linux-kernel - Re: [RFC PATCH v3 8/9] can: slcan: add support to set bit time register (btr)

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Message-ID: <20220727113054.ffcckzlcipcxer2c@pengutronix.de>
Date:   Wed, 27 Jul 2022 13:30:54 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Dario Binacchi <dario.binacchi@...rulasolutions.com>
Cc:     linux-kernel@...r.kernel.org, linux-can@...r.kernel.org,
        Oliver Hartkopp <socketcan@...tkopp.net>,
        michael@...rulasolutions.com,
        Amarula patchwork <linux-amarula@...rulasolutions.com>,
        Jeroen Hofstee <jhofstee@...tronenergy.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Wolfgang Grandegger <wg@...ndegger.com>, netdev@...r.kernel.org
Subject: Re: [RFC PATCH v3 8/9] can: slcan: add support to set bit time
 register (btr)

On 26.07.2022 23:02:16, Dario Binacchi wrote:
> It allows to set the bit time register with tunable values.
> The setting can only be changed if the interface is down:
> 
> ip link set dev can0 down
> ethtool --set-tunable can0 can-btr 0x31c
> ip link set dev can0 up

As far as I understand, setting the btr is an alternative way to set the
bitrate, right? I don't like the idea of poking arbitrary values into a
hardware from user space.

Do you have a use case for this?

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
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