From 9b2fe630d6a7144558224e4e5dfcc22d19b47a02 Mon Sep 17 00:00:00 2001 From: Jeffy Chen Date: Fri, 23 Dec 2016 15:05:11 +0800 Subject: rockchip/rk3288: rtc-rk808: fix rtc time reading issue After we set the GET_TIME bit, the rtc time can't be read immediately. We should wait up to 31.25 us, about one cycle of 32khz. Otherwise reading RTC time will return a old time. BUG=chrome-os-partner:61078 BRANCH=veyron TEST=Build and Boot Original-Change-Id: I6ec07fc6c4d6d8b27b12031423b86b8ab15da6f6 Original-Signed-off-by: Jeffy Chen Original-Reviewed-on: https://chromium-review.googlesource.com/423272 Original-Reviewed-by: Julius Werner Change-Id: I9806b624d6e968e51d52aab8c052ae3fa77f247d Signed-off-by: Patrick Georgi Original-Commit-Id: b4b708e29fbae0d8f5a2cece79711aa6b1887727 Original-Change-Id: I8c168c14437bb932a59ac0e91a01062df0cf11dc Original-Signed-off-by: Jeffy Chen Original-Reviewed-on: https://chromium-review.googlesource.com/427522 Original-Reviewed-by: Julius Werner Reviewed-on: https://review.coreboot.org/18127 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth --- src/soc/rockchip/common/rk808.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'src/soc/rockchip') diff --git a/src/soc/rockchip/common/rk808.c b/src/soc/rockchip/common/rk808.c index dc6b2ea23f..a68b838f48 100644 --- a/src/soc/rockchip/common/rk808.c +++ b/src/soc/rockchip/common/rk808.c @@ -181,6 +181,12 @@ int rtc_get(struct rtc_time *time) rk808_clrsetbits(RTC_CTRL, RTC_CTRL_GET_TIME, 0); rk808_clrsetbits(RTC_CTRL, 0, RTC_CTRL_GET_TIME | RTC_CTRL_RTC_READSEL); + /* + * After we set the GET_TIME bit, the rtc time can't be read + * immediately. So we should wait up to 31.25 us. + */ + udelay(32); + ret |= rk808_read(RTC_SECOND, &value); time->sec = bcd2bin(value & 0x7f); -- cgit v1.2.3