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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Hans Verkuil <hverkuil+cisco@kernel.org>
Cc: linux-i2c@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Jan Dabros <jsd@semihalf.com>, Andi Shyti <andi.shyti@kernel.org>
Subject: Re: i2c-designware: not possible to write to different i2c addresses in one transfer?
Date: Wed, 15 Oct 2025 13:51:20 +0200	[thread overview]
Message-ID: <aO-KuJ_T9cXsNpIh@ninjato> (raw)
In-Reply-To: <ee6afdd7-3117-43cd-831f-e0ec5ee46f46@kernel.org>

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Hi Hans,

lucky you, I happen to have a board with that controller on the table
currently :)

> This worked fine for the Raspberry Pi 4B using the broadcom i2c driver, but for
> the Raspberry Pi 5 using the designware driver it fails with -EINVAL and these
> kernel messages:
> 
> [  272.284689] i2c_designware 1f00074000.i2c: i2c_dw_xfer_msg: invalid target address

Confirmed.

> Looking in i2c-designware-master.c it seems it cannot handle consecutive messages for
> different addresses.

I agree. I leave the final judgement to the experts (Andy, Mika), but I
already anticipate that I need to extend the existing
I2C_AQ_COMB_SAME_ADDR quirk into a more generic one. And set the quirk
in this driver.

Thanks for the report,

   Wolfram


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  reply	other threads:[~2025-10-15 11:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-15 11:25 i2c-designware: not possible to write to different i2c addresses in one transfer? Hans Verkuil
2025-10-15 11:51 ` Wolfram Sang [this message]
2025-10-15 13:40   ` Andy Shevchenko
2025-10-18 18:17     ` Hans Verkuil
2025-10-18 19:21       ` Andy Shevchenko
2025-10-20  9:41       ` Hans Verkuil
2025-10-19 17:53     ` Wolfram Sang
2025-10-20  7:15       ` Hans Verkuil
2025-10-20 11:59 ` Mika Westerberg
2025-10-20 12:29   ` Hans Verkuil
2025-10-20 12:45     ` Mika Westerberg

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