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authorMichael Heimpold <mhei@heimpold.de>2015-12-13 12:08:37 +0100
committerStefano Babic <sbabic@denx.de>2016-01-03 15:56:36 +0100
commitfe21eaf92de4d78413e69c95ba23a869e17454f7 (patch)
tree01d3207cc7ee372bcc37b81f0f75c93309a6c0f4 /arch/arm/cpu/arm926ejs
parenta1ed155298eeb29000d9b1033be094c0f7c45212 (diff)
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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')
-rw-r--r--arch/arm/cpu/arm926ejs/mxs/spl_power_init.c34
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 1972de8..1ec8e2b 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) {