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authorIngo Molnar <mingo@kernel.org>2015-03-05 20:52:18 +0100
committerIngo Molnar <mingo@kernel.org>2015-03-05 20:52:18 +0100
commit33ca8a53f262b4af40611bea331b8c87d133af72 (patch)
treed6468c820a556c4915bcb5b761204a0fb19e8225 /drivers/rtc/rtc-rk808.c
parentdb2dcb4f91d5fec5c346a82c309187ee821e2495 (diff)
parent13a7a6ac0a11197edcd0f756a035f472b42cdf8b (diff)
Merge tag 'v4.0-rc2' into irq/core, to refresh the tree before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/rtc/rtc-rk808.c')
-rw-r--r--drivers/rtc/rtc-rk808.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-rk808.c b/drivers/rtc/rtc-rk808.c
index df42257668ac..91ca0bc1b484 100644
--- a/drivers/rtc/rtc-rk808.c
+++ b/drivers/rtc/rtc-rk808.c
@@ -67,15 +67,21 @@ static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
/* Force an update of the shadowed registers right now */
ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
BIT_RTC_CTRL_REG_RTC_GET_TIME,
- 0);
+ BIT_RTC_CTRL_REG_RTC_GET_TIME);
if (ret) {
dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
return ret;
}
+ /*
+ * After we set the GET_TIME bit, the rtc time can't be read
+ * immediately. So we should wait up to 31.25 us, about one cycle of
+ * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
+ * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
+ */
ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
BIT_RTC_CTRL_REG_RTC_GET_TIME,
- BIT_RTC_CTRL_REG_RTC_GET_TIME);
+ 0);
if (ret) {
dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
return ret;