[PATCH 6.6 190/396] drm/bridge: add ->edid_read hook and drm_bridge_edid_read()

Greg Kroah-Hartman
2024-04-01T16:45:11Z

From: Jani Nikula <jani.nikula@intel.com>

[ Upstream commit d807ad80d811ba0c22adfd871e2a46491f80d6e2 ]

Add new struct drm_edid based ->edid_read hook and
drm_bridge_edid_read() function to call the hook.

v2: Include drm/drm_edid.h

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/9d08d22eaffcb9c59a2b677e45d7e61fc689bc2f.1706038510.git.jani.nikula@intel.com
Stable-dep-of: 171b711b26cc ("drm/bridge: lt8912b: do not return negative values from .get_modes()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/drm_bridge.c | 46 +++++++++++++++++++++++++++++++++++-
include/drm/drm_bridge.h | 33 ++++++++++++++++++++++++++
2 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 39e68e45bb124..67354afbd7168 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -27,8 +27,9 @@
#include <linux/mutex.h>

#include <drm/drm_atomic_state_helper.h>
-#include <drm/drm_debugfs.h>
#include <drm/drm_bridge.h>
+#include <drm/drm_debugfs.h>
+#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
#include <drm/drm_of.h>
@@ -1206,6 +1207,47 @@ int drm_bridge_get_modes(struct drm_bridge *bridge,
}
EXPORT_SYMBOL_GPL(drm_bridge_get_modes);

+/**
+ * drm_bridge_edid_read - read the EDID data of the connected display
+ * @bridge: bridge control structure
+ * @connector: the connector to read EDID for
+ *
+ * If the bridge supports output EDID retrieval, as reported by the
+ * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.edid_read to get
+ * the EDID and return it. Otherwise return NULL.
+ *
+ * If &drm_bridge_funcs.edid_read is not set, fall back to using
+ * drm_bridge_get_edid() and wrapping it in struct drm_edid.
+ *
+ * RETURNS:
+ * The retrieved EDID on success, or NULL otherwise.
+ */
+const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge,
+ struct drm_connector *connector)
+{
+ if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
+ return NULL;
+
+ /* Transitional: Fall back to ->get_edid. */
+ if (!bridge->funcs->edid_read) {
+ const struct drm_edid *drm_edid;
+ struct edid *edid;
+
+ edid = drm_bridge_get_edid(bridge, connector);
+ if (!edid)
+ return NULL;
+
+ drm_edid = drm_edid_alloc(edid, (edid->extensions + 1) * EDID_LENGTH);
+
+ kfree(edid);
+
+ return drm_edid;
+ }
+
+ return bridge->funcs->edid_read(bridge, connector);
+}
+EXPORT_SYMBOL_GPL(drm_bridge_edid_read);
+
/**
* drm_bridge_get_edid - get the EDID data of the connected display
* @bridge: bridge control structure
@@ -1215,6 +1257,8 @@ EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
* DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
* get the EDID and return it. Otherwise return NULL.
*
+ * Deprecated. Prefer using drm_bridge_edid_read().
+ *
* RETURNS:
* The retrieved EDID on success, or NULL otherwise.
*/
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 103ff57fc83cf..b20cfe5bf30b3 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -555,6 +555,37 @@ struct drm_bridge_funcs {
int (*get_modes)(struct drm_bridge *bridge,
struct drm_connector *connector);

+ /**
+ * @edid_read:
+ *
+ * Read the EDID data of the connected display.
+ *
+ * The @edid_read callback is the preferred way of reporting mode
+ * information for a display connected to the bridge output. Bridges
+ * that support reading EDID shall implement this callback and leave
+ * the @get_modes callback unimplemented.
+ *
+ * The caller of this operation shall first verify the output
+ * connection status and refrain from reading EDID from a disconnected
+ * output.
+ *
+ * This callback is optional. Bridges that implement it shall set the
+ * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
+ *
+ * The connector parameter shall be used for the sole purpose of EDID
+ * retrieval, and shall not be stored internally by bridge drivers for
+ * future usage.
+ *
+ * RETURNS:
+ *
+ * An edid structure newly allocated with drm_edid_alloc() or returned
+ * from drm_edid_read() family of functions on success, or NULL
+ * otherwise. The caller is responsible for freeing the returned edid
+ * structure with drm_edid_free().
+ */
+ const struct drm_edid *(*edid_read)(struct drm_bridge *bridge,
+ struct drm_connector *connector);
+
/**
* @get_edid:
*
@@ -888,6 +919,8 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
int drm_bridge_get_modes(struct drm_bridge *bridge,
struct drm_connector *connector);
+const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge,
+ struct drm_connector *connector);
struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
struct drm_connector *connector);
void drm_bridge_hpd_enable(struct drm_bridge *bridge,
--
2.43.0