power: regulator: Add a driver for the AXP PMIC drivevbus

AXP PMICs have a pin which can either report the USB VBUS state, or
driving a regulator that supplies USB VBUS. Add a regulator driver for
controlling this pin. The selection between input and output is done via
the x-powers,drive-vbus-en pin on the PMIC (parent) node.

Signed-off-by: Samuel Holland <samuel@sholland.org>

drivers/power/pmic/axp.c

@@ -51,6 +51,7 @@ static const struct pmic_child_info axp_pmic_child_info[] = {
 	{ "cldo",	"axp_regulator" },
 	{ "dc",		"axp_regulator" },
 	{ "dldo",	"axp_regulator" },
+	{ "drivevbus",	"axp_drivevbus" },
 	{ "eldo",	"axp_regulator" },
 	{ "fldo",	"axp_regulator" },
 	{ "ldo",	"axp_regulator" },

drivers/power/regulator/Kconfig

@@ -57,6 +57,13 @@ config SPL_REGULATOR_AXP
 	  Enable support in SPL for the regulators (DCDCs, LDOs) in the
 	  X-Powers AXP152, AXP2xx, and AXP8xx PMICs.
 
+config REGULATOR_AXP_DRIVEVBUS
+	bool "Enable driver for X-Powers AXP PMIC drivevbus"
+	depends on DM_REGULATOR && PMIC_AXP
+	help
+	  Enable support for sensing or driving the USB VBUS on
+	  X-Powers AXP2xx and AXP8xx PMICs.
+
 config REGULATOR_AXP_USB_POWER
 	bool "Enable driver for X-Powers AXP PMIC USB power supply"
 	depends on DM_REGULATOR && PMIC_AXP

drivers/power/regulator/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_$(SPL_)DM_REGULATOR) += regulator-uclass.o
 obj-$(CONFIG_REGULATOR_ACT8846) += act8846.o
 obj-$(CONFIG_REGULATOR_AS3722)	+= as3722_regulator.o
 obj-$(CONFIG_$(SPL_)REGULATOR_AXP) += axp_regulator.o
+obj-$(CONFIG_$(SPL_)REGULATOR_AXP_DRIVEVBUS) += axp_drivevbus.o
 obj-$(CONFIG_$(SPL_)REGULATOR_AXP_USB_POWER) += axp_usb_power.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_DA9063) += da9063.o
 obj-$(CONFIG_DM_REGULATOR_MAX77686) += max77686.o

drivers/power/regulator/axp_drivevbus.c

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <dm.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+
+#define AXP_VBUS_IPSOUT			0x30
+#define AXP_VBUS_IPSOUT_DRIVEBUS		BIT(2)
+#define AXP_MISC_CTRL			0x8f
+#define AXP_MISC_CTRL_N_VBUSEN_FUNC		BIT(4)
+
+static int axp_drivevbus_get_enable(struct udevice *dev)
+{
+	int ret;
+
+	ret = pmic_reg_read(dev->parent, AXP_VBUS_IPSOUT);
+	if (ret < 0)
+		return ret;
+
+	return !!(ret & AXP_VBUS_IPSOUT_DRIVEBUS);
+}
+
+static int axp_drivevbus_set_enable(struct udevice *dev, bool enable)
+{
+	return pmic_clrsetbits(dev->parent, AXP_VBUS_IPSOUT,
+			       AXP_VBUS_IPSOUT_DRIVEBUS,
+			       enable ? AXP_VBUS_IPSOUT_DRIVEBUS : 0);
+}
+
+static const struct dm_regulator_ops axp_drivevbus_ops = {
+	.get_enable		= axp_drivevbus_get_enable,
+	.set_enable		= axp_drivevbus_set_enable,
+};
+
+static int axp_drivevbus_probe(struct udevice *dev)
+{
+	struct dm_regulator_uclass_plat *uc_plat = dev_get_uclass_plat(dev);
+	int ret;
+
+	uc_plat->type = REGULATOR_TYPE_FIXED;
+
+	if (dev_read_bool(dev->parent, "x-powers,drive-vbus-en")) {
+		ret = pmic_clrsetbits(dev->parent, AXP_MISC_CTRL,
+				      AXP_MISC_CTRL_N_VBUSEN_FUNC, 0);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+U_BOOT_DRIVER(axp_drivevbus) = {
+	.name		= "axp_drivevbus",
+	.id		= UCLASS_REGULATOR,
+	.probe		= axp_drivevbus_probe,
+	.ops		= &axp_drivevbus_ops,
+};