On Sun, Aug 07, 2022 at 05:54:28PM +0300, 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. A little, but it's not unusual. > We can use the generic name "nuvoton, npcm-kcs-bmc" as you suggested > 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. I'm ok with that option. I guess I should have mentioned it. Add nuvoton,npcm-kcs-bmc to the driver's of_device_id table. Then use that in that compatible string in the device tree. Leave the 750 compatible string in the table for backwards compatibility. There's no point in having a bunch of those strings if they are all the same. If a new one comes out that is different, we can handle that when the time comes. -corey > > > > I'm pretty sure the only reason to have muliple compatible entries in a > > device tree is to cover multiple kernels where the name changed. > > > > -corey > > > > > > > > > > -corey > > > > > > > > > - interrupts : interrupt generated by the controller > > > > > - kcs_chan : The KCS channel number in the controller > > > > > > > > > > -- > > > > > 2.33.0 > > > > > > > > > > > Best regards, > > > > > > Tomer > > Best regards, > > Tomer
