[U-Boot] [PATCH] misc:pmic:trats: Correct procedure of enabling/disabling USB regulators

[Lukasz Majewski]

In the MAX8997, LDO regulators needs to preserve previously set voltage
values.

Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
Cc: Minkyu Kang <mk7.kang at samsung.com>
---
 board/samsung/trats/trats.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/board/samsung/trats/trats.c b/board/samsung/trats/trats.c
index 10cf5b3..a20268d 100644
--- a/board/samsung/trats/trats.c
+++ b/board/samsung/trats/trats.c
@@ -218,6 +218,7 @@ int board_mmc_init(bd_t *bis)
 static int s5pc210_phy_control(int on)
 {
 	int ret = 0;
+	u32 val = 0;
 	struct pmic *p = get_pmic();
 
 	if (pmic_probe(p))
@@ -226,11 +227,17 @@ static int s5pc210_phy_control(int on)
 	if (on) {
 		ret |= pmic_set_output(p, MAX8997_REG_SAFEOUTCTRL,
 				      ENSAFEOUT1, LDO_ON);
-		ret |= pmic_reg_write(p, MAX8997_REG_LDO3CTRL, EN_LDO);
-		ret |= pmic_reg_write(p, MAX8997_REG_LDO8CTRL, EN_LDO);
+		ret |= pmic_reg_read(p, MAX8997_REG_LDO3CTRL, &val);
+		ret |= pmic_reg_write(p, MAX8997_REG_LDO3CTRL, EN_LDO | val);
+
+		ret |= pmic_reg_read(p, MAX8997_REG_LDO8CTRL, &val);
+		ret |= pmic_reg_write(p, MAX8997_REG_LDO8CTRL, EN_LDO | val);
 	} else {
-		ret |= pmic_reg_write(p, MAX8997_REG_LDO8CTRL, DIS_LDO);
-		ret |= pmic_reg_write(p, MAX8997_REG_LDO3CTRL, DIS_LDO);
+		ret |= pmic_reg_read(p, MAX8997_REG_LDO8CTRL, &val);
+		ret |= pmic_reg_write(p, MAX8997_REG_LDO8CTRL, DIS_LDO | val);
+
+		ret |= pmic_reg_read(p, MAX8997_REG_LDO3CTRL, &val);
+		ret |= pmic_reg_write(p, MAX8997_REG_LDO3CTRL, DIS_LDO | val);
 		ret |= pmic_set_output(p, MAX8997_REG_SAFEOUTCTRL,
 				      ENSAFEOUT1, LDO_OFF);
 	}
-- 
1.7.2.3