mode].int_en));
> +	/* Disable mode interrupts */
> +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> +			   ADUX1020_MODE_INT_MASK, ADUX1020_MODE_INT_DISABLE);
> +
> +fail:
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
> +static int adux1020_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct adux1020_data *data = iio_priv(indio_dev);
> +	u16 buf[3];
> +	int ret = -EINVAL;
> +	unsigned int regval;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->type) {
> +		case IIO_PROXIMITY:
> +			adux1020_set_mode(data, ADUX1020_MODE_PROX_I);
> +			ret = adux1020_measure(data, ADUX1020_MODE_PROX_I, buf);
> +			if (ret < 0)
> +				return ret;
> +
> +			*val = buf[0];
> +			ret = IIO_VAL_INT;
			return IIO_VAL_INT;
> +			break;
> +		default:
			return -EINVAL;
> +			break;
> +		}
> +		break;
> +	case IIO_CHAN_INFO_PROCESSED:
> +		switch (chan->type) {
> +		case IIO_CURRENT:
> +			ret = regmap_read(data->regmap,
> +					  ADUX1020_REG_LED_CURRENT, &regval);
> +			if (ret < 0)
> +				return ret;
> +
> +			regval = regval & ADUX1020_LED_CURRENT_MASK;
> +
> +			*val = adux1020_led_current[regval][0];
> +			*val2 = adux1020_led_current[regval][1];
> +
> +			ret = IIO_VAL_INT_PLUS_MICRO;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		switch (chan->type) {
> +		case IIO_PROXIMITY:
> +			ret = regmap_read(data->regmap, ADUX1020_REG_FREQUENCY,
> +					  &regval);
> +			if (ret < 0)
> +				return ret;
> +
> +			regval = (regval & ADUX1020_PROX_FREQ_MASK) >>
> +				  ADUX1020_PROX_FREQ_SHIFT;
> +
> +			*val = adux1020_rate[regval][0];
> +			*val2 = adux1020_rate[regval][1];
> +
> +			ret = IIO_VAL_INT_PLUS_MICRO;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return ret;
> +};
> +
> +static int adux1020_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int val, int val2, long mask)
> +{
> +	struct adux1020_data *data = iio_priv(indio_dev);
> +	int i, ret = -EINVAL;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		if (chan->type == IIO_PROXIMITY) {
Indent is very deep. I would suggest flipping conditions a bit.

		if (chan->type != IIO_PROXIMITY)
			return -EINVAL;

		for (i = 0; i < ARRAY_SIZE(adux1020_rate); i++) {
			if ((val != adux1020_rate[i][0]) ||
		            (val2 != adux1020_rate[i][1]))
				continue;
			return regmap_update_bits(data->regmap,
						  ADUX1020_REG_FREQUENCY,
						  ADUX1020_PROX_FREQ_MASK,
						  i << ADUX1020_PROX_FREQ_SHIFT);

		}
		return -EINVAL;	

> +			for (i = 0; i < ARRAY_SIZE(adux1020_rate); i++) {
> +				if ((val == adux1020_rate[i][0]) &&
> +				     (val2 == adux1020_rate[i][1])) {
> +					ret = regmap_update_bits(data->regmap,
> +						ADUX1020_REG_FREQUENCY,
> +						ADUX1020_PROX_FREQ_MASK,
> +						i << ADUX1020_PROX_FREQ_SHIFT);
> +				}
> +			}
> +		}
> +		break;

direct return preferred if there is no cleanup to be done (like here).

> +	case IIO_CHAN_INFO_PROCESSED:
> +		if (chan->type == IIO_CURRENT) {
> +			for (i = 0; i < ARRAY_SIZE(adux1020_led_current); i++) {
> +				if ((val == adux1020_led_current[i][0]) &&
> +				     (val2 == adux1020_led_current[i][1])) {
> +					ret = regmap_update_bits(data->regmap,
> +						ADUX1020_REG_LED_CURRENT,
> +						ADUX1020_LED_CURRENT_MASK, i);
> +				}
> +			}
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static int adux1020_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 adux1020_data *data = iio_priv(indio_dev);
> +
> +	regmap_write(data->regmap, ADUX1020_REG_INT_ENABLE,
> +		     ADUX1020_INT_ENABLE);

Check returns from regmap everywhere.  I've had far too many dodgy
i2c buses in the past to assume they will always work!

> +
> +	regmap_write(data->regmap, ADUX1020_REG_INT_POLARITY, 0);
> +
> +	switch (chan->type) {
> +	case IIO_PROXIMITY:
> +		if (dir == IIO_EV_DIR_RISING) {
> +			regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> +					   ADUX1020_PROX_ON1_INT,
> +					   state ? 0 : ADUX1020_PROX_ON1_INT);
> +		} else {
> +			regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> +					   ADUX1020_PROX_OFF1_INT,
> +					   state ? 0 : ADUX1020_PROX_OFF1_INT);
> +		}
> +
> +		/*
> +		 * Trigger proximity interrupt when the intensity is above
> +		 * or below threshold
> +		 */
> +		regmap_update_bits(data->regmap, ADUX1020_REG_PROX_TYPE,
> +				   ADUX1020_PROX_TYPE, ADUX1020_PROX_TYPE);
> +
> +		/* Set proximity mode */
> +		adux1020_set_mode(data, ADUX1020_MODE_PROX_I);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int adux1020_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 adux1020_data *data = iio_priv(indio_dev);
> +	int ret, mask;
> +	unsigned int regval;
> +
> +	switch (chan->type) {
> +	case IIO_PROXIMITY:
> +		if (dir == IIO_EV_DIR_RISING)
> +			mask = ADUX1020_PROX_ON1_INT;
> +		else
> +			mask = ADUX1020_PROX_OFF1_INT;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_read(data->regmap, ADUX1020_REG_INT_MASK, &regval);
> +	if (ret < 0)
> +		return ret;
> +
> +	return !(regval & mask);
> +}
> +
> +static int adux1020_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 adux1020_data *data = iio_priv(indio_dev);
> +	u8 reg;
> +	int ret;
> +	unsigned int regval;
> +
> +	switch (chan->type) {
> +	case IIO_PROXIMITY:
> +		if (dir == IIO_EV_DIR_RISING)
> +			reg = ADUX1020_REG_PROX_TH_ON1;
> +		else
> +			reg = ADUX1020_REG_PROX_TH_OFF1;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_read(data->regmap, reg, &regval);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = regval;
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static int adux1020_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 adux1020_data *data = iio_priv(indio_dev);
> +	u8 reg;
> +
> +	switch (chan->type) {
> +	case IIO_PROXIMITY:
> +		if (dir == IIO_EV_DIR_RISING)
> +			reg = ADUX1020_REG_PROX_TH_ON1;
> +		else
> +			reg = ADUX1020_REG_PROX_TH_OFF1;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	/* Full scale threshold value is 0-65535  */
> +	if (val < 0 || val > 65535)
> +		return -EINVAL;
> +
> +	return regmap_write(data->regmap, reg, val);
> +}
> +
> +static const struct iio_event_spec adux1020_proximity_event[] = {
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_RISING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_ENABLE),
> +	},
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_FALLING,
> +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> +			BIT(IIO_EV_INFO_ENABLE),
> +	},
> +};
> +
> +static const struct iio_chan_spec adux1020_channels[] = {
> +	{
> +		.type = IIO_PROXIMITY,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SAMP_FREQ),
> +		.event_spec = adux1020_proximity_event,
> +		.num_event_specs = ARRAY_SIZE(adux1020_proximity_event),
> +	},
> +	{
> +		.type = IIO_CURRENT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> +		.extend_name = "led",

out channel?

> +	},
> +};
> +
> +static IIO_CONST_ATTR(sampling_frequency_available,
> +		      "0.1 0.2 0.5 1 2 5 10 20 50 100 190 450 820 1400");
> +
> +static struct attribute *adux1020_attributes[] = {
> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group adux1020_attribute_group = {
> +	.attrs = adux1020_attributes,
> +};
> +
> +static const struct iio_info adux1020_info = {
> +	.attrs = &adux1020_attribute_group,
> +	.read_raw = adux1020_read_raw,
> +	.write_raw = adux1020_write_raw,
> +	.read_event_config = adux1020_read_event_config,
> +	.write_event_config = adux1020_write_event_config,
> +	.read_event_value = adux1020_read_thresh,
> +	.write_event_value = adux1020_write_thresh,
> +};
> +
> +static irqreturn_t adux1020_interrupt_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct adux1020_data *data = iio_priv(indio_dev);
> +	int ret, status;
> +
> +	ret = regmap_read(data->regmap, ADUX1020_REG_INT_STATUS, &status);
> +	if (ret < 0)

interrupt handlers have to return an irqreturn_t, so you can't just
return random error codes.

> +		return ret;
> +
> +	status &= ADUX1020_MODE_INT_STATUS_MASK;
> +
> +	if (status & ADUX1020_INT_PROX_ON1) {
> +		iio_push_event(indio_dev,
> +				IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
> +					IIO_EV_TYPE_THRESH,
> +					IIO_EV_DIR_RISING),
> +				iio_get_time_ns(indio_dev));
> +	}
> +
> +	if (status & ADUX1020_INT_PROX_OFF1) {
> +		iio_push_event(indio_dev,
> +				IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
> +					IIO_EV_TYPE_THRESH,
> +					IIO_EV_DIR_FALLING),
> +				iio_get_time_ns(indio_dev));
> +	}
> +
> +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_STATUS,
> +			   ADUX1020_MODE_INT_MASK, status);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int adux1020_chip_init(struct adux1020_data *data)
> +{
> +	struct i2c_client *client = data->client;
> +	int ret, i;
> +	unsigned int val;
> +
> +	ret = regmap_read(data->regmap, ADUX1020_REG_CHIP_ID, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	val &= ADUX1020_CHIP_ID_MASK;
> +
> +	if (val != ADUX1020_CHIP_ID) {
as val is only used here,

	if (val & ADUX1020_CHIP_ID_MASK != ADUX1020_CHIP_ID) {

Saves a bit of code and isn't significantly harder to read.

> +		dev_err(&client->dev, "invalid chip id 0x%04x\n", val);
> +		return -ENODEV;
> +	};
> +
> +	dev_dbg(&client->dev, "Detected ADUX1020 with chip id: 0x%04x\n", val);
> +
> +	/* Perform software reset */

Try to avoid comments where the code is fairly self explanatory.
They are just potential places to diverge from reality in the future ;)

> +	regmap_update_bits(data->regmap, ADUX1020_REG_SW_RESET,
> +			   ADUX1020_SW_RESET, ADUX1020_SW_RESET);

This is i2c so not exactly 100% reliable (depends on good board
design etc).  Hence I'd add error checking for all these reads and
writes.

> +
> +	/* Load default configuration */
> +	for (i = 0; i < ARRAY_SIZE(adux1020_def_conf); i++)
> +		regmap_write(data->regmap, adux1020_def_conf[i][0],
> +			     adux1020_def_conf[i][1]);
> +
> +	adux1020_flush_fifo(data);
> +
> +	/* Use LED_IREF for proximity mode */
> +	regmap_update_bits(data->regmap, ADUX1020_REG_LED_CURRENT,
> +			   ADUX1020_LED_PIREF_EN, 0);
> +
> +	/* Mask all interrupts */
> +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> +			   ADUX1020_MODE_INT_MASK, ADUX1020_MODE_INT_DISABLE);
> +
> +	return 0;
> +}
> +
> +static int adux1020_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct adux1020_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->dev.parent = &client->dev;
> +	indio_dev->info = &adux1020_info;
> +	indio_dev->name = ADUX1020_DRV_NAME;
> +	indio_dev->channels = adux1020_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(adux1020_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	data->regmap = devm_regmap_init_i2c(client, &adux1020_regmap_config);
> +	if (IS_ERR(data->regmap)) {
> +		dev_err(&client->dev, "regmap initialization failed.\n");
> +		return PTR_ERR(data->regmap);
> +	}
> +
> +	data->client = client;
> +	data->indio_dev = indio_dev;
> +	mutex_init(&data->lock);
> +
> +	ret = adux1020_chip_init(data);
> +	if (ret)

		return ret;

> +		goto err_out;
> +
> +	if (client->irq) {
> +		ret = devm_request_threaded_irq(&client->dev, client->irq,
> +				NULL, adux1020_interrupt_handler,
> +				IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> +				ADUX1020_DRV_NAME, indio_dev);
> +		if (ret) {
> +			dev_err(&client->dev, "irq request error %d\n", -ret);
> +			goto err_out;

Direct returns are preferred in kernel code as they are generally easier
to review.  No need to check the error handling if we immediately know
there isn't any to be done!

			return ret;
> +		}
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to register IIO device\n");
> +		goto err_out;

This error path does no error handling so you can return directly here.
		return ret;

But... Then there is no point in having the return here as you might
as well drop it out of the brackets and replace the return 0 below with
return ret;

> +	}
> +
> +	return 0;
> +
> +err_out:
> +	return ret;
> +}
> +
> +static int adux1020_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +
> +	iio_device_unregister(indio_dev);
If we have a remove with only iio_device_unregister it normally
implies we could have used devm_iio_device_register and allowed
the automatic unwinding to do it for us.

Make that change and you shouldn't need a remove function at all.
In turn, there is no reason to then call i2c_set_clientdata()

> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id adux1020_id[] = {
> +	{ "adux1020", 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, adux1020_id);
> +
> +static const struct of_device_id adux1020_of_match[] = {
> +	{ .compatible = "adi,adux1020" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, adux1020_of_match);
> +
> +static struct i2c_driver adux1020_driver = {
> +	.driver = {
> +		.name	= ADUX1020_DRV_NAME,
> +		.of_match_table = adux1020_of_match,
> +	},
> +	.probe		= adux1020_probe,
> +	.remove		= adux1020_remove,
> +	.id_table	= adux1020_id,
> +};
> +module_i2c_driver(adux1020_driver);
> +
> +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>");
> +MODULE_DESCRIPTION("ADUX1020 photometric sensor");
> +MODULE_LICENSE("GPL");

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