On 10:28-20230807, Andrew Davis wrote:
> On 8/7/23 12:38 AM, Dhruva Gole wrote:
> > Andrew,
> >
> > On 03/08/23 02:23, Andrew Davis wrote:
> > > GPIO nodes defined in the top-level J7200 SoC dtsi files are incomplete
> > > and may not be functional unless they are extended with pinmux and
> > > device information.
> > >
> > > Disable the GPIO nodes in the dtsi files and only enable the ones that
> > > are actually pinned out on a given board.
> > >
> > > Signed-off-by: Andrew Davis <afd@xxxxxx>
> > > ---
> > > .../boot/dts/ti/k3-j7200-common-proc-board.dts | 18 ++++--------------
> > > arch/arm64/boot/dts/ti/k3-j7200-main.dtsi | 4 ++++
> > > .../arm64/boot/dts/ti/k3-j7200-mcu-wakeup.dtsi | 2 ++
> > > 3 files changed, 10 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
> > > index dee9056f56051..4a5c4f36baeec 100644
> > > --- a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
> > > +++ b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
> > > @@ -240,27 +240,17 @@ &main_uart3 {
> > > pinctrl-0 = <&main_uart3_pins_default>;
> > > };
> > > -&main_gpio2 {
> > > - status = "disabled";
> > > -};
> > > -
> > > -&main_gpio4 {
> > > - status = "disabled";
> > > -};
> > > -
> > > -&main_gpio6 {
> > > - status = "disabled";
> > > +&main_gpio0 {
> > > + status = "okay";
> > > + /* default pins */
> >
> > Small question, where is the pmx for main_gpio0? What does "default pins"
> > refer to here? Where are they pinmuxed?
> >
>
> Good question, where is the pmx for main_gpio0? I don't know, it was
> never defined before either, we only are noticing this now as we are
> disabling by default instead of leaving an unfinished node enabled
> by default. (another benefit of this disabled by default scheme).
>
> What is really happening is GPIO nodes we tend to pinmux differently
> than normal device nodes. Their pinmux selections tends to be spread
> out in all the nodes that make use of these GPIO pins, not all together
> here in this node.
>
> For instance in this device we use one of the main_gpio0 pins as a
> GPIO toggled regulator, and we define the pinmux for it in that node
> (see vdd-sd-dv-default-pins).
>
> We can either define the rest of the pins not used elsewhere
> here, or we can consider GPIO an exception to the rule, I'd say
> the latter is fine for now.
GPIO pinmux are typically defined where they need - the only place where
they are explicitly called out in gpio is when they are meant to be used by
libgpio - typically in the case of dev boards.
Just drop the comments of /* default pins */ - that is just mis-leading.
--
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D
