linux-kernel - Re: [PATCH v3 2/2] watchdog: mediatek: mt7988: add wdt support

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Message-ID: <3a9d2d26-87c5-47b2-b03d-81b398a54abf@roeck-us.net>
Date:   Mon, 20 Nov 2023 10:06:03 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Daniel Golle <daniel@...rotopia.org>
Cc:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v3 2/2] watchdog: mediatek: mt7988: add wdt support

On 11/20/23 09:33, Daniel Golle wrote:
> On Mon, Nov 20, 2023 at 09:19:46AM -0800, Guenter Roeck wrote:
>> On 11/14/23 09:04, Daniel Golle wrote:
>>> [...]
>>> @@ -89,6 +93,11 @@ static const struct mtk_wdt_data mt7986_data = {
>>>    	.toprgu_sw_rst_num = MT7986_TOPRGU_SW_RST_NUM,
>>>    };
>>> +static const struct mtk_wdt_data mt7988_data = {
>>> +	.toprgu_sw_rst_num = 24,
>>
>> Kind of odd to have this defined locally, while the others are in include files,
>> but not worth arguing about.
> 
>>>From I have just learned from Krzysztof Kozlowski those headers shouldn't
> even exist in first place, as the listed IDs are not actually referenced
> anywhere in the driver, hence they aren't actually bindings [1].
> 
> Quote from that thread:
> | >>> Where is the driver change using these IDs?
> | >> It isn't needed as the driver doesn't list the IDs. [...]
> | > Then it is not a binding.
> ---
> 
> Now that they do exist it's too late to change that for everything
> already existing, I suppose. However, it also doesn't seem like adding
> such a header for MT7988 as well is going to be acknowledged, hence we
> will have to live with the inconsistency in the driver in which older
> SoCs will obtain the number of resets from a macro in their respective
> dt-bindings header while newer SoCs won't have such header and hence
> it will have to be defined in the driver itself (as that's also the
> only place where that number is being used).
> 

As I said, not worth arguing about. However, it seems to me that "too late
to change that for everything" isn't really correct. If MTxxxx_TOPRGU_RST_NUM
isn't supposed to be in devicetree include files, all those defines could be
removed from the from there and be added to the watchdog driver. I don't know
about the other defines in include/dt-bindings/reset/mediatek,mtXXXX-resets.h -
many of those _are_ used in dtsi files, but many others are not.

In summary, while I don't really know/understand what is supposed to be defined
in include/dt-bindings/, whatever is known to _not_ to be there (such as the
total number of reset pins on a SoC) could be moved into the driver(s) using it.

Of course, it might well be that there is a rule saying that anything in
include/dt-bindings/ must not be removed from it even if it is not supposed
to be there. In that case, my apologies for the noise.

Thanks,
Guenter