Hi Doug, There is no better way at the moment, but... On Wednesday 15 of May 2013 09:44:22 Doug Anderson wrote: > Linus, > > I'm currently working towards adapting exynos5250-snow (the ARM > Chromebook) to work well in the new world of pinctrl. We've got a > backport of exynos5250 pinctrl in our kernel-3.8 tree and are now > fixing all of the bugs that have popped up. Patches will be sent > upstream (where applicable) shortly. > > > ...but I'm running into an issue when trying to specify pullups / > pulldowns and drive strengths on lines that are just GPIOs or just > interrupts. This is important not just for power usage but also for > proper functioning (the default internal pulldown was overpowering the > weak external pullup in one case). In the old GPIO specifier you > could do specify pulls, but the new simpler one doesn't allow it. > > I've managed to make things work and you can see my progress at > <https://gerrit.chromium.org/gerrit/#/c/51232/>, but it feels a bit > awkward. Is there a better way? If so, then I'm all ears! :) > > > If not, then I guess that what I have will have to do for now. ...but > I really wish that: > > * The GPIO specifier could specify initial drive strength and pull > values for pins. > * The interrupt specifier could specify pull values for pins (drive > strength shouldn't be needed since these are inputs). > > Some examples from the gerrit CL referenced above... > > Here's how I need to do things when I'm using "just an interrupt": > > pinctrl@11400000 { > cyapa_irq: cyapa-irq { > samsung,pins = "gpx1-2"; > samsung,pin-function = <0xf>; You can omit samsung,pin-function here. > samsung,pin-pud = <0>; > samsung,pin-drv = <0>; For inputs I guess you can omit samsung,pin-drv as well. > }; > }; > > trackpad { > reg = <0x67>; > compatible = "cypress,cyapa"; > interrupts = <2 0>; > interrupt-parent = <&gpx1>; > pinctrl-names = "default"; > pinctrl-0 = <&cyapa_irq>; > wakeup-source; > }; > > > I really wish I could add a 3rd number to the interrupt specifier for > pud and skip the pinctrl bit: > > trackpad { > reg = <0x67>; > compatible = "cypress,cyapa"; > interrupts = <2 0 0>; Hmm, looks pretty good to me. > interrupt-parent = <&gpx1>; > wakeup-source; > }; > > > An example with the GPIO specifier instead of the interrupt one: > > pinctrl@11400000 { > ptn3460_gpios: ptn3460-gpios { > samsung,pins = "gpy2-5", "gpx1-5"; > samsung,pin-function = <1>; > samsung,pin-pud = <0>; > samsung,pin-drv = <0>; > }; > }; > > ptn3460-bridge@20 { > compatible = "nxp,ptn3460"; > reg = <0x20>; > powerdown-gpio = <&gpy2 5 0>; > reset-gpio = <&gpx1 5 0>; > edid-emulation = <5>; > pinctrl-names = "default"; > pinctrl-0 = <&ptn3460_gpios>; > }; > > > I don't want to specify function/direction (code can handle that), but > do wish I could specify the pulls and strength. Perhaps: > > ptn3460-bridge@20 { > compatible = "nxp,ptn3460"; > reg = <0x20>; > powerdown-gpio = <&gpy2 5 0 0 0>; > reset-gpio = <&gpx1 5 0 0 0>; This looks fine to me as well. Implementation of both shouldn't be too complicated, so it might be worth giving a try. Keep in mind that old bindings must be supported as well (based on #interrupt-cells and #gpio-cells values, I guess). Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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