On Mon, Aug 21, 2023 at 5:37 AM Liu Ying <victor.liu@xxxxxxx> wrote:
>
> The DATAEN_ACTIVE_LOW bit in DSI_DPI_CFG_POL register is set to zero,
> so set the DRM_BUS_FLAG_DE_HIGH flag in input_bus_cfg.flags. It appears
> that the DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE flag also makes sense, so
> set it in input_bus_cfg.flags too. With this patch, the flags set by
> drm_atomic_bridge_propagate_bus_flags() are overridden (see comment in
> that function) in case any downstream bridges propagates invalid flags
> to this bridge. A real problematic case is to connect a RM67191 MIPI
> DSI panel whose driver sets DRM_BUS_FLAG_DE_LOW and
> DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE bus flags.
>
> Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
> ---
> v1->v3:
> * No change.
>
> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 945d46a76995..ed9288a9c444 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -23,6 +23,7 @@
> #include <drm/bridge/dw_mipi_dsi.h>
> #include <drm/drm_atomic_helper.h>
> #include <drm/drm_bridge.h>
> +#include <drm/drm_connector.h>
> #include <drm/drm_crtc.h>
> #include <drm/drm_mipi_dsi.h>
> #include <drm/drm_modes.h>
> @@ -567,6 +568,17 @@ dw_mipi_dsi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> return input_fmts;
> }
>
> +static int dw_mipi_dsi_bridge_atomic_check(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state)
> +{
> + bridge_state->input_bus_cfg.flags =
> + DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;
> +
> + return 0;
> +}
> +
> static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
> {
> u32 val;
> @@ -1036,6 +1048,7 @@ static const struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
> .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> .atomic_get_input_bus_fmts = dw_mipi_dsi_bridge_atomic_get_input_bus_fmts,
> + .atomic_check = dw_mipi_dsi_bridge_atomic_check,
> .atomic_reset = drm_atomic_helper_bridge_reset,
> .atomic_pre_enable = dw_mipi_dsi_bridge_atomic_pre_enable,
> .atomic_enable = dw_mipi_dsi_bridge_atomic_enable,
> --
> 2.37.1
>
Reviewed-by: Robert Foss <rfoss@xxxxxxxxxx>
