usb: dwc3-generic: support external vbus regulator

Add support for a vbus-supply regulator specified in devicetree. This
provides generic support to avoid hardcoded GPIO configuration in board
init code.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>

diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index 6fb2de8a5acef3ba237039acb8e41190556e2ff0..a379a0002e7742c8392f8b84ae40a658a7285f2c 100644 (file)
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -21,6 +21,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <malloc.h>
+#include <power/regulator.h>
 #include <usb.h>
 #include "core.h"
 #include "gadget.h"
@@ -47,6 +48,7 @@ struct dwc3_generic_priv {
 struct dwc3_generic_host_priv {
        struct xhci_ctrl xhci_ctrl;
        struct dwc3_generic_priv gen_priv;
+       struct udevice *vbus_supply;
 };
 
 static int dwc3_generic_probe(struct udevice *dev,
@@ -240,11 +242,24 @@ static int dwc3_generic_host_probe(struct udevice *dev)
        if (rc)
                return rc;
 
+       rc = device_get_supply_regulator(dev, "vbus-supply", &priv->vbus_supply);
+       if (rc)
+               debug("%s: No vbus regulator found: %d\n", dev->name, rc);
+
+       /* Only returns an error if regulator is valid and failed to enable due to a driver issue */
+       rc = regulator_set_enable_if_allowed(priv->vbus_supply, true);
+       if (rc)
+               return rc;
+
        hccr = (struct xhci_hccr *)priv->gen_priv.base;
        hcor = (struct xhci_hcor *)(priv->gen_priv.base +
                        HC_LENGTH(xhci_readl(&(hccr)->cr_capbase)));
 
-       return xhci_register(dev, hccr, hcor);
+       rc = xhci_register(dev, hccr, hcor);
+       if (rc)
+               regulator_set_enable_if_allowed(priv->vbus_supply, false);
+
+       return rc;
 }
 
 static int dwc3_generic_host_remove(struct udevice *dev)
@@ -252,9 +267,12 @@ static int dwc3_generic_host_remove(struct udevice *dev)
        struct dwc3_generic_host_priv *priv = dev_get_priv(dev);
        int rc;
 
-       rc = xhci_deregister(dev);
+       /* This function always returns 0 */
+       xhci_deregister(dev);
+
+       rc = regulator_set_enable_if_allowed(priv->vbus_supply, false);
        if (rc)
-               return rc;
+               debug("%s: Failed to disable vbus regulator: %d\n", dev->name, rc);
 
        return dwc3_generic_remove(dev, &priv->gen_priv);
 }