power: regulator: add qcom-usb-vbus

Add regulator driver that allow some Qualcomm PMIC to
feed VBUS output to peripherals that are connected.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Acked-by: Caleb Connolly <caleb.connolly@linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Caleb Connolly <caleb.connolly@linaro.org>
Link: https://lore.kernel.org/r/20250227094911.497219-3-rui.silva@linaro.org
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 8f102a9..bab6831 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -224,6 +224,13 @@
 	  implements get/set api for a limited set of regulators used
 	  by u-boot.
 
+config DM_REGULATOR_QCOM_USB_VBUS
+	bool "Enable driver model for Qualcomm USB vbus regulator"
+	depends on DM_REGULATOR
+	---help---
+	  Enable support for the Qualcomm USB Vbus regulator. The driver
+	  implements get/set api for the regulator to be used by u-boot.
+
 config SPL_DM_REGULATOR_GPIO
 	bool "Enable Driver Model for GPIO REGULATOR in SPL"
 	depends on DM_REGULATOR_GPIO && SPL_GPIO
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 4382d4b..054a93e 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -22,6 +22,7 @@
 obj-$(CONFIG_$(XPL_)DM_REGULATOR_FIXED) += fixed.o
 obj-$(CONFIG_$(XPL_)DM_REGULATOR_GPIO) += gpio-regulator.o
 obj-$(CONFIG_DM_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
+obj-$(CONFIG_DM_REGULATOR_QCOM_USB_VBUS) += qcom_usb_vbus_regulator.o
 obj-$(CONFIG_$(PHASE_)REGULATOR_RK8XX) += rk8xx.o
 obj-$(CONFIG_DM_REGULATOR_S2MPS11) += s2mps11_regulator.o
 obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
diff --git a/drivers/power/regulator/qcom_usb_vbus_regulator.c b/drivers/power/regulator/qcom_usb_vbus_regulator.c
new file mode 100644
index 0000000..2d58ef5
--- /dev/null
+++ b/drivers/power/regulator/qcom_usb_vbus_regulator.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) 2025, Linaro Limited
+ */
+#define pr_fmt(fmt) "qcom_usb_vbus: " fmt
+
+#include <bitfield.h>
+#include <errno.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <log.h>
+#include <asm/gpio.h>
+#include <linux/bitops.h>
+#include <linux/printk.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+
+#define CMD_OTG				0x50
+#define OTG_EN				BIT(0)
+// The 0 bit in this register's bit field is undocumented
+#define OTG_CFG				0x56
+#define OTG_EN_SRC_CFG			BIT(1)
+
+struct qcom_usb_vbus_priv {
+	phys_addr_t base;
+};
+
+static int qcom_usb_vbus_regulator_of_to_plat(struct udevice *dev)
+{
+	struct qcom_usb_vbus_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_read_addr(dev);
+	if (priv->base == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int qcom_usb_vbus_regulator_get_enable(struct udevice *dev)
+{
+	struct qcom_usb_vbus_priv *priv = dev_get_priv(dev);
+	int otg_en_reg = priv->base + CMD_OTG;
+	int ret;
+
+	ret = pmic_reg_read(dev->parent, otg_en_reg);
+	if (ret < 0)
+		log_err("failed to read usb vbus: %d\n", ret);
+	else
+		ret &= OTG_EN;
+
+	return ret;
+}
+
+static int qcom_usb_vbus_regulator_set_enable(struct udevice *dev, bool enable)
+{
+	struct qcom_usb_vbus_priv *priv = dev_get_priv(dev);
+	int otg_en_reg = priv->base + CMD_OTG;
+	int ret;
+
+	if (enable) {
+		ret = pmic_clrsetbits(dev->parent, otg_en_reg, 0, OTG_EN);
+		if (ret < 0) {
+			log_err("error enabling: %d\n", ret);
+			return ret;
+		}
+	} else {
+		ret = pmic_clrsetbits(dev->parent, otg_en_reg, OTG_EN, 0);
+		if (ret < 0) {
+			log_err("error disabling: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int qcom_usb_vbus_regulator_probe(struct udevice *dev)
+{
+	struct qcom_usb_vbus_priv *priv = dev_get_priv(dev);
+	int otg_cfg_reg = priv->base + OTG_CFG;
+	int ret;
+
+	/* Disable HW logic for VBUS enable */
+	ret = pmic_clrsetbits(dev->parent, otg_cfg_reg, OTG_EN_SRC_CFG, 0);
+	if (ret < 0) {
+		log_err("error setting EN_SRC_CFG: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct dm_regulator_ops qcom_usb_vbus_regulator_ops = {
+	.get_enable = qcom_usb_vbus_regulator_get_enable,
+	.set_enable = qcom_usb_vbus_regulator_set_enable,
+};
+
+static const struct udevice_id qcom_usb_vbus_regulator_ids[] = {
+	{ .compatible = "qcom,pm8150b-vbus-reg"},
+	{ },
+};
+
+U_BOOT_DRIVER(qcom_usb_vbus_regulator) = {
+	.name = "qcom-usb-vbus-regulator",
+	.id = UCLASS_REGULATOR,
+	.of_match = qcom_usb_vbus_regulator_ids,
+	.of_to_plat = qcom_usb_vbus_regulator_of_to_plat,
+	.ops = &qcom_usb_vbus_regulator_ops,
+	.probe = qcom_usb_vbus_regulator_probe,
+	.priv_auto = sizeof(struct qcom_usb_vbus_priv),
+};