Add OTG "like" capability for devices that share a transceiver between port A and device port

Documentation/devicetree/bindings/usb/atmel-usb.txt

@@ -18,13 +18,20 @@ Required properties:
  - atmel,oc-gpio: If present, specifies a gpio that needs to be
    activated for the overcurrent detection.
 
+Optional properties:
+ - id-gpio:  If present, specifies a gpio used for OTG "like" detection.
+   This is only applicable to devices that share a transceiver between 
+   host port A and the device port.  Both OHCI and UDC nodes should have
+   this property.
+
 usb0: ohci@00500000 {
 	compatible = "atmel,at91rm9200-ohci", "usb-ohci";
 	reg = <0x00500000 0x100000>;
 	clocks = <&uhphs_clk>, <&uhphs_clk>, <&uhpck>;
 	clock-names = "ohci_clk", "hclk", "uhpck";
 	interrupts = <20 4>;
 	num-ports = <2>;
+	id-gpio = <&pioE, 26, 0>;
 };
 
 EHCI
@@ -93,6 +100,10 @@ Required properties:
 Optional properties:
  - atmel,vbus-gpio: If present, specifies a gpio that allows to detect whether
    vbus is present (USB is connected).
+ - id-gpio:  If present, specifies a gpio used for OTG "like" detection.
+   This is only applicable to devices that share a transceiver between 
+   host port A and the device port.  Both OHCI and UDC nodes should have 
+   this property.
 
 Required child node properties:
  - name: Name of the endpoint.
@@ -112,6 +123,7 @@ usb2: gadget@fff78000 {
 	clocks = <&utmi>, <&udphs_clk>;
 	clock-names = "hclk", "pclk";
 	atmel,vbus-gpio = <&pioB 19 0>;
+	id-gpio = <&pioE, 26, 0>;
 
 	ep@0 {
 		reg = <0>;

drivers/usb/gadget/udc/atmel_usba_udc.c

@@ -1945,6 +1945,20 @@ static irqreturn_t usba_vbus_irq_thread(int irq, void *devid)
 	/* debounce */
 	udelay(10);
 
+	/* If ID pin is pulled low, configure USB port as host */
+	if (gpio_is_valid(udc->id_pin)) {
+		if (!(gpio_get_value(udc->id_pin))) {
+			udc->id_prev = 0;
+			usba_writel(udc, CTRL, USBA_DISABLE_MASK);
+			return IRQ_HANDLED;
+		}
+
+		if (udc->id_prev != gpio_get_value(udc->id_pin)) {
+			udc->id_prev = 1;
+			return IRQ_HANDLED;
+		}
+	}
+
 	mutex_lock(&udc->vbus_mutex);
 
 	vbus = vbus_is_present(udc);
@@ -1983,10 +1997,19 @@ static int atmel_usba_start(struct usb_gadget *gadget,
 
 	/* If Vbus is present, enable the controller and wait for reset */
 	udc->vbus_prev = vbus_is_present(udc);
-	if (udc->vbus_prev) {
+
+	if (gpio_is_valid(udc->id_pin)) {
+		if ((udc->vbus_prev) && gpio_get_value(udc->id_pin)) {
 		ret = usba_start(udc);
-		if (ret)
-			goto err;
+			if (ret)
+				goto err;
+		}
+	} else {
+		if (udc->vbus_prev) {
+			ret = usba_start(udc);
+			if (ret)
+				goto err;
+		}
 	}
 
 	mutex_unlock(&udc->vbus_mutex);
@@ -2082,6 +2105,8 @@ static struct usba_ep * atmel_udc_of_init(struct platform_device *pdev,
 						&flags);
 	udc->vbus_pin_inverted = (flags & OF_GPIO_ACTIVE_LOW) ? 1 : 0;
 
+	udc->id_pin = of_get_named_gpio_flags(np, "id-gpio", 0, &flags);
+
 	if (fifo_mode == 0) {
 		pp = NULL;
 		while ((pp = of_get_next_child(np, pp)))
@@ -2234,6 +2259,7 @@ static struct usba_ep * usba_udc_pdata(struct platform_device *pdev,
 
 	udc->vbus_pin = pdata->vbus_pin;
 	udc->vbus_pin_inverted = pdata->vbus_pin_inverted;
+	udc->id_pin = pdata->id_pin;
 	udc->num_ep = pdata->num_ep;
 
 	INIT_LIST_HEAD(&eps[0].ep.ep_list);
@@ -2309,6 +2335,7 @@ static int usba_udc_probe(struct platform_device *pdev)
 	udc->pclk = pclk;
 	udc->hclk = hclk;
 	udc->vbus_pin = -ENODEV;
+	udc->id_pin = -ENODEV;
 
 	ret = -ENOMEM;
 	udc->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));

drivers/usb/gadget/udc/atmel_usba_udc.h

@@ -356,6 +356,8 @@ struct usba_udc {
 
 	u16 test_mode;
 	int vbus_prev;
+	int id_prev;
+	int id_pin;
 
 	u32 int_enb_cache;
 

drivers/usb/host/ohci-at91.c

@@ -46,6 +46,7 @@ struct at91_usbh_data {
 	u8 vbus_pin_active_low[AT91_MAX_USBH_PORTS];
 	u8 overcurrent_status[AT91_MAX_USBH_PORTS];
 	u8 overcurrent_changed[AT91_MAX_USBH_PORTS];
+	int id_gpio;
 };
 
 struct ohci_at91_priv {
@@ -508,6 +509,29 @@ static irqreturn_t ohci_hcd_at91_overcurrent_irq(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t ohci_at91_otg_irq(int irq, void *data)
+{
+	struct platform_device *pdev = data;
+	struct at91_usbh_data *pdata = dev_get_platdata(&pdev->dev);
+
+	/* debounce */
+	mdelay(10);
+
+	/* OTG "like" connector can only be on port A as it shares a
+	   transceiver with the UDP, so vbus_pin index is 0 */
+	if (gpio_is_valid(pdata->id_gpio)) {
+		if (gpio_get_value(pdata->id_gpio)) {
+			/* id pin is high, we are not a host so set VBUS low */
+			gpio_direction_output(pdata->vbus_pin[0], 1);
+		} else {
+			/* id pin is low, we are now a host, set VBUS hi */
+			gpio_direction_output(pdata->vbus_pin[0], 0);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
 static const struct of_device_id at91_ohci_dt_ids[] = {
 	{ .compatible = "atmel,at91rm9200-ohci" },
 	{ /* sentinel */ }
@@ -557,6 +581,7 @@ static int ohci_hcd_at91_drv_probe(struct platform_device *pdev)
 
 		gpio = of_get_named_gpio_flags(np, "atmel,vbus-gpio", i,
 					       &flags);
+
 		pdata->vbus_pin[i] = gpio;
 		if (!gpio_is_valid(gpio))
 			continue;
@@ -619,6 +644,34 @@ static int ohci_hcd_at91_drv_probe(struct platform_device *pdev)
 		}
 	}
 
+	/* Get ID pin (if present) for OTG "like" detection */
+	pdata->id_gpio = of_get_named_gpio_flags(np, "id-gpio", 0, &flags);
+
+	if (gpio_is_valid(pdata->id_gpio)) {
+		ret = gpio_request(pdata->id_gpio, "otg_id_pin");
+		if (ret) {
+			dev_err(&pdev->dev, "can't request ID pin %d\n", pdata->id_gpio);
+		}
+
+		ret = gpio_direction_input(pdata->id_gpio);
+
+		if (ret) {
+			dev_err(&pdev->dev, "can't configure ID pin %d as input\n", pdata->id_gpio);
+			gpio_free(pdata->id_gpio);
+		}
+
+		ret = request_irq(gpio_to_irq(pdata->id_gpio), ohci_at91_otg_irq, 0, "otg_irq", pdev);
+
+		if (ret) {
+			gpio_free(pdata->id_gpio);
+			dev_err(&pdev->dev, "OTG IRQ request failed.  id_gpio: %d\n", pdata->id_gpio);
+		}
+
+		if (!gpio_get_value(pdata->id_gpio)) {
+			gpio_direction_output(pdata->vbus_pin[0], 0);
+		}
+	}
+
 	device_init_wakeup(&pdev->dev, 1);
 	return usb_hcd_at91_probe(&ohci_at91_hc_driver, pdev);
 }
@@ -642,6 +695,11 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
 			free_irq(gpio_to_irq(pdata->overcurrent_pin[i]), pdev);
 			gpio_free(pdata->overcurrent_pin[i]);
 		}
+
+		if (gpio_is_valid(pdata->id_gpio)) {
+			free_irq(gpio_to_irq(pdata->id_gpio), pdev);
+			gpio_free(pdata->id_gpio);
+		}
 	}
 
 	device_init_wakeup(&pdev->dev, 0);

include/linux/usb/atmel_usba_udc.h

@@ -16,6 +16,7 @@ struct usba_ep_data {
 struct usba_platform_data {
 	int			vbus_pin;
 	int			vbus_pin_inverted;
+	int 			id_pin;
 	int			num_ep;
 	struct usba_ep_data	ep[0];
 };