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. -Olof -- 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
