commit 51d3a0c999e18a802a654171b5e05952b4630148
author Laxman Dewangan <ldewangan@nvidia.com> Thu Apr 18 18:32:48 2013 +0530
committer Mark Brown <broonie@opensource.wolfsonmicro.com> Thu Apr 18 18:23:53 2013 +0100
tree 4ddc1594d7f4d132d40b6e3adf62892ba01eb2cc
parent 28d1e8cd671a53d6b4f967abbbc2a55f7bd333f6

regulator: palmas: preserve modes of rails during enable/disable

The Palma device like TPS65913 have the mode mask which is also
used for enable/disable the rails. The mode bits are defined as
	00: OFF
	01: AUTO
	10: ECO
	11: Forced PWM

and modes are set accordingly as
	REGULATOR_MODE_NORMAL: AUTO
	REGULATOR_MODE_IDLE: ECO
	REGULATOR_MODE_FAST: PWM

Two issue observed:
1. If client calls following sequence:
	regulator_enable(),
	regulator_set_mode(FAST),
	regulator_disable()

	and again the regulator_enable() then the mode is reset
	to NORMAL inplace of keeping the mode as FAST.

	Fixing this by storing the current mode configured by client
	and restoring modes when enable() is called after disable().

2. In following sequence, the regulator get enabled:
	regulator_disable()
	regulator_set_mode(FAST),

	Fixing this by updating new mode in register only if it is
	enabled.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Graeme Gregory <gg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/palmas-regulator.c

diff --git a/drivers/regulator/palmas-regulator.c b/drivers/regulator/palmas-regulator.c
index 3336916..38447ac 100644
--- a/drivers/regulator/palmas-regulator.c
+++ b/drivers/regulator/palmas-regulator.c
@@ -274,7 +274,10 @@
 	palmas_smps_read(pmic->palmas, palmas_regs_info[id].ctrl_addr, &reg);
 
 	reg &= ~PALMAS_SMPS12_CTRL_MODE_ACTIVE_MASK;
-	reg |= SMPS_CTRL_MODE_ON;
+	if (pmic->current_reg_mode[id])
+		reg |= pmic->current_reg_mode[id];
+	else
+		reg |= SMPS_CTRL_MODE_ON;
 
 	palmas_smps_write(pmic->palmas, palmas_regs_info[id].ctrl_addr, reg);
 
@@ -296,16 +299,19 @@
 	return 0;
 }
 
-
 static int palmas_set_mode_smps(struct regulator_dev *dev, unsigned int mode)
 {
 	struct palmas_pmic *pmic = rdev_get_drvdata(dev);
 	int id = rdev_get_id(dev);
 	unsigned int reg;
+	bool rail_enable = true;
 
 	palmas_smps_read(pmic->palmas, palmas_regs_info[id].ctrl_addr, &reg);
 	reg &= ~PALMAS_SMPS12_CTRL_MODE_ACTIVE_MASK;
 
+	if (reg == SMPS_CTRL_MODE_OFF)
+		rail_enable = false;
+
 	switch (mode) {
 	case REGULATOR_MODE_NORMAL:
 		reg |= SMPS_CTRL_MODE_ON;
@@ -319,8 +325,11 @@
 	default:
 		return -EINVAL;
 	}
-	palmas_smps_write(pmic->palmas, palmas_regs_info[id].ctrl_addr, reg);
 
+	pmic->current_reg_mode[id] = reg & PALMAS_SMPS12_CTRL_MODE_ACTIVE_MASK;
+	if (rail_enable)
+		palmas_smps_write(pmic->palmas,
+			palmas_regs_info[id].ctrl_addr, reg);
 	return 0;
 }
 
@@ -330,9 +339,7 @@
 	int id = rdev_get_id(dev);
 	unsigned int reg;
 
-	palmas_smps_read(pmic->palmas, palmas_regs_info[id].ctrl_addr, &reg);
-	reg &= PALMAS_SMPS12_CTRL_STATUS_MASK;
-	reg >>= PALMAS_SMPS12_CTRL_STATUS_SHIFT;
+	reg = pmic->current_reg_mode[id] & PALMAS_SMPS12_CTRL_MODE_ACTIVE_MASK;
 
 	switch (reg) {
 	case SMPS_CTRL_MODE_ON:
@@ -871,7 +878,8 @@
 			/*
 			 * Read and store the RANGE bit for later use
 			 * This must be done before regulator is probed,
-			 * otherwise we error in probe with unsupportable ranges.
+			 * otherwise we error in probe with unsupportable
+			 * ranges. Read the current smps mode for later use.
 			 */
 			addr = palmas_regs_info[id].vsel_addr;
 
@@ -888,6 +896,14 @@
 						palmas_regs_info[id].vsel_addr);
 			pmic->desc[id].vsel_mask =
 					PALMAS_SMPS12_VOLTAGE_VSEL_MASK;
+
+			/* Read the smps mode for later use. */
+			addr = palmas_regs_info[id].ctrl_addr;
+			ret = palmas_smps_read(pmic->palmas, addr, &reg);
+			if (ret)
+				goto err_unregister_regulator;
+			pmic->current_reg_mode[id] = reg &
+					PALMAS_SMPS12_CTRL_MODE_ACTIVE_MASK;
 		}
 
 		pmic->desc[id].type = REGULATOR_VOLTAGE;