From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754923AbbL3UwV (ORCPT ); Wed, 30 Dec 2015 15:52:21 -0500 Received: from mail-pa0-f53.google.com ([209.85.220.53]:36621 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753728AbbL3UwT (ORCPT ); Wed, 30 Dec 2015 15:52:19 -0500 From: Mark Salyzyn To: linux-kernel@vger.kernel.org Cc: Mark Salyzyn , Alessandro Zummo , Alexandre Belloni , rtc-linux@googlegroups.com Subject: rtc-palmas: correct for bcd year Date: Wed, 30 Dec 2015 12:51:45 -0800 Message-Id: <1451508726-31769-1-git-send-email-salyzyn@android.com> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Replace bcd2bin and bin2bcd with one that maps years 1970 to 2129 in a pattern that works with the underlying hardware. The only transition that does not work correctly for this rtc clock is the transition from 2099 to 2100, it proceeds to 2000. The rtc clock retains and transitions the year correctly in all other circumstances. Signed-off-by: Mark Salyzyn --- drivers/rtc/rtc-palmas.c | 44 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c index 7ea2c47..3e9663d 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); -- 2.6.0.rc2.230.g3dd15c0