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From: Wolfram Sang <wsa@the-dreams.de>
To: Jean Delvare <jdelvare@suse.de>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH] i2c: algo-bit: add support for I2C_M_STOP
Date: Wed, 21 Jun 2017 16:30:18 +0200	[thread overview]
Message-ID: <20170621143018.GA1571@katana> (raw)
In-Reply-To: <20170621091843.657de813@endymion>

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Hi Jean,

> There's no problem with the scope. The problem is with the
> initialization. The way you did, did_stop gets reset to false with
> every iteration, which isn't what you want.

Ouch, where is my brown paper bag...

> I looked at how 10-bit addressing works again and in fact it is simply
> impossible to not use repeated start when reading from a 10-bit address
> slave. Only the first 2 bits of the 10-bit address are repeated in the
> read part of the transaction. If there was a stop between the two parts
> then there would be no way to know which 10-bit slave should send the
> data.

Which reminds me: Have you ever seen a 10-bit client device in the wild?
I wanted to buy one for testing reasons but was not able to locate one.
I only know a Renesas IP core which has 10-bit slave capability (but no
driver support for that yet).

Regards,

   Wolfram


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  reply	other threads:[~2017-06-21 14:30 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-17 17:12 [PATCH] i2c: algo-bit: add support for I2C_M_STOP Wolfram Sang
2017-06-19  8:30 ` Jean Delvare
2017-06-20 17:28   ` Wolfram Sang
2017-06-21  7:18     ` Jean Delvare
2017-06-21 14:30       ` Wolfram Sang [this message]
2017-06-22  9:06         ` Jean Delvare
2017-06-22 10:15           ` Wolfram Sang

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