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authorStefan Agner <stefan@agner.ch>2016-02-08 23:50:13 +0300
committerStefan Agner <stefan@agner.ch>2016-05-05 20:09:06 +0300
commit2c80661d2ea9bac9bc7ba519097745829add1871 (patch)
treeed9ac6fc008fdf8517b240c09d4b2e6ee11d3a12 /drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
parentf0aa08387b92e432166d7143993da2635c8821e8 (diff)
downloadlinux-2c80661d2ea9bac9bc7ba519097745829add1871.tar.xz
drm/fsl-dcu: use bus_flags for pixel clock polarity
The drivers current default configuration drives the pixel data on rising edge of the pixel clock. However, most display sample data on rising edge... This leads to color shift artefacts visible especially at edges. This patch changes the relevant defines to be useful and actually set the bits, and changes pixel clock polarity to drive the pixel data on falling edge by default. The patch also adds an explicit pixel clock polarity flag to the display introduced with the driver (NEC WQVGA "nec,nl4827hc19-05b") using the new bus_flags field to retain the initial behavior. Signed-off-by: Stefan Agner <stefan@agner.ch>
Diffstat (limited to 'drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c')
-rw-r--r--drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 365809edf29a..89c0084c2814 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -66,6 +66,7 @@ static void fsl_dcu_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
{
struct drm_device *dev = crtc->dev;
struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
+ struct drm_connector *con = &fsl_dev->connector.base;
struct drm_display_mode *mode = &crtc->state->mode;
unsigned int hbp, hfp, hsw, vbp, vfp, vsw, index, pol = 0;
@@ -80,6 +81,10 @@ static void fsl_dcu_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
vfp = mode->vsync_start - mode->vdisplay;
vsw = mode->vsync_end - mode->vsync_start;
+ /* INV_PXCK as default (most display sample data on rising edge) */
+ if (!(con->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE))
+ pol |= DCU_SYN_POL_INV_PXCK;
+
if (mode->flags & DRM_MODE_FLAG_NHSYNC)
pol |= DCU_SYN_POL_INV_HS_LOW;