drivers/iio/light/al3320a.c

   1 /*
   2  * AL3320A - Dyna Image Ambient Light Sensor
   3  *
   4  * Copyright (c) 2014, Intel Corporation.
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
  11  *
  12  * TODO: interrupt support, thresholds
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/i2c.h>
  19
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/sysfs.h>
  22
  23 #define AL3320A_DRV_NAME "al3320a"
  24
  25 #define AL3320A_REG_CONFIG              0x00
  26 #define AL3320A_REG_STATUS              0x01
  27 #define AL3320A_REG_INT                 0x02
  28 #define AL3320A_REG_WAIT                0x06
  29 #define AL3320A_REG_CONFIG_RANGE        0x07
  30 #define AL3320A_REG_PERSIST             0x08
  31 #define AL3320A_REG_MEAN_TIME           0x09
  32 #define AL3320A_REG_ADUMMY              0x0A
  33 #define AL3320A_REG_DATA_LOW            0x22
  34
  35 #define AL3320A_REG_LOW_THRESH_LOW      0x30
  36 #define AL3320A_REG_LOW_THRESH_HIGH     0x31
  37 #define AL3320A_REG_HIGH_THRESH_LOW     0x32
  38 #define AL3320A_REG_HIGH_THRESH_HIGH    0x33
  39
  40 #define AL3320A_CONFIG_DISABLE          0x00
  41 #define AL3320A_CONFIG_ENABLE           0x01
  42
  43 #define AL3320A_GAIN_SHIFT              1
  44 #define AL3320A_GAIN_MASK               (BIT(2) | BIT(1))
  45
  46 /* chip params default values */
  47 #define AL3320A_DEFAULT_MEAN_TIME       4
  48 #define AL3320A_DEFAULT_WAIT_TIME       0 /* no waiting */
  49
  50 #define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
  51
  52 enum al3320a_range {
  53         AL3320A_RANGE_1, /* 33.28 Klx */
  54         AL3320A_RANGE_2, /* 8.32 Klx  */
  55         AL3320A_RANGE_3, /* 2.08 Klx  */
  56         AL3320A_RANGE_4  /* 0.65 Klx  */
  57 };
  58
  59 static const int al3320a_scales[][2] = {
  60         {0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
  61 };
  62
  63 struct al3320a_data {
  64         struct i2c_client *client;
  65 };
  66
  67 static const struct iio_chan_spec al3320a_channels[] = {
  68         {
  69                 .type   = IIO_LIGHT,
  70                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  71                                       BIT(IIO_CHAN_INFO_SCALE),
  72         }
  73 };
  74
  75 static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
  76
  77 static struct attribute *al3320a_attributes[] = {
  78         &iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
  79         NULL,
  80 };
  81
  82 static const struct attribute_group al3320a_attribute_group = {
  83         .attrs = al3320a_attributes,
  84 };
  85
  86 static int al3320a_init(struct al3320a_data *data)
  87 {
  88         int ret;
  89
  90         /* power on */
  91         ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
  92                                         AL3320A_CONFIG_ENABLE);
  93         if (ret < 0)
  94                 return ret;
  95
  96         ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
  97                                         AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
  98         if (ret < 0)
  99                 return ret;
 100
 101         ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
 102                                         AL3320A_DEFAULT_MEAN_TIME);
 103         if (ret < 0)
 104                 return ret;
 105
 106         ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
 107                                         AL3320A_DEFAULT_WAIT_TIME);
 108         if (ret < 0)
 109                 return ret;
 110
 111         return 0;
 112 }
 113
 114 static int al3320a_read_raw(struct iio_dev *indio_dev,
 115                             struct iio_chan_spec const *chan, int *val,
 116                             int *val2, long mask)
 117 {
 118         struct al3320a_data *data = iio_priv(indio_dev);
 119         int ret;
 120
 121         switch (mask) {
 122         case IIO_CHAN_INFO_RAW:
 123                 /*
 124                  * ALS ADC value is stored in two adjacent registers:
 125                  * - low byte of output is stored at AL3320A_REG_DATA_LOW
 126                  * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
 127                  */
 128                 ret = i2c_smbus_read_word_data(data->client,
 129                                                AL3320A_REG_DATA_LOW);
 130                 if (ret < 0)
 131                         return ret;
 132                 *val = ret;
 133                 return IIO_VAL_INT;
 134         case IIO_CHAN_INFO_SCALE:
 135                 ret = i2c_smbus_read_byte_data(data->client,
 136                                                AL3320A_REG_CONFIG_RANGE);
 137                 if (ret < 0)
 138                         return ret;
 139
 140                 ret = (ret & AL3320A_GAIN_MASK) >> AL3320A_GAIN_SHIFT;
 141                 *val = al3320a_scales[ret][0];
 142                 *val2 = al3320a_scales[ret][1];
 143
 144                 return IIO_VAL_INT_PLUS_MICRO;
 145         }
 146         return -EINVAL;
 147 }
 148
 149 static int al3320a_write_raw(struct iio_dev *indio_dev,
 150                              struct iio_chan_spec const *chan, int val,
 151                              int val2, long mask)
 152 {
 153         struct al3320a_data *data = iio_priv(indio_dev);
 154         int i;
 155
 156         switch (mask) {
 157         case IIO_CHAN_INFO_SCALE:
 158                 for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
 159                         if (val == al3320a_scales[i][0] &&
 160                             val2 == al3320a_scales[i][1])
 161                                 return i2c_smbus_write_byte_data(data->client,
 162                                         AL3320A_REG_CONFIG_RANGE,
 163                                         i << AL3320A_GAIN_SHIFT);
 164                 }
 165                 break;
 166         }
 167         return -EINVAL;
 168 }
 169
 170 static const struct iio_info al3320a_info = {
 171         .read_raw       = al3320a_read_raw,
 172         .write_raw      = al3320a_write_raw,
 173         .attrs          = &al3320a_attribute_group,
 174 };
 175
 176 static int al3320a_probe(struct i2c_client *client,
 177                          const struct i2c_device_id *id)
 178 {
 179         struct al3320a_data *data;
 180         struct iio_dev *indio_dev;
 181         int ret;
 182
 183         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 184         if (!indio_dev)
 185                 return -ENOMEM;
 186
 187         data = iio_priv(indio_dev);
 188         i2c_set_clientdata(client, indio_dev);
 189         data->client = client;
 190
 191         indio_dev->dev.parent = &client->dev;
 192         indio_dev->info = &al3320a_info;
 193         indio_dev->name = AL3320A_DRV_NAME;
 194         indio_dev->channels = al3320a_channels;
 195         indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
 196         indio_dev->modes = INDIO_DIRECT_MODE;
 197
 198         ret = al3320a_init(data);
 199         if (ret < 0) {
 200                 dev_err(&client->dev, "al3320a chip init failed\n");
 201                 return ret;
 202         }
 203         return devm_iio_device_register(&client->dev, indio_dev);
 204 }
 205
 206 static int al3320a_remove(struct i2c_client *client)
 207 {
 208         return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
 209                                          AL3320A_CONFIG_DISABLE);
 210 }
 211
 212 static const struct i2c_device_id al3320a_id[] = {
 213         {"al3320a", 0},
 214         {}
 215 };
 216 MODULE_DEVICE_TABLE(i2c, al3320a_id);
 217
 218 static struct i2c_driver al3320a_driver = {
 219         .driver = {
 220                 .name = AL3320A_DRV_NAME,
 221         },
 222         .probe          = al3320a_probe,
 223         .remove         = al3320a_remove,
 224         .id_table       = al3320a_id,
 225 };
 226
 227 module_i2c_driver(al3320a_driver);
 228
 229 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
 230 MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
 231 MODULE_LICENSE("GPL v2");