drm/panel-simple: add Evervision VGG644804 panel entry

Timings taken from the datasheet, although sometimes there are just
typical values and it's not clear if they are no min and max values or
if you must use the typical value exactly. To make things worse, there
is no back porch but only a combined sync and back porch length.

Unfortunately, there is not public datasheet. Therefore, here are the
relevant timings:
                 | min |  typ   | max |
-----------------+-----+--------+-----+
CLK frequency    |  -  | 25.175 |  -  |
HS period        |  -  |   800  |  -  |
HS pulse width   |  5  |    30  |  -  |
HS-DEN time      | 112 |   144  | 175 |
DEN pulse width  |  -  |   640  |  -  |
VS pulse width   |  1  |     3  |  5  |
VS-DEN time      |  -  |    35  |  -  |
VS period        |  -  |   525  |  -  |
Signed-off-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231123102404.2022201-2-mwalle@kernel.orgSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231123102404.2022201-2-mwalle@kernel.org

drivers/gpu/drm/panel/panel-simple.c

@@ -2002,6 +2002,33 @@ static const struct panel_desc eink_vb3300_kca = {
 	.connector_type = DRM_MODE_CONNECTOR_DPI,
 };
 
+static const struct display_timing evervision_vgg644804_timing = {
+	.pixelclock = { 25175000, 25175000, 25175000 },
+	.hactive = { 640, 640, 640 },
+	.hfront_porch = { 16, 16, 16 },
+	.hback_porch = { 82, 114, 170 },
+	.hsync_len = { 5, 30, 30 },
+	.vactive = { 480, 480, 480 },
+	.vfront_porch = { 10, 10, 10 },
+	.vback_porch = { 30, 32, 34 },
+	.vsync_len = { 1, 3, 5 },
+	.flags = DISPLAY_FLAGS_HSYNC_LOW | DISPLAY_FLAGS_VSYNC_LOW |
+		 DISPLAY_FLAGS_DE_HIGH | DISPLAY_FLAGS_PIXDATA_POSEDGE |
+		 DISPLAY_FLAGS_SYNC_POSEDGE,
+};
+
+static const struct panel_desc evervision_vgg644804 = {
+	.timings = &evervision_vgg644804_timing,
+	.num_timings = 1,
+	.bpc = 8,
+	.size = {
+		.width = 115,
+		.height = 86,
+	},
+	.bus_format = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,
+	.bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE,
+};
+
 static const struct display_timing evervision_vgg804821_timing = {
 	.pixelclock = { 27600000, 33300000, 50000000 },
 	.hactive = { 800, 800, 800 },
@@ -4366,6 +4393,9 @@ static const struct of_device_id platform_of_match[] = {
 	}, {
 		.compatible = "eink,vb3300-kca",
 		.data = &eink_vb3300_kca,
+	}, {
+		.compatible = "evervision,vgg644804",
+		.data = &evervision_vgg644804,
 	}, {
 		.compatible = "evervision,vgg804821",
 		.data = &evervision_vgg804821,