usb: isp1760-hcd: convert to readl_poll_timeout_atomic()

Use readl_poll_timeout_atomic() to simplify code
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1600668815-12135-7-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/isp1760/isp1760-hcd.c

@@ -22,6 +22,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/mm.h>
 #include <linux/timer.h>
 #include <asm/unaligned.h>
@@ -380,18 +381,15 @@ static int handshake(struct usb_hcd *hcd, u32 reg,
 		      u32 mask, u32 done, int usec)
 {
 	u32 result;
+	int ret;
+
+	ret = readl_poll_timeout_atomic(hcd->regs + reg, result,
+					((result & mask) == done ||
+					 result == U32_MAX), 1, usec);
+	if (result == U32_MAX)
+		return -ENODEV;
 
-	do {
-		result = reg_read32(hcd->regs, reg);
-		if (result == ~0)
-			return -ENODEV;
-		result &= mask;
-		if (result == done)
-			return 0;
-		udelay(1);
-		usec--;
-	} while (usec > 0);
-	return -ETIMEDOUT;
+	return ret;
 }
 
 /* reset a non-running (STS_HALT == 1) controller */