[U-Boot-Users] Hard SPI driver for 834x

Wolfgang Denk wd at denx.de
Mon Jun 12 22:24:27 CEST 2006

Dear Ben,

in message <1150123895.10177.36.camel at saruman.qstreams.net> you wrote:
> Going through the U-boot code, I found two quite different SPI
> implementations, in addition to a spattering of board-specific code:
> CONFIG_SPI is very EEPROM-specific, while CONFIG_SOFT_SPI is nice and
> generic, but is of course bit-banged.  My application uses hard SPI, but
> I want to use U-boot as a hardware debug platform so generic is good.

You are right; CONFIG_SPI should probably be renamed into

> I propose adding CONFIG_HARD_SPI, which does nothing other than #ifdef
> compile the hard driver.  I will then re-use the data structures and
> commands from CONFIG_SOFT_SPI.


> My questions:
> 1.  The /cpu directory has 'mpc83xx', while in fact there are at least
> two groups of chips in this family that have quite different
> peripherals.  Should I put my code here and use #ifdef CONFIG_MPC8349,
> or start an 'mpc834x' branch?

The current code is all MPC834x, so there should be no changes needed
for a 8349. As soon as other code will be added which  turns  out  to
fit  not  well  we  will consider renaming the current directory into

> 2.  Where is the appropriate place to call 'spi_init()'?  In my patch,
> I've placed it in /lib_ppc/board.c along with 'i2c_init()'.  Should it
> instead go in board code?

I think your decision is OK.

> 3.  Should I put changes to README in the same patch, or would you
> prefer a different one?  Patch size should be < 15kB, so size isn't
> really an issue.

I'd appreciate to see the README changes  in  the  same  patch;  this
makes understanding much easier.

> 4.  More embarassingly, is there a trick to getting new files to show up
> when calling 'git diff' on the u-boot tree?  I've tried 'git-add',

They turn up when you create a patch; I usually use "cg-mkpatch".

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
How does a project get to be a year late?      ... One day at a time.

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