regulator: Add support for QCOM PMIC VBUS booster

Some Qualcomm PMICs have the capability to source the VBUS output to
connected peripherals.  This driver will register a regulator to the
regulator list to enable or disable this source by an external driver.
Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
Link: https://lore.kernel.org/r/20200626185516.18018-5-wcheng@codeaurora.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/Kconfig

@@ -836,6 +836,16 @@ config REGULATOR_QCOM_SPMI
 	  Qualcomm SPMI PMICs as a module. The module will be named
 	  "qcom_spmi-regulator".
 
+config REGULATOR_QCOM_USB_VBUS
+	tristate "Qualcomm USB Vbus regulator driver"
+	depends on SPMI || COMPILE_TEST
+	help
+	  If you say yes to this option, support will be included for the
+	  regulator used to enable the VBUS output.
+
+	  Say M here if you want to include support for enabling the VBUS output
+	  as a module. The module will be named "qcom_usb_vbus_regulator".
+
 config REGULATOR_RC5T583
 	tristate "RICOH RC5T583 Power regulators"
 	depends on MFD_RC5T583

drivers/regulator/Makefile

@@ -93,6 +93,7 @@ obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_SPMI) += qcom_spmi-regulator.o
+obj-$(CONFIG_REGULATOR_QCOM_USB_VBUS) += qcom_usb_vbus-regulator.o
 obj-$(CONFIG_REGULATOR_PALMAS) += palmas-regulator.o
 obj-$(CONFIG_REGULATOR_PFUZE100) += pfuze100-regulator.o
 obj-$(CONFIG_REGULATOR_PV88060) += pv88060-regulator.o

drivers/regulator/qcom_usb_vbus-regulator.c

+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Qualcomm PMIC VBUS output regulator driver
+//
+// Copyright (c) 2020, The Linux Foundation. All rights reserved.
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/regmap.h>
+
+#define CMD_OTG				0x40
+#define OTG_EN				BIT(0)
+#define OTG_CFG				0x53
+#define OTG_EN_SRC_CFG			BIT(1)
+
+static const struct regulator_ops qcom_usb_vbus_reg_ops = {
+	.enable = regulator_enable_regmap,
+	.disable = regulator_disable_regmap,
+	.is_enabled = regulator_is_enabled_regmap,
+};
+
+static struct regulator_desc qcom_usb_vbus_rdesc = {
+	.name = "usb_vbus",
+	.ops = &qcom_usb_vbus_reg_ops,
+	.owner = THIS_MODULE,
+	.type = REGULATOR_VOLTAGE,
+};
+
+static int qcom_usb_vbus_regulator_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct regulator_dev *rdev;
+	struct regmap *regmap;
+	struct regulator_config config = { };
+	struct regulator_init_data *init_data;
+	int ret;
+	u32 base;
+
+	ret = of_property_read_u32(dev->of_node, "reg", &base);
+	if (ret < 0) {
+		dev_err(dev, "no base address found\n");
+		return ret;
+	}
+
+	regmap = dev_get_regmap(dev->parent, NULL);
+	if (regmap) {
+		dev_err(dev, "Failed to get regmap\n");
+		return -ENOENT;
+	}
+
+	init_data = of_get_regulator_init_data(dev, dev->of_node,
+					       &qcom_usb_vbus_rdesc);
+	if (!init_data)
+		return -ENOMEM;
+
+	qcom_usb_vbus_rdesc.enable_reg = base + CMD_OTG;
+	qcom_usb_vbus_rdesc.enable_mask = OTG_EN;
+	config.dev = dev;
+	config.init_data = init_data;
+	config.regmap = regmap;
+
+	rdev = devm_regulator_register(dev, &qcom_usb_vbus_rdesc, &config);
+	if (IS_ERR(rdev)) {
+		ret = PTR_ERR(rdev);
+		dev_err(dev, "not able to register vbus reg %d\n", ret);
+		return ret;
+	}
+
+	/* Disable HW logic for VBUS enable */
+	regmap_update_bits(regmap, base + OTG_CFG, OTG_EN_SRC_CFG, 0);
+
+	return 0;
+}
+
+static const struct of_device_id qcom_usb_vbus_regulator_match[] = {
+	{ .compatible = "qcom,pm8150b-vbus-reg" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_usb_vbus_regulator_match);
+
+static struct platform_driver qcom_usb_vbus_regulator_driver = {
+	.driver		= {
+		.name	= "qcom-usb-vbus-regulator",
+		.of_match_table = qcom_usb_vbus_regulator_match,
+	},
+	.probe		= qcom_usb_vbus_regulator_probe,
+};
+module_platform_driver(qcom_usb_vbus_regulator_driver);
+
+MODULE_DESCRIPTION("Qualcomm USB vbus regulator driver");
+MODULE_LICENSE("GPL v2");