On Fri, Jul 4, 2014 at 2:28 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > On Mon, Jun 30, 2014 at 2:53 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote: >> On Thu, Jun 26, 2014 at 11:59:46PM +0100, Feng Kan wrote: > >>> +- #gpio-cells: Should be two. >>> + - first cell is the pin number >>> + - second cell is used to specify optional parameters (unused) >> >> Why is there an unused cell? >> >> Why not just make this a single cell if the binding defines no valid >> parameters? > > I don't get this either. The only reason would be that this cell > should contain flags (such as open collector) the code for using > it being inplemented later. Yes, open drain configuration and mux via pinctrl was something I planned for later. There was another reason for this as well, part of the gpio code I read was confusing me. So I look through the other gpio documentations and found an example that did this as well. int of_gpio_simple_xlate(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags) { /* * We're discouraging gpio_cells < 2, since that way you'll have to * write your own xlate function (that will have to retrive the GPIO * number and the flags from a single gpio cell -- this is possible, * but not recommended). */ Thanks, and please advise me on what to do next. > > If the controller is too primitive to use such flags it should be onecell. > > Yours, > Linus Walleij -- 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