linux-kernel - Re: [PATCH v5 08/36] i2c: tegra: Use reset_control

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Message-ID: <302ef1e3-30c3-68f8-7957-90c68be9d343@gmail.com>
Date:   Mon, 7 Sep 2020 17:33:05 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        linux-tegra@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 08/36] i2c: tegra: Use reset_control_reset()

07.09.2020 11:13, Andy Shevchenko пишет:
> On Sun, Sep 6, 2020 at 9:51 PM Dmitry Osipenko <digetx@...il.com> wrote:
>>
>> Use a single reset_control_reset() instead of assert/deasset couple in
>> order to make code cleaner a tad. Note that the reset_control_reset()
>> uses 1 microsecond delay instead of 2 that was used previously, but this
>> shouldn't matter. In addition don't ignore potential error of the reset
>> control by emitting a noisy warning if it fails, which shouldn't ever
>> happen in practice.
> 
> Still it's not clear if you check the datasheet or not. Some
> elaboration would be good to have.

I'll update the commit message with more details. Thanks!

> ...
> 
>> +       WARN_ON_ONCE(err);
> 
> Why screaming here? Wouldn't be dev_warn() enough?

The error condition is an indicator of a severe problem because the
reset shouldn't ever fail in practice, hence screaming is a preferred
behavour. I'll a add a comment to the code, telling this.