diff --git a/drivers/rtc/rtc-88pm80x.c b/drivers/rtc/rtc-88pm80x.c
index 466bf7f9a285..7da2a1fb50f8 100644
--- a/drivers/rtc/rtc-88pm80x.c
+++ b/drivers/rtc/rtc-88pm80x.c
@@ -116,12 +116,14 @@ static int pm80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	unsigned char buf[4];
 	unsigned long ticks, base, data;
 	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
-	base = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
 
 	/* load 32-bit read-only counter */
 	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
-	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	ticks = base + data;
 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 		base, data, ticks);
@@ -144,7 +146,8 @@ static int pm80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 
 	/* load 32-bit read-only counter */
 	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
-	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	base = ticks - data;
 	dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 		base, data, ticks);
@@ -165,11 +168,13 @@ static int pm80x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	int ret;
 
 	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
-	base = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
 
 	regmap_raw_read(info->map, PM800_RTC_EXPIRE1_1, buf, 4);
-	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	ticks = base + data;
 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 		base, data, ticks);
@@ -192,12 +197,14 @@ static int pm80x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	regmap_update_bits(info->map, PM800_RTC_CONTROL, PM800_ALARM1_EN, 0);
 
 	regmap_raw_read(info->map, PM800_RTC_EXPIRE2_1, buf, 4);
-	base = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	base = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	dev_dbg(info->dev, "%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3]);
 
 	/* load 32-bit read-only counter */
 	regmap_raw_read(info->map, PM800_RTC_COUNTER1, buf, 4);
-	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
+		(buf[1] << 8) | buf[0];
 	ticks = base + data;
 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
 		base, data, ticks);