diff options
Diffstat (limited to 'drivers/iio/light/cm32181.c')
| -rw-r--r-- | drivers/iio/light/cm32181.c | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c new file mode 100644 index 000000000..aebf7dd07 --- /dev/null +++ b/drivers/iio/light/cm32181.c @@ -0,0 +1,370 @@ +/* + * Copyright (C) 2013 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. + */ + +#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> + +/* Registers Address */ +#define CM32181_REG_ADDR_CMD 0x00 +#define CM32181_REG_ADDR_ALS 0x04 +#define CM32181_REG_ADDR_STATUS 0x06 +#define CM32181_REG_ADDR_ID 0x07 + +/* Number of Configurable Registers */ +#define CM32181_CONF_REG_NUM 0x01 + +/* CMD register */ +#define CM32181_CMD_ALS_ENABLE 0x00 +#define CM32181_CMD_ALS_DISABLE 0x01 +#define CM32181_CMD_ALS_INT_EN 0x02 + +#define CM32181_CMD_ALS_IT_SHIFT 6 +#define CM32181_CMD_ALS_IT_MASK (0x0F << CM32181_CMD_ALS_IT_SHIFT) +#define CM32181_CMD_ALS_IT_DEFAULT (0x00 << CM32181_CMD_ALS_IT_SHIFT) + +#define CM32181_CMD_ALS_SM_SHIFT 11 +#define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT) +#define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT) + +#define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */ +#define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ +#define CM32181_CALIBSCALE_DEFAULT 1000 +#define CM32181_CALIBSCALE_RESOLUTION 1000 +#define MLUX_PER_LUX 1000 + +static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = { + CM32181_REG_ADDR_CMD, +}; + +static const int als_it_bits[] = {12, 8, 0, 1, 2, 3}; +static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000, + 800000}; + +struct cm32181_chip { + struct i2c_client *client; + struct mutex lock; + u16 conf_regs[CM32181_CONF_REG_NUM]; + int calibscale; +}; + +/** + * cm32181_reg_init() - Initialize CM32181 registers + * @cm32181: pointer of struct cm32181. + * + * Initialize CM32181 ambient light sensor register to default values. + * + * Return: 0 for success; otherwise for error code. + */ +static int cm32181_reg_init(struct cm32181_chip *cm32181) +{ + struct i2c_client *client = cm32181->client; + int i; + s32 ret; + + ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID); + if (ret < 0) + return ret; + + /* check device ID */ + if ((ret & 0xFF) != 0x81) + return -ENODEV; + + /* Default Values */ + cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE | + CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT; + cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT; + + /* Initialize registers*/ + for (i = 0; i < CM32181_CONF_REG_NUM; i++) { + ret = i2c_smbus_write_word_data(client, cm32181_reg[i], + cm32181->conf_regs[i]); + if (ret < 0) + return ret; + } + + return 0; +} + +/** + * cm32181_read_als_it() - Get sensor integration time (ms) + * @cm32181: pointer of struct cm32181 + * @val2: pointer of int to load the als_it value. + * + * Report the current integartion time by millisecond. + * + * Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL. + */ +static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2) +{ + u16 als_it; + int i; + + als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD]; + als_it &= CM32181_CMD_ALS_IT_MASK; + als_it >>= CM32181_CMD_ALS_IT_SHIFT; + for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) { + if (als_it == als_it_bits[i]) { + *val2 = als_it_value[i]; + return IIO_VAL_INT_PLUS_MICRO; + } + } + + return -EINVAL; +} + +/** + * cm32181_write_als_it() - Write sensor integration time + * @cm32181: pointer of struct cm32181. + * @val: integration time by millisecond. + * + * Convert integration time (ms) to sensor value. + * + * Return: i2c_smbus_write_word_data command return value. + */ +static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val) +{ + struct i2c_client *client = cm32181->client; + u16 als_it; + int ret, i, n; + + n = ARRAY_SIZE(als_it_value); + for (i = 0; i < n; i++) + if (val <= als_it_value[i]) + break; + if (i >= n) + i = n - 1; + + als_it = als_it_bits[i]; + als_it <<= CM32181_CMD_ALS_IT_SHIFT; + + mutex_lock(&cm32181->lock); + cm32181->conf_regs[CM32181_REG_ADDR_CMD] &= + ~CM32181_CMD_ALS_IT_MASK; + cm32181->conf_regs[CM32181_REG_ADDR_CMD] |= + als_it; + ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD, + cm32181->conf_regs[CM32181_REG_ADDR_CMD]); + mutex_unlock(&cm32181->lock); + + return ret; +} + +/** + * cm32181_get_lux() - report current lux value + * @cm32181: pointer of struct cm32181. + * + * 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 cm32181_get_lux(struct cm32181_chip *cm32181) +{ + struct i2c_client *client = cm32181->client; + int ret; + int als_it; + unsigned long lux; + + ret = cm32181_read_als_it(cm32181, &als_it); + if (ret < 0) + return -EINVAL; + + lux = CM32181_MLUX_PER_BIT; + lux *= CM32181_MLUX_PER_BIT_BASE_IT; + lux /= als_it; + + ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS); + if (ret < 0) + return ret; + + lux *= ret; + lux *= cm32181->calibscale; + lux /= CM32181_CALIBSCALE_RESOLUTION; + lux /= MLUX_PER_LUX; + + if (lux > 0xFFFF) + lux = 0xFFFF; + + return lux; +} + +static int cm32181_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct cm32181_chip *cm32181 = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: + ret = cm32181_get_lux(cm32181); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_CALIBSCALE: + *val = cm32181->calibscale; + return IIO_VAL_INT; + case IIO_CHAN_INFO_INT_TIME: + *val = 0; + ret = cm32181_read_als_it(cm32181, val2); + return ret; + } + + return -EINVAL; +} + +static int cm32181_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct cm32181_chip *cm32181 = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_CALIBSCALE: + cm32181->calibscale = val; + return val; + case IIO_CHAN_INFO_INT_TIME: + ret = cm32181_write_als_it(cm32181, val2); + return ret; + } + + return -EINVAL; +} + +/** + * cm32181_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 values by millisecond. + * + * Return: string length. + */ +static ssize_t cm32181_get_it_available(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int i, n, len; + + n = ARRAY_SIZE(als_it_value); + for (i = 0, len = 0; i < n; i++) + len += sprintf(buf + len, "0.%06u ", als_it_value[i]); + return len + sprintf(buf + len, "\n"); +} + +static const struct iio_chan_spec cm32181_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, cm32181_get_it_available, NULL, 0); + +static struct attribute *cm32181_attributes[] = { + &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group cm32181_attribute_group = { + .attrs = cm32181_attributes +}; + +static const struct iio_info cm32181_info = { + .read_raw = &cm32181_read_raw, + .write_raw = &cm32181_write_raw, + .attrs = &cm32181_attribute_group, +}; + +static int cm32181_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct cm32181_chip *cm32181; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181)); + if (!indio_dev) { + dev_err(&client->dev, "devm_iio_device_alloc failed\n"); + return -ENOMEM; + } + + cm32181 = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + cm32181->client = client; + + mutex_init(&cm32181->lock); + indio_dev->dev.parent = &client->dev; + indio_dev->channels = cm32181_channels; + indio_dev->num_channels = ARRAY_SIZE(cm32181_channels); + indio_dev->info = &cm32181_info; + indio_dev->name = id->name; + indio_dev->modes = INDIO_DIRECT_MODE; + + ret = cm32181_reg_init(cm32181); + if (ret) { + dev_err(&client->dev, + "%s: register init failed\n", + __func__); + return ret; + } + + ret = devm_iio_device_register(&client->dev, indio_dev); + if (ret) { + dev_err(&client->dev, + "%s: regist device failed\n", + __func__); + return ret; + } + + return 0; +} + +static const struct i2c_device_id cm32181_id[] = { + { "cm32181", 0 }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, cm32181_id); + +static const struct of_device_id cm32181_of_match[] = { + { .compatible = "capella,cm32181" }, + { } +}; +MODULE_DEVICE_TABLE(of, cm32181_of_match); + +static struct i2c_driver cm32181_driver = { + .driver = { + .name = "cm32181", + .of_match_table = of_match_ptr(cm32181_of_match), + }, + .id_table = cm32181_id, + .probe = cm32181_probe, +}; + +module_i2c_driver(cm32181_driver); + +MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>"); +MODULE_DESCRIPTION("CM32181 ambient light sensor driver"); +MODULE_LICENSE("GPL"); |