linux-kernel - Re: [PATCH v5 1/2] dt-bindings: i2c: pca954x: Add timeout reset property

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Message-ID: <pkse4jc6muqwo4zrvb6auhcdv4zrt6zd5zmp4yea5usagw62o3@lgzwggtz4uv3>
Date: Mon, 21 Oct 2024 09:27:55 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: "Wojciech Siudy (Nokia)" <wojciech.siudy@...ia.com>
Cc: Rob Herring <robh@...nel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>, 
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, "andi.shyti@...nel.org" <andi.shyti@...nel.org>, 
	"peda@...ntia.se" <peda@...ntia.se>
Subject: Re: [PATCH v5 1/2] dt-bindings: i2c: pca954x: Add timeout reset
 property

On Sat, Oct 19, 2024 at 11:09:43AM +0000, Wojciech Siudy (Nokia) wrote:
> Hi!
> 
> > If you have a reset GPIO for the mux, then why wouldn't just use it
> > on timeout?
> 
> Because we cannot do that on every board. The reset GPIO is provided to
> ensure, that we have reset signal de-asserted during initialisation.
> You might have connected other devices to the same reset line so this
> must be a configurable option.
> 
> > What happens if you timeout and don't have this property? Just 
> give up?
> 
> This would be the case just like before introducting this change. Some
> aplications might do other attempt, the bus driver can try recovery.
> Unfortunately common reset line for multiple chips is not a rare
> situation.

And Linux handles it well now. This is reset of the I2C devices
(children), not the controller, right? If so, then:
1. It's not a property of the controller,
2. Linux already handles it - switch to reset controller framework.

Best regards,
Krzysztof