On 27/04/17 23:49, Sakari Ailus wrote: > Hi Kieran, > > On Thu, Apr 27, 2017 at 11:13:50PM +0100, Kieran Bingham wrote: >> Hi Sakari, >> >> Thanks for taking a look > > Sure! :-) > >> >> On 27/04/17 22:43, Sakari Ailus wrote: >>> Hi Kieran, >>> >>> Could I ask you to rebase your patches on top of my V4L2 fwnode patches >>> here? >>> >>> <URL:https://git.linuxtv.org/sailus/media_tree.git/log/?h=v4l2-acpi> >>> >>> It depends on the fwnode graph patches, merged here: >>> >>> <URL:https://git.linuxtv.org/sailus/media_tree.git/log/?h=v4l2-acpi-merge> >>> >>> I expect the fwnode graph patches in v4.12 so we'll have them in media-tree >>> master soon. >>> >>> (I'm pushing these branches right now, it may take a while until it's really >>> there.) >> >> Sure, I'll merge those into my base. >> >>> On Thu, Apr 27, 2017 at 07:26:00PM +0100, Kieran Bingham wrote: >>>> From: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx> >>>> >>>> Devices such as the the ADV748x support multiple parallel stream routes >>>> through a single chip. This leads towards needing to provide multiple >>>> distinct entities and subdevs from a single device-tree node. >>>> >>>> To distinguish these separate outputs, the device-tree binding must >>>> specify each endpoint link with a unique (to the device) non-zero port >>>> number. >>>> >>>> This number allows async subdev registrations to identify the correct >>>> subdevice to bind and link. >>>> >>>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx> >>>> --- >>>> drivers/media/v4l2-core/v4l2-async.c | 7 +++++++ >>>> drivers/media/v4l2-core/v4l2-subdev.c | 1 + >>>> include/media/v4l2-async.h | 1 + >>>> include/media/v4l2-subdev.h | 2 ++ >>>> 4 files changed, 11 insertions(+) >>>> >>>> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c >>>> index 1815e54e8a38..875e6ce646ec 100644 >>>> --- a/drivers/media/v4l2-core/v4l2-async.c >>>> +++ b/drivers/media/v4l2-core/v4l2-async.c >>>> @@ -42,6 +42,13 @@ static bool match_devname(struct v4l2_subdev *sd, >>>> >>>> static bool match_of(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) >>>> { >>>> + /* >>>> + * If set, we must match the device tree port, with the subdev port. >>>> + * This is a fast match, so do this first >>>> + */ >>>> + if (sd->port && sd->port != asd->match.of.port) >>> >>> Zero is an entirely valid value for a port. I think it'd be good not to >>> depend on non-zero port values for port matching. >> >> Well then that pretty much dashes my chances on not parsing the DT in the ADV >> driver. > > Hmm. I guess there's no really a way to avoid it. But we could make it > easier > >> >> >> >>>> + return -1; >>> >>> Any particular reason to return -1 from a function with bool return type? >> >> Ahem, I clearly can't read ;-) >> I think my mindset was thinking strcmp or something... > > But -1 is perfectly valid. If you wanted to make it look really interesting, > you could return -!false and still have exactly the same functionality. ;-) I'll consider -!false a recommendation for my next patch :D >>>> + >>>> return !of_node_cmp(of_node_full_name(sd->of_node), >>>> of_node_full_name(asd->match.of.node)); >>>> } >>>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c >>>> index da78497ae5ed..67f816f90ac3 100644 >>>> --- a/drivers/media/v4l2-core/v4l2-subdev.c >>>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c >>>> @@ -607,6 +607,7 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops) >>>> sd->flags = 0; >>>> sd->name[0] = '\0'; >>>> sd->grp_id = 0; >>>> + sd->port = 0; >>>> sd->dev_priv = NULL; >>>> sd->host_priv = NULL; >>>> #if defined(CONFIG_MEDIA_CONTROLLER) >>>> diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h >>>> index 5b501309b6a7..2988960613ec 100644 >>>> --- a/include/media/v4l2-async.h >>>> +++ b/include/media/v4l2-async.h >>>> @@ -56,6 +56,7 @@ struct v4l2_async_subdev { >>>> union { >>>> struct { >>>> const struct device_node *node; >>>> + u32 port; >>> >>> What if instead of storing the device's OF node, you'd store the port node >>> and used that for matching? >>> >>> Would that also solve the problem or do I miss something? >> >> Actually - I was 'trying' to prevent having to parse the DT in the adv748x >> driver if I didn't need to. >> >> Once I have to parse the DT, then yes, I think storing the endpoint node is >> probably the best thing to compare against. >> >> And actually - you might have just solved my open question in the cover letter ... >> >> I had got stuck in my mindset that if I were to use the endpoint 'leaf' node as >> a comparator - that it would be 'instead' of the root node. >> >> But actually - it could just be root-node + leaf-node to compare, which then >> allows us the fallback of comparing just the root nodes if the leaf isn't set. >> >> I'll respin with this either tomorrow or early next week. > > Endpoints are indeed another option. > > Is there something that would prevent switching from device node matching to > port / endpoint matching altogether? I don't think the driver changes should > be difficult to make. > > Supporting different options there will be painful as it will likely require > help from the driver to implement both --- separately. Ok - so a bit of pain either way... IMO - 'endpoint' matching is 'more correct' as then we are tying the subdev with precisely the object that it is linking to. It looks like there are 11 users of v4l2_async_notifier_register(), so yes, hopefully it might not actually be so much effort to go through and adapt each to match to the endpoint of_node instead! I'll have a go at this and see how far I get down the rabbit hole. >>>> } of; >>>> struct { >>>> const char *name; >>>> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h >>>> index 0ab1c5df6fac..1c1731b491e5 100644 >>>> --- a/include/media/v4l2-subdev.h >>>> +++ b/include/media/v4l2-subdev.h >>>> @@ -782,6 +782,7 @@ struct v4l2_subdev_platform_data { >>>> * @ctrl_handler: The control handler of this subdev. May be NULL. >>>> * @name: Name of the sub-device. Please notice that the name must be unique. >>>> * @grp_id: can be used to group similar subdevs. Value is driver-specific >>>> + * @port: driver-specific value to bind multiple subdevs with a single DT node. >>>> * @dev_priv: pointer to private data >>>> * @host_priv: pointer to private data used by the device where the subdev >>>> * is attached. >>>> @@ -814,6 +815,7 @@ struct v4l2_subdev { >>>> struct v4l2_ctrl_handler *ctrl_handler; >>>> char name[V4L2_SUBDEV_NAME_SIZE]; >>>> u32 grp_id; >>>> + u32 port; >>>> void *dev_priv; >>>> void *host_priv; >>>> struct video_device *devnode; >>> >
