1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/array_size.h>
4 #include <linux/dmi.h>
5 #include <linux/export.h>
6 #include <linux/mod_devicetable.h>
7 #include <linux/module.h>
8 #include <drm/drm_edid.h>
9 #include <drm/drm_utils.h>
10
11 struct drm_panel_min_backlight_quirk {
12 struct {
13 enum dmi_field field;
14 const char * const value;
15 } dmi_match;
16 struct drm_edid_ident ident;
17 u8 min_brightness;
18 };
19
20 static const struct drm_panel_min_backlight_quirk drm_panel_min_backlight_quirks[] = {
21 /* 13 inch matte panel */
22 {
23 .dmi_match.field = DMI_BOARD_VENDOR,
24 .dmi_match.value = "Framework",
25 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x0bca),
26 .ident.name = "NE135FBM-N41",
27 .min_brightness = 0,
28 },
29 /* 13 inch glossy panel */
30 {
31 .dmi_match.field = DMI_BOARD_VENDOR,
32 .dmi_match.value = "Framework",
33 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x095f),
34 .ident.name = "NE135FBM-N41",
35 .min_brightness = 0,
36 },
37 /* 13 inch 2.8k panel */
38 {
39 .dmi_match.field = DMI_BOARD_VENDOR,
40 .dmi_match.value = "Framework",
41 .ident.panel_id = drm_edid_encode_panel_id('B', 'O', 'E', 0x0cb4),
42 .ident.name = "NE135A1M-NY1",
43 .min_brightness = 0,
44 },
45 };
46
drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk * quirk,const struct drm_edid * edid)47 static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_min_backlight_quirk *quirk,
48 const struct drm_edid *edid)
49 {
50 if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value))
51 return false;
52
53 if (!drm_edid_match(edid, &quirk->ident))
54 return false;
55
56 return true;
57 }
58
59 /**
60 * drm_get_panel_min_brightness_quirk - Get minimum supported brightness level for a panel.
61 * @edid: EDID of the panel to check
62 *
63 * This function checks for platform specific (e.g. DMI based) quirks
64 * providing info on the minimum backlight brightness for systems where this
65 * cannot be probed correctly from the hard-/firm-ware.
66 *
67 * Returns:
68 * A negative error value or
69 * an override value in the range [0, 255] representing 0-100% to be scaled to
70 * the drivers target range.
71 */
drm_get_panel_min_brightness_quirk(const struct drm_edid * edid)72 int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid)
73 {
74 const struct drm_panel_min_backlight_quirk *quirk;
75 size_t i;
76
77 if (!IS_ENABLED(CONFIG_DMI))
78 return -ENODATA;
79
80 if (!edid)
81 return -EINVAL;
82
83 for (i = 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) {
84 quirk = &drm_panel_min_backlight_quirks[i];
85
86 if (drm_panel_min_backlight_quirk_matches(quirk, edid))
87 return quirk->min_brightness;
88 }
89
90 return -ENODATA;
91 }
92 EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk);
93
94 MODULE_DESCRIPTION("Quirks for panel backlight overrides");
95 MODULE_LICENSE("GPL");
96