Re: [PATCH 1/3] dt-bindings: mmc: spacemit,sdhci: add reset support

Yixun Lan
2025-12-22T02:12:13Z

Hi Krzysztof,

On 16:09 Sun 21 Dec , Krzysztof Kozlowski wrote:
> On Sun, Dec 21, 2025 at 04:20:26PM +0800, Yixun Lan wrote:
> > The SpacemiT SDHCI controller has two reset lines, one connect to AXI bus
> > which shared by all controllers, while another one connect to individual
> > controller separately.
> >
> > Signed-off-by: Yixun Lan <dlan@gentoo.org>
> > ---
> > Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > index 13d9382058fb..322c69b056f4 100644
> > --- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
> > @@ -32,12 +32,24 @@ properties:
> > - const: core
> > - const: io
> >
> > + resets:
> > + items:
> > + - description: axi reset, connect to AXI bus, shared by all controllers
> > + - description: sdh reset, connect to individual controller separately
> > +
> > + reset-names:
> > + items:
> > + - const: axi
> > + - const: sdh
> > +
> > required:
> > - compatible
> > - reg
> > - interrupts
> > - clocks
> > - clock-names
> > + - resets
> > + - reset-names
>
> This is an ABI break without mentioning in commit msg and without any
> justification.
>
Indeed, this will introduce a breakage when combining new kernel + old dtb

Since in current case, the eMMC works fine without reset line operation,
I then would make this property optional (drop it from 'required' section)
and switch to use devm_reset_control_get_optional_xx() API in driver code

Does this looks good to you?

--
Yixun Lan (dlan)