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

Peter Meerwald
2014-03-25T23:39:27Z

> 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@capellamicro.com>
> ---
> .../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@capellamicro.com>
> + *
> + * 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@linux.intel.com>
> + * 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@capellamicro.com>");
> +MODULE_DESCRIPTION("CM3218X ambient light sensor driver");
> +MODULE_LICENSE("GPL");