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rk3288: rtc-rk808: fix rtc time reading issue

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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

Change-Id: I6ec07fc6c4d6d8b27b12031423b86b8ab15da6f6
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/423272
Reviewed-by: Julius Werner <jwerner@chromium.org>
This commit is contained in:
Jeffy Chen 2016-12-23 15:05:11 +08:00 • committed by ChromeOS Commit Bot
commit 2e2c97674d
1 changed files with 6 additions and 0 deletions
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6
src/soc/rockchip/rk3288/rk808.c
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@ -185,6 +185,12 @@ 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);