On 13-11-11 02:01 AM, Linus Walleij wrote:
I would imagine that the platform-specific device tree bindings would need
to clearly explain what the valid values are, as they should.
But this is not a platform-specific binding. These are the
generic pin configuration bindings we're talking about.
Yes, the properties are generic, but I was under the impression that the
values can be "custom", such as these:
* @PIN_CONFIG_INPUT_SCHMITT: this will configure an input pin to run in
* schmitt-trigger mode. If the schmitt-trigger has adjustable hysteresis,
* the threshold value is given on a custom format as argument when
* setting pins to this mode.
and
* @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
* this parameter (on a custom format) tells the driver which alternative
* slew rate to use.
If we're
using integers, we could either have a) !0 and 0, or b) just 1 and 0, and
everything else is an error. Or c) the platform could decide that the value
provides addition info like pull-up-strength, so 0 = no pull up, >0 = pull
up enabled and the number is the pull up strength in Ohm (bindings should
indicate which values are valid), and everything else is an error.
That seems to make sense, I've just not seen any system (using
device tree) that can actually set the pull up/down resistance.
That said, if you can patch the OF core and the generic pin config
parser to do what you want with lists like that, it's your pick.
It may take some time though.
I don't mind patching the generic pin config, and I don't think the core
needs to change,
If you want arrays of booleans that is a matter for the OF core
parser I think.
I was thinking of just using integers and accepting only 1 and 0,
everything else is error.
What about you patch include/linux/pinctrl/pinconf-generic.h
to add PIN_CONFIG_INPUT_DISABLE with this semantic
and also patch the generic pinconf parser in
drivers/pinctrl/pinconf-generic.c
to handle this?
Sure, I can add PIN_CONFIG_INPUT_DISABLE. However I suspect people might be
confused by this and PIN_CONFIG_OUTPUT.
Just make sure you put in good documentation in that file
right there, it's using kerneldoc and for a good reason...
Thanks,
Sherman
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