Simplify bridge timing support by only supporting pixel clock polarity. This aligns pixel clock polarity handling for bridges with displays.
Signed-off-by: Stefan Agner stefan@agner.ch --- drivers/gpu/drm/pl111/pl111_display.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c index 754f6b25f265..31eb62e4476f 100644 --- a/drivers/gpu/drm/pl111/pl111_display.c +++ b/drivers/gpu/drm/pl111/pl111_display.c @@ -196,23 +196,13 @@ static void pl111_display_enable(struct drm_simple_display_pipe *pipe, const struct drm_bridge_timings *btimings = bridge->timings;
/* - * Here is when things get really fun. Sometimes the bridge - * timings are such that the signal out from PL11x is not - * stable before the receiving bridge (such as a dumb VGA DAC - * or similar) samples it. If that happens, we compensate by - * the only method we have: output the data on the opposite - * edge of the clock so it is for sure stable when it gets - * sampled. - * - * The PL111 manual does not contain proper timining diagrams - * or data for these details, but we know from experiments - * that the setup time is more than 3000 picoseconds (3 ns). - * If we have a bridge that requires the signal to be stable - * earlier than 3000 ps before the clock pulse, we have to - * output the data on the opposite edge to avoid flicker. + * Use LCD Timing 2 Register Invert Pixel Clock (IPC) bit + * to make sure to drive data on falling edge if requested + * by bridge. */ - if (btimings && btimings->setup_time_ps >= 3000) - tim2 ^= TIM2_IPC; + if (btimings && btimings->input_bus_flags & + DRM_BUS_FLAG_PIXDATA_NEGEDGE) + tim2 |= TIM2_IPC; }
tim2 |= cpl << 16;