diff options
| -rw-r--r-- | arch/arm/mach-at91/spl_atmel.c | 8 | ||||
| -rw-r--r-- | common/spl/Kconfig | 12 |
2 files changed, 20 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/spl_atmel.c b/arch/arm/mach-at91/spl_atmel.c index ef745c94775..85290be3696 100644 --- a/arch/arm/mach-at91/spl_atmel.c +++ b/arch/arm/mach-at91/spl_atmel.c @@ -44,7 +44,15 @@ static void switch_to_main_crystal_osc(void) #endif tmp = readl(&pmc->mor); +/* + * some boards have an external oscillator with driving. + * in this case we need to disable the internal SoC driving (bypass mode) + */ +#if defined(CONFIG_SPL_AT91_MCK_BYPASS) + tmp |= AT91_PMC_MOR_OSCBYPASS; +#else tmp &= ~AT91_PMC_MOR_OSCBYPASS; +#endif tmp &= ~AT91_PMC_MOR_KEY(0xff); tmp |= AT91_PMC_MOR_KEY(0x37); writel(tmp, &pmc->mor); diff --git a/common/spl/Kconfig b/common/spl/Kconfig index dd078fe79d1..0d01353ee84 100644 --- a/common/spl/Kconfig +++ b/common/spl/Kconfig @@ -1151,5 +1151,17 @@ config TPL_YMODEM_SUPPORT endif # TPL +config SPL_AT91_MCK_BYPASS + bool "Use external clock signal as a source of main clock for AT91 platforms" + depends on ARCH_AT91 + default n + help + Use external 8 to 24 Mhz clock signal as source of main clock instead + of an external crystal oscillator. + This option disables the internal driving on the XOUT pin. + The external source has to provide a stable clock on the XIN pin. + If this option is disabled, the SoC expects a crystal oscillator + that needs driving on both XIN and XOUT lines. + endif # SPL endmenu |