On 11/28/2014 01:30 PM, Mark Rutland wrote:
On Fri, Nov 28, 2014 at 12:09:14PM +0000, Jacek Anaszewski wrote:
On 11/28/2014 12:14 PM, Mark Rutland wrote:
On Fri, Nov 28, 2014 at 09:18:00AM +0000, Jacek Anaszewski wrote:
This patch adds a description of 'flashes' property
to the samsung-fimc.txt.
Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Pawel Moll <pawel.moll@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
Cc: <devicetree@xxxxxxxxxxxxxxx>
---
.../devicetree/bindings/media/samsung-fimc.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt b/Documentation/devicetree/bindings/media/samsung-fimc.txt
index 922d6f8..4b7ed03 100644
--- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
+++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
@@ -40,6 +40,12 @@ should be inactive. For the "active-a" state the camera port A must be activated
and the port B deactivated and for the state "active-b" it should be the other
way around.
+Optional properties:
+
+- flashes - array of strings with flash led names; the name has to
+ be same with the related led label
+ (see Documentation/devicetree/bindings/leds/common.txt)
+
Why is this not an array of phandles to the LED nodes? That's much
better than strings.
This is because a single flash led device can control many sub-leds,
which are represented by child nodes in the Device Tree.
Every sub-led is registered as a separate LED Flash class device
in the LED subsystem, but in fact they share the same struct device
and thus have access only to the parent's phandle.
But that's a Linux infrastrcture issue, no? You don't have to use the
node from the struct device to find the relevant phandle.
Right.
The LED Flash
class devices are wrapped by V4L2 sub-devices and register
asynchronously within a media device. Since the v4l2_subdev structure
has a 'name' field, it is convenient to initialize it with
parsed 'label' property of a child led node and match the
sub-devices in the media device basing on it.
While that might be convenient, I don't think it's fantastic to use that
to describe the relationship, as this leaks Linux internals (e.g. I can
refer to a name that doesn't exist in the DT but happens to be what
Linux used, and it would work). Also, are the labels guaranteed to be
globally unique?
The labels are used for initializing class device name and kernel
doesn't allow to initialize two devices with same names.
This implies that labels are guaranteed to be globally unique.
Unless I am missing something.
Regards,
Jacek
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