usb: gadget: zero: Add flexible auto remote wakeup test method

In order to increase test coverage, we can change the interval between
two remote wakeups every time, and the interval can be any user defined
value. This change will no affect current behavior if the user does not
use two introduced module paramters.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/zero.c

@@ -95,6 +95,18 @@ unsigned autoresume = DEFAULT_AUTORESUME;
 module_param(autoresume, uint, S_IRUGO);
 MODULE_PARM_DESC(autoresume, "zero, or seconds before remote wakeup");
 
+/* Maximum Autoresume time */
+unsigned max_autoresume;
+module_param(max_autoresume, uint, S_IRUGO);
+MODULE_PARM_DESC(max_autoresume, "maximum seconds before remote wakeup");
+
+/* Interval between two remote wakeups */
+unsigned autoresume_interval_ms;
+module_param(autoresume_interval_ms, uint, S_IRUGO);
+MODULE_PARM_DESC(autoresume_interval_ms,
+		"milliseconds to increase successive wakeup delays");
+
+static unsigned autoresume_step_ms;
 /*-------------------------------------------------------------------------*/
 
 static struct usb_device_descriptor device_desc = {
@@ -183,8 +195,16 @@ static void zero_suspend(struct usb_composite_dev *cdev)
 		return;
 
 	if (autoresume) {
-		mod_timer(&autoresume_timer, jiffies + (HZ * autoresume));
-		DBG(cdev, "suspend, wakeup in %d seconds\n", autoresume);
+		if (max_autoresume &&
+			(autoresume_step_ms > max_autoresume * 1000))
+				autoresume_step_ms = autoresume * 1000;
+
+		mod_timer(&autoresume_timer, jiffies +
+			msecs_to_jiffies(autoresume_step_ms));
+		DBG(cdev, "suspend, wakeup in %d milliseconds\n",
+			autoresume_step_ms);
+
+		autoresume_step_ms += autoresume_interval_ms;
 	} else
 		DBG(cdev, "%s\n", __func__);
 }
@@ -316,6 +336,7 @@ static int __init zero_bind(struct usb_composite_dev *cdev)
 	if (autoresume) {
 		sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 		loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+		autoresume_step_ms = autoresume * 1000;
 	}
 
 	/* support OTG systems */