Hi,
I need to change the clock frequency output of MMC2 CLK to 48MHz, so that it can be used to supply the clock signal to a Murata WL1271 wlan module.
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