rtc: max77686: Use ffs() to calculate tm_wday

max77686_rtc_calculate_wday() is used to calculate the day of the week
to be filled in struct rtc_time but that function only calculates the
number of bits shifted.  So the ffs() function can be used to find the
first bit set instead of a special function.

[akpm@linux-foundation.org: add comment clarifying ffs() use]
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
index b177ba199a3d11128d61c3145920e617d8d3f610..cf73e969c8cc9a1ac38add953e79f6f9f6892094 100644 (file)
--- a/drivers/rtc/rtc-max77686.c
+++ b/drivers/rtc/rtc-max77686.c
@@ -70,16 +70,6 @@ enum MAX77686_RTC_OP {
        MAX77686_RTC_READ,
 };
 
-static inline int max77686_rtc_calculate_wday(u8 shifted)
-{
-       int counter = -1;
-       while (shifted) {
-               shifted >>= 1;
-               counter++;
-       }
-       return counter;
-}
-
 static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
                                   int rtc_24hr_mode)
 {
@@ -93,7 +83,8 @@ static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
                        tm->tm_hour += 12;
        }
 
-       tm->tm_wday = max77686_rtc_calculate_wday(data[RTC_WEEKDAY] & 0x7f);
+       /* Only a single bit is set in data[], so fls() would be equivalent */
+       tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0x7f) - 1;
        tm->tm_mday = data[RTC_DATE] & 0x1f;
        tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
        tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;