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                 /* _RAW is here for backward ABI compatibility */
  58                 .info_mask_separate     = BIT(IIO_CHAN_INFO_RAW) |
  59                                           BIT(IIO_CHAN_INFO_PROCESSED),
  60         },
  61 };
  62
  63 /*
  64  * The event buffer contains timestamp and all the data from
  65  * the ACPI0008 block. There are multiple, but so far we only
  66  * support _ALI (illuminance). Once someone adds new channels
  67  * to acpi_als_channels[], the evt_buffer below will grow
  68  * automatically.
  69  */
  70 #define ACPI_ALS_EVT_NR_SOURCES         ARRAY_SIZE(acpi_als_channels)
  71 #define ACPI_ALS_EVT_BUFFER_SIZE                \
  72         (sizeof(s64) + (ACPI_ALS_EVT_NR_SOURCES * sizeof(s32)))
  73
  74 struct acpi_als {
  75         struct acpi_device      *device;
  76         struct mutex            lock;
  77
  78         s32                     evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
  79 };
  80
  81 /*
  82  * All types of properties the ACPI0008 block can report. The ALI, ALC, ALT
  83  * and ALP can all be handled by acpi_als_read_value() below, while the ALR is
  84  * special.
  85  *
  86  * The _ALR property returns tables that can be used to fine-tune the values
  87  * reported by the other props based on the particular hardware type and it's
  88  * location (it contains tables for "rainy", "bright inhouse lighting" etc.).
  89  *
  90  * So far, we support only ALI (illuminance).
  91  */
  92 #define ACPI_ALS_ILLUMINANCE    "_ALI"
  93 #define ACPI_ALS_CHROMATICITY   "_ALC"
  94 #define ACPI_ALS_COLOR_TEMP     "_ALT"
  95 #define ACPI_ALS_POLLING        "_ALP"
  96 #define ACPI_ALS_TABLES         "_ALR"
  97
  98 static int acpi_als_read_value(struct acpi_als *als, char *prop, s32 *val)
  99 {
 100         unsigned long long temp_val;
 101         acpi_status status;
 102
 103         status = acpi_evaluate_integer(als->device->handle, prop, NULL,
 104                                        &temp_val);
 105
 106         if (ACPI_FAILURE(status)) {
 107                 ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS %s", prop));
 108                 return -EIO;
 109         }
 110
 111         *val = temp_val;
 112
 113         return 0;
 114 }
 115
 116 static void acpi_als_notify(struct acpi_device *device, u32 event)
 117 {
 118         struct iio_dev *indio_dev = acpi_driver_data(device);
 119         struct acpi_als *als = iio_priv(indio_dev);
 120         s32 *buffer = als->evt_buffer;
 121         s64 time_ns = iio_get_time_ns();
 122         s32 val;
 123         int ret;
 124
 125         mutex_lock(&als->lock);
 126
 127         memset(buffer, 0, ACPI_ALS_EVT_BUFFER_SIZE);
 128
 129         switch (event) {
 130         case ACPI_ALS_NOTIFY_ILLUMINANCE:
 131                 ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &val);
 132                 if (ret < 0)
 133                         goto out;
 134                 *buffer++ = val;
 135                 break;
 136         default:
 137                 /* Unhandled event */
 138                 dev_dbg(&device->dev, "Unhandled ACPI ALS event (%08x)!\n",
 139                         event);
 140                 goto out;
 141         }
 142
 143         iio_push_to_buffers_with_timestamp(indio_dev, als->evt_buffer, time_ns);
 144
 145 out:
 146         mutex_unlock(&als->lock);
 147 }
 148
 149 static int acpi_als_read_raw(struct iio_dev *indio_dev,
 150                              struct iio_chan_spec const *chan, int *val,
 151                              int *val2, long mask)
 152 {
 153         struct acpi_als *als = iio_priv(indio_dev);
 154         s32 temp_val;
 155         int ret;
 156
 157         if ((mask != IIO_CHAN_INFO_PROCESSED) && (mask != IIO_CHAN_INFO_RAW))
 158                 return -EINVAL;
 159
 160         /* we support only illumination (_ALI) so far. */
 161         if (chan->type != IIO_LIGHT)
 162                 return -EINVAL;
 163
 164         ret = acpi_als_read_value(als, ACPI_ALS_ILLUMINANCE, &temp_val);
 165         if (ret < 0)
 166                 return ret;
 167
 168         *val = temp_val;
 169
 170         return IIO_VAL_INT;
 171 }
 172
 173 static const struct iio_info acpi_als_info = {
 174         .driver_module          = THIS_MODULE,
 175         .read_raw               = acpi_als_read_raw,
 176 };
 177
 178 static int acpi_als_add(struct acpi_device *device)
 179 {
 180         struct acpi_als *als;
 181         struct iio_dev *indio_dev;
 182         struct iio_buffer *buffer;
 183
 184         indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
 185         if (!indio_dev)
 186                 return -ENOMEM;
 187
 188         als = iio_priv(indio_dev);
 189
 190         device->driver_data = indio_dev;
 191         als->device = device;
 192         mutex_init(&als->lock);
 193
 194         indio_dev->name = ACPI_ALS_DEVICE_NAME;
 195         indio_dev->dev.parent = &device->dev;
 196         indio_dev->info = &acpi_als_info;
 197         indio_dev->modes = INDIO_BUFFER_SOFTWARE;
 198         indio_dev->channels = acpi_als_channels;
 199         indio_dev->num_channels = ARRAY_SIZE(acpi_als_channels);
 200
 201         buffer = devm_iio_kfifo_allocate(&device->dev);
 202         if (!buffer)
 203                 return -ENOMEM;
 204
 205         iio_device_attach_buffer(indio_dev, buffer);
 206
 207         return devm_iio_device_register(&device->dev, indio_dev);
 208 }
 209
 210 static const struct acpi_device_id acpi_als_device_ids[] = {
 211         {"ACPI0008", 0},
 212         {},
 213 };
 214
 215 MODULE_DEVICE_TABLE(acpi, acpi_als_device_ids);
 216
 217 static struct acpi_driver acpi_als_driver = {
 218         .name   = "acpi_als",
 219         .class  = ACPI_ALS_CLASS,
 220         .ids    = acpi_als_device_ids,
 221         .ops = {
 222                 .add    = acpi_als_add,
 223                 .notify = acpi_als_notify,
 224         },
 225 };
 226
 227 module_acpi_driver(acpi_als_driver);
 228
 229 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
 230 MODULE_AUTHOR("Martin Liska <marxin.liska@gmail.com>");
 231 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
 232 MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
 233 MODULE_LICENSE("GPL");