On Fri, Sep 07, 2012 at 16:32:51, Domenico Andreoli wrote:
> On Fri, Sep 07, 2012 at 09:10:50AM +0000, AnilKumar, Chimata wrote:
> > Hi Domenico,
>
> Hi,
>
> > On Fri, Sep 07, 2012 at 14:18:39, Domenico Andreoli wrote:
> > > On Sat, Sep 1, 2012 at 10:16 AM, AnilKumar Ch <anilkumar@xxxxxx> wrote:
> > > > Adopt pinctrl support to leds-gpio driver based on leds-gpio
> > > > device pointer, pinctrl driver configure SoC pins to GPIO
> > > > mode according to definitions provided in .dts file.
> > >
> > > Shouldn't be the interaction with the pinctrl layer left to gpiolib?
> > >
> >
> > No, these gpio's are configured specifically for user leds.
>
> So there are some special pad configs to make the leds work which are not
> only muxing and direction setting? Because I expect these to be managed
> privately between gpiolib and pinctrl but now I'm not sure any more,
> I'll look the code.
How can gpio driver knows that leds-gpio driver require
these 4 pins?
>
> > So, leds-gpio driver should have this call, because these gpio
> > pins are used by leds-gpio driver.
> >
> > + am33xx_pinmux: pinmux@44e10800 {
> > + userled_pins: pinmux_userled_pins {
> > + pinctrl-single,pins = <
> > + 0x54 0x7
> > + 0x58 0x17
> > + 0x5c 0x7
> > + 0x60 0x17
> > + >;
> > + };
> > + };
> > +
> >
> > [...]
> >
> > + leds {
> > + compatible = "gpio-leds";
> > + pinctrl-names = "default";
> > + pinctrl-0 = <&userled_pins>;
> > ^^^^^^^^^^^^
>
> I'm surprised to not see any gpio controller (ala irq) involved.
GPIO controller data will be in GPIO node, should not be here.
>
> > Lets take gpio-keypad driver, in that case we have to configure
> > pins as INPUT mode (generic gpio driver might not know what
> > the end usecase is) and this leds case we configure as OUTPUT
> > mode.
>
> gpio direction is modeled by gpiolib so, if no other out-of-gpiolib
> capabilities are required for that led gpio, there is no need to directly
> use pinctrl.
>
Here leds-gpio driver requirement is to set mux configuration of
those 4 pins to GPIO mode (mode 7) as well direction OUTPUT/INPUT.
Set mux mode to 7 (GPIO usage) should be from led driver, because
this driver have the requirement.
Thanks
AnilKumar
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