rtc: pcf2123: use sign_extend32() for sign extension

Use sign_extend32() instead of open coding sign extension.

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
index f22e060..b4478cc 100644 (file)
--- a/drivers/rtc/rtc-pcf2123.c
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -96,7 +96,7 @@
 #define CD_TMR_TE              BIT(3)  /* Countdown timer enable */
 
 /* PCF2123_REG_OFFSET BITS */
-#define OFFSET_SIGN_BIT                BIT(6)  /* 2's complement sign bit */
+#define OFFSET_SIGN_BIT                6       /* 2's complement sign bit */
 #define OFFSET_COARSE          BIT(7)  /* Coarse mode offset */
 #define OFFSET_STEP            (2170)  /* Offset step in parts per billion */
 
@@ -217,7 +217,7 @@ static int pcf2123_read_offset(struct device *dev, long *offset)
        if (reg & OFFSET_COARSE)
                reg <<= 1; /* multiply by 2 and sign extend */
        else
-               reg |= (reg & OFFSET_SIGN_BIT) << 1; /* sign extend only */
+               reg = sign_extend32(reg, OFFSET_SIGN_BIT);
 
        *offset = ((long)reg) * OFFSET_STEP;