[U-Boot-Users] Question about setting the sys clk freq based on a pull up on io.
wd at denx.de
Wed Nov 19 09:59:06 CET 2003
in message <3FBACF35.4020006 at esteem.com> you wrote:
> My problem is how do I go about this without severly modifying U-Boots
> structure. In analyzing how to do this I determined that the
> configuration and reading of the IO pin sould be done in a
> board_pre_init function. This rases the issue of passing values between
> the init functions called by board_init_f. My second issue is how do I
You can store the cpu_clk / bus_clk in the global_data structure.
> deal with the two frquencies since only one can be defined as
> CONFIG_SYS_CLK_FREQ(which is used in several places) without sticking
> lots of nasty board specific ifdefs through out the code.
I don't see the need for #ifdef's.
> (Note I didn't look at them all). We realy don't want to have to specify
> at compile time what frequency we intend on using. This may become an
I see no need that CONFIG_SYS_CLK_FREQ must be a constant. Instead of
#define CONFIG_SYS_CLK_FREQ 33333333
you can - for example - use
#define CONFIG_SYS_CLK_FREQ my_function_to_read_clocks()
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de
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