From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Date: Wed, 04 Feb 2015 22:14:46 +0000
Subject: Re: [PATCH] clk: shmobile: div6: Avoid division by zero in .round_rate()
Message-Id: <54D299D6.7060809@cogentembedded.com>
List-Id: <linux-sh.vger.kernel.org>
References: <1423052841-15194-1-git-send-email-geert+renesas@glider.be> <20150204173233.GA30930@katana> <54D25AAA.8070904@cogentembedded.com> <20150204220152.421.38508@quantum> <54D29760.4010009@cogentembedded.com>
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To: Mike Turquette <mturquette@linaro.org>, Wolfram Sang <wsa@the-dreams.de>, Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Stephen Boyd <sboyd@codeaurora.org>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>, Ulrich Hecht <ulrich.hecht+renesas@gmail.com>, Wolfram Sang <wsa@sang-engineering.com>, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org

Hello.

On 02/05/2015 01:04 AM, Sergei Shtylyov wrote:

>>>>> Anyone may call clk_round_rate() with a zero rate value, so we have to
>>>>> protect against that.

>>>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

>>>> Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

>>>> I agree that this should not be fixed in the core because the fixup is
>>>> really driver dependant.

>>>      Dunno, zero frequency seems generally insane to me.

>> It is useful to find the lowest frequency a clock can support. Basically
>> it is a search for the floor frequency.

>     Why not just use 1? Or are you assuming that some hardware could actually
> support 0 Hz?

    Replying to myself: yes, this has happened to me, when I forgot to 
override the EXTAL frequency in the board .dts file (default was 0).

>> Regards,
>> Mike

WBR, Sergei