On Sun, Jan 19, 2014 at 11:11:41AM -0800, Olof Johansson wrote: > On Sun, Jan 19, 2014 at 11:08 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Sunday 19 January 2014 11:03:24 Olof Johansson wrote: > >> > > >> > Yes, because iMX6 specifies #pwm-cells as 2, there's no flags able to > >> > be specified in the pwms declaration in pwmleds. So that doesn't work. > >> > There's no property to tell pwmleds that it should use inverted sense > >> > either. > >> > >> Adding a property for active-low to the pwm-leds binding would be > >> easy, and backwards compatible. I'm surprised the original binding > >> didn't specify it. The leds-pwm driver already seems to support it for > >> C-configured instances. > >> > >> I'm also surprised that the imx pwm driver even has a #pwm-cells of > >> two, since the driver only supports one output. It'd be nice if they > >> had allocated the extra cell for flags, but it's hard to change now, > >> unless you do a new binding/compatible value and deprecate the old one. > > > > Actually I think it's not that hard to change: The binding can specify > > that either #pwm-cells=<2> or #pwm-cells=<3> is supported, and the > > driver extended to handle both cases. This would maintain backwards > > compatibility for old dtb files, though no forward compatibility for > > new dtb files with old kernels. > > Ah, yes, if you add a cell that can be done. There'll still be the > "dead" first cell that will always be 0, but that's alright. Does it not mean that PWM specifications of: <&pwm1 0 n> <&pwm2 0 n> would need to be converted to: <&pwm1 0 n 0> <&pwm2 0 n 0> in every DT file referring to these PWMs - because isn't this just treated in DT as one single array of values? (If DT knew how many were in each specification, we wouldn't need the #foo-cells...) -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit". -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
