Re: [Gumstix-users] PXA270 Interrupt Help

[Ned F. <nfo...@wh...>]

rketcham wrote:
> Dave,
> Ahhh. That's good to know. I'm actually working on a driver to communicate
> with my SPI to UART chip.   I wanted the SPI chip to raise an interrupt when
> it's RX buffer reached a certain level. On the interrupt, I want the
> interrupt service routine to check several registers on the SPI chip to
> determine the cause of the interrupt and retrieve data from the buffer.
> 
> To do this, I think I only need access to three registers on the PXA270: 
> 
> SSDR2 for TX and RX  (0x41700010)
> GPCR2 for GPIO clear (0x40E0002C)
> GPSR2 for GPIO set(0x40E00020)
> 
> The last two are for my chip select (although, I could use the Frame pin). 
> What's the usual way for doing this?

If you are new to kernel programming and are trying to write a device
driver, as was my situation last year, I recommend that an easier to way
to learn would be to read a good reference book.  I found the following
to be very helpful: "Linux Device Drivers" THIRD EDITION, by Jonathan
Corbet, Alessandro, Rubini, and Greg Kroah-Hartman, published by
O'Reilly.  The third edition covers the 2.6 kernel.

Even though I was expanding a driver that already existed and worked
(pxa2xx_spi.c), I could never have understood all the things I needed to
know by polling a mailing list.

-- 
Ned Forrester                                       nfo...@wh...
Oceanographic Systems Lab                                  508-289-2226
Applied Ocean Physics and Engineering Dept.
Woods Hole Oceanographic Institution          Woods Hole, MA 02543, USA
http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212
http://www.whoi.edu/hpb/Site.do?id=1532
http://www.whoi.edu/page.do?pid=10079