From: Michael Lawnick <ml.lawnick-Mmb7MZpHnFY@public.gmane.org>
To: Ben Dooks <ben.dooks-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
SH-Linux <linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: rcar-i2c: always reads a byte
Date: Wed, 12 Mar 2014 09:27:47 +0100 [thread overview]
Message-ID: <53201A83.7040605@gmx.de> (raw)
In-Reply-To: <531F3686.7050808-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org>
Hi,
Ben Dooks schrieb:
> I have noticed the following behaviour with the i2c-rcar driver
> with the following single i2c_msg structure:
>
> msg[0].addr = 0x12;
> msg[0].flags = I2C_M_RD;
> msg[0].len = 0;
> msg[0].buf = data;
isn't this illegal?
This should lead to 50% chance of blocked bus: After sending read-bit
the slave ACK's and puts first data bit onto SDL. If it is '0', master
won't be able to signal stop nor arbitrate the bus for other transaction
until slave runs into internal timeout (*if* supported).
Only 9 SCL toggles will be able to free bus again.
But maybe I'm missing something.
KR
Michael
next prev parent reply other threads:[~2014-03-12 8:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-11 16:15 rcar-i2c: always reads a byte Ben Dooks
2014-03-11 16:40 ` Wolfram Sang
2014-03-11 16:41 ` Ben Dooks
2014-03-11 16:47 ` Wolfram Sang
2014-03-11 17:10 ` Ben Dooks
2014-05-05 15:51 ` Wolfram Sang
2014-03-11 17:24 ` Wolfram Sang
2014-03-11 17:31 ` Ben Dooks
2014-03-11 17:46 ` Wolfram Sang
[not found] ` <531F3686.7050808-4yDnlxn2s6sWdaTGBSpHTA@public.gmane.org>
2014-03-12 8:27 ` Michael Lawnick [this message]
2014-03-12 8:39 ` Paul Carpenter
2014-03-12 9:00 ` Michael Lawnick
[not found] ` <53201A83.7040605-Mmb7MZpHnFY@public.gmane.org>
2014-05-05 13:21 ` Wolfram Sang
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