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_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 7418dcd..6d05240 100644 (file)
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -379,7 +379,12 @@ static int tilcdc_crtc_mode_set(struct drm_crtc *crtc,
        else
                tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_SYNC_EDGE);
 
-       if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+       /*
+        * use value from adjusted_mode here as this might have been
+        * changed as part of the fixup for slave encoders to solve the
+        * issue where tilcdc timings are not VESA compliant
+        */
+       if (adjusted_mode->flags & DRM_MODE_FLAG_NHSYNC)
                tilcdc_set(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_HSYNC);
        else
                tilcdc_clear(dev, LCDC_RASTER_TIMING_2_REG, LCDC_INVERT_HSYNC);

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_slave.c b/drivers/gpu/drm/tilcdc/tilcdc_slave.c
index dfffaf0..23b3203 100644 (file)
--- a/drivers/gpu/drm/tilcdc/tilcdc_slave.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_slave.c
@@ -73,13 +73,38 @@ static void slave_encoder_prepare(struct drm_encoder *encoder)
        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,