From: Michael Walle <michael@walle.cc>
To: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>,
Tudor Ambarus <Tudor.Ambarus@microchip.com>
Cc: linux-i2c@vger.kernel.org
Subject: wrong assumption in i2c-at91-master.c ?
Date: Mon, 07 Mar 2022 16:57:27 +0100 [thread overview]
Message-ID: <591de05fde401e8899726e015b837cd1@walle.cc> (raw)
Hi,
I saw that the at91 i2c driver has some kind of heuristic in
at91_twi_xfer(). It assumes that if there are exactly two
messages to transfer, the first is the address write of a
common i2c write address, read data transaction. I don't
think that assumption is correct.
Also there is no check if msg->len is actually smaller
than the width of the address which can be written to
AT91_TWI_IADR.
I think, what is at least missing is that, the first
one is actually a write and have at max 3 bytes (IIRC
thats the max width of AT91_TWI_IADR).
Actually, I don't find any code at all which would
handle multiple messages. Looks like it just supports
num == 2 (and assumes the first message fits into the
AT91_TWI_IADR) and num == 1.
-michael
next reply other threads:[~2022-03-07 15:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 15:57 Michael Walle [this message]
2022-03-07 17:09 ` wrong assumption in i2c-at91-master.c ? Codrin.Ciubotariu
2022-03-07 17:23 ` Michael Walle
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