[RFC v2 2/7] media: rc: Add cec protocol handling

[Kamil Debski]

Hi Mauro,

I have some more comments/questions below.

From: Mauro Carvalho Chehab [mailto:mchehab at osg.samsung.com]
Sent: Sunday, March 08, 2015 3:21 PM
> 
> Em Thu, 22 Jan 2015 17:04:34 +0100
> Kamil Debski <k.debski at samsung.com> escreveu:
> 
> (c/c linux-input ML)
> 
> > Add cec protocol handling the RC framework.
> 
> I added some comments, that reflects my understanding from what's there
> at the keymap definitions found at:
> 	http://xtreamerdev.googlecode.com/files/CEC_Specs.pdf
> 
> 
> >
> > Signed-off-by: Kamil Debski <k.debski at samsung.com>
> > ---
> >  drivers/media/rc/keymaps/Makefile |    1 +
> >  drivers/media/rc/keymaps/rc-cec.c |  133
> +++++++++++++++++++++++++++++++++++++
> >  drivers/media/rc/rc-main.c        |    1 +
> >  include/media/rc-core.h           |    1 +
> >  include/media/rc-map.h            |    5 +-
> >  5 files changed, 140 insertions(+), 1 deletion(-)  create mode

[snip]

> 
> > +	{ 0x60, KEY_PLAY }, /* XXX CEC Spec: Play Function */
> > +	{ 0x61, KEY_PLAYPAUSE }, /* XXX CEC Spec: Pause-Play Function */
> > +	{ 0x62, KEY_RECORD }, /* XXX CEC Spec: Record Function */
> > +	{ 0x63, KEY_PAUSE }, /* XXX CEC Spec: Pause-Record Function */
> > +	{ 0x64, KEY_STOP }, /* XXX CEC Spec: Stop Function */
> > +	{ 0x65, KEY_MUTE }, /* XXX CEC Spec: Mute Function */
> > +	/* 0x66: CEC Spec: Restore Volume Function */
> > +	{ 0x67, KEY_TUNER }, /* XXX CEC Spec: Tune Function */
> > +	{ 0x68, KEY_MEDIA }, /* CEC Spec: Select Media Function */
> > +	{ 0x69, KEY_SWITCHVIDEOMODE} /* XXX CEC Spec: Select A/V Input
> Function */,
> > +	{ 0x6a, KEY_AUDIO} /* CEC Spec: Select Audio Input Function */,
> > +	{ 0x6b, KEY_POWER} /* CEC Spec: Power Toggle Function */,
> > +	{ 0x6c, KEY_SLEEP} /* XXX CEC Spec: Power Off Function */,
> > +	{ 0x6d, KEY_WAKEUP} /* XXX CEC Spec: Power On Function */,
> 
> Those "function" keycodes look weird. What's the difference between
> those and the pure non-function variants?

The note 2 applies to most of these function buttons. It says:
"2 During a recording or timed recording, a device may ask the user
for confirmation of this action before executing it."
 
> The spec (CEC 13.13.3) says that:
> 
> 	"Unlike the other codes, which just pass remote control presses
> 	 to the target (often with manufacturer-specific results),
> 	 the Functions are deterministic, ie they specify exactly the
> state
> 	 after executing these commands. Several of these also have
> further
> 	 operands, specifying the function in more detail, immediately
> 	 following the relevant [UI Command] operand."
> 
> Some codes are actually compund ones. For example, 0x60 has a "play
> mode"
> operand. So, the actual mapping would be:
> 
> 0x60 + 0x24 - "play forward"
> 0x61 + 0x20 - "play reverse"
> ...
> (see CEC17 for operand descriptions)
> 
> So, IMHO, the mapping should be
> 
> 	{ 0x6024, KEY_PLAY },
> 	{ 0x6020, KEY_PLAY_REVERSE }, // to be created

The note 1 says that they can be issued without the additional operand
specified:
"1 Functions with additional operands may also be used without the
additional operand: in this case the behavior is manufacturer-specific."

Will this do?
	{ 0x60, KEY_PLAY },
	{ 0x6024, KEY_PLAY },
 	{ 0x6020, KEY_PLAY_REVERSE }, // to be created
Or will the framework get confused that an incomplete key code was
received?

Another question I have is about the following operations:
0x67 Tune Function
0x68 Select Media Function
0x69 Select A/V Input Function
0x6a Select Audio Input Function
These operations take an additional operand that is large number.
1-255 for 0x68-0x6a or even a more complex operand such as the channel
number for 0x67.

Any suggestion on how to implement these correctly?

> 	...
> 
> 
> > +	/* 0x6e-0x70: Reserved */
> > +	{ 0x71, KEY_BLUE }, /* XXX CEC Spec: F1 (Blue) */
> > +	{ 0x72, KEY_RED }, /* XXX CEC Spec: F2 (Red) */
> > +	{ 0x73, KEY_GREEN }, /* XXX CEC Spec: F3 (Green) */
> > +	{ 0x74, KEY_YELLOW }, /* XXX CEC Spec: F4 (Yellow) */
> > +	{ 0x75, KEY_F5 },
> > +	{ 0x76, KEY_CONNECT }, /* XXX CEC Spec: Data - see Note 3 */
> > +	/* Note 3: This is used, for example, to enter or leave a digital
> TV
> > +	 * data broadcast application. */
> 

[snip]

Best wishes,
-- 
Kamil Debski
Samsung R&D Institute Poland