[U-Boot-Users] [PATCH 02/21] AT91CAP9ADK: Normalize SPI timings

[Stelian Pop]

Le mardi 06 mai 2008 à 14:23 -0500, Ken.Fuchs at bench.com a écrit :
> Stelian Pop's patch:
> 
> > diff --git a/include/configs/at91cap9adk.h 
> 
> > -#define AT91_SPI_CLK			20000000
> > -#define DATAFLASH_TCSS			(0xFA << 16)
> > -#define DATAFLASH_TCHS			(0x8 << 24)
> > +#define AT91_SPI_CLK			15000000
> > +#define DATAFLASH_TCSS			(0x1a << 16)
> > +#define DATAFLASH_TCHS			(0x1 << 24)
> 
> What do you mean by "Normalize SPI timings"?
> 
> Why are you replacing 20000000 Hz with 15000000 Hz?
> Faster would be better as long as the SPI bus
> operates reliably, right?

I used here what the kernel people use. I tend to be more confident in
the values used in the kernel (where the code is used by many) than in
some random speed picked up from Atmel's example files.

As for TCSS/TCHS, the values comes from Atmel's bootstrap project.

-- 
Stelian Pop <stelian at popies.net>