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ARM: mxs: allow boards to select DC-DC switching clock source

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For some board designs, it might be useful to switch the DC-DC
clock source to something else rather the default 24 MHz, e.g.
for EMI reasons.

For this, override the mxs_power_setup_dcdc_clocksource function
in your board support files.

Example:
void mxs_power_setup_dcdc_clocksource(void)
{
    mxs_power_switch_dcdc_clocksource(POWER_MISC_FREQSEL_20MHZ);
}

Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
This commit is contained in:
Michael Heimpold 2015-12-13 12:08:37 +01:00 committed by Stefano Babic
parent a1ed155298
commit fe21eaf92d
2 changed files with 36 additions and 0 deletions
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34
arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
View File

@ -247,6 +247,39 @@ static void mxs_power_setup_5v_detect(void)
POWER_5VCTRL_PWRUP_VBUS_CMPS);
}
/**
* mxs_power_switch_dcdc_clocksource() - Switch PLL clock for DC-DC converters
* @freqsel: One of the POWER_MISC_FREQSEL_xxx defines to select the clock
*
* This function configures and then enables an alternative PLL clock source
* for the DC-DC converters.
*/
void mxs_power_switch_dcdc_clocksource(uint32_t freqsel)
{
struct mxs_power_regs *power_regs =
(struct mxs_power_regs *)MXS_POWER_BASE;
/* Select clocksource for DC-DC converters */
clrsetbits_le32(&power_regs->hw_power_misc,
POWER_MISC_FREQSEL_MASK,
freqsel);
setbits_le32(&power_regs->hw_power_misc,
POWER_MISC_SEL_PLLCLK);
}
/**
* mxs_power_setup_dcdc_clocksource() - Setup PLL clock source for DC-DC converters
*
* Normally, there is no need to switch DC-DC clocksource. This is the reason,
* why this function is a stub and does nothing. However, boards can implement
* this function when required and call mxs_power_switch_dcdc_clocksource() to
* switch to an alternative clock source.
*/
__weak void mxs_power_setup_dcdc_clocksource(void)
{
debug("SPL: Using default DC-DC clocksource\n");
}
/**
* mxs_src_power_init() - Preconfigure the power block
*
@ -872,6 +905,7 @@ static void mxs_power_configure_power_source(void)
debug("SPL: Configuring power source\n");
mxs_power_setup_dcdc_clocksource();
mxs_src_power_init();
if (readl(&power_regs->hw_power_sts) & POWER_STS_VDD5V_GT_VDDIO) {

2
arch/arm/include/asm/arch-mxs/sys_proto.h
View File

@ -25,6 +25,8 @@ int mxsmmc_initialize(bd_t *bis, int id, int (*wp)(int), int (*cd)(int));
void mxs_common_spl_init(const uint32_t arg, const uint32_t *resptr,
const iomux_cfg_t *iomux_setup,
const unsigned int iomux_size);
void mxs_power_switch_dcdc_clocksource(uint32_t freqsel);
#endif
struct mxs_pair {