[PATCH] power: qcom_smbb: Add otg regulator for control of vbus

[Tim Bird <tim.bird@sonymobile.com>]

Add a regulator to control the OTG chargepath switch.  The OTG
switch gets its power from pm8941_5vs1, and that should be expressed
as an usb_otg_in-supply property in the DT node for the charger driver.
The regulator name is "otg".  This is used by USB code to control VBUS
direction.

Signed-off-by: Tim Bird <tim.bird@sonymobile.com>
---
 .../devicetree/bindings/power_supply/qcom_smbb.txt | 20 ++++++
 drivers/power/qcom_smbb.c                          | 74 ++++++++++++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/Documentation/devicetree/bindings/power_supply/qcom_smbb.txt b/Documentation/devicetree/bindings/power_supply/qcom_smbb.txt
index 65b88fa..dc0f91d 100644
--- a/Documentation/devicetree/bindings/power_supply/qcom_smbb.txt
+++ b/Documentation/devicetree/bindings/power_supply/qcom_smbb.txt
@@ -105,6 +105,23 @@ PROPERTIES
                regulation must be done externally to fully comply with
                the JEITA safety guidelines if this flag is set.
 
+- usb_otg_in-supply:
+  Usage: optional
+  Value type: <phandle>
+  Description: Reference to the regulator supplying power to the USB_OTG_IN
+               pin.
+
+child nodes:
+- otg:
+  Usage: optional
+  Description: This node is used to define a regulator which is used by
+               other parts of the system to control the direction of VBUS
+               voltage - specifically: whether to supply voltage to VBUS for
+               host mode operation of the OTG port. The driver registers a
+               regulator with this name, which can be looked up by string.
+               Alternatively, you can add a DT label, which can then be
+               referenced by phandle.
+
 EXAMPLE
 charger@1000 {
        compatible = "qcom,pm8941-charger";
@@ -128,4 +145,7 @@ charger@1000 {
 
        qcom,fast-charge-current-limit = <1000000>;
        qcom,dc-charge-current-limit = <1000000>;
+       usb_otg_in-supply = <&pm8941_5vs1>;
+
+       otg {};
 };
diff --git a/drivers/power/qcom_smbb.c b/drivers/power/qcom_smbb.c
index 0dabfe8..fa2983a 100644
--- a/drivers/power/qcom_smbb.c
+++ b/drivers/power/qcom_smbb.c
@@ -34,6 +34,9 @@
 #include <linux/power_supply.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
 
 #define SMBB_CHG_VMAX		0x040
 #define SMBB_CHG_VSAFE		0x041
@@ -71,6 +74,8 @@
 #define BTC_CTRL_HOT_EXT_N	BIT(0)
 
 #define SMBB_USB_IMAX		0x344
+#define SMBB_USB_OTG_CTL	0x348
+#define OTG_CTL_EN		BIT(0)
 #define SMBB_USB_ENUM_TIMER_STOP 0x34e
 #define ENUM_TIMER_STOP		BIT(0)
 #define SMBB_USB_SEC_ACCESS	0x3d0
@@ -123,6 +128,9 @@ struct smbb_charger {
 	struct power_supply *dc_psy;
 	struct power_supply *bat_psy;
 	struct regmap *regmap;
+
+	struct regulator_desc otg_rdesc;
+	struct regulator_dev *otg_reg;
 };
 
 static int smbb_vbat_weak_fn(unsigned int index)
@@ -778,12 +786,56 @@ static const struct power_supply_desc dc_psy_desc = {
 	.property_is_writeable = smbb_charger_writable_property,
 };
 
+static int smbb_chg_otg_enable(struct regulator_dev *rdev)
+{
+	struct smbb_charger *chg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = regmap_update_bits(chg->regmap, chg->addr + SMBB_USB_OTG_CTL,
+				OTG_CTL_EN, OTG_CTL_EN);
+	if (rc)
+		dev_err(chg->dev, "failed to update OTG_CTL\n");
+	return rc;
+}
+
+static int smbb_chg_otg_disable(struct regulator_dev *rdev)
+{
+	struct smbb_charger *chg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = regmap_update_bits(chg->regmap, chg->addr + SMBB_USB_OTG_CTL,
+				OTG_CTL_EN, 0);
+	if (rc)
+		dev_err(chg->dev, "failed to update OTG_CTL\n");
+	return rc;
+}
+
+static int smbb_chg_otg_is_enabled(struct regulator_dev *rdev)
+{
+	struct smbb_charger *chg = rdev_get_drvdata(rdev);
+	unsigned int value = 0;
+	int rc;
+
+	rc = regmap_read(chg->regmap, chg->addr + SMBB_USB_OTG_CTL, &value);
+	if (rc)
+		dev_err(chg->dev, "failed to read OTG_CTL\n");
+
+	return !!(value & OTG_CTL_EN);
+}
+
+static struct regulator_ops smbb_chg_otg_ops = {
+	.enable = smbb_chg_otg_enable,
+	.disable = smbb_chg_otg_disable,
+	.is_enabled = smbb_chg_otg_is_enabled,
+};
+
 static int smbb_charger_probe(struct platform_device *pdev)
 {
 	struct power_supply_config bat_cfg = {};
 	struct power_supply_config usb_cfg = {};
 	struct power_supply_config dc_cfg = {};
 	struct smbb_charger *chg;
+	struct regulator_config config = { };
 	int rc, i;
 
 	chg = devm_kzalloc(&pdev->dev, sizeof(*chg), GFP_KERNEL);
@@ -884,6 +936,28 @@ static int smbb_charger_probe(struct platform_device *pdev)
 		}
 	}
 
+	/*
+	 * otg regulator is used to control VBUS voltage direction
+	 * when USB switches between host and gadget mode
+	 */
+	chg->otg_rdesc.id = -1;
+	chg->otg_rdesc.name = "otg";
+	chg->otg_rdesc.ops = &smbb_chg_otg_ops;
+	chg->otg_rdesc.owner = THIS_MODULE;
+	chg->otg_rdesc.type = REGULATOR_VOLTAGE;
+	chg->otg_rdesc.supply_name = "usb_otg_in";
+	chg->otg_rdesc.fixed_uV = 5000000;
+	chg->otg_rdesc.n_voltages = 1;
+	chg->otg_rdesc.of_match = "otg";
+
+	config.dev = &pdev->dev;
+	config.driver_data = chg;
+
+	chg->otg_reg = devm_regulator_register(&pdev->dev, &chg->otg_rdesc,
+					       &config);
+	if (IS_ERR(chg->otg_reg))
+		return PTR_ERR(chg->otg_reg);
+
 	chg->jeita_ext_temp = of_property_read_bool(pdev->dev.of_node,
 			"qcom,jeita-extended-temp-range");
 
-- 
1.8.2.2