USB: ohci: da8xx: Allow a regulator to handle VBUS

Using a regulator to handle VBUS will eliminate the need for
platform data and callbacks, and make the driver more generic
allowing different types of regulators to handle VBUS.

The regulator equivalents to the platform callbacks are:
    set_power   ->  regulator_enable/regulator_disable
    get_power   ->  regulator_is_enabled
    get_oci     ->  regulator_get_error_flags
    ocic_notify ->  regulator event notification

Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ohci-da8xx.c

@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_data/usb-davinci.h>
+#include <linux/regulator/consumer.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
 #include <asm/unaligned.h>
@@ -36,8 +37,12 @@ static int (*orig_ohci_hub_control)(struct usb_hcd  *hcd, u16 typeReq,
 static int (*orig_ohci_hub_status_data)(struct usb_hcd *hcd, char *buf);
 
 struct da8xx_ohci_hcd {
+	struct usb_hcd *hcd;
 	struct clk *usb11_clk;
 	struct phy *usb11_phy;
+	struct regulator *vbus_reg;
+	struct notifier_block nb;
+	unsigned int reg_enabled;
 };
 
 #define to_da8xx_ohci(hcd) (struct da8xx_ohci_hcd *)(hcd_to_ohci(hcd)->priv)
@@ -83,56 +88,103 @@ static void ohci_da8xx_disable(struct usb_hcd *hcd)
 
 static int ohci_da8xx_set_power(struct usb_hcd *hcd, int on)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
+	int ret;
 
 	if (hub && hub->set_power)
 		return hub->set_power(1, on);
 
+	if (!da8xx_ohci->vbus_reg)
+		return 0;
+
+	if (on && !da8xx_ohci->reg_enabled) {
+		ret = regulator_enable(da8xx_ohci->vbus_reg);
+		if (ret) {
+			dev_err(dev, "Failed to enable regulator: %d\n", ret);
+			return ret;
+		}
+		da8xx_ohci->reg_enabled = 1;
+
+	} else if (!on && da8xx_ohci->reg_enabled) {
+		ret = regulator_disable(da8xx_ohci->vbus_reg);
+		if (ret) {
+			dev_err(dev, "Failed  to disable regulator: %d\n", ret);
+			return ret;
+		}
+		da8xx_ohci->reg_enabled = 0;
+	}
+
 	return 0;
 }
 
 static int ohci_da8xx_get_power(struct usb_hcd *hcd)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
 
 	if (hub && hub->get_power)
 		return hub->get_power(1);
 
+	if (da8xx_ohci->vbus_reg)
+		return regulator_is_enabled(da8xx_ohci->vbus_reg);
+
 	return 1;
 }
 
 static int ohci_da8xx_get_oci(struct usb_hcd *hcd)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
+	unsigned int flags;
+	int ret;
 
 	if (hub && hub->get_oci)
 		return hub->get_oci(1);
 
+	if (!da8xx_ohci->vbus_reg)
+		return 0;
+
+	ret = regulator_get_error_flags(da8xx_ohci->vbus_reg, &flags);
+	if (ret)
+		return ret;
+
+	if (flags & REGULATOR_ERROR_OVER_CURRENT)
+		return 1;
+
 	return 0;
 }
 
 static int ohci_da8xx_has_set_power(struct usb_hcd *hcd)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
 
 	if (hub && hub->set_power)
 		return 1;
 
+	if (da8xx_ohci->vbus_reg)
+		return 1;
+
 	return 0;
 }
 
 static int ohci_da8xx_has_oci(struct usb_hcd *hcd)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
 
 	if (hub && hub->get_oci)
 		return 1;
 
+	if (da8xx_ohci->vbus_reg)
+		return 1;
+
 	return 0;
 }
 
@@ -160,15 +212,39 @@ static void ohci_da8xx_ocic_handler(struct da8xx_ohci_root_hub *hub,
 		hub->set_power(port, 0);
 }
 
+static int ohci_da8xx_regulator_event(struct notifier_block *nb,
+				unsigned long event, void *data)
+{
+	struct da8xx_ohci_hcd *da8xx_ohci =
+				container_of(nb, struct da8xx_ohci_hcd, nb);
+
+	if (event & REGULATOR_EVENT_OVER_CURRENT) {
+		ocic_mask |= 1 << 1;
+		ohci_da8xx_set_power(da8xx_ohci->hcd, 0);
+	}
+
+	return 0;
+}
+
 static int ohci_da8xx_register_notify(struct usb_hcd *hcd)
 {
+	struct da8xx_ohci_hcd *da8xx_ohci = to_da8xx_ohci(hcd);
 	struct device *dev		= hcd->self.controller;
 	struct da8xx_ohci_root_hub *hub	= dev_get_platdata(dev);
+	int ret = 0;
+
+	if (hub && hub->ocic_notify) {
+		ret = hub->ocic_notify(ohci_da8xx_ocic_handler);
+	} else if (da8xx_ohci->vbus_reg) {
+		da8xx_ohci->nb.notifier_call = ohci_da8xx_regulator_event;
+		ret = devm_regulator_register_notifier(da8xx_ohci->vbus_reg,
+						&da8xx_ohci->nb);
+	}
 
-	if (hub && hub->ocic_notify)
-		return hub->ocic_notify(ohci_da8xx_ocic_handler);
+	if (ret)
+		dev_err(dev, "Failed to register notifier: %d\n", ret);
 
-	return 0;
+	return ret;
 }
 
 static void ohci_da8xx_unregister_notify(struct usb_hcd *hcd)
@@ -331,6 +407,7 @@ static int ohci_da8xx_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	da8xx_ohci = to_da8xx_ohci(hcd);
+	da8xx_ohci->hcd = hcd;
 
 	da8xx_ohci->usb11_clk = devm_clk_get(&pdev->dev, "usb11");
 	if (IS_ERR(da8xx_ohci->usb11_clk)) {
@@ -348,6 +425,19 @@ static int ohci_da8xx_probe(struct platform_device *pdev)
 		goto err;
 	}
 
+	da8xx_ohci->vbus_reg = devm_regulator_get_optional(&pdev->dev, "vbus");
+	if (IS_ERR(da8xx_ohci->vbus_reg)) {
+		error = PTR_ERR(da8xx_ohci->vbus_reg);
+		if (error == -ENODEV) {
+			da8xx_ohci->vbus_reg = NULL;
+		} else if (error == -EPROBE_DEFER) {
+			goto err;
+		} else {
+			dev_err(&pdev->dev, "Failed to get regulator\n");
+			goto err;
+		}
+	}
+
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	hcd->regs = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(hcd->regs)) {