diff options
| -rw-r--r-- | drivers/rtc/rtc-isl12057.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-isl12057.c b/drivers/rtc/rtc-isl12057.c index 8c3f60737df..b538fabfcfd 100644 --- a/drivers/rtc/rtc-isl12057.c +++ b/drivers/rtc/rtc-isl12057.c @@ -41,6 +41,7 @@ #define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */ #define ISL12057_REG_RTC_DT 0x04 /* Date */ #define ISL12057_REG_RTC_MO 0x05 /* Month */ +#define ISL12057_REG_RTC_MO_CEN BIT(7) /* Century bit */ #define ISL12057_REG_RTC_YR 0x06 /* Year */ #define ISL12057_RTC_SEC_LEN 7 @@ -99,24 +100,35 @@ static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */ tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; + + /* Check if years register has overflown from 99 to 00 */ + if (regs[ISL12057_REG_RTC_MO] & ISL12057_REG_RTC_MO_CEN) + tm->tm_year += 100; } static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) { + u8 century_bit; + /* * The clock has an 8 bit wide bcd-coded register for the year. + * It also has a century bit encoded in MO flag which provides + * information about overflow of year register from 99 to 00. * tm_year is an offset from 1900 and we are interested in the - * 2000-2099 range, so any value less than 100 is invalid. + * 2000-2199 range, so any value less than 100 or larger than + * 299 is invalid. */ - if (tm->tm_year < 100) + if (tm->tm_year < 100 || tm->tm_year > 299) return -EINVAL; + century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0; + regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); - regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); - regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); + regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit; + regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100); regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); return 0; |