drivers/gpu/drm/drm_panel_backlight_quirks.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/array_size.h>
   4 #include <linux/dmi.h>
   5 #include <linux/mod_devicetable.h>
   6 #include <linux/module.h>
   7 #include <drm/drm_edid.h>
   8 #include <drm/drm_utils.h>
   9
  10 struct drm_panel_min_backlight_quirk {
  11         struct {
  12                 enum dmi_field field;
  13                 const char * const value;
  14         } dmi_match;
  15         struct drm_edid_ident ident;
  16         u8 min_brightness;
  17 };
  18
  19 static const struct drm_panel_min_backlight_quirk drm_panel_min_backlight_quirks[] = {
  20         /* 13 inch matte panel */
  21         {
  22                 .dmi_match.field = DMI_BOARD_VENDOR,
  23                 .dmi_match.value = "Framework",
  24                 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x0bca),
  25                 .ident.name = "NE135FBM-N41",
  26                 .min_brightness = 0,
  27         },
  28         /* 13 inch glossy panel */
  29         {
  30                 .dmi_match.field = DMI_BOARD_VENDOR,
  31                 .dmi_match.value = "Framework",
  32                 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x095f),
  33                 .ident.name = "NE135FBM-N41",
  34                 .min_brightness = 0,
  35         },
  36         /* 13 inch 2.8k panel */
  37         {
  38                 .dmi_match.field = DMI_BOARD_VENDOR,
  39                 .dmi_match.value = "Framework",
  40                 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x0cb4),
  41                 .ident.name = "NE135A1M-NY1",
  42                 .min_brightness = 0,
  43         },
  44 };
  45
  46 static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk *quirk,
  47                                                   const struct drm_edid *edid)
  48 {
  49         if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value))
  50                 return false;
  51
  52         if (!drm_edid_match(edid, &quirk->ident))
  53                 return false;
  54
  55         return true;
  56 }
  57
  58 /**
  59  * drm_get_panel_min_brightness_quirk - Get minimum supported brightness level for a panel.
  60  * @edid: EDID of the panel to check
  61  *
  62  * This function checks for platform specific (e.g. DMI based) quirks
  63  * providing info on the minimum backlight brightness for systems where this
  64  * cannot be probed correctly from the hard-/firm-ware.
  65  *
  66  * Returns:
  67  * A negative error value or
  68  * an override value in the range [0, 255] representing 0-100% to be scaled to
  69  * the drivers target range.
  70  */
  71 int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid)
  72 {
  73         const struct drm_panel_min_backlight_quirk *quirk;
  74         size_t i;
  75
  76         if (!IS_ENABLED(CONFIG_DMI))
  77                 return -ENODATA;
  78
  79         if (!edid)
  80                 return -EINVAL;
  81
  82         for (i = 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) {
  83                 quirk = &drm_panel_min_backlight_quirks[i];
  84
  85                 if (drm_panel_min_backlight_quirk_matches(quirk, edid))
  86                         return quirk->min_brightness;
  87         }
  88
  89         return -ENODATA;
  90 }
  91 EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk);
  92
  93 MODULE_DESCRIPTION("Quirks for panel backlight overrides");
  94 MODULE_LICENSE("GPL");