SPI driver development questions

From: Andrea Galbusera
Date: Tue Jul 18 2006 - 10:15:59 EST

I have to develop an SPI device driver to make a PowerPC (mcp5200)
custom board "talk" to an FPGA in order to program it at power on.

I'm using 2.6.16 kernel with support for the spi subsystem enabled. I
also had a look at some new spi-related files coming from 2.6.17

What I'd like to do is to be able to program my FPGA from user space
(namely init scripts), possibly using a standard char device
interface. The binary stream to program the FPGA is stored on the
linux filesystem, so this sounds as the most confortable way to go.

Let me say I have to use the dedicated SPI controller on the 5200, not
the generic PSC module.

I read docs in Documentation/spi and Documentation/driver-model, but
still many questions fly around...

How should I proceed?
Do I have to write a SPI Master Controller Driver for the 5200 first
and than a specific device driver for my FPGA? If so should the master
driver be similar to linux/drivers/spi/spi_mpc83xx.c, taking into
account low level differences in managing the interface?
What exactly will this master driver "export" to the specific device
driver for my FPGA?
I cannot figure out, after registering the master driver how to "bind"
the device driver to the master.

Andrea G.
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