linux-kernel - [PATCH 3/9] rtc: ds1343: use burst write to set time

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Date:   Sat, 19 Oct 2019 22:49:35 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     linux-rtc@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Subject: [PATCH 3/9] rtc: ds1343: use burst write to set time

To avoid possible race condition, use regmap_bulk_write to write all the
date/time registers at once instead of sequentially.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-ds1343.c | 52 ++++++++++------------------------------
 1 file changed, 12 insertions(+), 40 deletions(-)

diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
index 9d7d571e722b..8a4f1fbb57fd 100644
--- a/drivers/rtc/rtc-ds1343.c
+++ b/drivers/rtc/rtc-ds1343.c
@@ -236,46 +236,18 @@ static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
 {
 	struct ds1343_priv *priv = dev_get_drvdata(dev);
-	int res;
-
-	res = regmap_write(priv->map, DS1343_SECONDS_REG,
-				bin2bcd(dt->tm_sec));
-	if (res)
-		return res;
-
-	res = regmap_write(priv->map, DS1343_MINUTES_REG,
-				bin2bcd(dt->tm_min));
-	if (res)
-		return res;
-
-	res = regmap_write(priv->map, DS1343_HOURS_REG,
-				bin2bcd(dt->tm_hour) & 0x3F);
-	if (res)
-		return res;
-
-	res = regmap_write(priv->map, DS1343_DAY_REG,
-				bin2bcd(dt->tm_wday + 1));
-	if (res)
-		return res;
-
-	res = regmap_write(priv->map, DS1343_DATE_REG,
-				bin2bcd(dt->tm_mday));
-	if (res)
-		return res;
-
-	res = regmap_write(priv->map, DS1343_MONTH_REG,
-				bin2bcd(dt->tm_mon + 1));
-	if (res)
-		return res;
-
-	dt->tm_year %= 100;
-
-	res = regmap_write(priv->map, DS1343_YEAR_REG,
-				bin2bcd(dt->tm_year));
-	if (res)
-		return res;
-
-	return 0;
+	u8 buf[7];
+
+	buf[0] = bin2bcd(dt->tm_sec);
+	buf[1] = bin2bcd(dt->tm_min);
+	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
+	buf[3] = bin2bcd(dt->tm_wday + 1);
+	buf[4] = bin2bcd(dt->tm_mday);
+	buf[5] = bin2bcd(dt->tm_mon + 1);
+	buf[6] = bin2bcd(dt->tm_year - 100);
+
+	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
+				 buf, sizeof(buf));
 }
 
 static int ds1343_update_alarm(struct device *dev)
-- 
2.21.0