pxa27x_udc: add ability to work without D+ gpio and usb_mode switch

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>

drivers/usb/gadget/udc/pxa27x_udc.c

@@ -1406,6 +1406,7 @@ static int pxa_ep_enable(struct usb_ep *_ep,
 		return -EINVAL;
 
 	udc_usb_ep = container_of(_ep, struct udc_usb_ep, usb_ep);
+
 	if (udc_usb_ep->pxa_ep) {
 		ep = udc_usb_ep->pxa_ep;
 		ep_warn(ep, "usb_ep %s already enabled, doing nothing\n",
@@ -1513,6 +1514,15 @@ static void dplus_pullup(struct pxa_udc *udc, int on)
 			udc->udc_command(PXA2XX_UDC_CMD_CONNECT);
 		else
 			udc->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
+	} else {
+		u32 v = udc_readl(udc, UP2OCR);
+		if (on)
+			v |= UP2OCR_DPPUE;
+		else
+			v &= ~(UP2OCR_DPPUE);
+		/* change D+ only if port is switch to device mode */
+		if (!(v & UP2OCR_HXS))
+			udc_writel(udc, UP2OCR, v);
 	}
 	udc->pullup_on = on;
 }
@@ -1603,9 +1613,6 @@ static int pxa_udc_pullup(struct usb_gadget *_gadget, int is_active)
 {
 	struct pxa_udc *udc = to_gadget_udc(_gadget);
 
-	if (!udc->gpiod && !udc->udc_command)
-		return -EOPNOTSUPP;
-
 	dplus_pullup(udc, is_active);
 
 	if (should_enable_udc(udc))
@@ -1697,6 +1704,7 @@ static void udc_disable(struct pxa_udc *udc)
 
 	ep0_idle(udc);
 	udc->gadget.speed = USB_SPEED_UNKNOWN;
+
 	clk_disable(udc->clk);
 
 	udc->enabled = 0;
@@ -1806,6 +1814,7 @@ static int pxa27x_udc_start(struct usb_gadget *g,
 
 	/* first hook up the driver ... */
 	udc->driver = driver;
+	dplus_pullup(udc, 1);
 
 	if (!IS_ERR_OR_NULL(udc->transceiver)) {
 		retval = otg_set_peripheral(udc->transceiver->otg,
@@ -1858,6 +1867,7 @@ static int pxa27x_udc_stop(struct usb_gadget *g)
 
 	stop_activity(udc, NULL);
 	udc_disable(udc);
+	dplus_pullup(udc, 0);
 
 	udc->driver = NULL;
 
@@ -2395,6 +2405,65 @@ static struct pxa_udc memory = {
 	}
 };
 
+static ssize_t usb_mode_show(struct device *dev, struct device_attribute *attr,
+	char *buf)
+{
+	struct pxa_udc *udc = dev_get_drvdata(dev);
+
+	if (udc_readl(udc, UP2OCR) & UP2OCR_HXS)
+		return sprintf(buf, "host\n");
+	else
+		return sprintf(buf, "device\n");
+}
+
+static ssize_t usb_mode_set(struct device *dev, struct device_attribute *attr,
+	const char *buf, size_t count)
+{
+	u32 v;
+	struct pxa_udc *udc = dev_get_drvdata(dev);
+
+	if (strncmp(buf, "host", min(count, (size_t)4)) == 0) {
+		v = udc_readl(udc, UP2OCR);
+		/* Enable D+ and D- pull down,
+		   Transceiver output select = 1 -> Host
+		 */
+		v |= (UP2OCR_HXS |UP2OCR_DPPDE | UP2OCR_DMPDE);
+		/* Disable D+ pull up */
+		v &= ~(UP2OCR_DPPUE);
+		/* Enable transceiver */
+		v |= UP2OCR_HXOE;;
+		udc_writel(udc, UP2OCR, v);
+
+		return count;
+	} else if (strncmp(buf, "device", min(count, (size_t)6)) == 0) {
+		v = udc_readl(udc, UP2OCR);
+		/* Disable D+ and D- pull down,
+		   Transceiver output select = 0 -> UDC
+		 */
+		v &= ~(UP2OCR_HXS |UP2OCR_DPPDE | UP2OCR_DMPDE);
+		/* Enable transceiver */
+		v |= UP2OCR_HXOE;
+		/* Enable D+ pull up if necessary */
+		if (udc->pullup_on)
+			v |= UP2OCR_DPPUE;
+		udc_writel(udc, UP2OCR, v);
+
+		return count;
+	}
+	return -EINVAL;
+}
+
+static DEVICE_ATTR(usb_mode, 0644, usb_mode_show, usb_mode_set);
+
+static const struct attribute *attrs[] = {
+	&dev_attr_usb_mode.attr,
+	NULL,
+};
+
+static const struct attribute_group attr_group = {
+	.attrs	= (struct attribute **)attrs,
+};
+
 #if defined(CONFIG_OF)
 static const struct of_device_id udc_pxa_dt_ids[] = {
 	{ .compatible = "marvell,pxa270-udc" },
@@ -2417,6 +2486,7 @@ static int pxa_udc_probe(struct platform_device *pdev)
 	int retval = 0, gpio;
 	struct pxa2xx_udc_mach_info *mach = dev_get_platdata(&pdev->dev);
 	unsigned long gpio_flags;
+	u32 v;
 
 	if (mach) {
 		gpio_flags = mach->gpio_pullup_inverted ? GPIOF_ACTIVE_LOW : 0;
@@ -2446,9 +2516,9 @@ static int pxa_udc_probe(struct platform_device *pdev)
 	udc->transceiver = usb_get_phy(USB_PHY_TYPE_USB2);
 
 	if (IS_ERR(udc->gpiod)) {
-		dev_err(&pdev->dev, "Couldn't find or request D+ gpio : %ld\n",
+		dev_warn(&pdev->dev, "Couldn't find or request D+ gpio : %ld, using UP2OCR\n",
 			PTR_ERR(udc->gpiod));
-		return PTR_ERR(udc->gpiod);
+		udc->gpiod = NULL;
 	}
 	if (udc->gpiod)
 		gpiod_direction_output(udc->gpiod, 0);
@@ -2480,7 +2550,22 @@ static int pxa_udc_probe(struct platform_device *pdev)
 	if (retval)
 		goto err;
 
+	retval = sysfs_create_group(&pdev->dev.kobj, &attr_group);
+	if (retval)
+		goto err;
+
 	pxa_init_debugfs(udc);
+
+	/* Switch to device mode by default */
+	v = udc_readl(udc, UP2OCR);
+	/* Disable D+ and D- pull down,
+	   Transceiver output select = 0 -> UDC
+	 */
+	v &= ~(UP2OCR_HXS |UP2OCR_DPPDE | UP2OCR_DMPDE);
+	/* Enable transceiver */
+	v |= UP2OCR_HXOE;
+	udc_writel(udc, UP2OCR, v);
+
 	if (should_enable_udc(udc))
 		udc_enable(udc);
 	return 0;
@@ -2499,6 +2584,7 @@ static int pxa_udc_remove(struct platform_device *_dev)
 
 	usb_del_gadget_udc(&udc->gadget);
 	pxa_cleanup_debugfs(udc);
+	sysfs_remove_group(&_dev->dev.kobj, &attr_group);
 
 	usb_put_phy(udc->transceiver);