Hi!
On Thu, Feb 27, 2020 at 02:03:23PM +0100, Geert Uytterhoeven wrote:
> Currently, the DT bindings for an SPI controller specify that
> "#address-cells" must be fixed to one. However, that applies to an SPI
> controller in master mode only. When running in SPI slave mode,
> "#address-cells" should be zero.
>
> Fix this making the value of "#address-cells" dependent on the presence
> of "spi-slave".
>
> Fixes: 0a1b929356830257 ("spi: Add YAML schemas for the generic SPI options")
> Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> Is this the right way to specify this? I couldn't find an example, so
> this needed some trial-and-error.
>
> As of dtc commit 403cc79f06a135ae ("checks: Update SPI bus check for
> 'spi-slave'") and Linux commit c2e7075ca8303631 ("scripts/dtc: Update to
> upstream version v1.4.7-57-gf267e674d145"), dtc knows about SPI slave.
>
> However, when using "#address-cells = <0>" with W=1:
>
> Warning (avoid_unnecessary_addr_size): /soc/spi@e6e10000: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
>
> Just removing #address-cells (using /delete-property/ in the board DTS)
> to fix this warning causes:
>
> Warning (spi_bus_bridge): /soc/spi@e6e10000: incorrect #address-cells for SPI bus
>
> as spi_bus_bridge() uses node_addr_cells(), which defaults to 2 (due to
> dtc's ppc64 heritage? But node_size_cells() defaults to 1, not 2?).
>
> How should this be fixed?
> Should "#address-cells = <0>" be left out or not?
> Should node_{addr,size}_cells() in dtc default to zero?
>
> Thanks!
> ---
> .../devicetree/bindings/spi/spi-controller.yaml | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml
> index 1e0ca6ccf64bbd0a..ba2646258b94980e 100644
> --- a/Documentation/devicetree/bindings/spi/spi-controller.yaml
> +++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml
> @@ -20,7 +20,8 @@ properties:
> pattern: "^spi(@.*|-[0-9a-f])*$"
>
> "#address-cells":
> - const: 1
> + minimum: 0
> + maximum: 1
Nit: This would be better described as an enum: [0, 1]
> "#size-cells":
> const: 0
> @@ -52,6 +53,18 @@ properties:
> description:
> The SPI controller acts as a slave, instead of a master.
>
> +if:
> + required:
> + [ spi-slave ]
Nit: Usually, that notation is when you would do it on the same line,
if you want to go to a new line, it would make more sense to use -
Maxime
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