Re: [PATCH V3 1/1] iio: add Capella cm3218x ambient light sensor driver.

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> Add Capella Microsystem CM3218X family Ambient Light Sensor IIO driver.
> This driver will convert raw data to lux value.  Default parameters are
> for reference only.  It will detect ACPI table to load per-system manufacturing
> parameters.
> 
> V2: Follow Jonathan Cameron's advise to separate device id.
> Also, follow Peter Meerwald's advise to correct whitespace, prefix, and,
> comments.
> 
> V3: Follow Peter Meerwald's advise to create a separated i2c_client handler to
> access SMBus ARA register.

couple of minor comments...

> Signed-off-by: Kevin Tsai <ktsai@xxxxxxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/i2c/trivial-devices.txt    |   1 +
>  drivers/iio/light/Kconfig                          |  11 +
>  drivers/iio/light/Makefile                         |   1 +
>  drivers/iio/light/cm3218x.c                        | 745 +++++++++++++++++++++
>  4 files changed, 758 insertions(+)
>  create mode 100644 drivers/iio/light/cm3218x.c
> 
> diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> index 1a1ac2e..c3c869b 100644
> --- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> +++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
> @@ -17,6 +17,7 @@ at,24c08		i2c serial eeprom  (24cxx)
>  atmel,24c02		i2c serial eeprom  (24cxx)
>  atmel,at97sc3204t	i2c trusted platform module (TPM)
>  capella,cm32181		CM32181: Ambient Light Sensor
> +capella,cm3218x		CM3218X: Ambient Light Sensor
>  catalyst,24c32		i2c serial eeprom
>  dallas,ds1307		64 x 8, Serial, I2C Real-Time Clock
>  dallas,ds1338		I2C RTC with 56-Byte NV RAM
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index d12b2a0..97a341a 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -38,6 +38,17 @@ config CM32181
>  	 To compile this driver as a module, choose M here:
>  	 the module will be called cm32181.
>  
> +config CM3218X
> +	depends on I2C

depends on I2C && ACPI ???

> +	tristate "CM3218X driver"
> +	help
> +	 Say Y here if you use cm3218x.
> +	 This option enables ambient light sensor using
> +	 Capella cm3218x device driver.
> +
> +	 To compile this driver as a module, choose M here:
> +	 the module will be called cm3218x.
> +
>  config CM36651
>  	depends on I2C
>  	tristate "CM36651 driver"
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index 60e35ac..a506c23 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
>  obj-$(CONFIG_CM32181)		+= cm32181.o
> +obj-$(CONFIG_CM3218X)		+= cm3218x.o
>  obj-$(CONFIG_CM36651)		+= cm36651.o
>  obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
>  obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
> diff --git a/drivers/iio/light/cm3218x.c b/drivers/iio/light/cm3218x.c
> new file mode 100644
> index 0000000..efd0d0a
> --- /dev/null
> +++ b/drivers/iio/light/cm3218x.c
> @@ -0,0 +1,745 @@
> +/*
> + * Copyright (C) 2014 Capella Microsystems Inc.
> + * Author: Kevin Tsai <ktsai@xxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2, as published
> + * by the Free Software Foundation.
> + *
> + * Special thanks Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> + * help to add ACPI support.
> + *
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/events.h>
> +#include <linux/init.h>
> +#include <linux/acpi.h>
> +
> +/* Registers Address */
> +#define CM3218X_REG_ADDR_CMD 0x00
> +#define CM3218X_REG_ADDR_WH 0x01
> +#define CM3218X_REG_ADDR_WL 0x02
> +#define CM3218X_REG_ADDR_TEST 0x03
> +#define CM3218X_REG_ADDR_ALS 0x04
> +#define CM3218X_REG_ADDR_STATUS 0x06
> +#define CM3218X_REG_ADDR_ID 0x07
> +
> +/* Number of Configurable Registers */
> +#define CM3218X_CONF_REG_NUM 16
> +
> +/* CMD register */
> +#define CM3218X_CMD_ALS_DISABLE BIT(0)
> +#define CM3218X_CMD_ALS_INT_EN BIT(1)
> +#define CM3218X_CMD_ALS_THRES_WINDOW BIT(2)
> +
> +#define CM3218X_CMD_ALS_PERS_SHIFT 4
> +#define CM3218X_CMD_ALS_PERS_MASK (0x03 << CM3218X_CMD_ALS_PERS_SHIFT)
> +#define CM3218X_CMD_ALS_PERS_DEFAULT (0x01 << CM3218X_CMD_ALS_PERS_SHIFT)
> +
> +#define CM3218X_CMD_ALS_IT_SHIFT 6
> +#define CM3218X_CMD_ALS_IT_MASK (0x0F << CM3218X_CMD_ALS_IT_SHIFT)
> +#define CM3218X_CMD_ALS_IT_DEFAULT (0x01 << CM3218X_CMD_ALS_IT_SHIFT)
> +
> +#define CM3218X_CMD_ALS_HS_SHIFT 11
> +#define CM3218X_CMD_ALS_HS_MASK (0x01 << CM3218X_CMD_ALS_HS_SHIFT)
> +#define CM3218X_CMD_ALS_HS_DEFAULT (0x00 << CM3218X_CMD_ALS_HS_SHIFT)
> +
> +#define CM3218X_CMD_DEFAULT (CM3218X_CMD_ALS_THRES_WINDOW |\
> +		CM3218X_CMD_ALS_PERS_DEFAULT |\
> +		CM3218X_CMD_ALS_IT_DEFAULT |\
> +		CM3218X_CMD_ALS_HS_DEFAULT)
> +
> +#define CM3218X_WH_DEFAULT 0xFFFF
> +#define CM3218X_WL_DEFAULT 0x0000
> +
> +#define CM3218X_CALIBSCALE_DEFAULT 100000
> +#define CM3218X_CALIBSCALE_RESOLUTION 100000
> +#define CM3218X_MLUX_PER_LUX 1000
> +#define CM3218X_THRESHOLD_PERCENT 10	/* 10 percent */
> +
> +#define CM3218X_ARA 0x0C
> +
> +/* CM3218X family */
> +enum {
> +	cm3218,
> +	cm32181,
> +	cm32182
> +};
> +
> +/* CM3218 Family */
> +#define CM3218_MLUX_PER_BIT_DEFAULT 5	/* Depend on system */
> +#define CM3218_MLUX_PER_BIT_BASE_IT 800000
> +static const int CM3218_als_it_bits[] = {0, 1, 2, 3};
> +static const int CM3218_als_it_values[] = {100000, 200000, 400000, 800000};
> +
> +/* CM32181 Family */
> +#define CM32181_MLUX_PER_BIT_DEFAULT 5
> +#define CM32181_MLUX_PER_BIT_BASE_IT 800000
> +static const int CM32181_als_it_bits[] = {12, 8, 0, 1, 2, 3};
> +static const int CM32181_als_it_values[] = {
> +			25000, 50000, 100000, 200000, 400000, 800000};
> +
> +struct cm3218x_als_info {
> +	u32 id;
> +	int int_type;
> +#define CM3218X_INT_TYPE_SMBUS 0
> +#define CM3218X_INT_TYPE_I2C 1
> +	int regs_bmp;
> +	int calibscale;
> +	int mlux_per_bit;
> +	int mlux_per_bit_base_it;
> +	const int *als_it_bits;
> +	const int *als_it_values;
> +	int num_als_it;
> +	int als_raw;
> +};
> +
> +static struct cm3218x_als_info cm3218_info = {
> +	3218, CM3218X_INT_TYPE_SMBUS, 0x0F, CM3218X_CALIBSCALE_DEFAULT,
> +	CM3218_MLUX_PER_BIT_DEFAULT, CM3218_MLUX_PER_BIT_BASE_IT,
> +	CM3218_als_it_bits, CM3218_als_it_values,
> +	ARRAY_SIZE(CM3218_als_it_bits), 0};

const?

> +
> +static struct cm3218x_als_info cm32181_info = {
> +	32181, CM3218X_INT_TYPE_I2C, 0x0F, CM3218X_CALIBSCALE_DEFAULT,
> +	CM32181_MLUX_PER_BIT_DEFAULT, CM32181_MLUX_PER_BIT_BASE_IT,
> +	CM32181_als_it_bits, CM32181_als_it_values,
> +	ARRAY_SIZE(CM32181_als_it_bits), 0};
> +
> +static struct cm3218x_als_info cm32182_info = {
> +	32182, CM3218X_INT_TYPE_I2C, 0x0F, CM3218X_CALIBSCALE_DEFAULT,
> +	CM32181_MLUX_PER_BIT_DEFAULT, CM32181_MLUX_PER_BIT_BASE_IT,
> +	CM32181_als_it_bits, CM32181_als_it_values,
> +	ARRAY_SIZE(CM32181_als_it_bits), 0};
> +
> +struct cm3218x_chip {
> +	struct i2c_client *client;
> +	struct i2c_client *ara;
> +	struct mutex lock;
> +	u16 conf_regs[CM3218X_CONF_REG_NUM];
> +	struct cm3218x_als_info *als_info;
> +};
> +
> +static int cm3218x_get_lux(struct cm3218x_chip *chip);
> +static int cm3218x_threshold_update(struct cm3218x_chip *chip, int percent);
> +static int cm3218x_read_als_it(struct cm3218x_chip *chip, int *val2);
> +
> +/**
> + * cm3218x_interrupt_config() - Enable/Disable CM3218X interrupt
> + * @chip:	pointer of struct cm3218x.
> + * @enable:	0 to disable; otherwise to enable
> + *
> + * Config CM3218X interrupt control bit.
> + *
> + * Return: 0 for success; otherwise for error code.
> + */
> +static int cm3218x_interrupt_config(struct cm3218x_chip *chip, int enable)
> +{
> +	struct i2c_client *client = chip->client;
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	int status;
> +
> +	if (!als_info)
> +		return -ENODEV;
> +
> +	/* Force to clean interrupt */
> +	if (als_info->int_type == CM3218X_INT_TYPE_I2C) {
> +		status = i2c_smbus_read_word_data(client,
> +				CM3218X_REG_ADDR_STATUS);
> +		if (status < 0)
> +			als_info->int_type = CM3218X_INT_TYPE_SMBUS;
> +	}
> +	if (chip->ara && als_info->int_type == CM3218X_INT_TYPE_SMBUS)
> +		i2c_smbus_read_byte(chip->ara);
> +
> +	if (enable)
> +		chip->conf_regs[CM3218X_REG_ADDR_CMD] |=
> +			CM3218X_CMD_ALS_INT_EN;
> +	else
> +		chip->conf_regs[CM3218X_REG_ADDR_CMD] &=
> +			~CM3218X_CMD_ALS_INT_EN;
> +
> +	status = i2c_smbus_write_word_data(client, CM3218X_REG_ADDR_CMD,
> +		chip->conf_regs[CM3218X_REG_ADDR_CMD]);
> +
> +	if (status < 0)
> +		return -ENODEV;
> +
> +	return status;
> +}
> +
> +/**
> + * cm3218x_acpi_get_cpm_info() - Get CPM object from ACPI
> + * @client	pointer of struct i2c_client.
> + * @obj_name	pointer of ACPI object name.
> + * @count	maximum size of return array.
> + * @vals	pointer of array for return elements.
> + *
> + * Convert ACPI CPM table to array. Special thanks Srinivas Pandruvada's
> + * help to implement this routine.
> + *
> + * Return: -ENODEV for fail.  Otherwise is number of elements.
> + */
> +static int cm3218x_acpi_get_cpm_info(struct i2c_client *client, char *obj_name,
> +							int count, u64 *vals)
> +{
> +	acpi_handle handle;
> +	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
> +	int i;
> +	acpi_status status;
> +	union acpi_object *cpm;
> +
> +	handle = ACPI_HANDLE(&client->dev);
> +	if (!handle)
> +		return -ENODEV;
> +
> +	status = acpi_evaluate_object(handle, obj_name, NULL, &buffer);
> +	if (ACPI_FAILURE(status)) {
> +		dev_err(&client->dev, "object %s not found\n", obj_name);
> +		return -ENODEV;
> +	}
> +
> +	cpm = buffer.pointer;
> +	for (i = 0; i < cpm->package.count && i < count; ++i) {
> +		union acpi_object *elem;
> +		elem = &(cpm->package.elements[i]);
> +		vals[i] = elem->integer.value;
> +	}
> +
> +	kfree(buffer.pointer);
> +
> +	return cpm->package.count;
> +}
> +
> +/**
> + * cm3218x_reg_init() - Initialize CM3218X registers
> + * @chip:	pointer of struct cm3218x.
> + *
> + * Initialize CM3218X ambient light sensor register to default values.
> + *
> +  Return: 0 for success; otherwise for error code.
> + */
> +static int cm3218x_reg_init(struct cm3218x_chip *chip)
> +{
> +	struct i2c_client *client = chip->client;
> +	int i;
> +	s32 ret;
> +	int cpm_elem_count;
> +	u64 cpm_elems[20];
> +	struct cm3218x_als_info *als_info;
> +
> +	/* Default device */
> +	chip->als_info = &cm3218_info;
> +	chip->conf_regs[CM3218X_REG_ADDR_CMD] = CM3218X_CMD_DEFAULT;
> +	chip->conf_regs[CM3218X_REG_ADDR_WH] = CM3218X_WH_DEFAULT;
> +	chip->conf_regs[CM3218X_REG_ADDR_WL] = CM3218X_WL_DEFAULT;
> +
> +	/* Disable interrupt */
> +	cm3218x_interrupt_config(chip, 0);
> +
> +	/* Disable Test Mode */
> +	i2c_smbus_write_word_data(client, CM3218X_REG_ADDR_TEST, 0x0000);
> +
> +	/* Disable device */
> +	i2c_smbus_write_word_data(client, CM3218X_REG_ADDR_CMD,
> +		CM3218X_CMD_ALS_DISABLE);
> +
> +	/* Identify device */
> +	ret = i2c_smbus_read_word_data(client, CM3218X_REG_ADDR_ID);
> +	if (ret < 0)
> +		return ret;
> +	switch (ret & 0xFF) {
> +	case 0x18:
> +		als_info = chip->als_info = &cm3218_info;
> +		if (ret & 0x0800)
> +			als_info->int_type = CM3218X_INT_TYPE_I2C;
> +		else
> +			als_info->int_type = CM3218X_INT_TYPE_SMBUS;
> +		break;
> +	case 0x81:
> +		als_info = chip->als_info = &cm32181_info;
> +		break;
> +	case 0x82:
> +		als_info = chip->als_info = &cm32182_info;
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	if (ACPI_HANDLE(&client->dev)) {
> +		/* Load from ACPI */
> +		cpm_elem_count = cm3218x_acpi_get_cpm_info(client, "CPM0",
> +							ARRAY_SIZE(cpm_elems),
> +							cpm_elems);
> +		if (cpm_elem_count > 0) {
> +			int header_num = 3;
> +			int reg_num = cpm_elem_count - header_num;
> +
> +			als_info->regs_bmp = cpm_elems[2];
> +			for (i = 0; i < reg_num; i++)
> +				if (als_info->regs_bmp & (1<<i))
> +					chip->conf_regs[i] =
> +						cpm_elems[header_num+i];
> +		}
> +
> +		cpm_elem_count = cm3218x_acpi_get_cpm_info(client, "CPM1",
> +							ARRAY_SIZE(cpm_elems),
> +							cpm_elems);
> +		if (cpm_elem_count > 0) {
> +			als_info->mlux_per_bit = (int)cpm_elems[0] / 100;
> +			als_info->calibscale = (int)cpm_elems[1];
> +		}
> +	}
> +
> +	/* Force to disable interrupt */
> +	chip->conf_regs[CM3218X_REG_ADDR_CMD] &= ~CM3218X_CMD_ALS_INT_EN;
> +
> +	/* Initialize registers */
> +	for (i = 0; i < CM3218X_CONF_REG_NUM; i++) {
> +		if (als_info->regs_bmp & (1<<i)) {
> +			ret = i2c_smbus_write_word_data(client, i,
> +						chip->conf_regs[i]);
> +			if (ret < 0)
> +				return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + *  cm3218x_read_als_it() - Get sensor integration time (ms)
> + *  @chip:	pointer of struct cm3218x
> + *  @val2:	pointer of int to load the als_it value.
> + *
> + *  Report the current integartion time in milliseconds.

integration

> + *
> + *  Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL.
> + */
> +static int cm3218x_read_als_it(struct cm3218x_chip *chip, int *val2)
> +{
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	u16 als_it;
> +	int i;
> +
> +	als_it = chip->conf_regs[CM3218X_REG_ADDR_CMD];
> +	als_it &= CM3218X_CMD_ALS_IT_MASK;
> +	als_it >>= CM3218X_CMD_ALS_IT_SHIFT;
> +	for (i = 0; i < als_info->num_als_it; i++) {
> +		if (als_it == als_info->als_it_bits[i]) {
> +			*val2 = als_info->als_it_values[i];
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +/**
> + * cm3218x_write_als_it() - Write sensor integration time
> + * @chip:	pointer of struct cm3218x.
> + * @val:	integration time in milliseconds.
> + *
> + * Convert integration time (ms) to sensor value.
> + *
> + * Return: i2c_smbus_write_word_data command return value.
> + */
> +static int cm3218x_write_als_it(struct cm3218x_chip *chip, int val)
> +{
> +	struct i2c_client *client = chip->client;
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	u16 als_it;
> +	int ret, i;
> +
> +	for (i = 0; i < als_info->num_als_it; i++)
> +		if (val <= als_info->als_it_values[i])
> +			break;
> +	if (i >= als_info->num_als_it)
> +		i = als_info->num_als_it - 1;
> +
> +	als_it = als_info->als_it_bits[i];
> +	als_it <<= CM3218X_CMD_ALS_IT_SHIFT;
> +
> +	mutex_lock(&chip->lock);
> +	chip->conf_regs[CM3218X_REG_ADDR_CMD] &=
> +			~CM3218X_CMD_ALS_IT_MASK;
> +	chip->conf_regs[CM3218X_REG_ADDR_CMD] |=
> +			als_it;
> +	ret = i2c_smbus_write_word_data(client, CM3218X_REG_ADDR_CMD,
> +			chip->conf_regs[CM3218X_REG_ADDR_CMD]);
> +	mutex_unlock(&chip->lock);
> +
> +	return ret;
> +}
> +
> +/**
> + * cm3218x_get_lux() - report current lux value
> + * @chip:	pointer of struct cm3218x.
> + *
> + * Convert sensor raw data to lux.  It depends on integration
> + * time and calibscale variable.
> + *
> + * Return: Positive value is lux, otherwise is error code.
> + */
> +static int cm3218x_get_lux(struct cm3218x_chip *chip)
> +{
> +	struct i2c_client *client = chip->client;
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	int ret;
> +	int als_it;
> +	u64 tmp;
> +
> +	/* Calculate mlux per bit based on als_it */
> +	ret = cm3218x_read_als_it(chip, &als_it);
> +	if (ret < 0)
> +		return -EINVAL;
> +	tmp = (__force u64)als_info->mlux_per_bit;
> +	tmp *= als_info->mlux_per_bit_base_it;
> +	tmp = div_u64(tmp, als_it);
> +
> +	/* Get als_raw */
> +	if (!(chip->conf_regs[CM3218X_REG_ADDR_CMD] & CM3218X_CMD_ALS_INT_EN))
> +		als_info->als_raw = i2c_smbus_read_word_data(
> +					client,
> +					CM3218X_REG_ADDR_ALS);
> +	if (als_info->als_raw < 0)
> +		return als_info->als_raw;
> +
> +	tmp *= als_info->als_raw;
> +	tmp *= als_info->calibscale;
> +	tmp = div_u64(tmp, CM3218X_CALIBSCALE_RESOLUTION);
> +	tmp = div_u64(tmp, CM3218X_MLUX_PER_LUX);
> +
> +	if (tmp > 0xFFFF)
> +		tmp = 0xFFFF;
> +
> +	return (int)tmp;
> +}
> +
> +static int cm3218x_read_raw(struct iio_dev *indio_dev,
> +			struct iio_chan_spec const *chan,
> +			int *val, int *val2, long mask)
> +{
> +	struct cm3218x_chip *chip = iio_priv(indio_dev);
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_PROCESSED:
> +		ret = cm3218x_get_lux(chip);
> +		if (ret < 0)
> +			return ret;
> +		*val = ret;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_CALIBSCALE:
> +		*val = als_info->calibscale;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_INT_TIME:
> +		*val = 0;
> +		ret = cm3218x_read_als_it(chip, val2);
> +		return ret;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int cm3218x_write_raw(struct iio_dev *indio_dev,
> +			struct iio_chan_spec const *chan,
> +			int val, int val2, long mask)
> +{
> +	struct cm3218x_chip *chip = iio_priv(indio_dev);
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	long ms;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_CALIBSCALE:
> +		als_info->calibscale = val;
> +		return val;
> +	case IIO_CHAN_INFO_INT_TIME:
> +		ms = val * 1000000 + val2;
> +		return cm3218x_write_als_it(chip, (int)ms);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +/**
> + * cm3218x_get_it_available() - Get available ALS IT value
> + * @dev:	pointer of struct device.
> + * @attr:	pointer of struct device_attribute.
> + * @buf:	pointer of return string buffer.
> + *
> + * Display the available integration time in milliseconds.
> + *
> + * Return: string length.
> + */
> +static ssize_t cm3218x_get_it_available(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct cm3218x_chip *chip = iio_priv(dev_to_iio_dev(dev));
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	int i, len;
> +
> +	for (i = 0, len = 0; i < als_info->num_als_it; i++)
> +		len += scnprintf(buf + len, PAGE_SIZE - len, "%u.%06u ",
> +			als_info->als_it_values[i]/1000000,
> +			als_info->als_it_values[i]%1000000);
> +	return len + scnprintf(buf + len, PAGE_SIZE - len, "\n");
> +}
> +
> +/**
> + * cm3218x_threshold_update() - Update the threshold registers.
> + * @chip:	pointer of struct cm3218x_chip.
> + * @percent:	+/- percent.
> + *
> + * Based on the current ALS value, tupdate the hi and low threshold registers.

tupdate?

> + *
> + * Return: 0 for success; otherwise for error code.
> + */
> +static int cm3218x_threshold_update(struct cm3218x_chip *chip, int percent)
> +{
> +	struct i2c_client *client = chip->client;
> +	struct cm3218x_als_info *als_info = chip->als_info;
> +	int ret;
> +	int wh, wl;
> +
> +	ret = als_info->als_raw = i2c_smbus_read_word_data(client,
> +					CM3218X_REG_ADDR_ALS);
> +	if (ret < 0)
> +		return ret;
> +
> +	wh = wl = ret;
> +	ret *= percent;
> +	ret /= 100;
> +	if (ret < 1)
> +		ret = 1;
> +	wh += ret;
> +	wl -= ret;
> +	if (wh > 65535)
> +		wh = 65535;
> +	if (wl < 0)
> +		wl = 0;
> +
> +	chip->conf_regs[CM3218X_REG_ADDR_WH] = wh;
> +	ret = i2c_smbus_write_word_data(
> +		client,
> +		CM3218X_REG_ADDR_WH,
> +		chip->conf_regs[CM3218X_REG_ADDR_WH]);
> +	if (ret < 0)
> +		return ret;
> +
> +	chip->conf_regs[CM3218X_REG_ADDR_WL] = wl;
> +	ret = i2c_smbus_write_word_data(
> +		client,
> +		CM3218X_REG_ADDR_WL,
> +		chip->conf_regs[CM3218X_REG_ADDR_WL]);
> +
> +	return ret;
> +}
> +
> +/**
> + * cm3218x_event_handler() - Interrupt handling routine.
> + * @irq:	irq number.
> + * @private:	pointer of void.
> + *
> + * Clean interrupt and reset threshold registers.
> + *
> + * Return: IRQ_HANDLED.
> + */
> +static irqreturn_t cm3218x_event_handler(int irq, void *private)
> +{
> +	struct iio_dev *dev_info = private;
> +	struct cm3218x_chip *chip = iio_priv(dev_info);
> +	int ret;
> +
> +	mutex_lock(&chip->lock);
> +
> +	/* Disable interrupt */
> +	ret = cm3218x_interrupt_config(chip, 0);
> +	if (ret < 0)
> +		goto error_handler_unlock;
> +
> +	/* Update Hi/Lo windows */
> +	ret = cm3218x_threshold_update(chip, CM3218X_THRESHOLD_PERCENT);
> +	if (ret < 0)
> +		goto error_handler_unlock;
> +
> +	/* Enable interrupt */
> +	ret = cm3218x_interrupt_config(chip, 1);

no need to check ret value

> +	if (ret < 0)
> +		goto error_handler_unlock;
> +
> +error_handler_unlock:
> +	mutex_unlock(&chip->lock);
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct iio_chan_spec cm3218x_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.info_mask_separate =
> +			BIT(IIO_CHAN_INFO_PROCESSED) |
> +			BIT(IIO_CHAN_INFO_CALIBSCALE) |
> +			BIT(IIO_CHAN_INFO_INT_TIME),
> +	}
> +};
> +
> +static IIO_DEVICE_ATTR(in_illuminance_integration_time_available,
> +			S_IRUGO, cm3218x_get_it_available, NULL, 0);
> +
> +static struct attribute *cm3218x_attributes[] = {
> +	&iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group cm3218x_attribute_group = {
> +	.attrs = cm3218x_attributes
> +};
> +
> +static const struct iio_info cm3218x_info = {
> +	.driver_module		= THIS_MODULE,
> +	.read_raw		= &cm3218x_read_raw,
> +	.write_raw		= &cm3218x_write_raw,
> +	.attrs			= &cm3218x_attribute_group,
> +};
> +
> +static int cm3218x_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct cm3218x_chip *chip;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
> +	if (!indio_dev) {
> +		dev_err(&client->dev, "devm_iio_device_alloc failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	chip = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	chip->client = client;
> +	chip->ara = i2c_new_dummy(client->adapter, CM3218X_ARA);
> +

there is no i2c_unregister_device(chip->ara) in the error path below; but 
i2c_unregister_device(chip->ara) is called in _remove()

> +	mutex_init(&chip->lock);
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->channels = cm3218x_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(cm3218x_channels);
> +	indio_dev->info = &cm3218x_info;
> +	if (id && id->name)
> +		indio_dev->name = id->name;
> +	else
> +		indio_dev->name = (char *)dev_name(&client->dev);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = cm3218x_reg_init(chip);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"%s: register init failed\n",
> +			__func__);
> +		return ret;
> +	}
> +
> +	if (client->irq) {
> +		ret = request_threaded_irq(client->irq,
> +					NULL,
> +					cm3218x_event_handler,
> +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +					"cm3218x_event",
> +					indio_dev);
> +
> +		if (ret < 0) {
> +			dev_err(&client->dev, "irq request error %d\n",
> +				-ret);
> +			goto error_disable_int;
> +		}
> +	}
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&client->dev,
> +			"%s: regist device failed\n",
> +			__func__);
> +		goto error_free_irq;
> +	}
> +
> +	if (client->irq) {
> +		ret = cm3218x_threshold_update(chip, CM3218X_THRESHOLD_PERCENT);
> +		if (ret < 0)
> +			goto error_free_irq;
> +
> +		ret = cm3218x_interrupt_config(chip, 1);
> +		if (ret < 0)
> +			goto error_free_irq;
> +	}
> +
> +	return 0;
> +
> +error_free_irq:
> +	free_irq(client->irq, indio_dev);

in _remove() free_irq() is only called when client->irq != 0

> +error_disable_int:
> +	cm3218x_interrupt_config(chip, 0);
> +	return ret;
> +}
> +
> +static int cm3218x_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct cm3218x_chip *chip = iio_priv(indio_dev);
> +
> +	cm3218x_interrupt_config(chip, 0);
> +	if (chip->ara)
> +		i2c_unregister_device(chip->ara);
> +	if (client->irq)
> +		free_irq(client->irq, indio_dev);
> +	iio_device_unregister(indio_dev);
> +	return 0;
> +}
> +
> +static const struct i2c_device_id cm3218x_id[] = {
> +	{ "cm3218", cm3218},
> +	{ "cm32181", cm32181},
> +	{ "cm32182", cm32182},
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, cm3218x_id);
> +
> +static const struct of_device_id cm3218x_of_match[] = {
> +	{ .compatible = "capella,cm3218" },
> +	{ }
> +};
> +
> +static const struct acpi_device_id cm3218x_acpi_match[] = {
> +	{ "CPLM3218", 0},
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, cm3218x_acpi_match);
> +
> +static struct i2c_driver cm3218x_driver = {
> +	.driver = {
> +		.name	= "cm3218x",
> +		.acpi_match_table = ACPI_PTR(cm3218x_acpi_match),
> +		.of_match_table = of_match_ptr(cm3218x_of_match),
> +		.owner	= THIS_MODULE,
> +	},
> +	.id_table	= cm3218x_id,
> +	.probe		= cm3218x_probe,
> +	.remove		= cm3218x_remove,
> +};
> +
> +module_i2c_driver(cm3218x_driver);
> +
> +MODULE_AUTHOR("Kevin Tsai <ktsai@xxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("CM3218X ambient light sensor driver");
> +MODULE_LICENSE("GPL");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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