linux-kernel - Re: [PATCH v4 05/11] clk: Introduce clk-tps68470 driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 1 Nov 2021 12:42:37 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andy@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Daniel Scally <djrscally@...il.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Kate Hsuan <hpa@...hat.com>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>
Subject: Re: [PATCH v4 05/11] clk: Introduce clk-tps68470 driver

On Mon, Nov 1, 2021 at 12:27 PM Hans de Goede <hdegoede@...hat.com> wrote:
> On 10/25/21 13:24, Andy Shevchenko wrote:
> > On Mon, Oct 25, 2021 at 12:42 PM Hans de Goede <hdegoede@...hat.com> wrote:

...

> >> +       for (i = 0; i < ARRAY_SIZE(clk_freqs); i++) {
> >> +               diff = clk_freqs[i].freq - rate;
> >> +               if (diff == 0)
> >> +                       return i;
> >
> >> +               diff = abs(diff);
> >
> > This needs a comment why higher (lower) frequency is okay.
>
> This function is called in 2 places:
>
> 1. From tps68470_clk_round_rate(), where higher/lower clearly is ok,
> (see the function name) so no comment needed.
>
> 2. From tps68470_clk_set_rate() where it is NOT ok and this is
> enforced in the caller:
>
>         unsigned int idx = tps68470_clk_cfg_lookup(rate);
>
>         if (rate != clk_freqs[idx].freq)
>                 return -EINVAL;
>
> This is not easy to describe in a comment, while being obvious
> if someone looking at this actually looks at the callers.

Hmm... but try your best. :-)

While at it, recently I have learned about util_macros.h. Any use of it here?
Or amending it there and re-using it here?

> >> +               if (diff < best_diff) {
> >> +                       best_diff = diff;
> >> +                       best_idx = i;
> >> +               }
> >> +       }

-- 
With Best Regards,
Andy Shevchenko