Commit 7cd70656 authored by Neil Armstrong's avatar Neil Armstrong
Browse files

drm/bridge: display-connector: implement bus fmts callbacks 



Since this bridge is tied to the connector, it acts like a passthrough,
so concerning the output & input bus formats, either pass the bus formats from the
previous bridge or return fallback data like done in the bridge function:
drm_atomic_bridge_chain_select_bus_fmts() & select_bus_fmt_recursive.

This permits avoiding skipping the negociation if the remaining bridge chain has
all the bits in place.

Without this bus fmt negociation breaks on drm/meson HDMI pipeline when attaching
dw-hdmi with DRM_BRIDGE_ATTACH_NO_CONNECTOR, because the last bridge of the
display-connector doesn't implement buf fmt callbacks and MEDIA_BUS_FMT_FIXED
is used leading to select an unsupported default bus format from dw-hdmi.

Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211020123947.2585572-2-narmstrong@baylibre.com
parent 3f2532d6

drivers/gpu/drm/bridge/display-connector.c

+86 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>



#include <drm/drm_atomic_helper.h>

#include <drm/drm_bridge.h>

#include <drm/drm_edid.h>
@@ -87,10 +88,95 @@ static struct edid *display_connector_get_edid(struct drm_bridge *bridge, 
	return drm_get_edid(connector, conn->bridge.ddc);

}



/*

 * Since this bridge is tied to the connector, it acts like a passthrough,

 * so concerning the output bus formats, either pass the bus formats from the

 * previous bridge or return fallback data like done in the bridge function:

 * drm_atomic_bridge_chain_select_bus_fmts().

 * This supports negotiation if the bridge chain has all bits in place.

 */

static u32 *display_connector_get_output_bus_fmts(struct drm_bridge *bridge,

					struct drm_bridge_state *bridge_state,

					struct drm_crtc_state *crtc_state,

					struct drm_connector_state *conn_state,

					unsigned int *num_output_fmts)

{

	struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);

	struct drm_bridge_state *prev_bridge_state;



	if (!prev_bridge || !prev_bridge->funcs->atomic_get_output_bus_fmts) {

		struct drm_connector *conn = conn_state->connector;

		u32 *out_bus_fmts;



		*num_output_fmts = 1;

		out_bus_fmts = kmalloc(sizeof(*out_bus_fmts), GFP_KERNEL);

		if (!out_bus_fmts)

			return NULL;



		if (conn->display_info.num_bus_formats &&

		    conn->display_info.bus_formats)

			out_bus_fmts[0] = conn->display_info.bus_formats[0];

		else

			out_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;



		return out_bus_fmts;

	}



	prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,

							    prev_bridge);



	return prev_bridge->funcs->atomic_get_output_bus_fmts(prev_bridge, prev_bridge_state,

							      crtc_state, conn_state,

							      num_output_fmts);

}



/*

 * Since this bridge is tied to the connector, it acts like a passthrough,

 * so concerning the input bus formats, either pass the bus formats from the

 * previous bridge or MEDIA_BUS_FMT_FIXED (like select_bus_fmt_recursive())

 * when atomic_get_input_bus_fmts is not supported.

 * This supports negotiation if the bridge chain has all bits in place.

 */

static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge,

					struct drm_bridge_state *bridge_state,

					struct drm_crtc_state *crtc_state,

					struct drm_connector_state *conn_state,

					u32 output_fmt,

					unsigned int *num_input_fmts)

{

	struct drm_bridge *prev_bridge = drm_bridge_get_prev_bridge(bridge);

	struct drm_bridge_state *prev_bridge_state;



	if (!prev_bridge || !prev_bridge->funcs->atomic_get_input_bus_fmts) {

		u32 *in_bus_fmts;



		*num_input_fmts = 1;

		in_bus_fmts = kmalloc(sizeof(*in_bus_fmts), GFP_KERNEL);

		if (!in_bus_fmts)

			return NULL;



		in_bus_fmts[0] = MEDIA_BUS_FMT_FIXED;



		return in_bus_fmts;

	}



	prev_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,

							    prev_bridge);



	return prev_bridge->funcs->atomic_get_input_bus_fmts(prev_bridge, prev_bridge_state,

							     crtc_state, conn_state, output_fmt,

							     num_input_fmts);

}



static const struct drm_bridge_funcs display_connector_bridge_funcs = {

	.attach = display_connector_attach,

	.detect = display_connector_detect,

	.get_edid = display_connector_get_edid,

	.atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts,

	.atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts,

	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,

	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,

	.atomic_reset = drm_atomic_helper_bridge_reset,

};



static irqreturn_t display_connector_hpd_irq(int irq, void *arg)