rtc: at91rm9200: use FIELD_PREP/FIELD_GET

Use FIELD_PREP and FIELD_GET instead of hardcoding already defined values.

Link: https://lore.kernel.org/r/20191229204421.337612-6-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-at91rm9200.c

@@ -14,6 +14,7 @@
  */
 
 #include <linux/bcd.h>
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/interrupt.h>
@@ -161,20 +162,20 @@ static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 	} while ((time != at91_rtc_read(timereg)) ||
 			(date != at91_rtc_read(calreg)));
 
-	tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
-	tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
-	tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
+	tm->tm_sec  = bcd2bin(FIELD_GET(AT91_RTC_SEC, time));
+	tm->tm_min  = bcd2bin(FIELD_GET(AT91_RTC_MIN, time));
+	tm->tm_hour = bcd2bin(FIELD_GET(AT91_RTC_HOUR, time));
 
 	/*
 	 * The Calendar Alarm register does not have a field for
 	 * the year - so these will return an invalid value.
 	 */
 	tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;	/* century */
-	tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);	/* year */
+	tm->tm_year += bcd2bin(FIELD_GET(AT91_RTC_YEAR, date));	/* year */
 
-	tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1;	/* day of the week [0-6], Sunday=0 */
-	tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
-	tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
+	tm->tm_wday = bcd2bin(FIELD_GET(AT91_RTC_DAY, date)) - 1;	/* day of the week [0-6], Sunday=0 */
+	tm->tm_mon  = bcd2bin(FIELD_GET(AT91_RTC_MONTH, date)) - 1;
+	tm->tm_mday = bcd2bin(FIELD_GET(AT91_RTC_DATE, date));
 }
 
 /*
@@ -211,16 +212,17 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 	at91_rtc_write_idr(AT91_RTC_ACKUPD);
 
 	at91_rtc_write(AT91_RTC_TIMR,
-			  bin2bcd(tm->tm_sec) << 0
-			| bin2bcd(tm->tm_min) << 8
-			| bin2bcd(tm->tm_hour) << 16);
+			  FIELD_PREP(AT91_RTC_SEC, bin2bcd(tm->tm_sec))
+			| FIELD_PREP(AT91_RTC_MIN, bin2bcd(tm->tm_min))
+			| FIELD_PREP(AT91_RTC_HOUR, bin2bcd(tm->tm_hour)));
 
 	at91_rtc_write(AT91_RTC_CALR,
-			  bin2bcd((tm->tm_year + 1900) / 100)	/* century */
-			| bin2bcd(tm->tm_year % 100) << 8	/* year */
-			| bin2bcd(tm->tm_mon + 1) << 16		/* tm_mon starts at zero */
-			| bin2bcd(tm->tm_wday + 1) << 21	/* day of the week [0-6], Sunday=0 */
-			| bin2bcd(tm->tm_mday) << 24);
+			  FIELD_PREP(AT91_RTC_CENT,
+				     bin2bcd((tm->tm_year + 1900) / 100))
+			| FIELD_PREP(AT91_RTC_YEAR, bin2bcd(tm->tm_year % 100))
+			| FIELD_PREP(AT91_RTC_MONTH, bin2bcd(tm->tm_mon + 1))
+			| FIELD_PREP(AT91_RTC_DAY, bin2bcd(tm->tm_wday + 1))
+			| FIELD_PREP(AT91_RTC_DATE, bin2bcd(tm->tm_mday)));
 
 	/* Restart Time/Calendar */
 	cr = at91_rtc_read(AT91_RTC_CR);
@@ -259,13 +261,13 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	at91_rtc_write_idr(AT91_RTC_ALARM);
 	at91_rtc_write(AT91_RTC_TIMALR,
-		  bin2bcd(alrm->time.tm_sec) << 0
-		| bin2bcd(alrm->time.tm_min) << 8
-		| bin2bcd(alrm->time.tm_hour) << 16
+		  FIELD_PREP(AT91_RTC_SEC, bin2bcd(alrm->time.tm_sec))
+		| FIELD_PREP(AT91_RTC_MIN, bin2bcd(alrm->time.tm_min))
+		| FIELD_PREP(AT91_RTC_HOUR, bin2bcd(alrm->time.tm_hour))
 		| AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 	at91_rtc_write(AT91_RTC_CALALR,
-		  bin2bcd(alrm->time.tm_mon + 1) << 16		/* tm_mon starts at zero */
-		| bin2bcd(alrm->time.tm_mday) << 24
+		  FIELD_PREP(AT91_RTC_MONTH, bin2bcd(alrm->time.tm_mon + 1))
+		| FIELD_PREP(AT91_RTC_DATE, bin2bcd(alrm->time.tm_mday))
 		| AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 
 	if (alrm->enabled) {