From 9dbe3852964166fdf3ac4aff4cb67311dfa243bc Mon Sep 17 00:00:00 2001
From: Akinobu Mita <akinobu.mita@gmail.com>
Date: Mon, 15 Feb 2016 23:49:07 +0900
Subject: [PATCH] rtc: rx8025: protect ctrl1 register update by rtc->ops_lock

The ctrl1 register is accessed by alarm operations.  But it is updated
in threaded interrupt handler without acquiring rtc->ops_lock.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
 drivers/rtc/rtc-rx8025.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/rtc/rtc-rx8025.c b/drivers/rtc/rtc-rx8025.c
index 18240f526ade..259995281e0d 100644
--- a/drivers/rtc/rtc-rx8025.c
+++ b/drivers/rtc/rtc-rx8025.c
@@ -146,8 +146,10 @@ static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 {
 	struct i2c_client *client = dev_id;
 	struct rx8025_data *rx8025 = i2c_get_clientdata(client);
+	struct mutex *lock = &rx8025->rtc->ops_lock;
 	int status;
 
+	mutex_lock(lock);
 	status = rx8025_read_reg(client, RX8025_REG_CTRL2);
 	if (status < 0)
 		goto out;
@@ -172,6 +174,8 @@ static irqreturn_t rx8025_handle_irq(int irq, void *dev_id)
 	}
 
 out:
+	mutex_unlock(lock);
+
 	return IRQ_HANDLED;
 }