drivers/iio/light/acpi-als.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ACPI Ambient Light Sensor Driver
   4  *
   5  * Based on ALS driver:
   6  * Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
   7  *
   8  * Rework for IIO subsystem:
   9  * Copyright (C) 2012-2013 Martin Liska <marxin.liska@gmail.com>
  10  *
  11  * Final cleanup and debugging:
  12  * Copyright (C) 2013-2014 Marek Vasut <marex@denx.de>
  13  * Copyright (C) 2015 Gabriele Mazzotta <gabriele.mzt@gmail.com>
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/acpi.h>
  18 #include <linux/err.h>
  19 #include <linux/mutex.h>
  20
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/buffer.h>
  23 #include <linux/iio/kfifo_buf.h>
  24
  25 #define ACPI_ALS_CLASS                  "als"
  26 #define ACPI_ALS_DEVICE_NAME            "acpi-als"
  27 #define ACPI_ALS_NOTIFY_ILLUMINANCE     0x80
  28
  29 ACPI_MODULE_NAME("acpi-als");
  30
  31 /*
  32  * So far, there's only one channel in here, but the specification for
  33  * ACPI0008 says there can be more to what the block can report. Like
  34  * chromaticity and such. We are ready for incoming additions!
  35  */
  36 static const struct iio_chan_spec acpi_als_channels[] = {
  37         {
  38                 .type           = IIO_LIGHT,
  39                 .scan_type      = {
  40                         .sign           = 's',
  41                         .realbits       = 32,
  42                         .storagebits    = 32,
  43                 },
  44                 /* _RAW is here for backward ABI compatibility */
  45                 .info_mask_separate     = BIT(IIO_CHAN_INFO_RAW) |
  46                                           BIT(IIO_CHAN_INFO_PROCESSED),
  47         },
  48 };
  49
  50 /*
  51  * The event buffer contains timestamp and all the data from
  52  * the ACPI0008 block. There are multiple, but so far we only
  53  * support _ALI (illuminance). Once someone adds new channels
  54  * to acpi_als_channels[], the evt_buffer below will grow
  55  * automatically.
  56  */
  57 #define ACPI_ALS_EVT_NR_SOURCES         ARRAY_SIZE(acpi_als_channels)
  58 #define ACPI_ALS_EVT_BUFFER_SIZE                \
  59         (sizeof(s64) + (ACPI_ALS_EVT_NR_SOURCES * sizeof(s32)))
  60
  61 struct acpi_als {
  62         struct acpi_device      *device;
  63         struct mutex            lock;
  64
  65         s32                     evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
  66 };
  67
  68 /*
  69  * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
  70  * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
  71  * special.
  72  *
  73  * The _ALR property returns tables that can be used to fine-tune the values
  74  * reported by the other props based on the particular hardware type and it's
  75  * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
  76  *
  77  * So far, we support only ALI (illuminance).
  78  */
  79 #define ACPI_ALS_ILLUMINANCE    "_ALI"
  80 #define ACPI_ALS_CHROMATICITY   "_ALC"
  81 #define ACPI_ALS_COLOR_TEMP     "_ALT"
  82 #define ACPI_ALS_POLLING        "_ALP"
  83 #define ACPI_ALS_TABLES         "_ALR"
  84
  85 static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
  86 {
  87         unsigned long long temp_val;
  88         acpi_status status;
  89
  90         status = acpi_evaluate_integer(als->device->handle, prop, NULL,
  91                                        &temp_val);
  92
  93         if (ACPI_FAILURE(status)) {
  94                 ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS %s", prop));
  95                 return -EIO;
  96         }
  97
  98         *val = temp_val;
  99
 100         return 0;
 101 }
 102
 103 static void acpi_als_notify(struct acpi_device *device, u32 event)
 104 {
 105         struct iio_dev *indio_dev = acpi_driver_data(device);
 106         struct acpi_als *als = iio_priv(indio_dev);
 107         s32 *buffer = als->evt_buffer;
 108         s64 time_ns = iio_get_time_ns(indio_dev);
 109         s32 val;
 110         int ret;
 111
 112         mutex_lock(&als->lock);
 113
 114         memset(buffer, 0, ACPI_ALS_EVT_BUFFER_SIZE);
 115
 116         switch (event) {
 117         case ACPI_ALS_NOTIFY_ILLUMINANCE:
 118                 ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
 119                 if (ret < 0)
 120                         goto out;
 121                 *buffer++ = val;
 122                 break;
 123         default:
 124                 /* Unhandled event */
 125                 dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
 126                         event);
 127                 goto out;
 128         }
 129
 130         iio_push_to_buffers_with_timestamp(indio_dev, als->evt_buffer, time_ns);
 131
 132 out:
 133         mutex_unlock(&als->lock);
 134 }
 135
 136 static int acpi_als_read_raw(struct iio_dev *indio_dev,
 137                              struct iio_chan_spec const *chan, int *val,
 138                              int *val2, long mask)
 139 {
 140         struct acpi_als *als = iio_priv(indio_dev);
 141         s32 temp_val;
 142         int ret;
 143
 144         if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
 145                 return -EINVAL;
 146
 147         /* we support only illumination (_ALI) so far. */
 148         if (chan->type != IIO_LIGHT)
 149                 return -EINVAL;
 150
 151         ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
 152         if (ret < 0)
 153                 return ret;
 154
 155         *val = temp_val;
 156
 157         return IIO_VAL_INT;
 158 }
 159
 160 static const struct iio_info acpi_als_info = {
 161         .read_raw               = acpi_als_read_raw,
 162 };
 163
 164 static int acpi_als_add(struct acpi_device *device)
 165 {
 166         struct acpi_als *als;
 167         struct iio_dev *indio_dev;
 168         struct iio_buffer *buffer;
 169
 170         indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
 171         if (!indio_dev)
 172                 return -ENOMEM;
 173
 174         als = iio_priv(indio_dev);
 175
 176         device->driver_data = indio_dev;
 177         als->device = device;
 178         mutex_init(&als->lock);
 179
 180         indio_dev->name = ACPI_ALS_DEVICE_NAME;
 181         indio_dev->dev.parent = &device->dev;
 182         indio_dev->info = &acpi_als_info;
 183         indio_dev->modes = INDIO_BUFFER_SOFTWARE;
 184         indio_dev->channels = acpi_als_channels;
 185         indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
 186
 187         buffer = devm_iio_kfifo_allocate(&device->dev);
 188         if (!buffer)
 189                 return -ENOMEM;
 190
 191         iio_device_attach_buffer(indio_dev, buffer);
 192
 193         return devm_iio_device_register(&device->dev, indio_dev);
 194 }
 195
 196 static const struct acpi_device_id acpi_als_device_ids[] = {
 197         {"ACPI0008", 0},
 198         {},
 199 };
 200
 201 MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
 202
 203 static struct acpi_driver acpi_als_driver = {
 204         .name   = "acpi_als",
 205         .class  = ACPI_ALS_CLASS,
 206         .ids    = acpi_als_device_ids,
 207         .ops = {
 208                 .add    = acpi_als_add,
 209                 .notify = acpi_als_notify,
 210         },
 211 };
 212
 213 module_acpi_driver(acpi_als_driver);
 214
 215 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
 216 MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
 217 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
 218 MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
 219 MODULE_LICENSE("GPL");