From a71e2ac1f32097fbb2beab098687a7a95c84543e Mon Sep 17 00:00:00 2001
From: Chris Brandt <chris.brandt@renesas.com>
Date: Thu, 26 Sep 2019 07:19:09 -0500
Subject: [PATCH] i2c: riic: Clear NACK in tend isr
Git-commit: a71e2ac1f32097fbb2beab098687a7a95c84543e
Patch-mainline: v5.4-rc1
References: bsc#1051510

The NACKF flag should be cleared in INTRIICNAKI interrupt processing as
description in HW manual.

This issue shows up quickly when PREEMPT_RT is applied and a device is
probed that is not plugged in (like a touchscreen controller). The result
is endless interrupts that halt system boot.

Fixes: 310c18a41450 ("i2c: riic: add driver")
Cc: stable@vger.kernel.org
Reported-by: Chien Nguyen <chien.nguyen.eb@rvc.renesas.com>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/i2c/busses/i2c-riic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c
index f31413fd9521..800414886f6b 100644
--- a/drivers/i2c/busses/i2c-riic.c
+++ b/drivers/i2c/busses/i2c-riic.c
@@ -202,6 +202,7 @@ static irqreturn_t riic_tend_isr(int irq, void *data)
 	if (readb(riic->base + RIIC_ICSR2) & ICSR2_NACKF) {
 		/* We got a NACKIE */
 		readb(riic->base + RIIC_ICDRR);	/* dummy read */
+		riic_clear_set_bit(riic, ICSR2_NACKF, 0, RIIC_ICSR2);
 		riic->err = -ENXIO;
 	} else if (riic->bytes_left) {
 		return IRQ_NONE;
-- 
2.16.4