219 lines
5 KiB
C
219 lines
5 KiB
C
![]() |
/*
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* veml6070.c - Support for Vishay VEML6070 UV A light sensor
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*
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* Copyright 2016 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* IIO driver for VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)
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*
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* TODO: integration time, ACK signal
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/mutex.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#define VEML6070_DRV_NAME "veml6070"
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#define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */
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#define VEML6070_ADDR_DATA_LSB 0x39 /* LSB data */
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#define VEML6070_COMMAND_ACK BIT(5) /* raise interrupt when over threshold */
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#define VEML6070_COMMAND_IT GENMASK(3, 2) /* bit mask integration time */
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#define VEML6070_COMMAND_RSRVD BIT(1) /* reserved, set to 1 */
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#define VEML6070_COMMAND_SD BIT(0) /* shutdown mode when set */
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#define VEML6070_IT_10 0x04 /* integration time 1x */
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struct veml6070_data {
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struct i2c_client *client1;
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struct i2c_client *client2;
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u8 config;
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struct mutex lock;
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};
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static int veml6070_read(struct veml6070_data *data)
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{
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int ret;
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u8 msb, lsb;
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mutex_lock(&data->lock);
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/* disable shutdown */
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ret = i2c_smbus_write_byte(data->client1,
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data->config & ~VEML6070_COMMAND_SD);
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if (ret < 0)
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goto out;
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msleep(125 + 10); /* measurement takes up to 125 ms for IT 1x */
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ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */
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if (ret < 0)
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goto out;
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msb = ret;
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ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */
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if (ret < 0)
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goto out;
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lsb = ret;
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/* shutdown again */
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ret = i2c_smbus_write_byte(data->client1, data->config);
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if (ret < 0)
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goto out;
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ret = (msb << 8) | lsb;
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out:
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mutex_unlock(&data->lock);
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return ret;
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}
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static const struct iio_chan_spec veml6070_channels[] = {
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{
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.type = IIO_INTENSITY,
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.modified = 1,
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.channel2 = IIO_MOD_LIGHT_UV,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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},
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{
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.type = IIO_UVINDEX,
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.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
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}
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};
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static int veml6070_to_uv_index(unsigned val)
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{
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/*
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* conversion of raw UV intensity values to UV index depends on
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* integration time (IT) and value of the resistor connected to
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* the RSET pin (default: 270 KOhm)
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*/
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unsigned uvi[11] = {
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187, 373, 560, /* low */
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746, 933, 1120, /* moderate */
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1308, 1494, /* high */
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1681, 1868, 2054}; /* very high */
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int i;
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for (i = 0; i < ARRAY_SIZE(uvi); i++)
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if (val <= uvi[i])
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return i;
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return 11; /* extreme */
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}
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static int veml6070_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct veml6070_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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case IIO_CHAN_INFO_PROCESSED:
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ret = veml6070_read(data);
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if (ret < 0)
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return ret;
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if (mask == IIO_CHAN_INFO_PROCESSED)
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*val = veml6070_to_uv_index(ret);
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else
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*val = ret;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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}
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static const struct iio_info veml6070_info = {
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.read_raw = veml6070_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int veml6070_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct veml6070_data *data;
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struct iio_dev *indio_dev;
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int ret;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client1 = client;
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mutex_init(&data->lock);
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indio_dev->dev.parent = &client->dev;
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indio_dev->info = &veml6070_info;
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indio_dev->channels = veml6070_channels;
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indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
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indio_dev->name = VEML6070_DRV_NAME;
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indio_dev->modes = INDIO_DIRECT_MODE;
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data->client2 = i2c_new_dummy(client->adapter, VEML6070_ADDR_DATA_LSB);
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if (!data->client2) {
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dev_err(&client->dev, "i2c device for second chip address failed\n");
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return -ENODEV;
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}
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data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |
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VEML6070_COMMAND_SD;
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ret = i2c_smbus_write_byte(data->client1, data->config);
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if (ret < 0)
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goto fail;
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ret = iio_device_register(indio_dev);
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if (ret < 0)
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goto fail;
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return ret;
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fail:
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i2c_unregister_device(data->client2);
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return ret;
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}
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static int veml6070_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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struct veml6070_data *data = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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i2c_unregister_device(data->client2);
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return 0;
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}
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static const struct i2c_device_id veml6070_id[] = {
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{ "veml6070", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, veml6070_id);
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static struct i2c_driver veml6070_driver = {
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.driver = {
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.name = VEML6070_DRV_NAME,
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},
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.probe = veml6070_probe,
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.remove = veml6070_remove,
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.id_table = veml6070_id,
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};
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module_i2c_driver(veml6070_driver);
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MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
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MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
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MODULE_LICENSE("GPL");
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