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From: Paul Brook <paul@codesourcery.com>
To: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-devel@nongnu.org, john.williams@petalogix.com,
	edgar.iglesias@gmail.com
Subject: Re: [Qemu-devel] [RFC PATCH v1 1/4] SPI: initial support
Date: Tue, 3 Apr 2012 18:45:09 +0100	[thread overview]
Message-ID: <201204031845.09827.paul@codesourcery.com> (raw)
In-Reply-To: <CAEgOgz4-oxai_Yyc8jkxiSNxZkG8HVdNn9tV7BNb2rqjTXgDVg@mail.gmail.com>

> > I'm no SPI expert, but a bit of googling suggests that it's
> > a synchronous duplex bus, so you always send a byte of data
> > to the slave and get one back in return (even if for some slaves
> > it might be random garbage).

Waitaminute. So this is just basic synchronous serial?

We already have an API for this. hw/spi.c.

If you're building higer level protocols they should be layered on top of the 
SPI, same as smbus is a protocol layer on top of I2C.

Paul

  parent reply	other threads:[~2012-04-03 17:45 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-30  6:37 [Qemu-devel] [RFC PATCH v1 0/4] SPI bus support + Xilinx SPI controller Peter A. G. Crosthwaite
2012-03-30  6:37 ` [Qemu-devel] [RFC PATCH v1 1/4] SPI: initial support Peter A. G. Crosthwaite
2012-03-30  7:37   ` Peter Maydell
2012-03-30  7:50     ` Peter Crosthwaite
2012-04-02 17:39   ` Peter Maydell
2012-04-02 23:51     ` Peter Crosthwaite
2012-04-03  0:48       ` Peter Crosthwaite
2012-04-03 17:45       ` Paul Brook [this message]
2012-04-03 18:08         ` Peter Maydell
2012-04-03 21:22           ` Paul Brook
2012-04-04  0:48             ` Peter Crosthwaite
2012-04-04 16:52               ` Paul Brook
2012-04-05  0:32                 ` Peter Crosthwaite
2012-04-05  7:18                   ` Peter Maydell
2012-04-02 23:57     ` Peter Crosthwaite
2012-04-03  0:27       ` Andreas Färber
2012-03-30  6:37 ` [Qemu-devel] [RFC PATCH v1 2/4] m25p80: initial verion Peter A. G. Crosthwaite
2012-04-03  7:03   ` Stefan Hajnoczi
2012-04-04 12:53   ` Andreas Färber
2012-06-05  0:47     ` Peter Crosthwaite
2012-06-05 12:38       ` Andreas Färber
2012-03-30  6:37 ` [Qemu-devel] [RFC PATCH v1 3/4] xilinx_spi: initial version Peter A. G. Crosthwaite
2012-03-30  6:37 ` [Qemu-devel] [RFC PATCH v1 4/4] petalogix-ml605: added spi controller with m25p80 Peter A. G. Crosthwaite

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