diff options
| author | Stefan Agner <stefan@agner.ch> | 2016-12-14 12:48:09 -0800 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2017-03-10 11:10:49 +1000 |
| commit | 53990e416bb7adaa59d045f325a47f31a11b75ee (patch) | |
| tree | d87ea97b09ecedad96ffaf192c35dc1ee616517f /drivers/gpu/drm/mxsfb | |
| parent | 10f2889ba35aeb251b9945ec4c461af8c124c41f (diff) | |
| download | linux-53990e416bb7adaa59d045f325a47f31a11b75ee.tar.bz2 | |
drm: mxsfb: fix pixel clock polarity
The DRM subsystem specifies the pixel clock polarity from a
controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
the controller drives the data on pixel clocks falling edge.
That is the controllers DOTCLK_POL=0 (Default is data launched
at negative edge).
Also change the data enable logic to be high active by default
and only change if explicitly requested via bus_flags. With
that defaults are:
- Data enable: high active
- Pixel clock polarity: controller drives data on negative edge
Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/mxsfb')
| -rw-r--r-- | drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c index 259f71b3a76a..165abd227436 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c @@ -196,9 +196,16 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb) vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH; if (m->flags & DRM_MODE_FLAG_PVSYNC) vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH; - if (bus_flags & DRM_BUS_FLAG_DE_HIGH) + /* Make sure Data Enable is high active by default */ + if (!(bus_flags & DRM_BUS_FLAG_DE_LOW)) vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH; - if (bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE) + /* + * DRM_BUS_FLAG_PIXDATA_ defines are controller centric, + * controllers VDCTRL0_DOTCLK is display centric. + * Drive on positive edge -> display samples on falling edge + * DRM_BUS_FLAG_PIXDATA_POSEDGE -> VDCTRL0_DOTCLK_ACT_FALLING + */ + if (bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE) vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING; writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0); |