Re: [PATCH] drm/panel: simple: Fix AUO G121EAN01 panel timings according to the docs

From: Neil Armstrong
Date: Mon Aug 14 2023 - 08:38:06 EST


On 04/08/2023 17:12, Luca Ceresoli wrote:
Commit 03e909acd95a ("drm/panel: simple: Add support for AUO G121EAN01.4
panel") added support for this panel model, but the timings it implements
are very different from what the datasheet describes. I checked both the
G121EAN01.0 datasheet from [0] and the G121EAN01.4 one from [1] and they
all have the same timings: for example the LVDS clock typical value is 74.4
MHz, not 66.7 MHz as implemented.

Replace the timings with the ones from the documentation. These timings
have been tested and the clock frequencies verified with an oscilloscope to
ensure they are correct.

Also use struct display_timing instead of struct drm_display_mode in order
to also specify the minimum and maximum values.

[0] https://embedded.avnet.com/product/g121ean01-0/
[1] https://embedded.avnet.com/product/g121ean01-4/

Fixes: 03e909acd95a ("drm/panel: simple: Add support for AUO G121EAN01.4 panel")
Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
---
drivers/gpu/drm/panel/panel-simple.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 701013b3ad13..56854f78441e 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -999,21 +999,21 @@ static const struct panel_desc auo_g104sn02 = {
.connector_type = DRM_MODE_CONNECTOR_LVDS,
};
-static const struct drm_display_mode auo_g121ean01_mode = {
- .clock = 66700,
- .hdisplay = 1280,
- .hsync_start = 1280 + 58,
- .hsync_end = 1280 + 58 + 8,
- .htotal = 1280 + 58 + 8 + 70,
- .vdisplay = 800,
- .vsync_start = 800 + 6,
- .vsync_end = 800 + 6 + 4,
- .vtotal = 800 + 6 + 4 + 10,
+static const struct display_timing auo_g121ean01_timing = {
+ .pixelclock = { 60000000, 74400000, 90000000 },
+ .hactive = { 1280, 1280, 1280 },
+ .hfront_porch = { 20, 50, 100 },
+ .hback_porch = { 20, 50, 100 },
+ .hsync_len = { 30, 100, 200 },
+ .vactive = { 800, 800, 800 },
+ .vfront_porch = { 2, 10, 25 },
+ .vback_porch = { 2, 10, 25 },
+ .vsync_len = { 4, 18, 50 },
};
static const struct panel_desc auo_g121ean01 = {
- .modes = &auo_g121ean01_mode,
- .num_modes = 1,
+ .timings = &auo_g121ean01_timing,
+ .num_timings = 1,
.bpc = 8,
.size = {
.width = 261,

Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>