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SubjectRe: [PATCH v4] iio: Add Dyna-Image AL3320A ambient light sensor driver
From
On Mon, Sep 1, 2014 at 8:39 PM, Peter Meerwald <pmeerw@pmeerw.net> wrote:
> Hello Daniel,
>
>> Minimal implementation. This driver provides raw illuminance readings.
>>
>> This is based on drivers/hwmon/al3320.c (*) driver from msm tree written
>> by Tsechih Lin <Tsechih_Lin@asus.com>
>>
>> * https://android.googlesource.com/kernel/msm.git
>>
>> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
>> ---
>> Changes since v3: (reported by Hartmut and Jonathan)
>> * dropped the local store for the range, instead read it when necessary
>> * removed wrapper functions
>> * added in_illuminance_scale_available attribute
>> * fix bug when reading raw value, use i2c_smbus_read_word instead of
>> i2c_smbus_read_word_swapped and fix the endianess after read.
>
> no need to fix endianness
>
>> * small coding style fixes
>>
>> Changes since v2: (reported by Peter Meerwald)
>> * removed definition of DATA_HIGH and SW_RESET as they are not used
>> * added a comment to al3320a_get_adc_value() function
>> * added thresholds on TODO list
>> * small style fixes
>>
>> Changes since v1: (reported by Peter Meerwald)
>> * used u8 instead of int for passing gain and mean_time
>> * used i2c_smbus_read_word_swapped instead of 2 x i2c_smbus_read_byte_data
>> * used devm_iio_device_register instead of iio_device_register
>> * small style fixes
>>
>>
>> drivers/iio/light/Kconfig | 10 ++
>> drivers/iio/light/Makefile | 1 +
>> drivers/iio/light/al3320a.c | 229 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 240 insertions(+)
>> create mode 100644 drivers/iio/light/al3320a.c
>>
>> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
>> index bf05ca5..5bea821 100644
>> --- a/drivers/iio/light/Kconfig
>> +++ b/drivers/iio/light/Kconfig
>> @@ -17,6 +17,16 @@ config ADJD_S311
>> This driver can also be built as a module. If so, the module
>> will be called adjd_s311.
>>
>> +config AL3320A
>> + tristate "AL3320A ambient light sensor"
>> + depends on I2C
>> + help
>> + Say Y here if you want to build a driver for the Dyna Image AL3320A
>> + ambient light sensor.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called al3320a.
>> +
>> config APDS9300
>> tristate "APDS9300 ambient light sensor"
>> depends on I2C
>> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
>> index 8b8c09f..47877a3 100644
>> --- a/drivers/iio/light/Makefile
>> +++ b/drivers/iio/light/Makefile
>> @@ -4,6 +4,7 @@
>>
>> # When adding new entries keep the list in alphabetical order
>> obj-$(CONFIG_ADJD_S311) += adjd_s311.o
>> +obj-$(CONFIG_AL3320A) += al3320a.o
>> obj-$(CONFIG_APDS9300) += apds9300.o
>> obj-$(CONFIG_CM32181) += cm32181.o
>> obj-$(CONFIG_CM36651) += cm36651.o
>> diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
>> new file mode 100644
>> index 0000000..ad9135a
>> --- /dev/null
>> +++ b/drivers/iio/light/al3320a.c
>> @@ -0,0 +1,229 @@
>> +/*
>> + * AL3320A - Dyna Image Ambient Light Sensor
>> + *
>> + * Copyright (c) 2014, Intel Corporation.
>> + *
>> + * 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 AL3320A (7-bit I2C slave address 0x1C).
>> + *
>> + * TODO: interrupt support, thresholds
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/i2c.h>
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +
>> +#define AL3320A_DRV_NAME "al3320a"
>> +
>> +#define AL3320A_REG_CONFIG 0x00
>> +#define AL3320A_REG_STATUS 0x01
>> +#define AL3320A_REG_INT 0x02
>> +#define AL3320A_REG_WAIT 0x06
>> +#define AL3320A_REG_CONFIG_RANGE 0x07
>> +#define AL3320A_REG_PERSIST 0x08
>> +#define AL3320A_REG_MEAN_TIME 0x09
>> +#define AL3320A_REG_ADUMMY 0x0A
>> +#define AL3320A_REG_DATA_LOW 0x22
>> +
>> +#define AL3320A_REG_LOW_THRESH_LOW 0x30
>> +#define AL3320A_REG_LOW_THRESH_HIGH 0x31
>> +#define AL3320A_REG_HIGH_THRESH_LOW 0x32
>> +#define AL3320A_REG_HIGH_THRESH_HIGH 0x33
>> +
>> +#define AL3320A_CONFIG_DISABLE 0x00
>> +#define AL3320A_CONFIG_ENABLE 0x01
>> +
>> +#define AL3320A_GAIN_SHIFT 1
>> +
>> +/* chip params default values */
>> +#define AL3320A_DEFAULT_MEAN_TIME 4
>> +#define AL3320A_DEFAULT_WAIT_TIME 0 /* no waiting */
>> +
>> +#define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
>> +
>> +enum al3320a_range {
>> + AL3320A_RANGE_1, /* 33.28K lux */
>> + AL3320A_RANGE_2, /* 8.32K lux */
>> + AL3320A_RANGE_3, /* 2.08K lux */
>> + AL3320A_RANGE_4 /* 0.65K lux */
>> +};
>> +
>> +static const int al3320a_scales[][2] = {
>> + {0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
>> +};
>> +
>> +struct al3320a_data {
>> + struct i2c_client *client;
>> +};
>> +
>> +static const struct iio_chan_spec al3320a_channels[] = {
>> + {
>> + .type = IIO_LIGHT,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>> + BIT(IIO_CHAN_INFO_SCALE),
>> + }
>> +};
>> +
>> +static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
>> +
>> +static struct attribute *al3320a_attributes[] = {
>> + &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
>> + NULL,
>> +};
>> +
>> +static const struct attribute_group al3320a_attribute_group = {
>> + .attrs = al3320a_attributes,
>> +};
>> +
>> +static int al3320a_init(struct al3320a_data *data)
>> +{
>> + int ret;
>> +
>> + /* power on */
>> + ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
>> + AL3320A_CONFIG_ENABLE);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
>> + AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
>> + AL3320A_DEFAULT_MEAN_TIME);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
>> + AL3320A_DEFAULT_WAIT_TIME);
>> + if (ret < 0)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static int al3320a_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan, int *val,
>> + int *val2, long mask)
>> +{
>> + struct al3320a_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_RAW:
>> + /*
>> + * ALS ADC value is stored in two adjacent registers:
>> + * - low byte of output is stored at AL3320A_REG_DATA_LOW
>> + * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
>> + */
>> + ret = i2c_smbus_read_word_data(data->client,
>> + AL3320A_REG_DATA_LOW);
>
> i2c_smbus_read_word_data() must be used if the data is in I2C byte order
> (i.e. LSB first)
>
> i2c_smbus_read_word_swapped() must be used if the data is NOT in I2C byte
> order (i.e. MSB first)
>
> this has nothing to do with CPU byteorder; i2c_smbus_read_word_xxx() will
> take care to report the 16-bit value in native endianness
>
>> + if (ret < 0)
>> + return ret;
>> + *val = le16_to_cpu((__le16)ret);
>
> so it should be
> *val = ret;
I see. thanks! I will fix this asap.

Daniel.


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