diff options
Diffstat (limited to 'drivers/iio/light/al3320a.c')
| -rw-r--r-- | drivers/iio/light/al3320a.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c new file mode 100644 index 000000000..66623face --- /dev/null +++ b/drivers/iio/light/al3320a.c @@ -0,0 +1,231 @@ +/* + * 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 +#define AL3320A_GAIN_MASK (BIT(2) | BIT(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, /* 33.28 Klx */ + AL3320A_RANGE_2, /* 8.32 Klx */ + AL3320A_RANGE_3, /* 2.08 Klx */ + AL3320A_RANGE_4 /* 0.65 Klx */ +}; + +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); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + ret = i2c_smbus_read_byte_data(data->client, + AL3320A_REG_CONFIG_RANGE); + if (ret < 0) + return ret; + + ret = (ret & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT; + *val = al3320a_scales[ret][0]; + *val2 = al3320a_scales[ret][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 i2c_smbus_write_byte_data(data->client, + AL3320A_REG_CONFIG_RANGE, + i << AL3320A_GAIN_SHIFT); + } + break; + } + return -EINVAL; +} + +static const struct iio_info al3320a_info = { + .read_raw = al3320a_read_raw, + .write_raw = al3320a_write_raw, + .attrs = &al3320a_attribute_group, +}; + +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 < 0) { + 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) +{ + return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG, + AL3320A_CONFIG_DISABLE); +} + +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@intel.com>"); +MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver"); +MODULE_LICENSE("GPL v2"); |