USB: EHCI: DT support for generic bus glue

This lets us use the ehci-platform driver on platforms without special
requirements for their ehci controllers. In particular, this is true
for the vt8500/wm8x50 platforms, which currently have a separate
driver that causes problems with multiplatform configurations.

Tested-by: Tony Prisk <linux@prisktech.co.nz>
Tested-by: Peter Vasil <petervasil@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-hcd.c

@@ -1269,11 +1269,6 @@ MODULE_LICENSE ("GPL");
 #define PLATFORM_DRIVER		ehci_octeon_driver
 #endif
 
-#ifdef CONFIG_ARCH_VT8500
-#include "ehci-vt8500.c"
-#define	PLATFORM_DRIVER		vt8500_ehci_driver
-#endif
-
 #ifdef CONFIG_PLAT_SPEAR
 #include "ehci-spear.c"
 #define PLATFORM_DRIVER		spear_ehci_hcd_driver

drivers/usb/host/ehci-platform.c

@@ -18,11 +18,13 @@
  *
  * Licensed under the GNU/GPL. See COPYING for details.
  */
+#include <linux/dma-mapping.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/hrtimer.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
@@ -62,22 +64,32 @@ static const struct ehci_driver_overrides platform_overrides __initdata = {
 	.reset =	ehci_platform_reset,
 };
 
+static struct usb_ehci_pdata ehci_platform_defaults;
+
 static int ehci_platform_probe(struct platform_device *dev)
 {
 	struct usb_hcd *hcd;
 	struct resource *res_mem;
-	struct usb_ehci_pdata *pdata = dev->dev.platform_data;
+	struct usb_ehci_pdata *pdata;
 	int irq;
 	int err = -ENOMEM;
 
-	if (!pdata) {
-		WARN_ON(1);
-		return -ENODEV;
-	}
-
 	if (usb_disabled())
 		return -ENODEV;
 
+	/*
+	 * use reasonable defaults so platforms don't have to provide these.
+	 * with DT probing on ARM, none of these are set.
+	 */
+	if (!dev->dev.platform_data)
+		dev->dev.platform_data = &ehci_platform_defaults;
+	if (!dev->dev.dma_mask)
+		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+	if (!dev->dev.coherent_dma_mask)
+		dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+
+	pdata = dev->dev.platform_data;
+
 	irq = platform_get_irq(dev, 0);
 	if (irq < 0) {
 		dev_err(&dev->dev, "no irq provided");
@@ -139,6 +151,9 @@ static int ehci_platform_remove(struct platform_device *dev)
 	if (pdata->power_off)
 		pdata->power_off(dev);
 
+	if (pdata == &ehci_platform_defaults)
+		dev->dev.platform_data = NULL;
+
 	return 0;
 }
 
@@ -183,6 +198,12 @@ static int ehci_platform_resume(struct device *dev)
 #define ehci_platform_resume	NULL
 #endif /* CONFIG_PM */
 
+static const struct of_device_id vt8500_ehci_ids[] = {
+	{ .compatible = "via,vt8500-ehci", },
+	{ .compatible = "wm,prizm-ehci", },
+	{}
+};
+
 static const struct platform_device_id ehci_platform_table[] = {
 	{ "ehci-platform", 0 },
 	{ }
@@ -203,6 +224,7 @@ static struct platform_driver ehci_platform_driver = {
 		.owner	= THIS_MODULE,
 		.name	= "ehci-platform",
 		.pm	= &ehci_platform_pm_ops,
+		.of_match_table = of_match_ptr(vt8500_ehci_ids),
 	}
 };