drivers/iio/light/acpi-als.c

   1 /*
   2  * ACPI Ambient Light Sensor Driver
   3  *
   4  * Based on ALS driver:
   5  * Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
   6  *
   7  * Rework for IIO subsystem:
   8  * Copyright (C) 2012-2013 Martin Liska <marxin.liska@gmail.com>
   9  *
  10  * Final cleanup and debugging:
  11  * Copyright (C) 2013-2014 Marek Vasut <marex@denx.de>
  12  * Copyright (C) 2015 Gabriele Mazzotta <gabriele.mzt@gmail.com>
  13  *
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU General Public License as published by the
  16  * Free Software Foundation; either version 2 of the License, or (at your
  17  * option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful, but
  20  * WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  * General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License along
  25  * with this program; if not, write to the Free Software Foundation, Inc.,
  26  * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/acpi.h>
  31 #include <linux/err.h>
  32 #include <linux/mutex.h>
  33
  34 #include <linux/iio/iio.h>
  35 #include <linux/iio/buffer.h>
  36 #include <linux/iio/kfifo_buf.h>
  37
  38 #define ACPI_ALS_CLASS                  "als"
  39 #define ACPI_ALS_DEVICE_NAME            "acpi-als"
  40 #define ACPI_ALS_NOTIFY_ILLUMINANCE     0x80
  41
  42 ACPI_MODULE_NAME("acpi-als");
  43
  44 /*
  45  * So far, there's only one channel in here, but the specification for
  46  * ACPI0008 says there can be more to what the block can report. Like
  47  * chromaticity and such. We are ready for incoming additions!
  48  */
  49 static const struct iio_chan_spec acpi_als_channels[] = {
  50         {
  51                 .type           = IIO_LIGHT,
  52                 .scan_type      = {
  53                         .sign           = 's',
  54                         .realbits       = 32,
  55                         .storagebits    = 32,
  56                 },
  57                 .info_mask_separate     = BIT(IIO_CHAN_INFO_RAW),
  58         },
  59 };
  60
  61 /*
  62  * The event buffer contains timestamp and all the data from
  63  * the ACPI0008 block. There are multiple, but so far we only
  64  * support _ALI (illuminance). Once someone adds new channels
  65  * to acpi_als_channels[], the evt_buffer below will grow
  66  * automatically.
  67  */
  68 #define ACPI_ALS_EVT_NR_SOURCES         ARRAY_SIZE(acpi_als_channels)
  69 #define ACPI_ALS_EVT_BUFFER_SIZE                \
  70         (sizeof(s64) + (ACPI_ALS_EVT_NR_SOURCES * sizeof(s32)))
  71
  72 struct acpi_als {
  73         struct acpi_device      *device;
  74         struct mutex            lock;
  75
  76         s32                     evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
  77 };
  78
  79 /*
  80  * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
  81  * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
  82  * special.
  83  *
  84  * The _ALR property returns tables that can be used to fine-tune the values
  85  * reported by the other props based on the particular hardware type and it's
  86  * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
  87  *
  88  * So far, we support only ALI (illuminance).
  89  */
  90 #define ACPI_ALS_ILLUMINANCE    "_ALI"
  91 #define ACPI_ALS_CHROMATICITY   "_ALC"
  92 #define ACPI_ALS_COLOR_TEMP     "_ALT"
  93 #define ACPI_ALS_POLLING        "_ALP"
  94 #define ACPI_ALS_TABLES         "_ALR"
  95
  96 static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
  97 {
  98         unsigned long long temp_val;
  99         acpi_status status;
 100
 101         status = acpi_evaluate_integer(als->device->handle, prop, NULL,
 102                                        &temp_val);
 103
 104         if (ACPI_FAILURE(status)) {
 105                 ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS %s", prop));
 106                 return -EIO;
 107         }
 108
 109         *val = temp_val;
 110
 111         return 0;
 112 }
 113
 114 static void acpi_als_notify(struct acpi_device *device, u32 event)
 115 {
 116         struct iio_dev *indio_dev = acpi_driver_data(device);
 117         struct acpi_als *als = iio_priv(indio_dev);
 118         s32 *buffer = als->evt_buffer;
 119         s64 time_ns = iio_get_time_ns();
 120         s32 val;
 121         int ret;
 122
 123         mutex_lock(&als->lock);
 124
 125         memset(buffer, 0, ACPI_ALS_EVT_BUFFER_SIZE);
 126
 127         switch (event) {
 128         case ACPI_ALS_NOTIFY_ILLUMINANCE:
 129                 ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
 130                 if (ret < 0)
 131                         goto out;
 132                 *buffer++ = val;
 133                 break;
 134         default:
 135                 /* Unhandled event */
 136                 dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
 137                         event);
 138                 goto out;
 139         }
 140
 141         iio_push_to_buffers_with_timestamp(indio_dev, als->evt_buffer, time_ns);
 142
 143 out:
 144         mutex_unlock(&als->lock);
 145 }
 146
 147 static int acpi_als_read_raw(struct iio_dev *indio_dev,
 148                              struct iio_chan_spec const *chan, int *val,
 149                              int *val2, long mask)
 150 {
 151         struct acpi_als *als = iio_priv(indio_dev);
 152         s32 temp_val;
 153         int ret;
 154
 155         if (mask != IIO_CHAN_INFO_RAW)
 156                 return -EINVAL;
 157
 158         /* we support only illumination (_ALI) so far. */
 159         if (chan->type != IIO_LIGHT)
 160                 return -EINVAL;
 161
 162         ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
 163         if (ret < 0)
 164                 return ret;
 165
 166         *val = temp_val;
 167
 168         return IIO_VAL_INT;
 169 }
 170
 171 static const struct iio_info acpi_als_info = {
 172         .driver_module          = THIS_MODULE,
 173         .read_raw               = acpi_als_read_raw,
 174 };
 175
 176 static int acpi_als_add(struct acpi_device *device)
 177 {
 178         struct acpi_als *als;
 179         struct iio_dev *indio_dev;
 180         struct iio_buffer *buffer;
 181
 182         indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
 183         if (!indio_dev)
 184                 return -ENOMEM;
 185
 186         als = iio_priv(indio_dev);
 187
 188         device->driver_data = indio_dev;
 189         als->device = device;
 190         mutex_init(&als->lock);
 191
 192         indio_dev->name = ACPI_ALS_DEVICE_NAME;
 193         indio_dev->dev.parent = &device->dev;
 194         indio_dev->info = &acpi_als_info;
 195         indio_dev->modes = INDIO_BUFFER_SOFTWARE;
 196         indio_dev->channels = acpi_als_channels;
 197         indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
 198
 199         buffer = devm_iio_kfifo_allocate(&device->dev);
 200         if (!buffer)
 201                 return -ENOMEM;
 202
 203         iio_device_attach_buffer(indio_dev, buffer);
 204
 205         return devm_iio_device_register(&device->dev, indio_dev);
 206 }
 207
 208 static const struct acpi_device_id acpi_als_device_ids[] = {
 209         {"ACPI0008", 0},
 210         {},
 211 };
 212
 213 MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
 214
 215 static struct acpi_driver acpi_als_driver = {
 216         .name   = "acpi_als",
 217         .class  = ACPI_ALS_CLASS,
 218         .ids    = acpi_als_device_ids,
 219         .ops = {
 220                 .add    = acpi_als_add,
 221                 .notify = acpi_als_notify,
 222         },
 223 };
 224
 225 module_acpi_driver(acpi_als_driver);
 226
 227 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
 228 MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
 229 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
 230 MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
 231 MODULE_LICENSE("GPL");