On 14.12.2021 21:10, Rafał Miłecki wrote:
On 14.12.2021 20:59, Rob Herring wrote:
On Sat, Dec 11, 2021 at 12:16:25PM +0100, Rafał Miłecki wrote:
Rob: please kindly comment on this idea of storing pins/groups/functions
in DT.
I was never a fan of stuffing pin mux/ctrl into DT for what's mostly a
one time stuffing of register values. And given how many things run
before getting to the kernel, doing proper pin configuration in the
kernel is much too late (or redundant because it was actually already
done).
OK, thanks for sharing that. Given a pretty limited optimism on this
approach I'll simply drop it and do things the old good way.
I feel I need to post one more comment though.
***
What I find a really clean DT code for defining some BCM4908 groups:
groups {
led_0_grp {
pins = <&pin0 3>;
};
led_1_grp {
pins = <&pin1 3>;
};
nand_grp {
pins = <&pin32 0>, <&pin33 0>, <&pin34 0>, <&pin43 0>, <&pin44 0>, <&pin45 0>, <&pin56 1>;
};
};
***
Gets a bit cumbersome (for me) when using ANSI C structs. I remain
unconvinced about ANSI C being a good place for storing such data.
Maybe I'm just getting too old & grumpy ;)
struct bcm4908_pinctrl_pin_setup {
unsigned number;
unsigned function;
};
static const struct bcm4908_pinctrl_pin_setup led_0_pins[] = {
{ 0, 3 },
};
static const struct bcm4908_pinctrl_pin_setup led_1_pins[] = {
{ 0, 3 },
};
static const struct bcm4908_pinctrl_pin_setup nand_pins[] = {
{ 32, 0 }, { 33, 0 }, { 34, 0 }, { 43, 0 }, { 44, 0 }, { 45, 0 }, { 56, 1 },
};
struct bcm4908_pinctrl_grp {
const char *name;
const struct bcm4908_pinctrl_pin_setup *pins;
const unsigned int num_pins;
};
static const struct bcm4908_pinctrl_grp bcm4908_pinctrl_grps[] = {
{ "led_0_grp", led_0_pins, ARRAY_SIZE(led_0_pins) },
{ "led_1_grp", led_1_pins, ARRAY_SIZE(led_1_pins) },
{ "nand_grp", nand_pins, ARRAY_SIZE(nand_pins) },
};
