Re: [PATCH 1/5] dt-bindings: spi: zynqmp-qspi: Add reset

Rob Herring
2025-01-23T22:45:21Z

On Fri, Jan 17, 2025 at 11:12:15AM -0500, Sean Anderson wrote:
> On 1/17/25 02:14, Michal Simek wrote:
> >
> >
> > On 1/16/25 23:55, Sean Anderson wrote:
> >> Add a reset to help recover from cancelled operations.
> >>
> >> Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
> >> ---
> >>
> >> Documentation/devicetree/bindings/spi/spi-zynqmp-qspi.yaml | 6 ++++++
> >> 1 file changed, 6 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/spi/spi-zynqmp-qspi.yaml b/Documentation/devicetree/bindings/spi/spi-zynqmp-qspi.yaml
> >> index 04d4d3b4916d..901e15fcce2d 100644
> >> --- a/Documentation/devicetree/bindings/spi/spi-zynqmp-qspi.yaml
> >> +++ b/Documentation/devicetree/bindings/spi/spi-zynqmp-qspi.yaml
> >> @@ -36,12 +36,16 @@ properties:
> >> power-domains:
> >> maxItems: 1
> >> + resets:
> >> + maxItems: 1
> >> +
> >> required:
> >> - compatible
> >> - reg
> >> - interrupts
> >> - clock-names
> >> - clocks
> >> + - resets
> >
> > In 2/5 you are calling devm_reset_control_get_optional_exclusive() that's why I expect reset is not really required property.
>
> It's optional for the driver for backwards compatibility. But for the
> devicetree we make it mandatory since it should be included in all new
> devicetrees.

Generally, we discourage new required properties as that's an ABI
change. The exception is really when optional was a mistake. That's
arguably the case here if the h/w always has a reset.

Unfortunately, there's not a way to distinguish 'required' from
'required for new users'.

Rob