On Fri, Jun 14, 2013 at 9:31 AM, Srinivas KANDAGATLA
[off-list ref] wrote:

On 10/06/13 17:38, Srinivas Kandagatla wrote:

quoted

quoted

+++ b/arch/arm/boot/dts/stixxxx-pincfg.h

quoted

quoted

@@ -0,0 +1,94 @@
+#ifndef _STIXXXX_PINCFG_H_
+#define _STIXXXX_PINCFG_H_
+
+/* Alternate functions */
+#define ALT1   1
+#define ALT2   2
+#define ALT3   3
+#define ALT4   4
+#define ALT5   5
+#define ALT6   6
+#define ALT7   7

Why is this part of the DT definitions? In the pinctrl world this
is an intrinsic detail on how groups and functions are associated,
not something that you hard-code into the device tree. The
device tree should state how to combine functions with groups
and those will be strings, not numerals.

Hi Linus,
I would like to get correct understanding of the point your raised here.
I use these ALT function values in "st,function" property for pinctrl
group as shown in this simple example:

pinctrl_sbc_serial1:sbc_serial1 {
       st,function = <ALT3>;
       st,pins {
              tx      = <&PIO2 6 OUT>;
              rx      = <&PIO2 7 IN>;
       };
};

If I do something like what rockchip pinctrl did the pinctrl group will
look like.

pinctrl_sbc_serial1:sbc_serial1 {
       st,pins {
              tx      = <&PIO2 6 OUT ALT3>;
              rx      = <&PIO2 7 IN ALT3>;
       };
};

Is this the right way to do it?

Basically there is no right way to do it since we haven't been able
to agree on a common way to represent pin controllers in the
device tree.

Those I have looked closer at tend to encode the selected
function/group as a string rather than a numeral though.

Yours,
Linus Walleij