USB: gadget: pxa25x: basic transceiver support

This adds very basic otg_transceiver support, with vbus_session
and vbus_draw callbacks.

Now VBUS sensing can be handled by an external driver which registers
the otg_transceiver interface. It also allows gadget drivers to configure
the current drawn from VBUS. The UDC driver just passes their requests
along to the transceiver driver.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 46 insertions, 4 deletions

diff --git a/drivers/usb/gadget/pxa25x_udc.c b/drivers/usb/gadget/pxa25x_udc.c
index ed21e263f832..e6fedbd5a654 100644
--- a/drivers/usb/gadget/pxa25x_udc.c
+++ b/drivers/usb/gadget/pxa25x_udc.c
@@ -56,6 +56,7 @@
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
+#include <linux/usb/otg.h>
 
 /*
  * This driver is PXA25x only.  Grab the right register definitions.
@@ -1008,15 +1009,27 @@ static int pxa25x_udc_pullup(struct usb_gadget *_gadget, int is_active)
         return 0;
 }
 
+/* boards may consume current from VBUS, up to 100-500mA based on config.
+ * the 500uA suspend ceiling means that exclusively vbus-powered PXA designs
+ * violate USB specs.
+ */
+static int pxa25x_udc_vbus_draw(struct usb_gadget *_gadget, unsigned mA)
+{
+        struct pxa25x_udc       *udc;
+
+        udc = container_of(_gadget, struct pxa25x_udc, gadget);
+
+        if (udc->transceiver)
+                return otg_set_power(udc->transceiver, mA);
+        return -EOPNOTSUPP;
+}
+
 static const struct usb_gadget_ops pxa25x_udc_ops = {
         .get_frame      = pxa25x_udc_get_frame,
         .wakeup         = pxa25x_udc_wakeup,
         .vbus_session   = pxa25x_udc_vbus_session,
         .pullup         = pxa25x_udc_pullup,
-
-        // .vbus_draw ... boards may consume current from VBUS, up to
-        // 100-500mA based on config.  the 500uA suspend ceiling means
-        // that exclusively vbus-powered PXA designs violate USB specs.
+        .vbus_draw      = pxa25x_udc_vbus_draw,
 };
 
 /*-------------------------------------------------------------------------*/
@@ -1303,9 +1316,23 @@ fail:
          * for set_configuration as well as eventual disconnect.
          */
         DMSG("registered gadget driver '%s'\n", driver->driver.name);
+
+        /* connect to bus through transceiver */
+        if (dev->transceiver) {
+                retval = otg_set_peripheral(dev->transceiver, &dev->gadget);
+                if (retval) {
+                        DMSG("can't bind to transceiver\n");
+                        if (driver->unbind)
+                                driver->unbind(&dev->gadget);
+                        goto bind_fail;
+                }
+        }
+
         pullup(dev);
         dump_state(dev);
         return 0;
+bind_fail:
+        return retval;
 }
 EXPORT_SYMBOL(usb_gadget_register_driver);
 
@@ -1351,6 +1378,9 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
         stop_activity(dev, driver);
         local_irq_enable();
 
+        if (dev->transceiver)
+                (void) otg_set_peripheral(dev->transceiver, NULL);
+
         driver->unbind(&dev->gadget);
         dev->gadget.dev.driver = NULL;
         dev->driver = NULL;
@@ -2162,6 +2192,8 @@ static int __init pxa25x_udc_probe(struct platform_device *pdev)
         dev->dev = &pdev->dev;
         dev->mach = pdev->dev.platform_data;
 
+        dev->transceiver = otg_get_transceiver();
+
         if (gpio_is_valid(dev->mach->gpio_vbus)) {
                 if ((retval = gpio_request(dev->mach->gpio_vbus,
                                 "pxa25x_udc GPIO VBUS"))) {
@@ -2264,6 +2296,10 @@ lubbock_fail0:
         if (gpio_is_valid(dev->mach->gpio_vbus))
                 gpio_free(dev->mach->gpio_vbus);
  err_gpio_vbus:
+        if (dev->transceiver) {
+                otg_put_transceiver(dev->transceiver);
+                dev->transceiver = NULL;
+        }
         clk_put(dev->clk);
  err_clk:
         return retval;
@@ -2305,6 +2341,11 @@ static int __exit pxa25x_udc_remove(struct platform_device *pdev)
 
         clk_put(dev->clk);
 
+        if (dev->transceiver) {
+                otg_put_transceiver(dev->transceiver);
+                dev->transceiver = NULL;
+        }
+
         platform_set_drvdata(pdev, NULL);
         the_controller = NULL;
         return 0;
diff --git a/drivers/usb/gadget/pxa25x_udc.h b/drivers/usb/gadget/pxa25x_udc.h
index 1d51aa21e6eb..f572c5617462 100644
--- a/drivers/usb/gadget/pxa25x_udc.h
+++ b/drivers/usb/gadget/pxa25x_udc.h
@@ -128,6 +128,7 @@ struct pxa25x_udc {
         struct device                           *dev;
         struct clk                              *clk;
         struct pxa2xx_udc_mach_info             *mach;
+        struct otg_transceiver                  *transceiver;
         u64                                     dma_mask;
         struct pxa25x_ep                        ep [PXA_UDC_NUM_ENDPOINTS];