netdev - Re: [PATCH v5 2/4] can: ctucanfd: add HW timestamps to RX and error CAN frames

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Date:   Mon, 17 Oct 2022 14:11:22 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Pavel Pisa <pisa@....felk.cvut.cz>
Cc:     Matej Vasilevski <matej.vasilevski@...nam.cz>,
        Ondrej Ille <ondrej.ille@...il.com>,
        Wolfgang Grandegger <wg@...ndegger.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-can@...r.kernel.org, netdev@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v5 2/4] can: ctucanfd: add HW timestamps to RX and error
 CAN frames

On 16.10.2022 23:54:48, Pavel Pisa wrote:
[...]
> I hope/expect that it is not problem to call clk_prepare_enable twice
> on same reference when the clocks are the same. As I read the code the
> state is counted. If it is a problem then some if has to be put there
> when the core and timestamp clock are the same.

The clock prepare and enable are counting. If you call then twice, you
have to call disable and unprepare twice, too, to shut it down. This is
widely used in the kernel, e.g. if the same clock is passed to several
IP cores.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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