usb: gadget: bdc: use readl_poll_timeout() to simplify code

Use readl_poll_timeout() to poll register status

Cc: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/bdc/bdc_core.c

@@ -12,6 +12,7 @@
 #include <linux/spinlock.h>
 #include <linux/platform_device.h>
 #include <linux/interrupt.h>
+#include <linux/iopoll.h>
 #include <linux/ioport.h>
 #include <linux/io.h>
 #include <linux/list.h>
@@ -29,24 +30,19 @@
 #include "bdc_dbg.h"
 
 /* Poll till controller status is not OIP */
-static int poll_oip(struct bdc *bdc, int usec)
+static int poll_oip(struct bdc *bdc, u32 usec)
 {
 	u32 status;
-	/* Poll till STS!= OIP */
-	while (usec) {
-		status = bdc_readl(bdc->regs, BDC_BDCSC);
-		if (BDC_CSTS(status) != BDC_OIP) {
-			dev_dbg(bdc->dev,
-				"poll_oip complete status=%d",
-				BDC_CSTS(status));
-			return 0;
-		}
-		udelay(10);
-		usec -= 10;
-	}
-	dev_err(bdc->dev, "Err: operation timedout BDCSC: 0x%08x\n", status);
+	int ret;
 
-	return -ETIMEDOUT;
+	ret = readl_poll_timeout(bdc->regs + BDC_BDCSC, status,
+				 (BDC_CSTS(status) != BDC_OIP), 10, usec);
+	if (ret)
+		dev_err(bdc->dev, "operation timedout BDCSC: 0x%08x\n", status);
+	else
+		dev_dbg(bdc->dev, "%s complete status=%d", __func__, BDC_CSTS(status));
+
+	return ret;
 }
 
 /* Stop the BDC controller */