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Date:   Tue, 22 Nov 2022 08:45:19 +0100
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Subject: Re: [PATCH v2 2/7] dt-bindings: clock: renesas,r9a06g032-sysctrl: Add
 h2mode property
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Herve Codina <herve.codina@bootlin.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Magnus Damm <magnus.damm@gmail.com>,
        Gareth Williams <gareth.williams.jx@renesas.com>,
        linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>
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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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On 21/11/2022 21:46, Geert Uytterhoeven wrote:
>> This does not change anything. Herve wrote:
>>
>>> probe some devices (USB host and probably others)
>>
>> Why some can be probed earlier and some not, if there are no
>> dependencies? If there are dependencies, it's the same case with sysctrl
>> touching the register bit and the USB controller touching it (as well
>> via syscon, but that's obvious, I assume).
>>
>> Where is the synchronization problem?
> 
> The h2mode bit (and probably a few other controls we haven't figured out
> yet) in the sysctrl must be set before any of the USB devices is active.
> Hence it's safest for the sysctrl to do this before any of the USB drivers
> probes.

Again, this does not differ from many, many of other devices. All of
them must set something in system controller block, before they start
operating (or at specific time). It's exactly the same everywhere.

Best regards,
Krzysztof