Messages in this thread | | | Subject | Re: [PATCH 02/16] dt-bindings: spi: Add bcmbca-hsspi controller support | From | William Zhang <> | Date | Thu, 12 Jan 2023 11:50:21 -0800 |
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On 01/12/2023 12:21 AM, Krzysztof Kozlowski wrote: > On 11/01/2023 19:44, William Zhang wrote: >> >> >> On 01/11/2023 10:12 AM, Krzysztof Kozlowski wrote: >>> On 11/01/2023 19:04, William Zhang wrote: >>>> >>>> >>>> On 01/11/2023 01:02 AM, Krzysztof Kozlowski wrote: >>>>> On 10/01/2023 23:18, Florian Fainelli wrote: >>>>>> On 1/10/23 00:40, Krzysztof Kozlowski wrote: >>>>>>>>> No, it is discouraged in such forms. Family or IP block compatibles >>>>>>>>> should be prepended with a specific compatible. There were many issues >>>>>>>>> when people insisted on generic or family compatibles... >>>>>>>>> >>>>>>>>>> Otherwise we will have to have a compatible string with chip model for >>>>>>>>>> each SoC even they share the same IP. We already have more than ten of >>>>>>>>>> SoCs and the list will increase. I don't see this is a good solution too. >>>>>>>>> >>>>>>>>> You will have to do it anyway even with generic fallback, so I don't get >>>>>>>>> what is here to gain... I also don't get why Broadcom should be here >>>>>>>>> special, different than others. Why it is not a good solution for >>>>>>>>> Broadcom SoCs but it is for others? >>>>>>>>> >>>>>>>> I saw a few other vendors like these qcom ones: >>>>>>>> qcom,spi-qup.yaml >>>>>>>> - qcom,spi-qup-v1.1.1 # for 8660, 8960 and 8064 >>>>>>>> - qcom,spi-qup-v2.1.1 # for 8974 and later >>>>>>>> - qcom,spi-qup-v2.2.1 # for 8974 v2 and later >>>>>>>> qcom,spi-qup.yaml >>>>>>>> const: qcom,geni-spi >>>>>>> >>>>>>> IP block version numbers are allowed when there is clear mapping between >>>>>>> version and SoCs using it. This is the case for Qualcomm because there >>>>>>> is such clear mapping documented and available for Qualcomm engineers >>>>>>> and also some of us (although not public). >>>>>>> >>>>>>>> I guess when individual who only has one particular board/chip and is >>>>>>>> not aware of the IP family, it is understandable to use the chip >>>>>>>> specific compatible string. >>>>>>> >>>>>>> Family of devices is not a versioned IP block. >>>>>> >>>>>> Would it be acceptable to define for instance: >>>>>> >>>>>> - compatible = "brcm,bcm6868-hsspi", "brcm,bcmbca-hsspi"; >>>>> >>>>> Yes, this is perfectly valid. Although it does not solve William >>>>> concerns because it requires defining specific compatibles for all of >>>>> the SoCs. >>>>> >>>>> Best regards, >>>>> Krzysztof >>>>> >>>> As I mentioned in another email, I would be okay to use these >>>> compatibles to differentiate by ip rev and to conforms to brcm convention: >>>> "brcm,bcmXYZ-hsspi", "brcm,bcmbca-hsspi-v1.0", "brcm,bcmbca-hsspi"; >>>> "brcm,bcmXYZ-hsspi", "brcm,bcmbca-hsspi-v1.1", "brcm,bcmbca-hsspi"; >>> >>> >>> Drop the version in such case, no benefits. I assume XYZ is the SoC >>> model, so for example 6868. >>> >> Yes XYZ is the SoC model >>>> >>>> In the two drivers I included in this series, it will be bound to >>>> brcm,bcmbca-hsspi-v1.0 (in additional to brcm,bcm6328-hsspi) and >>>> brcm,bcmbca-hsspi-v1.1 respectively. This way we don't need to update >>>> the driver with a new soc specific compatible whenever a new chips comes >>>> out. >>> >>> I don't understand why do you bring it now as an argument. You defined >>> before that your driver will bind to the generic bcmbca compatible, so >>> now it is not enough? >>> >> No as we are adding chip model specific info here. The existing driver >> spi-bcm63xx-hsspi.c only binds to brcm,bcm6328-hsspi. This driver >> supports all the chips with rev1.0 controller so I am using this 6328 >> string for other chips with v1.0 in the dts patch, which is not ideal. > > Why? This is perfectly ideal and usual case. Why changing it? > >> Now I have to add more compatible to this driver and for each new chip >> with 1.0 in the future if any. > > Why you cannot use compatibility with older chipset? > IMHO it is really confusing that we have all the SoCs but have to bind to an antique SoC's spi controller compatible and people may think it is a mistake or typo when they don't know they are actually the same. I know there are usage like that but when we have clear knowledge of the IP block with rev info, I think it is much better to have a precise SoC model number and a general revision info in the compatible. As you know they are many usage of IP rev info in the compatible too. brcm,bcm6328-hsspi will stay so it does not break any existing dts reference to that.
Anyway if you still does not like this idea, I will drop the rev info and you have it your way.
> > Best regards, > Krzysztof > [unhandled content-type:application/pkcs7-signature]
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