On Thu, 6 Dec 2012 13:36:11 +0100, Peter Ujfalusi <peter.ujfalusi@xxxxxx> wrote:
> Hi Grant,
>
> On 12/06/2012 11:00 AM, Grant Likely wrote:
> > On Mon, 12 Nov 2012 15:41:10 +0100, Peter Ujfalusi <peter.ujfalusi@xxxxxx> wrote:
> >> Support for device tree booted kernel.
> >> When the kernel is booted with DeviceTree blob we support one led per
> >> leds-pwm device to have cleaner integration with the PWM subsystem.
> >>
> >> For usage see:
> >> Documentation/devicetree/bindings/leds/leds-pwm.txt
> >>
> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> >> ---
> >> .../devicetree/bindings/leds/leds-pwm.txt | 34 ++++++
> >> drivers/leds/leds-pwm.c | 125 +++++++++++++++------
> >> 2 files changed, 127 insertions(+), 32 deletions(-)
> >> create mode 100644 Documentation/devicetree/bindings/leds/leds-pwm.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/leds/leds-pwm.txt b/Documentation/devicetree/bindings/leds/leds-pwm.txt
> >> new file mode 100644
> >> index 0000000..9fe3040
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt
> >> @@ -0,0 +1,34 @@
> >> +LED connected to PWM
> >> +
> >> +Required properties:
> >> +- compatible : should be "pwm-leds".
> >> +- pwms : PWM property, please refer to:
> >> + Documentation/devicetree/bindings/pwm/pwm.txt
> >> +- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
> >> +- label : (optional) The label for this LED. If omitted, the label is
> >> + taken from the node name (excluding the unit address).
> >> +- max-brightness : Maximum brightness possible for the LED
> >> +- linux,default-trigger : (optional) This parameter, if present, is a
> >> + string defining the trigger assigned to the LED. Current triggers are:
> >> + "backlight" - LED will act as a back-light, controlled by the framebuffer
> >> + system
> >> + "default-on" - LED will turn on, but see "default-state" below
> >> + "heartbeat" - LED "double" flashes at a load average based rate
> >> + "ide-disk" - LED indicates disk activity
> >> + "timer" - LED flashes at a fixed, configurable rate
> >
> > The binding mostly looks good. However, it seems to be gratuitously
> > different from the gpio-leds binding and it duplicates property
> > definitions. Please match the gpio-leds behaviour with each led defined
> > as a sub node of the pwm-leds node.
>
> The GPIO and PWM bindings are substantially different. For start in pwm we do
> not have of_get_pwm* helpers. To get the PWM itself we need to use wpm_get()
That's just the implementation. I'm talking about the binding. :-)
Implementation should follow binding design, not the other way around.
Both bindings use the same pattern. There isn't a of_get_pwm helper now,
but there is nothing preventing one from being created if you need it.
in the controller:
#gpio-cells vs. #pwm-cells
in the user:
gpios = <[gpio specifier]> vs. pwms = <pwm specifier>
The PWM binding states that pwm-names is optional.
> which uses the pwms = <>; pwm-names = <>; properties on the device's main node.
> This is what I could do at the moment:
>
> twl_pwm: pwm {
> compatible = "ti,twl4030-pwm";
> #pwm-cells = <2>;
> };
>
> twl_led: pwmled {
> compatible = "ti,twl4030-pwmled";
> #pwm-cells = <2>;
> };
>
> pwmleds {
> compatible = "pwm-leds";
> pwms = <&twl_pwm 0 7812500
> &twl_pwmled 0 7812500>;
> pwm-names = "omap4::keypad",
> "omap4:green:chrg";
> kpad {
> label = "omap4::keypad";
> max-brightness = <127>;
> };
>
> charging {
> label = "omap4:green:chrg";
> max-brightness = <255>;
> };
That's just a goofy extra layer of indirection and still doesn't follow
the lead of the gpio-leds pattern. That makes it worse that your
original binding, not better.
It really needs to look like this:
pwmleds {
compatible = "pwm-leds";
kpad {
label = "omap4::keypad";
max-brightness = <127>;
pwms = <&twl_pwm 0 7812500>;
};
charging {
label = "omap4:green:chrg";
max-brightness = <255>;
pwms = <&twl_pwmled 0 7812500>;
};
};
g.
--
To unsubscribe from this list: send the line "unsubscribe linux-leds" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
