On 10/24/19 9:00 PM, Chris Packham wrote:
> The pinctrl node is used by the gpioa node. Which may have more
> descendants at a board level. If the pinctrl node isn't probed first the
> gpio is deferred and anything that needs a gpio pin on that chip is also
> deferred.
If what you care is to optimize your boot flow such that no re-probing
occurs, maybe another solution to look at is to re-order the order in
which subsystems are initialized or built (_initcall changes or
drivers/Makefile changes), because changing Device Tree certainly does
not scale over platforms and I recall Rob indicating that he wanted to
introduce randomized platform_device creation from
of_platform_bus_populate() at one point or another.
>
> Normally we and nodes in the device tree to be listed in their natural
> memory mapped address order but putting the pinctrl node first avoids
> the deferral of numerous devices so make an exception in this case.
That is a workaround more than a real solution, though I understand why
you would to do that. One downside is that the entries are no longer in
incrementing register address order and that is visually disturbing and
who knows, maybe a drive by contributor whose pet project will be to
order the Device Tree entries by incrementing addresses will change that
in the future...
>
> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
> ---
> arch/arm/boot/dts/bcm-nsp.dtsi | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/boot/dts/bcm-nsp.dtsi b/arch/arm/boot/dts/bcm-nsp.dtsi
> index da6d70f09ef1..dd7a65743c08 100644
> --- a/arch/arm/boot/dts/bcm-nsp.dtsi
> +++ b/arch/arm/boot/dts/bcm-nsp.dtsi
> @@ -172,6 +172,13 @@
> #address-cells = <1>;
> #size-cells = <1>;
>
> + pinctrl: pinctrl@3f1c0 {
> + compatible = "brcm,nsp-pinmux";
> + reg = <0x3f1c0 0x04>,
> + <0x30028 0x04>,
> + <0x3f408 0x04>;
> + };
> +
> gpioa: gpio@20 {
> compatible = "brcm,nsp-gpio-a";
> reg = <0x0020 0x70>,
> @@ -458,13 +465,6 @@
> "sata2";
> };
>
> - pinctrl: pinctrl@3f1c0 {
> - compatible = "brcm,nsp-pinmux";
> - reg = <0x3f1c0 0x04>,
> - <0x30028 0x04>,
> - <0x3f408 0x04>;
> - };
> -
> thermal: thermal@3f2c0 {
> compatible = "brcm,ns-thermal";
> reg = <0x3f2c0 0x10>;
>
--
Florian
