Re: [PATCH] Documentation: dt-binding: net: wireless: add bcm43430-fmac

[Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Fri, Sep 1, 2017 at 2:10 PM, Arend van Spriel
<arend.vanspriel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> wrote:
> On 01-09-17 18:49, Rob Herring wrote:
>>
>> On Wed, Aug 30, 2017 at 02:02:18PM +0200, Antony Antony wrote:
>>>
>>> hi,
>>>
>>> On Wed, Aug 30, 2017 at 10:28:20AM +0800, Chen-Yu Tsai wrote:
>>>>
>>>> On Wed, Aug 30, 2017 at 5:43 AM, Antony Antony <antony-AVhj06Q78b5AfugRpC6u6w@public.gmane.org>
>>>> wrote:
>>>
>>>
>>>>> a/Documentation/devicetree/bindings/net/wireless/brcm,bcm43xx-fmac.txt
>>>>> +++
>>>>> b/Documentation/devicetree/bindings/net/wireless/brcm,bcm43xx-fmac.txt
>>>>> @@ -6,7 +6,9 @@ connects the device to the system.
>>>>>
>>>>>   Required properties:
>>>>>
>>>>> - - compatible : Should be "brcm,bcm4329-fmac".
>>>>> + - compatible : should be one of the following:
>>>>> +       * "brcm,bcm4329-fmac"
>>>>> +       * "brcm,bcm43430-fmac"
>>>>
>>>>
>>>> You updated the bindings, but not the driver. So it's not actually
>>>> going to work. More specifically, OOB interrupts won't work.
>>>>
>>>
>>> understood, ignore this patch for now. Thanks Chen-Yu.
>>>
>>>> IIRC, The compatible string for this particular case, as it was
>>>> originally proposed, only serves as a placeholder for the driver
>>>> to check against. None of the instances in sunxi device trees
>>>> match the actual chip model. Actual model matching is done
>>>> through SDIO, as you've already seen.
>>>
>>>
>>> yes it seems SDIO driveer code is smarter, once it initialize
>>> brcm,bcm4329-fmac it ignore the DT info and read the chip details to
>>> locate
>>> firmware file.
>>>
>>> I also noticed other boards using bcm4329-fmac in similar situations.
>>> https://patchwork.kernel.org/patch/9739181/
>>>
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/amlogic/meson-gxbb-nanopi-k2.dts?h=v4.13-rc7
>>>
>>> I will resend "NanoPi NEO Plus2" dts with "brcm,bcm4329-fmac" and see
>>> where
>>> it goes.
>>
>>
>> Adding the compatible or instead of? The former would be better. You
>> should still have the actual chip in case you do have some difference to
>> handle.
>
>
> Hi Rob,
>
> Actually the Broadcom wifi chips themselves are discoverable. So once the
> driver has access to the register space of the device it can determine the
> actual chip, its revision, and exactly what cores (and their revision) are
> present in the chip. Hence there is a single compatible string as there is
> no need to convey the same information through device tree data.

So if a chip has different power on/off sequencing you can discover that?

I realize that most often you don't need it, but a more specific
compatible is there in case you do and so it doesn't require a DTB
update to handle some difference. But you can keep using one
compatible because I can't really enforce any of that.

Rob
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