linux-kernel - Re: [PATCH] phy: can-transceiver: Re-instate "mux-states" property presence check

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Message-ID: <9875d99a-4e16-4f0e-9249-69f0acc4c890@wanadoo.fr>
Date: Wed, 19 Mar 2025 23:06:50 +0900
From: Vincent Mailhol <mailhol.vincent@...adoo.fr>
To: Geert Uytterhoeven <geert+renesas@...der.be>
Cc: linux-can@...r.kernel.org, linux-phy@...ts.infradead.org,
 linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
 Rob Herring <robh@...nel.org>, Marc Kleine-Budde <mkl@...gutronix.de>,
 Vinod Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
 Peter Rosin <peda@...ntia.se>, Aswath Govindraju <a-govindraju@...com>
Subject: Re: [PATCH] phy: can-transceiver: Re-instate "mux-states" property
 presence check

For some reasons, I received your message twice (with a two minutes
interval between both messages). These look identical. I am answering
the most recent. :)

On 19/03/2025 at 22:27, Geert Uytterhoeven wrote:
> On the Renesas Gray Hawk Single development board:
> 
>     can-transceiver-phy can-phy0: /can-phy0: failed to get mux-state (0)
> 
> "mux-states" is an optional property for CAN transceivers.  However,
> mux_get() always prints an error message in case of an error, including
> when the property is not present, confusing the user.

Hmmm, I understand why you are doing this patch. But on the long term,
wouldn't it make more sense to have a devm_mux_state_get_optional()? Or
maybe add a property somewhere to inform devm_mux_state_get() that this
is optional?

Regardless, just see this as an open question. I am OK with the approach
of your patch.

> Fix this by re-instating the property presence check.
> 
> This is bascially a revert of commit d02dfd4ceb2e9f34 ("phy:
> can-transceiver: Drop unnecessary "mux-states" property presence
> check"), with two changes:
>   1. Use the proper API for checking whether a property is present,
>   2. Do not print an error message, as the mux core already takes care
>      of that.
> 
> Fixes: d02dfd4ceb2e9f34 ("phy: can-transceiver: Drop unnecessary "mux-states" property presence check")> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

Notwithstanding of above comment:

Reviewed-by: Vincent Mailhol <mailhol.vincent@...adoo.fr>


Yours sincerely,
Vincent Mailhol