From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc: Chris Brandt <chris.brandt@renesas.com>,
Andi Shyti <andi.shyti@kernel.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Andy Shevchenko <andy@kernel.org>,
linux-renesas-soc@vger.kernel.org, linux-i2c@vger.kernel.org,
linux-kernel@vger.kernel.org,
Biju Das <biju.das.jz@bp.renesas.com>,
Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH v9 2/2] i2c: riic: Recover from arbitration loss
Date: Thu, 1 May 2025 09:58:04 +0200 [thread overview]
Message-ID: <aBMpjKtQYYB-teNt@shikoro> (raw)
In-Reply-To: <CA+V-a8v5qFC+uxzC8Qw4F3M1XSFnVq90MWxbvmiRks=ZbkzZjw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 685 bytes --]
> Do you mean that upon detecting an arbitration loss, we simply clear
> the arbitration bit and retry?
Yes, after the bus is considered free again.
> However, when observing the SDA line after recovery, it goes LOW again
> during the transfer. I've attached a screenshot of this case: we
> recovered from a bus hang, the I2C recovery algorithm brought the bus
> to a STOP state, and then a START condition was issued. But after
> initiating the transfer, we can see the SDA line being held LOW again.
That looks weird. Why are there two SDA transitions around 30us? Why is
SDA changed while SCL is high around 45us? Then, this small SCL spike
around 55us... What device is this?
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2025-05-01 7:58 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-30 19:46 [PATCH v9 0/2] i2c: riic: Implement bus recovery Prabhakar
2025-04-30 19:46 ` [PATCH v9 1/2] " Prabhakar
2025-05-01 7:51 ` Wolfram Sang
2025-05-01 14:16 ` Fabrizio Castro
2025-04-30 19:46 ` [PATCH v9 2/2] i2c: riic: Recover from arbitration loss Prabhakar
2025-04-30 20:17 ` Wolfram Sang
2025-04-30 20:29 ` Lad, Prabhakar
2025-05-01 7:58 ` Wolfram Sang [this message]
2025-05-01 9:02 ` Lad, Prabhakar
2025-05-01 19:44 ` Wolfram Sang
2025-05-02 9:29 ` Lad, Prabhakar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aBMpjKtQYYB-teNt@shikoro \
--to=wsa+renesas@sang-engineering.com \
--cc=andi.shyti@kernel.org \
--cc=andy@kernel.org \
--cc=biju.das.jz@bp.renesas.com \
--cc=chris.brandt@renesas.com \
--cc=fabrizio.castro.jz@renesas.com \
--cc=geert+renesas@glider.be \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-renesas-soc@vger.kernel.org \
--cc=prabhakar.csengg@gmail.com \
--cc=prabhakar.mahadev-lad.rj@bp.renesas.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox