From f543650a79e7c00854ce06e5dbe7d1cc2b76b079 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Tue, 6 Nov 2018 12:57:48 +0000
Subject: [PATCH] sc16is7xx: Don't spin if no data received

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

See: https://github.com/raspberrypi/linux/issues/2676

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Fang Yafen <yafen@iscas.ac.cn>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
---
 drivers/tty/serial/sc16is7xx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index f86ec2d2635b..ae48749d72fd 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -696,6 +696,8 @@ static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 			rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
 			if (rxlen)
 				sc16is7xx_handle_rx(port, rxlen, iir);
+			else
+				return false;
 			break;
 		case SC16IS7XX_IIR_THRI_SRC:
 			sc16is7xx_handle_tx(port);
-- 
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