[U-Boot-Users] dynamic setting of CONFIG_SYS_CLK_FREQ

Kumar Gala kumar.gala at motorola.com
Thu Apr 22 19:28:57 CEST 2004

How bad would it be to do something like:

#define CONFIG_SYS_CLK_FREQ	(gd->sys_clk)

or is this what you meant by 'provide a suitable init fuction'

- kumar

On Apr 22, 2004, at 12:14 PM, Wolfgang Denk wrote:

> In message <66FC73FC-9476-11D8-A48D-000393DBC2E8 at motorola.com> you 
> wrote:
>> I was wondering if there where an examples in the current u-boot 
>> source
>> tree in which CONFIG_SYS_CLK_FREQ was determined dynamically.  I have 
>> a
> Not exactly for CONFIG_SYS_CLK_FREQ - but the TQM8xxL boards  contain
> code to measure the input clock against the (known) 32kHz clock.
>> system in which I can read a config register on the board to let me
>> know if the CONFIG_SYS_CLK_FREQ is 66Mhz or 33Mhz.  I was hoping to
>> have the 16550 uart (and anything else) that needed 
>> grab it from a variable instead.
> If you provide a suitable init fuction which sets the  value  in  the
> global  data  section eraly enough, you can probably shortcut the use
>> This is on an MPC85xx platform system.
> ...or any other.
> Best regards,
> Wolfgang Denk
> -- 
> Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
> Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
> "There are three principal ways to lose money: wine, women, and engi-
> neers. While the first two are more pleasant, the third is by far the
> more certain."                           - Baron Rothschild, ca. 1800

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