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-rw-r--r--arch/arm/cpu/armv7/mx6/soc.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index a9b38cc..8b6b7c1 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -376,6 +376,24 @@ static void clear_mmdc_ch_mask(void)
writel(0, &mxc_ccm->ccdr);
}
+static void init_bandgap(void)
+{
+ struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+ /*
+ * Ensure the bandgap has stabilized.
+ */
+ while (!(readl(&mxc_ccm->ana_misc0) & 0x80))
+ ;
+ /*
+ * For best noise performance of the analog blocks using the
+ * outputs of the bandgap, the reftop_selfbiasoff bit should
+ * be set.
+ */
+ writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &mxc_ccm->ana_misc0_set);
+}
+
+
#ifdef CONFIG_MX6SX
void vadc_power_up(void)
{
@@ -506,6 +524,12 @@ int arch_cpu_init(void)
clear_mmdc_ch_mask();
/*
+ * Disable self-bias circuit in the analog bandap.
+ * The self-bias circuit is used by the bandgap during startup.
+ * This bit should be set after the bandgap has initialized.
+ */
+ init_bandgap();
+ /*
* When low freq boot is enabled, ROM will not set AHB
* freq, so we need to ensure AHB freq is 132MHz in such
* scenario.