Hi Laurent,
On Thursday, 5 December 2019 12:40:22 GMT Laurent Pinchart wrote:
Hi Mihail,
Thank you for the patch.
Thanks for the quick reviews :).
On Wed, Dec 04, 2019 at 11:48:02AM +0000, Mihail Atanassov wrote:
A simple convenience function to initialize the struct drm_bridge. The goal is to standardize initialization for any bridge registered with drm_bridge_add() so that we can later add device links for consumers of those bridges.
v2:
- s/WARN_ON(!funcs)/WARN_ON(!funcs || !dev)/ as suggested by Daniel
- expand on some kerneldoc comments as suggested by Daniel
- update commit message as suggested by Daniel
Signed-off-by: Mihail Atanassov mihail.atanassov@arm.com
drivers/gpu/drm/drm_bridge.c | 34 +++++++++++++++++++++++++++++++++- include/drm/drm_bridge.h | 15 ++++++++++++++- 2 files changed, 47 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index cba537c99e43..50e1c1b46e20 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -64,7 +64,10 @@ static DEFINE_MUTEX(bridge_lock); static LIST_HEAD(bridge_list);
/**
- drm_bridge_add - add the given bridge to the global bridge list
- drm_bridge_add - add the given bridge to the global bridge list.
You add a final period here and in the documentation of struct drm_bridge, but the new function you're adding doesn't have one :-) I'd drop the period here and for drm_bridge to be consistent with the rest of the code.
- Drivers should call drm_bridge_init() prior adding it to the list.
s/should/shall/ s/prior adding it/prior to adding the bridge/
- Drivers should call drm_bridge_remove() to clean up the bridge list.
I'd replace this sentence with "Before deleting a bridge (usually when the driver is unbound from the device), drivers shall call drm_bridge_remove() to remove it from the global list."
- @bridge: bridge control structure
*/ @@ -89,6 +92,35 @@ void drm_bridge_remove(struct drm_bridge *bridge) } EXPORT_SYMBOL(drm_bridge_remove);
+/**
- drm_bridge_init - initialise a drm_bridge structure
initialise or initialize ? :-)
I have absolutely no clue :). Judging by the question I'm guessing the correct answer for the kernel is US spelling.
- @bridge: bridge control structure
- @funcs: control functions
- @dev: device associated with this drm_bridge
dev goes before funcs
- @timings: timing specification for the bridge; optional (may be NULL)
- @driver_private: pointer to the bridge driver internal context (may be NULL)
I'm not too sure about the last two parameters. Having NULL, NULL in most callers is confusing, and having a void * as one of the parameters means that the compiler won't catch errors if the two parameters are reversed. I think this is quite error prone.
There are very few drivers using driver_private (I count 6 of them, with 2 additional drivers that set driver_private but never use it). How about embedding the bridge structure in those 6 drivers and getting rid of the field altogether ? This could be part of a separate series, but in any case I'd drop driver_private from drm_bridge_init().
Ok, I'll do that first before refreshing this series.
- */
+void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
const struct drm_bridge_funcs *funcs,const struct drm_bridge_timings *timings,void *driver_private)+{
- WARN_ON(!funcs || !dev);
- bridge->dev = NULL;
NULL ? Shouldn't this be dev ?
Hehe, Daniel got caught on that one, too :). This is the drm_device pointer for the bound consumer, not the struct device that the bridge's lifetime is tied to. I was planning to rename them with my (eventual) device_links addition (some discussion around it here: https://patchwork.freedesktop.org/patch/342472/?series=70039&rev=1).
I guess if I do the drm_device part of the rename first, this patch will look less confusing, so I'll do that too.
- bridge->encoder = NULL;
- bridge->next = NULL;
+#ifdef CONFIG_OF
- bridge->of_node = dev->of_node;
+#endif
- bridge->timings = timings;
- bridge->funcs = funcs;
- bridge->driver_private = driver_private;
+} +EXPORT_SYMBOL(drm_bridge_init);
/**
- drm_bridge_attach - attach the bridge to an encoder's chain
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index c0a2286a81e9..949e4f401a53 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -373,7 +373,16 @@ struct drm_bridge_timings { };
/**
- struct drm_bridge - central DRM bridge control structure
- struct drm_bridge - central DRM bridge control structure.
- Bridge drivers should call drm_bridge_init() to initialize a bridge
- driver, and then register it with drm_bridge_add().
s/bridge driver/bridge structure/ (or drm_bridge structure)
- Users of bridges link a bridge driver into their overall display output
- pipeline by calling drm_bridge_attach().
- Modular drivers in OF systems can query the list of registered bridges
*/
- with of_drm_find_bridge().
struct drm_bridge { /** @dev: DRM device this bridge belongs to */ @@ -402,6 +411,10 @@ struct drm_bridge {
void drm_bridge_add(struct drm_bridge *bridge); void drm_bridge_remove(struct drm_bridge *bridge); +void drm_bridge_init(struct drm_bridge *bridge, struct device *dev,
const struct drm_bridge_funcs *funcs,const struct drm_bridge_timings *timings,void *driver_private);struct drm_bridge *of_drm_find_bridge(struct device_node *np); int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, struct drm_bridge *previous);