[PATCH] regulator: pca9450: Support regulator-off-in-suspend

From: Fabio Estevam <[email protected]>

The PCA9450 uses each regulator's ENMODE field to control whether the
regulator remains enabled when the PMIC transitions from RUN to STANDBY
mode.

The driver does not currently implement set_suspend_disable(), so a
regulator configured with regulator-off-in-suspend remains enabled
during system suspend.

Implement set_suspend_disable() for the buck regulators and LDO3-LDO5
by programming ENMODE to 10b. This keeps the regulator enabled in RUN
mode, turns it off when PMIC_STBY_REQ is asserted, and enables it again
when the PMIC returns to RUN mode.

Keep LDO1 and LDO2 on regulator operations without
set_suspend_disable(), because these regulators supply the SNVS domain
and must remain enabled in STANDBY mode.

Measured on a custom i.MX8MP board, turning off NVCC_SD2 (LDO5) during
system suspend reduced power consumption by approximately 64 mW.

Signed-off-by: Fabio Estevam <[email protected]>
---
 drivers/regulator/pca9450-regulator.c | 43 +++++++++++++++++++++++----
 include/linux/regulator/pca9450.h     |  3 ++
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/drivers/regulator/pca9450-regulator.c b/drivers/regulator/pca9450-regulator.c
index c41db70fa052..13082585140f 100644
--- a/drivers/regulator/pca9450-regulator.c
+++ b/drivers/regulator/pca9450-regulator.c
@@ -77,6 +77,24 @@ static const unsigned int pca9450_dvs_buck_ramp_table[] = {
 	25000, 12500, 6250, 3125
 };
 
+/*
+ * ENMODE = 10b keeps the regulator enabled in RUN mode and disables it
+ * while PMIC_STBY_REQ is asserted.
+ */
+static int pca9450_buck_set_suspend_disable(struct regulator_dev *rdev)
+{
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  rdev->desc->enable_mask,
+				  BUCK_ENMODE_ONREQ_STBYREQ);
+}
+
+static int pca9450_ldo_set_suspend_disable(struct regulator_dev *rdev)
+{
+	return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
+				  rdev->desc->enable_mask,
+				  LDO_ENMODE_ONREQ_STBYREQ);
+}
+
 static const struct regulator_ops pca9450_dvs_buck_regulator_ops = {
 	.enable = regulator_enable_regmap,
 	.disable = regulator_disable_regmap,
@@ -88,6 +106,7 @@ static const struct regulator_ops pca9450_dvs_buck_regulator_ops = {
 	.set_ramp_delay	= regulator_set_ramp_delay_regmap,
 	.set_mode = pca9450_buck_set_mode,
 	.get_mode = pca9450_buck_get_mode,
+	.set_suspend_disable = pca9450_buck_set_suspend_disable,
 };
 
 static const struct regulator_ops pca9450_buck_regulator_ops = {
@@ -100,6 +119,7 @@ static const struct regulator_ops pca9450_buck_regulator_ops = {
 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
 	.set_mode = pca9450_buck_set_mode,
 	.get_mode = pca9450_buck_get_mode,
+	.set_suspend_disable = pca9450_buck_set_suspend_disable,
 };
 
 static const struct regulator_ops pca9450_ldo_regulator_ops = {
@@ -111,6 +131,16 @@ static const struct regulator_ops pca9450_ldo_regulator_ops = {
 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
 };
 
+static const struct regulator_ops pca9450_ldo_suspend_regulator_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+	.list_voltage = regulator_list_voltage_linear_range,
+	.set_voltage_sel = regulator_set_voltage_sel_regmap,
+	.get_voltage_sel = regulator_get_voltage_sel_regmap,
+	.set_suspend_disable = pca9450_ldo_set_suspend_disable,
+};
+
 static unsigned int pca9450_ldo5_get_reg_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pca9450 *pca9450 = rdev_get_drvdata(rdev);
@@ -164,6 +194,7 @@ static const struct regulator_ops pca9450_ldo5_regulator_ops = {
 	.list_voltage = regulator_list_voltage_linear_range,
 	.set_voltage_sel = pca9450_ldo5_set_voltage_sel_regmap,
 	.get_voltage_sel = pca9450_ldo5_get_voltage_sel_regmap,
+	.set_suspend_disable = pca9450_ldo_set_suspend_disable,
 };
 
 /*
@@ -575,7 +606,7 @@ static struct pca9450_regulator_desc pca9450a_regulators[] = {
 			.of_match = of_match_ptr("LDO3"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO3,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO3_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
@@ -594,7 +625,7 @@ static struct pca9450_regulator_desc pca9450a_regulators[] = {
 			.of_match = of_match_ptr("LDO4"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO4,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO4_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
@@ -820,7 +851,7 @@ static struct pca9450_regulator_desc pca9450bc_regulators[] = {
 			.of_match = of_match_ptr("LDO3"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO3,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO3_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
@@ -839,7 +870,7 @@ static struct pca9450_regulator_desc pca9450bc_regulators[] = {
 			.of_match = of_match_ptr("LDO4"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO4,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO4_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
@@ -1040,7 +1071,7 @@ static struct pca9450_regulator_desc pca9451a_regulators[] = {
 			.of_match = of_match_ptr("LDO3"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO3,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO3_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
@@ -1059,7 +1090,7 @@ static struct pca9450_regulator_desc pca9451a_regulators[] = {
 			.of_match = of_match_ptr("LDO4"),
 			.regulators_node = of_match_ptr("regulators"),
 			.id = PCA9450_LDO4,
-			.ops = &pca9450_ldo_regulator_ops,
+			.ops = &pca9450_ldo_suspend_regulator_ops,
 			.type = REGULATOR_VOLTAGE,
 			.n_voltages = PCA9450_LDO4_VOLTAGE_NUM,
 			.linear_ranges = pca9450_ldo34_volts,
diff --git a/include/linux/regulator/pca9450.h b/include/linux/regulator/pca9450.h
index 0df8b3c48082..8925e9c9376b 100644
--- a/include/linux/regulator/pca9450.h
+++ b/include/linux/regulator/pca9450.h
@@ -213,6 +213,9 @@ enum {
 #define LDO5H_EN_MASK			0xC0
 #define LDO5HOUT_MASK			0x0F
 
+/* LDO ENMODE value: ON in RUN, OFF while PMIC_STBY_REQ is asserted */
+#define LDO_ENMODE_ONREQ_STBYREQ	0x80
+
 /* PCA9450_REG_IRQ bits */
 #define IRQ_PWRON			0x80
 #define IRQ_WDOGB			0x40
-- 
2.43.0