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 <wch...@codeaurora.org>
---
 drivers/regulator/Kconfig                   |  10 ++
 drivers/regulator/Makefile                  |   1 +
 drivers/regulator/qcom_usb_vbus-regulator.c | 147 ++++++++++++++++++++
 3 files changed, 158 insertions(+)
 create mode 100644 drivers/regulator/qcom_usb_vbus-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 074a2ef55943..f9165f9f9051 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -797,6 +797,16 @@ 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-regulator".
+
 config REGULATOR_RC5T583
        tristate "RICOH RC5T583 Power regulators"
        depends on MFD_RC5T583
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index c0d6b96ebd78..cbab28aa7b56 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -89,6 +89,7 @@ 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
diff --git a/drivers/regulator/qcom_usb_vbus-regulator.c 
b/drivers/regulator/qcom_usb_vbus-regulator.c
new file mode 100644
index 000000000000..2b8129a04684
--- /dev/null
+++ b/drivers/regulator/qcom_usb_vbus-regulator.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.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)
+
+struct qcom_vbus {
+       struct device   *dev;
+       u32             base;
+       struct regmap   *regmap;
+       struct regulator_dev *usb_vbus_reg;
+};
+
+static int qcom_usb_vbus_enable(struct regulator_dev *rdev)
+{
+       struct qcom_vbus *vbus_out = rdev_get_drvdata(rdev);
+       int rc;
+
+       rc = regmap_update_bits(vbus_out->regmap, vbus_out->base + CMD_OTG,
+                               OTG_EN, OTG_EN);
+       if (rc)
+               dev_err(vbus_out->dev, "failed to enable usb_vbus\n");
+
+       return rc;
+}
+
+static int qcom_usb_vbus_disable(struct regulator_dev *rdev)
+{
+       struct qcom_vbus *vbus_out = rdev_get_drvdata(rdev);
+       int rc;
+
+       rc = regmap_update_bits(vbus_out->regmap, vbus_out->base + CMD_OTG,
+                               OTG_EN, 0);
+       if (rc)
+               dev_err(vbus_out->dev, "failed to disable usb_vbus\n");
+
+       return rc;
+}
+
+static int qcom_usb_vbus_is_enabled(struct regulator_dev *rdev)
+{
+       struct qcom_vbus *vbus_out = rdev_get_drvdata(rdev);
+       unsigned int value = 0;
+       int rc;
+
+       rc = regmap_read(vbus_out->regmap, vbus_out->base + CMD_OTG, &value);
+       if (rc)
+               dev_err(vbus_out->dev, "failed to read OTG_CTL\n");
+
+       return !!(value & OTG_EN);
+}
+
+static const struct regulator_ops qcom_usb_vbus_reg_ops = {
+       .enable = qcom_usb_vbus_enable,
+       .disable = qcom_usb_vbus_disable,
+       .is_enabled = qcom_usb_vbus_is_enabled,
+};
+
+static const struct regulator_desc qcom_usb_vbus_rdesc = {
+       .name = "usb_vbus",
+       .ops = &qcom_usb_vbus_reg_ops,
+       .owner = THIS_MODULE,
+       .type = REGULATOR_VOLTAGE,
+};
+
+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 int qcom_usb_vbus_regulator_probe(struct platform_device *pdev)
+{
+       struct qcom_vbus *vbus_out;
+       struct device *dev = &pdev->dev;
+       struct regulator_config config = { };
+       struct regulator_init_data init_data = { };
+       int ret;
+       u32 reg;
+
+       ret = of_property_read_u32(dev->of_node, "reg", &reg);
+       if (ret < 0) {
+               dev_err(dev, "no base address found\n");
+               return ret;
+       }
+
+       vbus_out = devm_kzalloc(dev, sizeof(vbus_out), GFP_KERNEL);
+       if (!vbus_out)
+               return -ENOMEM;
+       vbus_out->base = reg;
+       vbus_out->dev = dev;
+
+       vbus_out->regmap = dev_get_regmap(dev->parent, NULL);
+       if (!vbus_out->regmap) {
+               dev_err(dev, "Failed to get regmap\n");
+               return -ENOENT;
+       }
+
+       init_data.constraints.valid_ops_mask |= REGULATOR_CHANGE_STATUS;
+       config.dev = dev;
+       config.driver_data = vbus_out;
+       config.init_data = &init_data;
+
+       vbus_out->usb_vbus_reg = devm_regulator_register(dev,
+                                                        &qcom_usb_vbus_rdesc,
+                                                        &config);
+       if (IS_ERR(vbus_out->usb_vbus_reg)) {
+               ret = PTR_ERR(vbus_out->usb_vbus_reg);
+               dev_err(dev, "not able to register vbus reg %d\n", ret);
+               return ret;
+       }
+
+       /* Disable HW logic for VBUS enable */
+       regmap_update_bits(vbus_out->regmap, vbus_out->base + OTG_CFG,
+                          OTG_EN_SRC_CFG, 0);
+
+       return 0;
+}
+
+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");
+MODULE_ALIAS("platform:qcom-usb-vbus-regulator");
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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