On Mon, Jan 20, 2014 at 09:14:46AM +0900, Simon Horman wrote: > On Sun, Jan 19, 2014 at 09:26:40PM +0100, Arnd Bergmann wrote: > > On Sunday 19 January 2014, Russell King - ARM Linux wrote: > > > 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: > > > > > > 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...) > > > > Right: if you change an existing dts file from #pwm-cells=<2> to > > #pwm-cells=<3>, that requires changing all references to the pwm > > controller at the same time. If both the per-soc .dtsi files > > and the per-board .dts files contain references to the same pwm > > controller, that can end up in significant work. I have not checked > > if this is the case for i.MX though. > > Would this change imply that old dtbs would no longer work with new kernels? Not necessarily. With Lothars patch the driver works with pwm-cells=2 and pwm-cells=3. The only problem is that if you compile an old board dts with a new SoC dtsi it will silently fail since the pwm-cells setting doesn't match the atcual cells in the dts. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- 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
