USB: pxa27x_udc: factor pullup code to prepare otg transceiver

Prepare pxa27x_udc to handle usb D+ pullup properly : it
should connect the pullup resistor and disconnect it only
if no external transceiver is handling it.

[ dbrownell@users.sourceforge.net: kerneldoc and gpio fixes ]

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 138 insertions, 8 deletions

diff --git a/drivers/usb/gadget/pxa27x_udc.c b/drivers/usb/gadget/pxa27x_udc.c
index 990f40f988d4..f8145590944f 100644
--- a/drivers/usb/gadget/pxa27x_udc.c
+++ b/drivers/usb/gadget/pxa27x_udc.c
@@ -30,6 +30,7 @@
 #include <linux/proc_fs.h>
 #include <linux/clk.h>
 #include <linux/irq.h>
+#include <linux/gpio.h>
 
 #include <asm/byteorder.h>
 #include <mach/hardware.h>
@@ -1471,6 +1472,32 @@ static struct usb_ep_ops pxa_ep_ops = {
         .fifo_flush     = pxa_ep_fifo_flush,
 };
 
+/**
+ * dplus_pullup - Connect or disconnect pullup resistor to D+ pin
+ * @udc: udc device
+ * @on: 0 if disconnect pullup resistor, 1 otherwise
+ * Context: any
+ *
+ * Handle D+ pullup resistor, make the device visible to the usb bus, and
+ * declare it as a full speed usb device
+ */
+static void dplus_pullup(struct pxa_udc *udc, int on)
+{
+        if (on) {
+                if (gpio_is_valid(udc->mach->gpio_pullup))
+                        gpio_set_value(udc->mach->gpio_pullup,
+                                       !udc->mach->gpio_pullup_inverted);
+                if (udc->mach->udc_command)
+                        udc->mach->udc_command(PXA2XX_UDC_CMD_CONNECT);
+        } else {
+                if (gpio_is_valid(udc->mach->gpio_pullup))
+                        gpio_set_value(udc->mach->gpio_pullup,
+                                       udc->mach->gpio_pullup_inverted);
+                if (udc->mach->udc_command)
+                        udc->mach->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
+        }
+        udc->pullup_on = on;
+}
 
 /**
  * pxa_udc_get_frame - Returns usb frame number
@@ -1500,21 +1527,91 @@ static int pxa_udc_wakeup(struct usb_gadget *_gadget)
         return 0;
 }
 
+static void udc_enable(struct pxa_udc *udc);
+static void udc_disable(struct pxa_udc *udc);
+
+/**
+ * should_enable_udc - Tells if UDC should be enabled
+ * @udc: udc device
+ * Context: any
+ *
+ * The UDC should be enabled if :
+ *  - the pullup resistor is connected
+ *  - and a gadget driver is bound
+ *
+ * Returns 1 if UDC should be enabled, 0 otherwise
+ */
+static int should_enable_udc(struct pxa_udc *udc)
+{
+        int put_on;
+
+        put_on = ((udc->pullup_on) && (udc->driver));
+        return put_on;
+}
+
+/**
+ * should_disable_udc - Tells if UDC should be disabled
+ * @udc: udc device
+ * Context: any
+ *
+ * The UDC should be disabled if :
+ *  - the pullup resistor is not connected
+ *  - or no gadget driver is bound
+ *
+ * Returns 1 if UDC should be disabled
+ */
+static int should_disable_udc(struct pxa_udc *udc)
+{
+        int put_off;
+
+        put_off = ((!udc->pullup_on) || (!udc->driver));
+        return put_off;
+}
+
+/**
+ * pxa_udc_pullup - Offer manual D+ pullup control
+ * @_gadget: usb gadget using the control
+ * @is_active: 0 if disconnect, else connect D+ pullup resistor
+ * Context: !in_interrupt()
+ *
+ * Returns 0 if OK, -EOPNOTSUPP if udc driver doesn't handle D+ pullup
+ */
+static int pxa_udc_pullup(struct usb_gadget *_gadget, int is_active)
+{
+        struct pxa_udc *udc = to_gadget_udc(_gadget);
+
+        if (!gpio_is_valid(udc->mach->gpio_pullup) && !udc->mach->udc_command)
+                return -EOPNOTSUPP;
+
+        dplus_pullup(udc, is_active);
+
+        if (should_enable_udc(udc))
+                udc_enable(udc);
+        if (should_disable_udc(udc))
+                udc_disable(udc);
+        return 0;
+}
+
 static const struct usb_gadget_ops pxa_udc_ops = {
         .get_frame      = pxa_udc_get_frame,
         .wakeup         = pxa_udc_wakeup,
+        .pullup         = pxa_udc_pullup,
         /* current versions must always be self-powered */
 };
 
 /**
  * udc_disable - disable udc device controller
  * @udc: udc device
+ * Context: any
  *
  * Disables the udc device : disables clocks, udc interrupts, control endpoint
  * interrupts.
  */
 static void udc_disable(struct pxa_udc *udc)
 {
+        if (!udc->enabled)
+                return;
+
         udc_writel(udc, UDCICR0, 0);
         udc_writel(udc, UDCICR1, 0);
 
@@ -1523,8 +1620,8 @@ static void udc_disable(struct pxa_udc *udc)
 
         ep0_idle(udc);
         udc->gadget.speed = USB_SPEED_UNKNOWN;
-        if (udc->mach->udc_command)
-                udc->mach->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
+
+        udc->enabled = 0;
 }
 
 /**
@@ -1570,6 +1667,9 @@ static __init void udc_init_data(struct pxa_udc *dev)
  */
 static void udc_enable(struct pxa_udc *udc)
 {
+        if (udc->enabled)
+                return;
+
         udc_writel(udc, UDCICR0, 0);
         udc_writel(udc, UDCICR1, 0);
         udc_clear_mask_UDCCR(udc, UDCCR_UDE);
@@ -1598,9 +1698,7 @@ static void udc_enable(struct pxa_udc *udc)
         /* enable ep0 irqs */
         pio_irq_enable(&udc->pxa_ep[0]);
 
-        dev_info(udc->dev, "UDC connecting\n");
-        if (udc->mach->udc_command)
-                udc->mach->udc_command(PXA2XX_UDC_CMD_CONNECT);
+        udc->enabled = 1;
 }
 
 /**
@@ -1612,6 +1710,9 @@ static void udc_enable(struct pxa_udc *udc)
  * usb traffic follows until a disconnect is reported.  Then a host may connect
  * again, or the driver might get unbound.
  *
+ * Note that the udc is not automatically enabled. Check function
+ * should_enable_udc().
+ *
  * Returns 0 if no error, -EINVAL, -ENODEV, -EBUSY otherwise
  */
 int usb_gadget_register_driver(struct usb_gadget_driver *driver)
@@ -1630,6 +1731,7 @@ int usb_gadget_register_driver(struct usb_gadget_driver *driver)
         /* first hook up the driver ... */
         udc->driver = driver;
         udc->gadget.dev.driver = &driver->driver;
+        dplus_pullup(udc, 1);
 
         retval = device_add(&udc->gadget.dev);
         if (retval) {
@@ -1645,7 +1747,8 @@ int usb_gadget_register_driver(struct usb_gadget_driver *driver)
         dev_dbg(udc->dev, "registered gadget driver '%s'\n",
                 driver->driver.name);
 
-        udc_enable(udc);
+        if (should_enable_udc(udc))
+                udc_enable(udc);
         return 0;
 
 bind_fail:
@@ -1699,6 +1802,7 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
 
         stop_activity(udc, driver);
         udc_disable(udc);
+        dplus_pullup(udc, 0);
 
         driver->unbind(&udc->gadget);
         udc->driver = NULL;
@@ -2212,7 +2316,7 @@ static int __init pxa_udc_probe(struct platform_device *pdev)
 {
         struct resource *regs;
         struct pxa_udc *udc = &memory;
-        int retval;
+        int retval = 0, gpio;
 
         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         if (!regs)
@@ -2224,6 +2328,19 @@ static int __init pxa_udc_probe(struct platform_device *pdev)
         udc->dev = &pdev->dev;
         udc->mach = pdev->dev.platform_data;
 
+        gpio = udc->mach->gpio_pullup;
+        if (gpio_is_valid(gpio)) {
+                retval = gpio_request(gpio, "USB D+ pullup");
+                if (retval == 0)
+                        gpio_direction_output(gpio,
+                                       udc->mach->gpio_pullup_inverted);
+        }
+        if (retval) {
+                dev_err(&pdev->dev, "Couldn't request gpio %d : %d\n",
+                        gpio, retval);
+                return retval;
+        }
+
         udc->clk = clk_get(&pdev->dev, NULL);
         if (IS_ERR(udc->clk)) {
                 retval = PTR_ERR(udc->clk);
@@ -2273,10 +2390,13 @@ err_clk:
 static int __exit pxa_udc_remove(struct platform_device *_dev)
 {
         struct pxa_udc *udc = platform_get_drvdata(_dev);
+        int gpio = udc->mach->gpio_pullup;
 
         usb_gadget_unregister_driver(udc->driver);
         free_irq(udc->irq, udc);
         pxa_cleanup_debugfs(udc);
+        if (gpio_is_valid(gpio))
+                gpio_free(gpio);
 
         platform_set_drvdata(_dev, NULL);
         the_controller = NULL;
@@ -2319,6 +2439,8 @@ static int pxa_udc_suspend(struct platform_device *_dev, pm_message_t state)
         }
 
         udc_disable(udc);
+        udc->pullup_resume = udc->pullup_on;
+        dplus_pullup(udc, 0);
 
         return 0;
 }
@@ -2346,7 +2468,9 @@ static int pxa_udc_resume(struct platform_device *_dev)
                                 ep->udccsr_value, ep->udccr_value);
         }
 
-        udc_enable(udc);
+        dplus_pullup(udc, udc->pullup_resume);
+        if (should_enable_udc(udc))
+                udc_enable(udc);
         /*
          * We do not handle OTG yet.
          *
diff --git a/drivers/usb/gadget/pxa27x_udc.h b/drivers/usb/gadget/pxa27x_udc.h
index 1d1b7936ee11..6f5234dff8a5 100644
--- a/drivers/usb/gadget/pxa27x_udc.h
+++ b/drivers/usb/gadget/pxa27x_udc.h
@@ -425,6 +425,9 @@ struct udc_stats {
  * @stats: statistics on udc usage
  * @udc_usb_ep: array of usb endpoints offered by the gadget
  * @pxa_ep: array of pxa available endpoints
+ * @enabled: UDC was enabled by a previous udc_enable()
+ * @pullup_on: if pullup resistor connected to D+ pin
+ * @pullup_resume: if pullup resistor should be connected to D+ pin on resume
  * @config: UDC active configuration
  * @last_interface: UDC interface of the last SET_INTERFACE host request
  * @last_alternate: UDC altsetting of the last SET_INTERFACE host request
@@ -450,6 +453,9 @@ struct pxa_udc {
         struct udc_usb_ep                       udc_usb_ep[NR_USB_ENDPOINTS];
         struct pxa_ep                           pxa_ep[NR_PXA_ENDPOINTS];
 
+        unsigned                                enabled:1;
+        unsigned                                pullup_on:1;
+        unsigned                                pullup_resume:1;
         unsigned                                config:2;
         unsigned                                last_interface:3;
         unsigned                                last_alternate:3;