Re: [PATCH RESEND] media: rc: gpio-ir-recv: add support for devicetree parsing
From: Sebastian Hesselbarth
Date: Fri Feb 08 2013 - 13:12:37 EST
On Fri, Feb 8, 2013 at 6:57 PM, Mauro Carvalho Chehab
> Em Wed, 06 Feb 2013 18:18:22 +0100
> Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx> escreveu:
>> On 02/06/2013 02:48 PM, Sylwester Nawrocki wrote:
>> > On 02/06/2013 09:03 AM, Sebastian Hesselbarth wrote:
>> >> This patch adds device tree parsing for gpio_ir_recv platform_data and
>> >> the mandatory binding documentation. It basically follows what we already
>> >> have for e.g. gpio_keys. All required device tree properties are OS
>> >> independent but optional properties allow linux specific support for rc
>> >> protocols and maps.
>> >> There was a similar patch sent by Matus Ujhelyi but that discussion
>> >> died after the first reviews.
>> >> Signed-off-by: Sebastian Hesselbarth<sebastian.hesselbarth@xxxxxxxxx>
>> >> ---
>> > ...
>> >> diff --git a/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt b/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt
>> >> new file mode 100644
>> >> index 0000000..937760c
>> >> --- /dev/null
>> >> +++ b/Documentation/devicetree/bindings/media/gpio-ir-receiver.txt
>> >> @@ -0,0 +1,20 @@
>> >> +Device-Tree bindings for GPIO IR receiver
>> >> +
>> >> +Required properties:
>> >> + - compatible = "gpio-ir-receiver";
>> >> + - gpios: OF device-tree gpio specification.
>> >> +
>> >> +Optional properties:
>> >> + - linux,allowed-rc-protocols: Linux specific u64 bitmask of allowed
>> >> + rc protocols.
>> > You likely need to specify in these bindings documentation which bit
>> > corresponds to which RC protocol.
>> > I'm not very familiar with the RC internals, but why it has to be
>> > specified statically in the device tree, when decoding seems to be
>> > mostly software defined ? I might be missing something though..
>> I am not familiar with RC internals either. Maybe somebody with more
>> insight in media/rc can clarify the specific needs for the rc subsystem.
>> I was just transferring the DT support approach taken by gpio_keys to
>> gpio_ir_recv as I will be using it on mach-dove/cubox soon.
> The allowed rc protocol field are there for devices with hardware IR
> support, where only a limited set of remote protocols can be decoded.
> For software decoders RC_BIT_ALL is the proper setup. Users of course
> can change it via sysfs at runtime, or a software decoder may be
> disabled at compilation time by not selecting its CONFIG_* var.
thanks for the clarification! So for v2 of the patch, you all agree on removing
linux,allowed-rc-protocols from device node properties?
>> > Couldn't this be configured at run time, with all protocols allowed
>> > as the default ?
>> Actually, this is how the internal rc code works. If there is nothing
>> defined for allowed_protocols it assumes that all protocols are supported.
>> That is why above node properties are optional.
>> About the binding documentation of allowed_protocols, rc_map, or the
>> default behavior of current linux code, I don't think they will stay
>> in-sync for long.
> Why not? The rc_map name is used either by Kernelspace or by Userspace,
> in order to provide the IR keycode name that matches a given keytable.
> There's no plans to change it, even in the long term.
Actually, I wasn't referring to changing names or bitmasks but updating
the binding documentation with new allowed protocols or supported map
For linux,rc-map-name property it should be enough to just write that it
relates to linux rc subsystem rc_map name - how to actually
set it to a useful name is documented in rc subsystem. And if the
property is not set at all, DT parsing in gpio_ir_recv assumes the
subsystem (or gpio_ir_recv platform) default, IIRC "rc-none".
I'll respin a v2 without allowed-protocols property soon.
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