X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Frtc%2Frtc-palmas.c;h=3e9663d0752b4b7d06bd9a091e6caab7ad29eb83;hb=3d6d4e5b2a7309f9110aa0fb9751918099779471;hp=7ea2c471feca3864a20612b9720e25314b5f5e77;hpb=f7c0af824711a88b47debbe295f17be6c0556539;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c
index 7ea2c471feca..3e9663d0752b 100644
--- a/drivers/rtc/rtc-palmas.c
+++ b/drivers/rtc/rtc-palmas.c
@@ -45,6 +45,42 @@ struct palmas_rtc {
 /* Total number of RTC registers needed to set time*/
 #define PALMAS_NUM_TIME_REGS	(PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
 
+/*
+ * Special bin2bcd mapping to deal with bcd storage of year.
+ *
+ *   0-69                -> 0xD0
+ *  70-99  (1970 - 1999) -> 0xD0 - 0xF9 (correctly rolls to 0x00)
+ * 100-199 (2000 - 2099) -> 0x00 - 0x99 (does not roll to 0xA0 :-( )
+ * 200-229 (2100 - 2129) -> 0xA0 - 0xC9 (really for completeness)
+ * 230-                  -> 0xC9
+ *
+ * Confirmed: the only transition that does not work correctly for this rtc
+ * clock is the transition from 2099 to 2100, it proceeds to 2000. We will
+ * accept this issue since the clock retains and transitions the year correctly
+ * in all other conditions.
+ */
+static unsigned char year_bin2bcd(int val)
+{
+	if (val < 70)
+		return 0xD0;
+	if (val < 100)
+		return bin2bcd(val - 20) | 0x80; /* KISS leverage of bin2bcd */
+	if (val >= 230)
+		return 0xC9;
+	if (val >= 200)
+		return bin2bcd(val - 180) | 0x80;
+	return bin2bcd(val - 100);
+}
+
+static int year_bcd2bin(unsigned char val)
+{
+	if (val >= 0xD0)
+		return bcd2bin(val & 0x7F) + 20;
+	if (val >= 0xA0)
+		return bcd2bin(val & 0x7F) + 180;
+	return bcd2bin(val) + 100;
+}
+
 static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
@@ -71,7 +107,7 @@ static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	tm->tm_hour = bcd2bin(rtc_data[2]);
 	tm->tm_mday = bcd2bin(rtc_data[3]);
 	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
-	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
+	tm->tm_year = year_bcd2bin(rtc_data[5]);
 
 	return ret;
 }
@@ -87,7 +123,7 @@ static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	rtc_data[2] = bin2bcd(tm->tm_hour);
 	rtc_data[3] = bin2bcd(tm->tm_mday);
 	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
-	rtc_data[5] = bin2bcd(tm->tm_year - 100);
+	rtc_data[5] = year_bin2bcd(tm->tm_year);
 
 	/* Stop RTC while updating the RTC time registers */
 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
@@ -142,7 +178,7 @@ static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	alm->time.tm_hour = bcd2bin(alarm_data[2]);
 	alm->time.tm_mday = bcd2bin(alarm_data[3]);
 	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
-	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
+	alm->time.tm_year = year_bcd2bin(alarm_data[5]);
 
 	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
 			&int_val);
@@ -173,7 +209,7 @@ static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	alarm_data[2] = bin2bcd(alm->time.tm_hour);
 	alarm_data[3] = bin2bcd(alm->time.tm_mday);
 	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
-	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
+	alarm_data[5] = year_bin2bcd(alm->time.tm_year);
 
 	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
 		PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);