drivers/thermal/int340x_thermal/int3406_thermal.c

   1 /*
   2  * INT3406 thermal driver for display participant device
   3  *
   4  * Copyright (C) 2016, Intel Corporation
   5  * Authors: Aaron Lu <aaron.lu@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/acpi.h>
  16 #include <linux/backlight.h>
  17 #include <linux/thermal.h>
  18 #include <acpi/video.h>
  19
  20 #define INT3406_BRIGHTNESS_LIMITS_CHANGED       0x80
  21
  22 struct int3406_thermal_data {
  23         int upper_limit;
  24         int lower_limit;
  25         acpi_handle handle;
  26         struct acpi_video_device_brightness *br;
  27         struct backlight_device *raw_bd;
  28         struct thermal_cooling_device *cooling_dev;
  29 };
  30
  31 /*
  32  * According to the ACPI spec,
  33  * "Each brightness level is represented by a number between 0 and 100,
  34  * and can be thought of as a percentage. For example, 50 can be 50%
  35  * power consumption or 50% brightness, as defined by the OEM."
  36  *
  37  * As int3406 device uses this value to communicate with the native
  38  * graphics driver, we make the assumption that it represents
  39  * the percentage of brightness only
  40  */
  41 #define ACPI_TO_RAW(v, d) (d->raw_bd->props.max_brightness * v / 100)
  42 #define RAW_TO_ACPI(v, d) (v * 100 / d->raw_bd->props.max_brightness)
  43
  44 static int
  45 int3406_thermal_get_max_state(struct thermal_cooling_device *cooling_dev,
  46                               unsigned long *state)
  47 {
  48         struct int3406_thermal_data *d = cooling_dev->devdata;
  49
  50         *state = d->upper_limit - d->lower_limit;
  51         return 0;
  52 }
  53
  54 static int
  55 int3406_thermal_set_cur_state(struct thermal_cooling_device *cooling_dev,
  56                               unsigned long state)
  57 {
  58         struct int3406_thermal_data *d = cooling_dev->devdata;
  59         int acpi_level, raw_level;
  60
  61         if (state > d->upper_limit - d->lower_limit)
  62                 return -EINVAL;
  63
  64         acpi_level = d->br->levels[d->upper_limit - state];
  65
  66         raw_level = ACPI_TO_RAW(acpi_level, d);
  67
  68         return backlight_device_set_brightness(d->raw_bd, raw_level);
  69 }
  70
  71 static int
  72 int3406_thermal_get_cur_state(struct thermal_cooling_device *cooling_dev,
  73                               unsigned long *state)
  74 {
  75         struct int3406_thermal_data *d = cooling_dev->devdata;
  76         int acpi_level;
  77         int index;
  78
  79         acpi_level = RAW_TO_ACPI(d->raw_bd->props.brightness, d);
  80
  81         /*
  82          * There is no 1:1 mapping between the firmware interface level
  83          * with the raw interface level, we will have to find one that is
  84          * right above it.
  85          */
  86         for (index = d->lower_limit; index < d->upper_limit; index++) {
  87                 if (acpi_level <= d->br->levels[index])
  88                         break;
  89         }
  90
  91         *state = d->upper_limit - index;
  92         return 0;
  93 }
  94
  95 static const struct thermal_cooling_device_ops video_cooling_ops = {
  96         .get_max_state = int3406_thermal_get_max_state,
  97         .get_cur_state = int3406_thermal_get_cur_state,
  98         .set_cur_state = int3406_thermal_set_cur_state,
  99 };
 100
 101 static int int3406_thermal_get_index(int *array, int nr, int value)
 102 {
 103         int i;
 104
 105         for (i = 2; i < nr; i++) {
 106                 if (array[i] == value)
 107                         break;
 108         }
 109         return i == nr ? -ENOENT : i;
 110 }
 111
 112 static void int3406_thermal_get_limit(struct int3406_thermal_data *d)
 113 {
 114         acpi_status status;
 115         unsigned long long lower_limit, upper_limit;
 116
 117         status = acpi_evaluate_integer(d->handle, "DDDL", NULL, &lower_limit);
 118         if (ACPI_SUCCESS(status))
 119                 d->lower_limit = int3406_thermal_get_index(d->br->levels,
 120                                         d->br->count, lower_limit);
 121
 122         status = acpi_evaluate_integer(d->handle, "DDPC", NULL, &upper_limit);
 123         if (ACPI_SUCCESS(status))
 124                 d->upper_limit = int3406_thermal_get_index(d->br->levels,
 125                                         d->br->count, upper_limit);
 126
 127         /* lower_limit and upper_limit should be always set */
 128         d->lower_limit = d->lower_limit > 0 ? d->lower_limit : 2;
 129         d->upper_limit = d->upper_limit > 0 ? d->upper_limit : d->br->count - 1;
 130 }
 131
 132 static void int3406_notify(acpi_handle handle, u32 event, void *data)
 133 {
 134         if (event == INT3406_BRIGHTNESS_LIMITS_CHANGED)
 135                 int3406_thermal_get_limit(data);
 136 }
 137
 138 static int int3406_thermal_probe(struct platform_device *pdev)
 139 {
 140         struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 141         struct int3406_thermal_data *d;
 142         struct backlight_device *bd;
 143         int ret;
 144
 145         if (!ACPI_HANDLE(&pdev->dev))
 146                 return -ENODEV;
 147
 148         d = devm_kzalloc(&pdev->dev, sizeof(*d), GFP_KERNEL);
 149         if (!d)
 150                 return -ENOMEM;
 151         d->handle = ACPI_HANDLE(&pdev->dev);
 152
 153         bd = backlight_device_get_by_type(BACKLIGHT_RAW);
 154         if (!bd)
 155                 return -ENODEV;
 156         d->raw_bd = bd;
 157
 158         ret = acpi_video_get_levels(ACPI_COMPANION(&pdev->dev), &d->br, NULL);
 159         if (ret)
 160                 return ret;
 161
 162         int3406_thermal_get_limit(d);
 163
 164         d->cooling_dev = thermal_cooling_device_register(acpi_device_bid(adev),
 165                                                          d, &video_cooling_ops);
 166         if (IS_ERR(d->cooling_dev))
 167                 goto err;
 168
 169         ret = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
 170                                           int3406_notify, d);
 171         if (ret)
 172                 goto err_cdev;
 173
 174         platform_set_drvdata(pdev, d);
 175
 176         return 0;
 177
 178 err_cdev:
 179         thermal_cooling_device_unregister(d->cooling_dev);
 180 err:
 181         kfree(d->br);
 182         return -ENODEV;
 183 }
 184
 185 static int int3406_thermal_remove(struct platform_device *pdev)
 186 {
 187         struct int3406_thermal_data *d = platform_get_drvdata(pdev);
 188
 189         thermal_cooling_device_unregister(d->cooling_dev);
 190         kfree(d->br);
 191         return 0;
 192 }
 193
 194 static const struct acpi_device_id int3406_thermal_match[] = {
 195         {"INT3406", 0},
 196         {}
 197 };
 198
 199 MODULE_DEVICE_TABLE(acpi, int3406_thermal_match);
 200
 201 static struct platform_driver int3406_thermal_driver = {
 202         .probe = int3406_thermal_probe,
 203         .remove = int3406_thermal_remove,
 204         .driver = {
 205                    .name = "int3406 thermal",
 206                    .acpi_match_table = int3406_thermal_match,
 207                    },
 208 };
 209
 210 module_platform_driver(int3406_thermal_driver);
 211
 212 MODULE_DESCRIPTION("INT3406 Thermal driver");
 213 MODULE_LICENSE("GPL v2");