linux-kernel - Re: [PATCH v9 2/2] i2c: riic: Recover from arbitration loss

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Message-ID: <aBPPLkmrYwSpNp6z@shikoro>
Date: Thu, 1 May 2025 21:44:46 +0200
From: Wolfram Sang <wsa+renesas@...g-engineering.com>
To: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
Cc: Chris Brandt <chris.brandt@...esas.com>,
	Andi Shyti <andi.shyti@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Andy Shevchenko <andy@...nel.org>,
	linux-renesas-soc@...r.kernel.org, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, Biju Das <biju.das.jz@...renesas.com>,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v9 2/2] i2c: riic: Recover from arbitration loss


> From 10µs to 50µs, the clock pulses are part of the recovery sequence.

Ahh, that explains. I thought this was all after the recovery.

> Around 55µs, the transfer function starts attempting to send data
> hence the clock pulse.

The short SCL spike around 55us is still strange. However, we might
violate t:buf time between STOP and START. Can you please try the
attached WIP patch?

> The slave device is versa clock geberator 5P35023 (exact part number
> on SMARC RZ/G2L 5P35023B-629NLGI)

Hmm, G3S has a versa clock generator as well. But I can't find a way to
wire GPIO lines to RIIC1 or I2C_PM.


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