On Thu, 15 Mar 2012 11:27:36 +0100, Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> wrote:
> * Arnd Bergmann wrote:
> > On Thursday 15 March 2012, Nicolas Ferre wrote:
> [...]
> > > + i2c1: i2c@1 {
> > > + ...
> > > + dma-request = <&sdma 2 &sdma 3>;
> > > + dma-request-names = "tx", "rx";
> > > + ...
> > > + };
> >
> > This is slightly different from how the proposed pwm binding works that
> > Thierry is working on, which uses an arbitrary property name instead of
> > requiring the use of a specific property but then allowing to give names
> > in another property.
> >
> > I don't care much which way it's done, but please try to agree on one
> > approach that is used for both.
> >
> > The one you have here is already used by reg and irq, while the other
> > one is used in gpio.
>
> I think we can just use pwm as the fixed property name. Or alternatively do
> something along the lines of the regulator bindings, where we use "-pwm" as
> the suffix for specifying PWM devices. For instance if a named PWM is
> requested, the OF support code would look for a <name>-pwm property, while
> requesting an unnamed PWM would simply look at the pwm property.
>
> When it comes to the labelling of PWM devices, I don't think both variants
> are exclusive. Currently the PWM framework uses name of the user OF device
> node for the PWM label. That is, if I have the following in the DTS:
>
> pwm {
> ..
> };
>
> backlight {
> compatible = "pwm-backlight";
> pwm = <&pwm 0 5000000>;
> ...
> };
>
> Then the PWM will be labelled "backlight":
>
> $ cat cat /sys/kernel/debug/pwm
> platform/tegra-pwm, 4 PWM devices
> pwm-0 (backlight ): requested enabled
> pwm-1 ((null) ):
> pwm-2 ((null) ):
> pwm-3 ((null) ):
>
> So if we decide to explicitly allow specifying names, then we can always add
> a pwm-names property (or <name>-pwm-names respectively) to use as label and
> fallback to the user OF device node name if that property is not present.
After implementing both schemes (ie. interrupts+interrupt-names && [*-]gpios)
I definitely prefer the fixed property name plus a separate names property.
It is easier to use common code with that scheme, and easier to statically
check for correctness.
g.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
