power: regulator: Add support for regulator-force-boot-off

Add support for regulator-force-boot-off DT property.
This property can be used by the board/device drivers for
turning off regulators on early init stages as pre-requisite
for the other components initialization.

Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

drivers/power/regulator/regulator-uclass.c

@@ -311,6 +311,17 @@ int regulator_autoset(struct udevice *dev)
 	return ret;
 }
 
+int regulator_unset(struct udevice *dev)
+{
+	struct dm_regulator_uclass_plat *uc_pdata;
+
+	uc_pdata = dev_get_uclass_plat(dev);
+	if (uc_pdata && uc_pdata->force_off)
+		return regulator_set_enable(dev, false);
+
+	return -EMEDIUMTYPE;
+}
+
 static void regulator_show(struct udevice *dev, int ret)
 {
 	struct dm_regulator_uclass_plat *uc_pdata;
@@ -443,6 +454,7 @@ static int regulator_pre_probe(struct udevice *dev)
 	uc_pdata->boot_on = dev_read_bool(dev, "regulator-boot-on");
 	uc_pdata->ramp_delay = dev_read_u32_default(dev, "regulator-ramp-delay",
 						    0);
+	uc_pdata->force_off = dev_read_bool(dev, "regulator-force-boot-off");
 
 	node = dev_read_subnode(dev, "regulator-state-mem");
 	if (ofnode_valid(node)) {
@@ -495,6 +507,32 @@ int regulators_enable_boot_on(bool verbose)
 	return ret;
 }
 
+int regulators_enable_boot_off(bool verbose)
+{
+	struct udevice *dev;
+	struct uclass *uc;
+	int ret;
+
+	ret = uclass_get(UCLASS_REGULATOR, &uc);
+	if (ret)
+		return ret;
+	for (uclass_first_device(UCLASS_REGULATOR, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		ret = regulator_unset(dev);
+		if (ret == -EMEDIUMTYPE) {
+			ret = 0;
+			continue;
+		}
+		if (verbose)
+			regulator_show(dev, ret);
+		if (ret == -ENOSYS)
+			ret = 0;
+	}
+
+	return ret;
+}
+
 UCLASS_DRIVER(regulator) = {
 	.id		= UCLASS_REGULATOR,
 	.name		= "regulator",

include/power/regulator.h

@@ -151,6 +151,7 @@ enum regulator_flag {
  * @max_uA*    - maximum amperage (micro Amps)
  * @always_on* - bool type, true or false
  * @boot_on*   - bool type, true or false
+ * @force_off* - bool type, true or false
  * TODO(sjg@chromium.org): Consider putting the above two into @flags
  * @ramp_delay - Time to settle down after voltage change (unit: uV/us)
  * @flags:     - flags value (see REGULATOR_FLAG_...)
@@ -176,6 +177,7 @@ struct dm_regulator_uclass_plat {
 	unsigned int ramp_delay;
 	bool always_on;
 	bool boot_on;
+	bool force_off;
 	const char *name;
 	int flags;
 	u8 ctrl_reg;
@@ -420,6 +422,15 @@ int regulator_set_mode(struct udevice *dev, int mode_id);
  */
 int regulators_enable_boot_on(bool verbose);
 
+/**
+ * regulators_enable_boot_off() - disable regulators needed for boot
+ *
+ * This disables all regulators which are marked to be off at boot time.
+ *
+ * This effectively calls regulator_unset() for every regulator.
+ */
+int regulators_enable_boot_off(bool verbose);
+
 /**
  * regulator_autoset: setup the voltage/current on a regulator
  *
@@ -439,6 +450,18 @@ int regulators_enable_boot_on(bool verbose);
  */
 int regulator_autoset(struct udevice *dev);
 
+/**
+ * regulator_unset: turn off a regulator
+ *
+ * The setup depends on constraints found in device's uclass's platform data
+ * (struct dm_regulator_uclass_platdata):
+ *
+ * - Disable - will set - if  'force_off' is set to true,
+ *
+ * The function returns on the first-encountered error.
+ */
+int regulator_unset(struct udevice *dev);
+
 /**
  * regulator_autoset_by_name: setup the regulator given by its uclass's
  * platform data name field. The setup depends on constraints found in device's