diff options
author | Michael Heimpold <mhei@heimpold.de> | 2015-12-13 12:08:37 +0100 |
---|---|---|
committer | Stefano Babic <sbabic@denx.de> | 2016-01-03 15:56:36 +0100 |
commit | fe21eaf92de4d78413e69c95ba23a869e17454f7 (patch) | |
tree | 01d3207cc7ee372bcc37b81f0f75c93309a6c0f4 /arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | |
parent | a1ed155298eeb29000d9b1033be094c0f7c45212 (diff) |
ARM: mxs: allow boards to select DC-DC switching clock source
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>
Diffstat (limited to 'arch/arm/cpu/arm926ejs/mxs/spl_power_init.c')
-rw-r--r-- | arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 1972de81a8e..1ec8e2b6438 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -248,6 +248,39 @@ static void mxs_power_setup_5v_detect(void) } /** + * 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 * * This function configures reasonable values for the DC-DC control loop @@ -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) { |