[PATCH v2 01/12] drm/tegra: rgb: Parameterize V- and H-sync polarities

From: Tomi Valkeinen
Date: Wed Aug 16 2023 - 07:26:21 EST


From: Thierry Reding <treding@xxxxxxxxxx>

The polarities of the V- and H-sync signals are encoded as flags in the
display mode, so use the existing information to setup the signals for
the RGB interface.

Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
[tomi.valkeinen@xxxxxxxxxxxxxxxx: default to positive sync]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/tegra/rgb.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c
index 79566c9ea8ff..fc66bbd913b2 100644
--- a/drivers/gpu/drm/tegra/rgb.c
+++ b/drivers/gpu/drm/tegra/rgb.c
@@ -99,6 +99,7 @@ static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)

static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
{
+ struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
struct tegra_output *output = encoder_to_output(encoder);
struct tegra_rgb *rgb = to_rgb(output);
u32 value;
@@ -108,10 +109,19 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);

- /* XXX: parameterize? */
+ /* configure H- and V-sync signal polarities */
value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
- value &= ~LVS_OUTPUT_POLARITY_LOW;
- value &= ~LHS_OUTPUT_POLARITY_LOW;
+
+ if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+ value |= LHS_OUTPUT_POLARITY_LOW;
+ else
+ value &= ~LHS_OUTPUT_POLARITY_LOW;
+
+ if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+ value |= LVS_OUTPUT_POLARITY_LOW;
+ else
+ value &= ~LVS_OUTPUT_POLARITY_LOW;
+
tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));

/* XXX: parameterize? */

--
2.34.1