mx6: soc: Clear the LDO ramp values up prior to setting the LDO voltages

Since ROM may modify the LDO ramp up time according to fuse setting,
it is safer to reset the ramp up field to its default value of 00:

00: 64 cycles of 24MHz clock;
01: 128 cycles of 24MHz clock;
02: 256 cycles of 24MHz clock;
03: 512 cycles of 24MHz clock;

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Jason Liu <r64343@freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

arch/arm/cpu/armv7/mx6/soc.c

@@ -93,6 +93,20 @@ void init_aips(void)
 	writel(0x00000000, &aips2->opacr4);
 }
 
+static void clear_ldo_ramp(void)
+{
+	struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR;
+	int reg;
+
+	/* ROM may modify LDO ramp up time according to fuse setting, so in
+	 * order to be in the safe side we neeed to reset these settings to
+	 * match the reset value: 0'b00
+	 */
+	reg = readl(&anatop->ana_misc2);
+	reg &= ~(0x3f << 24);
+	writel(reg, &anatop->ana_misc2);
+}
+
 /*
  * Set the VDDSOC
  *
@@ -113,6 +127,8 @@ static void set_vddsoc(u32 mv)
 	else
 		val = (mv - 700) / 25;
 
+	clear_ldo_ramp();
+
 	/*
 	 * Mask out the REG_CORE[22:18] bits (REG2_TRIG)
 	 * and set them to the calculated value (0.7V + val * 0.25V)