Re: [PATCH v2 3/3] iio: Add Vishay VEML6070 UV A light sensor driver

[Jonathan Cameron <jic23@kernel.org>]

On 20/03/16 15:20, Peter Meerwald-Stadler wrote:
> 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: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Looks good.

Applied to the togreg branch of iio.git - initially pushed out as testing
for the autobuilders to play with it.

Jonathan
> ---
>  drivers/iio/light/Kconfig    |  10 ++
>  drivers/iio/light/Makefile   |   1 +
>  drivers/iio/light/veml6070.c | 218 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 229 insertions(+)
>  create mode 100644 drivers/iio/light/veml6070.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index cfd3df8..d2fe64e 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -320,4 +320,14 @@ 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
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index b2c3105..a447c62 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -30,3 +30,4 @@ 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
> diff --git a/drivers/iio/light/veml6070.c b/drivers/iio/light/veml6070.c
> new file mode 100644
> index 0000000..bc1c4cb
> --- /dev/null
> +++ b/drivers/iio/light/veml6070.c
> @@ -0,0 +1,218 @@
> +/*
> + * 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");
>