On Dec 9, 2010, at 12:43 AM, Andy Shevchenko wrote:
> On Wed, Dec 8, 2010 at 10:36 PM, Paul Walmsley <[email protected]> wrote:
>> Anyway, if you want to try changing it from the kernel side, you'll need
>> code like this in the MMC driver or OMAP integration code (off the top of
>> my head, untested):
>
>> Please let me know if this doesn't work.
> IIRC, there is mmc_set_clock() method, but it isn't exported. Anyway,
> I have another issue with some specific code which also requires the
> same function to be exported.
In my u-boot-2010.03 board file (or with u-boot-2009.11 patched to incorporate
the mmc_set_dev() method)
I added the following lines of code.
- mmc_set_dev(2) select the MMC2 controller.
- mmc_clock_config attempts to use a clock divider value of 2, and this method
implements the logic
outlined in Section 22.5.2.7.2 of the OMAP35x TRM Rev D
@@ -34,6 +34,7 @@
#include <common.h>
#include <twl4030.h>
#include <asm/io.h>
+#include <asm/arch/mmc.h>
#include <asm/arch/mux.h>
#include <asm/arch/sys_proto.h>
#include <asm/arch/gpio.h>
@@ -292,6 +293,11 @@ xx GPI31 159 TCH_DOUT - McSPI4_SOMI
dieid_num_r();
omap3_dss_enable();
+ // Initialize MMC2 controller clock to 48Khz
+ mmc_set_dev(2);
+ mmc_init_setup();
+ mmc_clock_config(CLK_MISC, 2);
+
return 0;
}
This is having no effect, and the output clock from the bootloader stage is
still at 96MHz.
How can I change the MMC CLK output to 48MHz using either the boot loader or
the kernel?
Elvis Dowson
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