On 07/08/2022 16:54, Tomer Maimon wrote: > On Sun, 7 Aug 2022 at 15:11, Corey Minyard <minyard@xxxxxxx> wrote: >> >> On Sun, Aug 07, 2022 at 11:03:56AM +0300, Tomer Maimon wrote: >>> Hi Corey, >>> >>> Thanks for your comment. >>> >>> On Fri, 5 Aug 2022 at 14:58, Corey Minyard <minyard@xxxxxxx> wrote: >>>> >>>> On Thu, Aug 04, 2022 at 09:18:00PM +0300, Tomer Maimon wrote: >>>>> Add to npcm845 KCS compatible string a fallback to npcm750 KCS compatible >>>>> string becuase NPCM845 and NPCM750 BMCs are using identical KCS modules. >>>>> >>>>> Signed-off-by: Tomer Maimon <tmaimon77@xxxxxxxxx> >>>>> --- >>>>> Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt b/Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt >>>>> index cbc10a68ddef..4fda76e63396 100644 >>>>> --- a/Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt >>>>> +++ b/Documentation/devicetree/bindings/ipmi/npcm7xx-kcs-bmc.txt >>>>> @@ -7,7 +7,7 @@ used to perform in-band IPMI communication with their host. >>>>> Required properties: >>>>> - compatible : should be one of >>>>> "nuvoton,npcm750-kcs-bmc" >>>>> - "nuvoton,npcm845-kcs-bmc" >>>>> + "nuvoton,npcm845-kcs-bmc", "nuvoton,npcm750-kcs-bmc" >>>> >>>> This is just wrong. The compatible is supposed to identify the device, >>>> not the board the device is on. I think compatible here should be >>>> "npcm7xx-kcs-bmc", and just use that everywhere. It's fine if that is >>>> used on a board named npcm845. >>> The NPCM8XX is not a board, The Nuvoton NPCM8XX is a fourth-generation >>> BMC SoC device family. >> >> Ok, but same principle applies. >> >> If the device is exactly the same, then you would only use one of the >> "npcm7xx-kcs-bmc" and put that in both device trees. You can use >> "nuvoton,npcm750-kcs-bmc", it's really not that important. Or even >> "nuvoton,npcm-kcs-bmc" > If we use "nuvoton, npcm-kcs-bmc" we should take care of backward dts > compatibility, and I am not sure we like to change NPCM KCS driver. >> >> If the device has a minor difference that can be expressed in a >> parameter, then create a parameter for it. >> >> If the device has enough differences that a parameter or two doesn't >> cover it, then you put either nuvoton,npcm750-kcs-bmc or >> nuvoton,npcm750-kcs-bmc in the device tree. Not both. Then you need >> two entries in the of_device_id array and you use the data field or >> something to express the difference. >> >> Since there appears to be no difference, just put >> "nuvoton,npcm750-kcs-bmc" in the npcm845 and I will drop the patch >> adding all this. Then a patch can be added saying it applies to both >> the 7xx and 8xx series of BMC SOCs. If you want to change the name, >> then a patch will be needed for that, but then you will need multiple >> entries in your device tree, but you would not document it as such, as >> there would only be one that applies for this kernel. > > It little bit confusing to use nuvoton,npcm750-kcs-bmc that are > related to NPCM7XX for NPCM8XX KCS. > We can use the generic name "nuvoton, npcm-kcs-bmc" as you suggested No, please don't. It will be NAKed. :) > above but we should take care of backward dts compatibility, and I am > not sure we like to change NPCM KCS driver. > > We had a disscation with Arnd, Arnd asked us to use a fallback as we > did here if NPCM8XX device module is similar to NPCM7XX module: > https://lore.kernel.org/lkml/20220522155046.260146-5-tmaimon77@xxxxxxxxx/ > > I think we should use a fallback to describe the NPCM8XX KCS in the > dt-binding document. Best regards, Krzysztof
