Re: [PATCH v2] iio: Add Dyna-Image AL3320A ambient light sensor driver
From: Daniel Baluta
Date: Fri Aug 22 2014 - 05:08:55 EST
On Thu, Aug 21, 2014 at 6:31 PM, Peter Meerwald <pmeerw@xxxxxxxxxx> wrote:
>
>> 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@xxxxxxxx>
>>
>> * https://android.googlesource.com/kernel/msm.git
>
> some more comments on minor things below...
>
>> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
>> ---
>> 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 | 247 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 258 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..787ce2e
>> --- /dev/null
>> +++ b/drivers/iio/light/al3320a.c
>> @@ -0,0 +1,247 @@
>> +/*
>> + * 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
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/i2c.h>
>> +#include <linux/mutex.h>
>
> mutex is not needed
Correct. To be fixed in v3.
>
>> +
>> +#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
>
> PERSIST is not used, maybe add to TODO
Hmm, I think PERSIST is an internal part of interrupt support which is
already listed in TODO list.
>
>> +#define AL3320A_REG_MEAN_TIME 0x09
>> +#define AL3320A_REG_ADUMMY 0x0A
>> +#define AL3320A_REG_DATA_LOW 0x22
>> +#define AL3320A_REG_DATA_HIGH 0x23
>
> DATA_HIGH became unused by read_word_swapped()
Ok, removed in v3. I've seen that it is a common practice to define
only used registers. Anyhow, I think that drivers would be easier to
understand/maintain if all register definitions are listed from start.
>
>> +
>> +#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
>
> threshold are TODO
ok.
>
>> +
>> +#define AL3320A_CONFIG_DISABLE 0x00
>> +#define AL3320A_CONFIG_ENABLE BIT(0)
>> +#define AL3320A_CONFIG_SW_RESET BIT(2)
>
> SW_RESET is unused
Removed in v3.
>
>> +
>> +#define AL3320A_GAIN_SHIFT 1
>> +
>> +/* chip params default values */
>> +#define AL3320A_DEFAULT_MEAN_TIME 4
>> +#define AL3320A_DEFAULT_WAIT_TIME 0 /* no waiting */
>> +
>> +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;
>> + u8 range;
>> +};
>> +
>> +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 int al3320a_enable(struct al3320a_data *data)
>> +{
>> + return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
>> + AL3320A_CONFIG_ENABLE);
>> +}
>> +
>> +static int al3320a_disable(struct al3320a_data *data)
>> +{
>> + return i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
>> + AL3320A_CONFIG_DISABLE);
>> +}
>> +
>> +static int al3320a_set_config_range(struct al3320a_data *data, u8 gain)
>> +{
>> + int ret;
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
>> + gain << AL3320A_GAIN_SHIFT);
>> + if (ret >= 0)
>> + data->range = gain;
>> + return ret;
>> +}
>> +
>> +static int al3320a_set_mean_time(struct al3320a_data *data, u8 mean_time)
>> +{
>> + return i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
>> + mean_time);
>> +}
>> +
>> +static int al3320a_set_wait_time(struct al3320a_data *data, u8 wait_time)
>> +{
>> + return i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
>> + wait_time);
>> +}
>> +
>> +static int al3320a_get_adc_value(struct al3320a_data *data)
>> +{
>> + return i2c_smbus_read_word_swapped(data->client, AL3320A_REG_DATA_LOW);
>> +}
>> +
>> +static int al3320a_init(struct al3320a_data *data)
>> +{
>> + int ret;
>> +
>> + /* power on */
>> + ret = al3320a_enable(data);
>> + if (ret)
>> + return ret;
>> +
>> + ret = al3320a_set_config_range(data, AL3320A_RANGE_3);
>> + if (ret)
>> + return ret;
>> +
>> + ret = al3320a_set_mean_time(data, AL3320A_DEFAULT_MEAN_TIME);
>> + if (ret)
>> + return ret;
>> +
>> + ret = al3320a_set_wait_time(data, AL3320A_DEFAULT_WAIT_TIME);
>> + if (ret)
>> + 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:
>> + ret = al3320a_get_adc_value(data);
>> + if (ret < 0)
>> + return ret;
>> + *val = ret;
>> + return IIO_VAL_INT;
>> + case IIO_CHAN_INFO_SCALE:
>> + *val = al3320a_scales[data->range][0];
>> + *val2 = al3320a_scales[data->range][1];
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +static int al3320a_write_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 i;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_SCALE:
>> + for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
>> + if (val == al3320a_scales[i][0] &&
>> + val2 == al3320a_scales[i][1])
>> + return al3320a_set_config_range(data, i);
>> + }
>
> could add a break; here so it is not missed when handling more masks
Fixed in v3.
>
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +static const struct iio_info al3320a_info = {
>> + .driver_module = THIS_MODULE,
>> + .read_raw = al3320a_read_raw,
>> + .write_raw = al3320a_write_raw,
>> +};
>> +
>> +static int al3320a_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct al3320a_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;
>> +
>> + indio_dev->dev.parent = &client->dev;
>> + indio_dev->info = &al3320a_info;
>> + indio_dev->name = AL3320A_DRV_NAME;
>> + indio_dev->channels = al3320a_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> +
>> + ret = al3320a_init(data);
>> + if (ret) {
>> + dev_err(&client->dev, "al3320a chip init failed\n");
>> + return ret;
>> + }
>> +
>> + return devm_iio_device_register(&client->dev, indio_dev);
>> +}
>> +
>> +static int al3320a_remove(struct i2c_client *client)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
>> + struct al3320a_data *data = iio_priv(indio_dev);
>> +
>> + return al3320a_disable(data);
>
> extra space before al3320a_disable()
Good catch. Fixed in v3.
>
>> +}
>> +
>> +static const struct i2c_device_id al3320a_id[] = {
>> + {"al3320a", 0},
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, al3320a_id);
>> +
>> +static struct i2c_driver al3320a_driver = {
>> + .driver = {
>> + .name = AL3320A_DRV_NAME,
>> + },
>> + .probe = al3320a_probe,
>> + .remove = al3320a_remove,
>> + .id_table = al3320a_id,
>> +};
>> +
>> +module_i2c_driver(al3320a_driver);
>> +
>> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
>> +MODULE_LICENSE("GPL v2");
>>
>
> --
>
> Peter Meerwald
Thanks again Peter.
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