Hi,
On Sat, Oct 16, 2021 at 9:57 AM Philip Chen <philipchen@xxxxxxxxxxxx> wrote:
>
> Conventionally, panel is listed under the root in the device tree.
> When userland asks for display mode, ps8640 bridge is responsible
> for returning EDID when ps8640_bridge_get_edid() is called.
>
> Now enable a new option of listing the panel under "aux-bus" of ps8640
> bridge node in the device tree. In this case, panel driver can retrieve
> EDID by triggering AUX transactions, without ps8640_bridge_get_edid()
> calls at all.
>
> To prevent the "old" and "new" options from interfering with each
> other's logic flow, disable DRM_BRIDGE_OP_EDID when the new option
> is taken.
>
> Signed-off-by: Philip Chen <philipchen@xxxxxxxxxxxx>
> ---
>
> drivers/gpu/drm/bridge/parade-ps8640.c | 52 ++++++++++++++++++++------
> 1 file changed, 40 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
> index acfe1bf0f936..98884f799ea8 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8640.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8640.c
> @@ -14,6 +14,7 @@
> #include <linux/regulator/consumer.h>
>
> #include <drm/drm_bridge.h>
> +#include <drm/drm_dp_aux_bus.h>
You need a `select DRM_DP_AUX_BUS` in the Kconfig to avoid the errors
that the build robot found for you.
> #include <drm/drm_dp_helper.h>
> #include <drm/drm_mipi_dsi.h>
> #include <drm/drm_of.h>
> @@ -149,6 +150,24 @@ static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux)
> return container_of(aux, struct ps8640, aux);
> }
>
> +static bool ps8640_of_panel_on_aux_bus(struct device *dev)
> +{
> + struct device_node *bus, *panel;
> +
> + if (!dev->of_node)
> + return false;
You probably don't need the above check. I think things would be
pretty broken if we didn't have an "of_node".
> + bus = of_get_child_by_name(dev->of_node, "aux-bus");
> + if (!bus)
> + return false;
> +
> + panel = of_get_child_by_name(bus, "panel");
of_node_put(bus);
> + if (!panel)
> + return false;
of_node_put(panel);
Other than the above, this looks reasonable to me.
-Doug
