Re: [PATCH v1] spi: dt-bindings: spi-rockchip: restrict num-cs

[Luis de Arquer <ldearquer@gmail.com>]

On 1/23/24 11:49, Johan Jonker wrote:
> 
> 
> On 1/23/24 10:17, Luis de Arquer wrote:
>> On 1/22/24 23:59, Johan Jonker wrote:
>>> In the driver spi-rockchip.c max_native_cs is limited to 4 and the
>>> default num-cs property is 1. Restrict num-cs in spi-rockchip.yaml.
>>>
>>
> 
>> Doesn't num-cs include gpio chip selects too?
>> I have a setup with num-cs = <12> which uses non-native cs-gpios just fine
> 
> Given that bindings and Linux drivers capabilities are 2 separate things.
> However this document has also a purpose that must notify mainline maintainers if users submit bogus DT values.
> Currently that limit is set to 4 in the mainline driver.
> You are free to submit a real board file/patch serie afterwords as proof for review with 12 spi chips and then adjust this limit and increase ROCKCHIP_SPI_MAX_CS_NUM.

Hi Johan,

OK to that, I was not aware a driver could limit num-cs (I thought it 
could be extended with as many gpios as needed without involving the 
controller driver). I thought of num-cs as a spi subsystem generic thing.

In fact, I was reviewing the setup I mentioned, and even it defines 12 
cs in the controller with no driver complaints, so far only 3 of them 
are mapped to devices (I'll have to review the driver before going any 
futher!)

Luis


> 
> Johan
> 
>>
>> Luis
>>
>>> Signed-off-by: Johan Jonker <jbx6244@gmail.com>
>>> ---
>>>    Documentation/devicetree/bindings/spi/spi-rockchip.yaml | 5 +++++
>>>    1 file changed, 5 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/spi/spi-rockchip.yaml b/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
>>> index e4941e9212d1..00d555bcbad3 100644
>>> --- a/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
>>> +++ b/Documentation/devicetree/bindings/spi/spi-rockchip.yaml
>>> @@ -65,6 +65,11 @@ properties:
>>>          - const: tx
>>>          - const: rx
>>>
>>> +  num-cs:
>>> +    default: 1
>>> +    minimum: 1
>>> +    maximum: 4
>>> +
>>>      rx-sample-delay-ns:
>>>        default: 0
>>>        description:
>>> -- 
>>> 2.39.2
>>>
>>>
>>> _______________________________________________
>>> Linux-rockchip mailing list
>>> Linux-rockchip@lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-rockchip
>>