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Commit dfd2ab8d authored by Peter Meerwald-Stadler's avatar Peter Meerwald-Stadler Committed by Jonathan Cameron
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iio: Add Vishay VEML6070 UV A light sensor driver 

ultraviolet (UV) light sensor with I2C interface with a peak
sensitivity at 355 nm

strangely, chip uses two addresses 0x38 and 0x39 for LSB and
MSB data, resp.

datasheet: http://www.vishay.com/docs/84277/veml6070.pdf



Signed-off-by: default avatarPeter Meerwald-Stadler <pmeerw@pmeerw.net>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent e21a294d

drivers/iio/light/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -331,4 +331,14 @@ config VCNL4000 
	 To compile this driver as a module, choose M here: the

	 module will be called vcnl4000.



config VEML6070

	tristate "VEML6070 UV A light sensor"

	depends on I2C

	help

	 Say Y here if you want to build a driver for the Vishay VEML6070 UV A

	 light sensor.



	 To compile this driver as a module, choose M here: the

	 module will be called veml6070.



endmenu

drivers/iio/light/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -31,3 +31,4 @@ obj-$(CONFIG_TCS3472) += tcs3472.o 
obj-$(CONFIG_TSL4531)		+= tsl4531.o

obj-$(CONFIG_US5182D)		+= us5182d.o

obj-$(CONFIG_VCNL4000)		+= vcnl4000.o

obj-$(CONFIG_VEML6070)		+= veml6070.o

drivers/iio/light/veml6070.c

0 → 100644
+218 −0
Original line number Diff line number Diff line 
/*

 * veml6070.c - Support for Vishay VEML6070 UV A light sensor

 *

 * Copyright 2016 Peter Meerwald-Stadler <pmeerw@pmeerw.net>

 *

 * 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 VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)

 *

 * TODO: integration time, ACK signal

 */



#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/mutex.h>

#include <linux/err.h>

#include <linux/delay.h>



#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>



#define VEML6070_DRV_NAME "veml6070"



#define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */

#define VEML6070_ADDR_DATA_LSB	0x39 /* LSB data */



#define VEML6070_COMMAND_ACK	BIT(5) /* raise interrupt when over threshold */

#define VEML6070_COMMAND_IT	GENMASK(3, 2) /* bit mask integration time */

#define VEML6070_COMMAND_RSRVD	BIT(1) /* reserved, set to 1 */

#define VEML6070_COMMAND_SD	BIT(0) /* shutdown mode when set */



#define VEML6070_IT_10	0x04 /* integration time 1x */



struct veml6070_data {

	struct i2c_client *client1;

	struct i2c_client *client2;

	u8 config;

	struct mutex lock;

};



static int veml6070_read(struct veml6070_data *data)

{

	int ret;

	u8 msb, lsb;



	mutex_lock(&data->lock);



	/* disable shutdown */

	ret = i2c_smbus_write_byte(data->client1,

	    data->config & ~VEML6070_COMMAND_SD);

	if (ret < 0)

		goto out;



	msleep(125 + 10); /* measurement takes up to 125 ms for IT 1x */



	ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */

	if (ret < 0)

		goto out;

	msb = ret;



	ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */

	if (ret < 0)

		goto out;

	lsb = ret;



	/* shutdown again */

	ret = i2c_smbus_write_byte(data->client1, data->config);

	if (ret < 0)

		goto out;



	ret = (msb << 8) | lsb;



out:

	mutex_unlock(&data->lock);

	return ret;

}



static const struct iio_chan_spec veml6070_channels[] = {

	{

		.type = IIO_INTENSITY,

		.modified = 1,

		.channel2 = IIO_MOD_LIGHT_UV,

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),

	},

	{

		.type = IIO_UVINDEX,

		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),

	}

};



static int veml6070_to_uv_index(unsigned val)

{

	/*

	 * conversion of raw UV intensity values to UV index depends on

	 * integration time (IT) and value of the resistor connected to

	 * the RSET pin (default: 270 KOhm)

	 */

	unsigned uvi[11] = {

		187, 373, 560, /* low */

		746, 933, 1120, /* moderate */

		1308, 1494, /* high */

		1681, 1868, 2054}; /* very high */

	int i;



	for (i = 0; i < ARRAY_SIZE(uvi); i++)

		if (val <= uvi[i])

			return i;



	return 11; /* extreme */

}



static int veml6070_read_raw(struct iio_dev *indio_dev,

				struct iio_chan_spec const *chan,

				int *val, int *val2, long mask)

{

	struct veml6070_data *data = iio_priv(indio_dev);

	int ret;



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

	case IIO_CHAN_INFO_PROCESSED:

		ret = veml6070_read(data);

		if (ret < 0)

			return ret;

		if (mask == IIO_CHAN_INFO_PROCESSED)

			*val = veml6070_to_uv_index(ret);

		else

			*val = ret;

		return IIO_VAL_INT;

	default:

		return -EINVAL;

	}

}



static const struct iio_info veml6070_info = {

	.read_raw = veml6070_read_raw,

	.driver_module = THIS_MODULE,

};



static int veml6070_probe(struct i2c_client *client,

			  const struct i2c_device_id *id)

{

	struct veml6070_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->client1 = client;

	mutex_init(&data->lock);



	indio_dev->dev.parent = &client->dev;

	indio_dev->info = &veml6070_info;

	indio_dev->channels = veml6070_channels;

	indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);

	indio_dev->name = VEML6070_DRV_NAME;

	indio_dev->modes = INDIO_DIRECT_MODE;



	data->client2 = i2c_new_dummy(client->adapter, VEML6070_ADDR_DATA_LSB);

	if (!data->client2) {

		dev_err(&client->dev, "i2c device for second chip address failed\n");

		return -ENODEV;

	}



	data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |

		VEML6070_COMMAND_SD;

	ret = i2c_smbus_write_byte(data->client1, data->config);

	if (ret < 0)

		goto fail;



	ret = iio_device_register(indio_dev);

	if (ret < 0)

		goto fail;



	return ret;



fail:

	i2c_unregister_device(data->client2);

	return ret;

}



static int veml6070_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	struct veml6070_data *data = iio_priv(indio_dev);



	iio_device_unregister(indio_dev);

	i2c_unregister_device(data->client2);



	return 0;

}



static const struct i2c_device_id veml6070_id[] = {

	{ "veml6070", 0 },

	{ }

};

MODULE_DEVICE_TABLE(i2c, veml6070_id);



static struct i2c_driver veml6070_driver = {

	.driver = {

		.name   = VEML6070_DRV_NAME,

	},

	.probe  = veml6070_probe,

	.remove  = veml6070_remove,

	.id_table = veml6070_id,

};



module_i2c_driver(veml6070_driver);



MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");

MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");

MODULE_LICENSE("GPL");