drivers/iio/light/veml6070.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * veml6070.c - Support for Vishay VEML6070 UV A light sensor
   4  *
   5  * Copyright 2016 Peter Meerwald-Stadler <pmeerw@pmeerw.net>
   6  *
   7  * IIO driver for VEML6070 (7-bit I2C slave addresses 0x38 and 0x39)
   8  *
   9  * TODO: integration time, ACK signal
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/mutex.h>
  15 #include <linux/err.h>
  16 #include <linux/delay.h>
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/sysfs.h>
  20
  21 #define VEML6070_DRV_NAME "veml6070"
  22
  23 #define VEML6070_ADDR_CONFIG_DATA_MSB 0x38 /* read: MSB data, write: config */
  24 #define VEML6070_ADDR_DATA_LSB  0x39 /* LSB data */
  25
  26 #define VEML6070_COMMAND_ACK    BIT(5) /* raise interrupt when over threshold */
  27 #define VEML6070_COMMAND_IT     GENMASK(3, 2) /* bit mask integration time */
  28 #define VEML6070_COMMAND_RSRVD  BIT(1) /* reserved, set to 1 */
  29 #define VEML6070_COMMAND_SD     BIT(0) /* shutdown mode when set */
  30
  31 #define VEML6070_IT_10  0x04 /* integration time 1x */
  32
  33 struct veml6070_data {
  34         struct i2c_client *client1;
  35         struct i2c_client *client2;
  36         u8 config;
  37         struct mutex lock;
  38 };
  39
  40 static int veml6070_read(struct veml6070_data *data)
  41 {
  42         int ret;
  43         u8 msb, lsb;
  44
  45         mutex_lock(&data->lock);
  46
  47         /* disable shutdown */
  48         ret = i2c_smbus_write_byte(data->client1,
  49             data->config & ~VEML6070_COMMAND_SD);
  50         if (ret < 0)
  51                 goto out;
  52
  53         msleep(125 + 10); /* measurement takes up to 125 ms for IT 1x */
  54
  55         ret = i2c_smbus_read_byte(data->client2); /* read MSB, address 0x39 */
  56         if (ret < 0)
  57                 goto out;
  58         msb = ret;
  59
  60         ret = i2c_smbus_read_byte(data->client1); /* read LSB, address 0x38 */
  61         if (ret < 0)
  62                 goto out;
  63         lsb = ret;
  64
  65         /* shutdown again */
  66         ret = i2c_smbus_write_byte(data->client1, data->config);
  67         if (ret < 0)
  68                 goto out;
  69
  70         ret = (msb << 8) | lsb;
  71
  72 out:
  73         mutex_unlock(&data->lock);
  74         return ret;
  75 }
  76
  77 static const struct iio_chan_spec veml6070_channels[] = {
  78         {
  79                 .type = IIO_INTENSITY,
  80                 .modified = 1,
  81                 .channel2 = IIO_MOD_LIGHT_UV,
  82                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  83         },
  84         {
  85                 .type = IIO_UVINDEX,
  86                 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
  87         }
  88 };
  89
  90 static int veml6070_to_uv_index(unsigned val)
  91 {
  92         /*
  93          * conversion of raw UV intensity values to UV index depends on
  94          * integration time (IT) and value of the resistor connected to
  95          * the RSET pin (default: 270 KOhm)
  96          */
  97         unsigned uvi[11] = {
  98                 187, 373, 560, /* low */
  99                 746, 933, 1120, /* moderate */
 100                 1308, 1494, /* high */
 101                 1681, 1868, 2054}; /* very high */
 102         int i;
 103
 104         for (i = 0; i < ARRAY_SIZE(uvi); i++)
 105                 if (val <= uvi[i])
 106                         return i;
 107
 108         return 11; /* extreme */
 109 }
 110
 111 static int veml6070_read_raw(struct iio_dev *indio_dev,
 112                                 struct iio_chan_spec const *chan,
 113                                 int *val, int *val2, long mask)
 114 {
 115         struct veml6070_data *data = iio_priv(indio_dev);
 116         int ret;
 117
 118         switch (mask) {
 119         case IIO_CHAN_INFO_RAW:
 120         case IIO_CHAN_INFO_PROCESSED:
 121                 ret = veml6070_read(data);
 122                 if (ret < 0)
 123                         return ret;
 124                 if (mask == IIO_CHAN_INFO_PROCESSED)
 125                         *val = veml6070_to_uv_index(ret);
 126                 else
 127                         *val = ret;
 128                 return IIO_VAL_INT;
 129         default:
 130                 return -EINVAL;
 131         }
 132 }
 133
 134 static const struct iio_info veml6070_info = {
 135         .read_raw = veml6070_read_raw,
 136 };
 137
 138 static int veml6070_probe(struct i2c_client *client,
 139                           const struct i2c_device_id *id)
 140 {
 141         struct veml6070_data *data;
 142         struct iio_dev *indio_dev;
 143         int ret;
 144
 145         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 146         if (!indio_dev)
 147                 return -ENOMEM;
 148
 149         data = iio_priv(indio_dev);
 150         i2c_set_clientdata(client, indio_dev);
 151         data->client1 = client;
 152         mutex_init(&data->lock);
 153
 154         indio_dev->info = &veml6070_info;
 155         indio_dev->channels = veml6070_channels;
 156         indio_dev->num_channels = ARRAY_SIZE(veml6070_channels);
 157         indio_dev->name = VEML6070_DRV_NAME;
 158         indio_dev->modes = INDIO_DIRECT_MODE;
 159
 160         data->client2 = i2c_new_dummy_device(client->adapter, VEML6070_ADDR_DATA_LSB);
 161         if (IS_ERR(data->client2)) {
 162                 dev_err(&client->dev, "i2c device for second chip address failed\n");
 163                 return PTR_ERR(data->client2);
 164         }
 165
 166         data->config = VEML6070_IT_10 | VEML6070_COMMAND_RSRVD |
 167                 VEML6070_COMMAND_SD;
 168         ret = i2c_smbus_write_byte(data->client1, data->config);
 169         if (ret < 0)
 170                 goto fail;
 171
 172         ret = iio_device_register(indio_dev);
 173         if (ret < 0)
 174                 goto fail;
 175
 176         return ret;
 177
 178 fail:
 179         i2c_unregister_device(data->client2);
 180         return ret;
 181 }
 182
 183 static int veml6070_remove(struct i2c_client *client)
 184 {
 185         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 186         struct veml6070_data *data = iio_priv(indio_dev);
 187
 188         iio_device_unregister(indio_dev);
 189         i2c_unregister_device(data->client2);
 190
 191         return 0;
 192 }
 193
 194 static const struct i2c_device_id veml6070_id[] = {
 195         { "veml6070", 0 },
 196         { }
 197 };
 198 MODULE_DEVICE_TABLE(i2c, veml6070_id);
 199
 200 static struct i2c_driver veml6070_driver = {
 201         .driver = {
 202                 .name   = VEML6070_DRV_NAME,
 203         },
 204         .probe  = veml6070_probe,
 205         .remove  = veml6070_remove,
 206         .id_table = veml6070_id,
 207 };
 208
 209 module_i2c_driver(veml6070_driver);
 210
 211 MODULE_AUTHOR("Peter Meerwald-Stadler <pmeerw@pmeerw.net>");
 212 MODULE_DESCRIPTION("Vishay VEML6070 UV A light sensor driver");
 213 MODULE_LICENSE("GPL");