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
10struct 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
19static 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
46static 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 */
71int 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}
91EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk);
92
93MODULE_DESCRIPTION("Quirks for panel backlight overrides");
94MODULE_LICENSE("GPL");