LCDIF-DSIM glue logic inverts the HS/VS/DE signals and expecting
the i.MX8M Mini/Nano DSI host to add additional Data Enable signal
active low (DE_LOW). This makes the valid data transfer on each
horizontal line.
So, add additional bus flags DE_LOW setting via input_bus_flags
for i.MX8M Mini/Nano platforms.
Reviewed-by: Marek Vasut <marex@xxxxxxx>
Reviewed-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
Suggested-by: Marek Vasut <marex@xxxxxxx>
Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
---
Changes for v15, v13:
- none
Changes for v12:
- collect RB from Marek
Changes for v11:
- collect RB from Frieder
Changes for v10, v9:
- none
Changes for v8:
- add DE_LOW for i.MX8M Mini/Nano platforms.
Changes for v7, v6:
- none
Changes for v5:
- rebased based on updated bridge changes
Changes for v4 - v1:
- none
drivers/gpu/drm/exynos/exynos_drm_dsi.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 796480e4a18b..5d971b607e1a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -1736,6 +1736,10 @@ static const struct component_ops exynos_dsi_component_ops = {
.unbind = exynos_dsi_unbind,
};
+static const struct drm_bridge_timings dsim_bridge_timings_de_low = {
+ .input_bus_flags = DRM_BUS_FLAG_DE_LOW,
+};
+
static int exynos_dsi_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -1822,6 +1826,10 @@ static int exynos_dsi_probe(struct platform_device *pdev)
dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
dsi->bridge.pre_enable_prev_first = true;
+ /* DE_LOW: i.MX8M Mini/Nano LCDIF-DSIM glue logic inverts HS/VS/DE */
+ if (dsi->plat_data->hw_type == DSIM_TYPE_IMX8MM)
+ dsi->bridge.timings = &dsim_bridge_timings_de_low;
+
ret = component_add(dev, &exynos_dsi_component_ops);
if (ret)
goto err_disable_runtime;
--
2.25.1
