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From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
	Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-sunxi@googlegroups.com, Hans de Goede <hdegoede@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v2 1/4] i2c: sunxi: Add Reduced Serial Bus (RSB) support
Date: Thu, 5 Mar 2015 23:08:01 +0100	[thread overview]
Message-ID: <20150305220801.GE4522@lukather> (raw)
In-Reply-To: <20150305184044.GA881@katana>

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On Thu, Mar 05, 2015 at 07:40:44PM +0100, Wolfram Sang wrote:
> 
> > > I don't have the bandwidth for a full review right now. However, I
> > > already wanted to tell you guys that my gut feeling is that this
> > > protocol is quite far away from I2C. P2WI was already at the edge.
> > > Maybe there is a better place for such custom stuff? I dunno yet.
> > 
> > That's unfortunate, especially since it looks closer to SPI than what
> > P2WI even was.
> 
> SPI? I assume you mean I2C. Can you elaborate your reasoning?

Yeah, I obviously meant I2C, sorry.

P2WI had no address. It was a single-device bus. However, the way it
communicated with the device was very close to I2C, apart from a
parity bit instead of the ACK.

From that regard, RSB is a multiple device bus, using addresses, just
like I2C. The way it communicates is basically the one used by P2WI.

So really, it just is more I2C-alike than P2WI has ever been.

> > What would be your suggestion?
> 
> Let me quote:
> 
> "I don't have the bandwidth for a full review right now... I dunno
> yet."

Good thing that we are not talking about a full review then, but more
a philosophical discussion.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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  reply	other threads:[~2015-03-05 22:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-02  8:24 [PATCH v2 0/4] i2c: sunxi: Add Reduced Serial Bus (RSB) support Chen-Yu Tsai
     [not found] ` <1425284686-5116-1-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2015-03-02  8:24   ` [PATCH v2 1/4] " Chen-Yu Tsai
     [not found]     ` <1425284686-5116-2-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2015-03-04 16:53       ` Maxime Ripard
2015-03-04 17:27       ` Wolfram Sang
2015-03-05 18:28         ` Maxime Ripard
2015-03-05 18:40           ` Wolfram Sang
2015-03-05 22:08             ` Maxime Ripard [this message]
2015-03-06  6:36               ` Wolfram Sang
2015-03-02  8:24   ` [PATCH v2 2/4] i2c: sunxi: Add Reduced Serial Bus (RSB) DT bindings documentation Chen-Yu Tsai
     [not found]     ` <1425284686-5116-3-git-send-email-wens-jdAy2FN1RRM@public.gmane.org>
2015-03-04 16:39       ` Maxime Ripard
2015-03-02  8:24   ` [PATCH v2 3/4] ARM: dts: sun8i: Add Reduced Serial Bus controller device node to A23 dtsi Chen-Yu Tsai
2015-03-02  8:24   ` [PATCH v2 4/4] ARM: dts: sun8i: ippo-q8h-v5: Enable Reduced Serial Bus controller Chen-Yu Tsai

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