drm/tilcdc fixup mode to workaround sync for tda998x
Add a fixup function that will flip the hsync priority and
add a hskew value that is used to shift the tda998x to the
right by a variable number of pixels depending on the mode.
This works around an issue with the sync timings that tilcdc
is outputing.
Signed-off-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Russell King <rmk_kernel@arm.linux.org.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_slave.c b/drivers/gpu/drm/tilcdc/tilcdc_slave.c
index dfffaf0..23b3203 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_slave.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_slave.c
@@ -73,13 +73,38 @@
tilcdc_crtc_set_panel_info(encoder->crtc, &slave_info);
}
+static bool slave_encoder_fixup(struct drm_encoder *encoder,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ /*
+ * tilcdc does not generate VESA-complient sync but aligns
+ * VS on the second edge of HS instead of first edge.
+ * We use adjusted_mode, to fixup sync by aligning both rising
+ * edges and add HSKEW offset to let the slave encoder fix it up.
+ */
+ adjusted_mode->hskew = mode->hsync_end - mode->hsync_start;
+ adjusted_mode->flags |= DRM_MODE_FLAG_HSKEW;
+
+ if (mode->flags & DRM_MODE_FLAG_NHSYNC) {
+ adjusted_mode->flags |= DRM_MODE_FLAG_PHSYNC;
+ adjusted_mode->flags &= ~DRM_MODE_FLAG_NHSYNC;
+ } else {
+ adjusted_mode->flags |= DRM_MODE_FLAG_NHSYNC;
+ adjusted_mode->flags &= ~DRM_MODE_FLAG_PHSYNC;
+ }
+
+ return drm_i2c_encoder_mode_fixup(encoder, mode, adjusted_mode);
+}
+
+
static const struct drm_encoder_funcs slave_encoder_funcs = {
.destroy = slave_encoder_destroy,
};
static const struct drm_encoder_helper_funcs slave_encoder_helper_funcs = {
.dpms = drm_i2c_encoder_dpms,
- .mode_fixup = drm_i2c_encoder_mode_fixup,
+ .mode_fixup = slave_encoder_fixup,
.prepare = slave_encoder_prepare,
.commit = drm_i2c_encoder_commit,
.mode_set = drm_i2c_encoder_mode_set,