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From: Stephen Warren <swarren@wwwdotorg.org>
To: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-samsung-soc@vger.kernel.org, grundler@chromium.org,
	devicetree-discuss@lists.ozlabs.org,
	broonie@opensource.wolfsonmicro.com, w.sang@pengutronix.de,
	ben-linux@fluff.org, khali@linux-fr.org, naveen@chromium.org
Subject: Re: [PATCH 1/2] i2c-core: Add gpio based bus arbitration implementation
Date: Fri, 14 Dec 2012 09:06:49 -0700	[thread overview]
Message-ID: <50CB4E99.9060506@wwwdotorg.org> (raw)
In-Reply-To: <1355464254-12768-2-git-send-email-ch.naveen@samsung.com>

On 12/13/2012 10:50 PM, Naveen Krishna Chatradhi wrote:
> The arbitrator is a general purpose function which uses two GPIOs to
> communicate with another device to claim/release a bus.

> diff --git a/Documentation/devicetree/bindings/i2c/arbitrator-i2c.txt b/Documentation/devicetree/bindings/i2c/arbitrator-i2c.txt
> new file mode 100644
> index 0000000..cb91ea8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/arbitrator-i2c.txt
> @@ -0,0 +1,56 @@
> +Device-Tree bindings for i2c gpio based bus arbitrator
> +
> +bus-arbitration-gpios :
> +	Two GPIOs to use with the GPIO-based bus arbitration protocol
> +(see below).
> +The first should be an output, and is used to claim the I2C bus,
> +the second should be an input, and signals that the other side (Client)
> +wants to claim the bus. This allows two masters to share the same I2C bus.

I'm confused why this is even needed; the I2C protocol itself defines
how multi-master is supposed to work, just using the regular SCL/SDA lines.

  reply	other threads:[~2012-12-14 16:06 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-14  5:50 [PATCH 0/2] i2c: Implement generic gpio based bus arbitration Naveen Krishna Chatradhi
2012-12-14  5:50 ` [PATCH 1/2] i2c-core: Add gpio based bus arbitration implementation Naveen Krishna Chatradhi
2012-12-14 16:06   ` Stephen Warren [this message]
2012-12-15 14:21     ` Mark Brown
2013-01-24 11:13       ` Wolfram Sang
2013-01-24 11:18         ` Mark Brown
2013-01-24 11:39           ` Wolfram Sang
2013-01-26  5:00             ` Mark Brown
2012-12-19 12:32   ` Grant Likely
2012-12-19 17:14     ` Mark Brown
2012-12-20  0:17       ` Simon Glass
2012-12-20  0:58         ` Grant Likely
2012-12-20  0:53       ` Grant Likely
2012-12-14  5:50 ` [PATCH 2/2] i2c-s3c2410: Add GPIO based bus arbitration functionality Naveen Krishna Chatradhi

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