Instead of open coding, use the mipi_dsi_pixel_format_to_bpp() helper
function from drm_mipi_dsi.h in mtk_dsi_poweron() and for validation
in mtk_dsi_bridge_mode_valid().
Note that this function changes the behavior of this driver: previously,
in case of unknown formats, it would (wrongly) assume that it should
account for a 24-bits format - now it will return an error and refuse
to set clocks and/or enable the DSI.
This is done because setting the wrong data rate will only produce a
garbage output that the display will misinterpret both because this
driver doesn't actually provide any extra-spec format support and/or
because the data rate (hence, the HS clock) will be wrong.
Reviewed-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index b644505de98a..9501f4019199 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -598,19 +598,12 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
if (++dsi->refcount != 1)
return 0;
- switch (dsi->format) {
- case MIPI_DSI_FMT_RGB565:
- bit_per_pixel = 16;
- break;
- case MIPI_DSI_FMT_RGB666_PACKED:
- bit_per_pixel = 18;
- break;
- case MIPI_DSI_FMT_RGB666:
- case MIPI_DSI_FMT_RGB888:
- default:
- bit_per_pixel = 24;
- break;
+ ret = mipi_dsi_pixel_format_to_bpp(dsi->format);
+ if (ret < 0) {
+ dev_err(dev, "Unknown MIPI DSI format %d\n", dsi->format);
+ return ret;
}
+ bit_per_pixel = ret;
dsi->data_rate = DIV_ROUND_UP_ULL(dsi->vm.pixelclock * bit_per_pixel,
dsi->lanes);
@@ -793,12 +786,11 @@ mtk_dsi_bridge_mode_valid(struct drm_bridge *bridge,
const struct drm_display_mode *mode)
{
struct mtk_dsi *dsi = bridge_to_dsi(bridge);
- u32 bpp;
+ int bpp;
- if (dsi->format == MIPI_DSI_FMT_RGB565)
- bpp = 16;
- else
- bpp = 24;
+ bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+ if (bpp < 0)
+ return MODE_ERROR;
if (mode->clock * bpp / dsi->lanes > 1500000)
return MODE_CLOCK_HIGH;
--
2.43.0
