USB: pxa2xx_udc understands GPIO based VBUS sensing

This updates the PXA 25x UDC board-independent infrastructure for VBUS sensing
and the D+ pullup. The original code evolved from rather bizarre support on
Intel's "Lubbock" reference hardware, so that on more sensible hardware it
doesn't work as well as it could/should.

The change is just to teach the UDC driver how to use built-in PXA GPIO pins
directly. This reduces the amount of board-specfic object code needed, and
enables the use of a VBUS sensing IRQ on boards (like Gumstix) that have one.
With VBUS sensing, the UDC is unclocked until a host is actually connected.

Signed-off-by: David Brownell <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

arch/arm/mach-pxa/corgi.c

···
 /*
  * USB Device Controller
  */
-static void corgi_udc_command(int cmd)
-{
-	switch(cmd)	{
-	case PXA2XX_UDC_CMD_CONNECT:
-		GPSR(CORGI_GPIO_USB_PULLUP) = GPIO_bit(CORGI_GPIO_USB_PULLUP);
-		break;
-	case PXA2XX_UDC_CMD_DISCONNECT:
-		GPCR(CORGI_GPIO_USB_PULLUP) = GPIO_bit(CORGI_GPIO_USB_PULLUP);
-		break;
-	}
-}
-
 static struct pxa2xx_udc_mach_info udc_info __initdata = {
 	/* no connect GPIO; corgi can't tell connection status */
-	.udc_command		= corgi_udc_command,
+	.gpio_pullup		= CORGI_GPIO_USB_PULLUP,
 };
 
 
···
 	corgi_ssp_set_machinfo(&corgi_ssp_machinfo);
 
 	pxa_gpio_mode(CORGI_GPIO_IR_ON | GPIO_OUT);
-	pxa_gpio_mode(CORGI_GPIO_USB_PULLUP | GPIO_OUT);
 	pxa_gpio_mode(CORGI_GPIO_HSYNC | GPIO_IN);
 
  	pxa_set_udc_info(&udc_info);

drivers/usb/gadget/pxa2xx_udc.c

···
 static void pxa2xx_ep_fifo_flush (struct usb_ep *ep);
 static void nuke (struct pxa2xx_ep *, int status);
 
+/* one GPIO should be used to detect VBUS from the host */
+static int is_vbus_present(void)
+{
+	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;
+
+	if (mach->gpio_vbus)
+		return pxa_gpio_get(mach->gpio_vbus);
+	if (mach->udc_is_connected)
+		return mach->udc_is_connected();
+	return 1;
+}
+
+/* one GPIO should control a D+ pullup, so host sees this device (or not) */
+static void pullup_off(void)
+{
+	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;
+
+	if (mach->gpio_pullup)
+		pxa_gpio_set(mach->gpio_pullup, 0);
+	else if (mach->udc_command)
+		mach->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
+}
+
+static void pullup_on(void)
+{
+	struct pxa2xx_udc_mach_info		*mach = the_controller->mach;
+
+	if (mach->gpio_pullup)
+		pxa_gpio_set(mach->gpio_pullup, 1);
+	else if (mach->udc_command)
+		mach->udc_command(PXA2XX_UDC_CMD_CONNECT);
+}
+
 static void pio_irq_enable(int bEndpointAddress)
 {
         bEndpointAddress &= 0xf;
···
 
 #endif
 
+static irqreturn_t
+udc_vbus_irq(int irq, void *_dev, struct pt_regs *r)
+{
+	struct pxa2xx_udc	*dev = _dev;
+	int			vbus = pxa_gpio_get(dev->mach->gpio_vbus);
+
+	pxa2xx_udc_vbus_session(&dev->gadget, vbus);
+	return IRQ_HANDLED;
+}
+
 
 /*-------------------------------------------------------------------------*/
 
···
 static int __init pxa2xx_udc_probe(struct platform_device *pdev)
 {
 	struct pxa2xx_udc *dev = &memory;
-	int retval, out_dma = 1;
+	int retval, out_dma = 1, vbus_irq;
 	u32 chiprev;
 
 	/* insist on Intel/ARM/XScale */
···
 	/* other non-static parts of init */
 	dev->dev = &pdev->dev;
 	dev->mach = pdev->dev.platform_data;
+	if (dev->mach->gpio_vbus) {
+		vbus_irq = IRQ_GPIO(dev->mach->gpio_vbus & GPIO_MD_MASK_NR);
+		pxa_gpio_mode((dev->mach->gpio_vbus & GPIO_MD_MASK_NR)
+				| GPIO_IN);
+		set_irq_type(vbus_irq, IRQT_BOTHEDGE);
+	} else
+		vbus_irq = 0;
+	if (dev->mach->gpio_pullup)
+		pxa_gpio_mode((dev->mach->gpio_pullup & GPIO_MD_MASK_NR)
+				| GPIO_OUT | GPIO_DFLT_LOW);
 
 	init_timer(&dev->timer);
 	dev->timer.function = udc_watchdog;
···
 		HEX_DISPLAY(dev->stats.irqs);
 		LUB_DISC_BLNK_LED &= 0xff;
 #endif
-	}
+	} else
 #endif
+	if (vbus_irq) {
+		retval = request_irq(vbus_irq, udc_vbus_irq,
+				SA_INTERRUPT | SA_SAMPLE_RANDOM,
+				driver_name, dev);
+		if (retval != 0) {
+			printk(KERN_ERR "%s: can't get irq %i, err %d\n",
+				driver_name, vbus_irq, retval);
+			free_irq(IRQ_USB, dev);
+			return -EBUSY;
+		}
+	}
 	create_proc_files();
 
 	return 0;
···
 		free_irq(LUBBOCK_USB_IRQ, dev);
 	}
 #endif
+	if (dev->mach->gpio_vbus)
+		free_irq(IRQ_GPIO(dev->mach->gpio_vbus), dev);
 	platform_set_drvdata(pdev, NULL);
 	the_controller = NULL;
 	return 0;

drivers/usb/gadget/pxa2xx_udc.h

···
 
 static struct pxa2xx_udc *the_controller;
 
-/* one GPIO should be used to detect VBUS from the host */
-static inline int is_vbus_present(void)
+static inline int pxa_gpio_get(unsigned gpio)
 {
-	if (!the_controller->mach->udc_is_connected)
-		return 1;
-	return the_controller->mach->udc_is_connected();
+	return (GPLR(gpio) & GPIO_bit(gpio)) != 0;
 }
 
-/* one GPIO should control a D+ pullup, so host sees this device (or not) */
-static inline void pullup_off(void)
+static inline void pxa_gpio_set(unsigned gpio, int is_on)
 {
-	if (!the_controller->mach->udc_command)
-		return;
-	the_controller->mach->udc_command(PXA2XX_UDC_CMD_DISCONNECT);
-}
+	int mask = GPIO_bit(gpio);
 
-static inline void pullup_on(void)
-{
-	if (!the_controller->mach->udc_command)
-		return;
-	the_controller->mach->udc_command(PXA2XX_UDC_CMD_CONNECT);
+	if (is_on)
+		GPSR(gpio) = mask;
+	else
+		GPCR(gpio) = mask;
 }
 
 /*-------------------------------------------------------------------------*/

include/asm-arm/arch-pxa/udc.h

···
         void (*udc_command)(int cmd);
 #define	PXA2XX_UDC_CMD_CONNECT		0	/* let host see us */
 #define	PXA2XX_UDC_CMD_DISCONNECT	1	/* so host won't see us */
+
+	/* Boards following the design guidelines in the developer's manual,
+	 * with on-chip GPIOs not Lubbock's wierd hardware, can have a sane
+	 * VBUS IRQ and omit the methods above.  Store the GPIO number
+	 * here; for GPIO 0, also mask in one of the pxa_gpio_mode() bits.
+	 */
+	u16	gpio_vbus;			/* high == vbus present */
+	u16	gpio_pullup;			/* high == pullup activated */
 };
 
 extern void pxa_set_udc_info(struct pxa2xx_udc_mach_info *info);