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Release 4.7 drivers/iio/light/bh1750.c

/*
 * ROHM BH1710/BH1715/BH1721/BH1750/BH1751 ambient light sensor driver
 *
 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.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.
 *
 * Data sheets:
 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1710fvc-e.pdf
 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1715fvc-e.pdf
 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1721fvc-e.pdf
 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1750fvi-e.pdf
 *  http://rohmfs.rohm.com/en/products/databook/datasheet/ic/sensor/light/bh1751fvi-e.pdf
 *
 * 7-bit I2C slave addresses:
 *  0x23 (ADDR pin low)
 *  0x5C (ADDR pin high)
 *
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/module.h>


#define BH1750_POWER_DOWN		0x00

#define BH1750_ONE_TIME_H_RES_MODE	0x20 
/* auto-mode for BH1721 */

#define BH1750_CHANGE_INT_TIME_H_BIT	0x40

#define BH1750_CHANGE_INT_TIME_L_BIT	0x60

enum {
	
BH1710,
	
BH1721,
	
BH1750,
};

struct bh1750_chip_info;

struct bh1750_data {
	
struct i2c_client *client;
	
struct mutex lock;
	
const struct bh1750_chip_info *chip_info;
	
u16 mtreg;
};


struct bh1750_chip_info {
	
u16 mtreg_min;
	
u16 mtreg_max;
	
u16 mtreg_default;
	
int mtreg_to_usec;
	
int mtreg_to_scale;

	/*
         * For BH1710/BH1721 all possible integration time values won't fit
         * into one page so displaying is limited to every second one.
         * Note, that user can still write proper values which were not
         * listed.
         */
	
int inc;

	
u16 int_time_low_mask;
	
u16 int_time_high_mask;
}


static const bh1750_chip_info_tbl[] = {
	[BH1710] = { 140, 1022, 300, 400,  250000000, 2, 0x001F, 0x03E0 },
	[BH1721] = { 140, 1020, 300, 400,  250000000, 2, 0x0010, 0x03E0 },
	[BH1750] = { 31,  254,  69,  1740, 57500000,  1, 0x001F, 0x00E0 },
};


static int bh1750_change_int_time(struct bh1750_data *data, int usec) { int ret; u16 val; u8 regval; const struct bh1750_chip_info *chip_info = data->chip_info; if ((usec % chip_info->mtreg_to_usec) != 0) return -EINVAL; val = usec / chip_info->mtreg_to_usec; if (val < chip_info->mtreg_min || val > chip_info->mtreg_max) return -EINVAL; ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN); if (ret < 0) return ret; regval = (val & chip_info->int_time_high_mask) >> 5; ret = i2c_smbus_write_byte(data->client, BH1750_CHANGE_INT_TIME_H_BIT | regval); if (ret < 0) return ret; regval = val & chip_info->int_time_low_mask; ret = i2c_smbus_write_byte(data->client, BH1750_CHANGE_INT_TIME_L_BIT | regval); if (ret < 0) return ret; data->mtreg = val; return 0; }

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static int bh1750_read(struct bh1750_data *data, int *val) { int ret; __be16 result; const struct bh1750_chip_info *chip_info = data->chip_info; unsigned long delay = chip_info->mtreg_to_usec * data->mtreg; /* * BH1721 will enter continuous mode on receiving this command. * Note, that this eliminates need for bh1750_resume(). */ ret = i2c_smbus_write_byte(data->client, BH1750_ONE_TIME_H_RES_MODE); if (ret < 0) return ret; usleep_range(delay + 15000, delay + 40000); ret = i2c_master_recv(data->client, (char *)&result, 2); if (ret < 0) return ret; *val = be16_to_cpu(result); return 0; }

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static int bh1750_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { int ret, tmp; struct bh1750_data *data = iio_priv(indio_dev); const struct bh1750_chip_info *chip_info = data->chip_info; switch (mask) { case IIO_CHAN_INFO_RAW: switch (chan->type) { case IIO_LIGHT: mutex_lock(&data->lock); ret = bh1750_read(data, val); mutex_unlock(&data->lock); if (ret < 0) return ret; return IIO_VAL_INT; default: return -EINVAL; } case IIO_CHAN_INFO_SCALE: tmp = chip_info->mtreg_to_scale / data->mtreg; *val = tmp / 1000000; *val2 = tmp % 1000000; return IIO_VAL_INT_PLUS_MICRO; case IIO_CHAN_INFO_INT_TIME: *val = 0; *val2 = chip_info->mtreg_to_usec * data->mtreg; return IIO_VAL_INT_PLUS_MICRO; default: return -EINVAL; } }

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static int bh1750_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) { int ret; struct bh1750_data *data = iio_priv(indio_dev); switch (mask) { case IIO_CHAN_INFO_INT_TIME: if (val != 0) return -EINVAL; mutex_lock(&data->lock); ret = bh1750_change_int_time(data, val2); mutex_unlock(&data->lock); return ret; default: return -EINVAL; } }

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static ssize_t bh1750_show_int_time_available(struct device *dev, struct device_attribute *attr, char *buf) { int i; size_t len = 0; struct bh1750_data *data = iio_priv(dev_to_iio_dev(dev)); const struct bh1750_chip_info *chip_info = data->chip_info; for (i = chip_info->mtreg_min; i <= chip_info->mtreg_max; i += chip_info->inc) len += scnprintf(buf + len, PAGE_SIZE - len, "0.%06d ", chip_info->mtreg_to_usec * i); buf[len - 1] = '\n'; return len; }

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static IIO_DEV_ATTR_INT_TIME_AVAIL(bh1750_show_int_time_available); static struct attribute *bh1750_attributes[] = { &iio_dev_attr_integration_time_available.dev_attr.attr, NULL, }; static struct attribute_group bh1750_attribute_group = { .attrs = bh1750_attributes, }; static const struct iio_info bh1750_info = { .driver_module = THIS_MODULE, .attrs = &bh1750_attribute_group, .read_raw = bh1750_read_raw, .write_raw = bh1750_write_raw, }; static const struct iio_chan_spec bh1750_channels[] = { { .type = IIO_LIGHT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME) } };
static int bh1750_probe(struct i2c_client *client, const struct i2c_device_id *id) { int ret, usec; struct bh1750_data *data; struct iio_dev *indio_dev; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE)) return -EOPNOTSUPP; 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; data->chip_info = &bh1750_chip_info_tbl[id->driver_data]; usec = data->chip_info->mtreg_to_usec * data->chip_info->mtreg_default; ret = bh1750_change_int_time(data, usec); if (ret < 0) return ret; mutex_init(&data->lock); indio_dev->dev.parent = &client->dev; indio_dev->info = &bh1750_info; indio_dev->name = id->name; indio_dev->channels = bh1750_channels; indio_dev->num_channels = ARRAY_SIZE(bh1750_channels); indio_dev->modes = INDIO_DIRECT_MODE; return iio_device_register(indio_dev); }

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static int bh1750_remove(struct i2c_client *client) { struct iio_dev *indio_dev = i2c_get_clientdata(client); struct bh1750_data *data = iio_priv(indio_dev); iio_device_unregister(indio_dev); mutex_lock(&data->lock); i2c_smbus_write_byte(client, BH1750_POWER_DOWN); mutex_unlock(&data->lock); return 0; }

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#ifdef CONFIG_PM_SLEEP
static int bh1750_suspend(struct device *dev) { int ret; struct bh1750_data *data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); /* * This is mainly for BH1721 which doesn't enter power down * mode automatically. */ mutex_lock(&data->lock); ret = i2c_smbus_write_byte(data->client, BH1750_POWER_DOWN); mutex_unlock(&data->lock); return ret; }

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static SIMPLE_DEV_PM_OPS(bh1750_pm_ops, bh1750_suspend, NULL); #define BH1750_PM_OPS (&bh1750_pm_ops) #else #define BH1750_PM_OPS NULL #endif static const struct i2c_device_id bh1750_id[] = { { "bh1710", BH1710 }, { "bh1715", BH1750 }, { "bh1721", BH1721 }, { "bh1750", BH1750 }, { "bh1751", BH1750 }, { } }; MODULE_DEVICE_TABLE(i2c, bh1750_id); static struct i2c_driver bh1750_driver = { .driver = { .name = "bh1750", .pm = BH1750_PM_OPS, }, .probe = bh1750_probe, .remove = bh1750_remove, .id_table = bh1750_id, }; module_i2c_driver(bh1750_driver); MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>"); MODULE_DESCRIPTION("ROHM BH1710/BH1715/BH1721/BH1750/BH1751 als driver"); MODULE_LICENSE("GPL v2");

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