[U-Boot] [PATCH v2 2/6] mx6: soc: Clear the LDO ramp values up prior to setting the LDO voltages

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam at freescale.com>

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 at freescale.com>
Signed-off-by: Jason Liu <r64343 at freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v1:
- None

 arch/arm/cpu/armv7/mx6/soc.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index 6cbade7..13b9e36 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/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)
-- 
1.8.1.2