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| author | Baruch Siach <baruch@tkos.co.il> | 2018-06-21 20:40:23 +0300 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-07-12 20:16:08 +0200 |
| commit | 1a990fefb641398fb580a0ea0be99b0ff27cbb9b (patch) | |
| tree | 152181f3635cff43c34747fc2a14764349f56bcc /drivers/rtc/rtc-armada38x.c | |
| parent | dff700fa81938d8947c86b7909920e5e5f772afc (diff) | |
| download | lwn-1a990fefb641398fb580a0ea0be99b0ff27cbb9b.tar.gz lwn-1a990fefb641398fb580a0ea0be99b0ff27cbb9b.zip | |
rtc: armada38x: reset after rtc power loss
When the RTC block looses power it needs a reset sequence to make it
usable again. Otherwise, writes to the time register have no effect.
This reset sequence combines information from the mvebu_rtc driver in
the Marvell provided U-Boot, and the SolidRun provided U-Boot repo.
Tested on the Armada 388 based SolidRun Clearfog Base.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc/rtc-armada38x.c')
| -rw-r--r-- | drivers/rtc/rtc-armada38x.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index 1e4978c96ffd..bde53c8ccee2 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -30,6 +30,8 @@ #define RTC_IRQ_FREQ_1HZ BIT(2) #define RTC_CCR 0x18 #define RTC_CCR_MODE BIT(15) +#define RTC_CONF_TEST 0x1C +#define RTC_NOMINAL_TIMING BIT(13) #define RTC_TIME 0xC #define RTC_ALARM1 0x10 @@ -75,6 +77,7 @@ struct armada38x_rtc { void __iomem *regs_soc; spinlock_t lock; int irq; + bool initialized; struct value_to_freq *val_to_freq; struct armada38x_rtc_data *data; }; @@ -226,6 +229,23 @@ static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm) return 0; } +static void armada38x_rtc_reset(struct armada38x_rtc *rtc) +{ + u32 reg; + + reg = rtc->data->read_rtc_reg(rtc, RTC_CONF_TEST); + /* If bits [7:0] are non-zero, assume RTC was uninitialized */ + if (reg & 0xff) { + rtc_delayed_write(0, rtc, RTC_CONF_TEST); + msleep(500); /* Oscillator startup time */ + rtc_delayed_write(0, rtc, RTC_TIME); + rtc_delayed_write(SOC_RTC_ALARM1 | SOC_RTC_ALARM2, rtc, + RTC_STATUS); + rtc_delayed_write(RTC_NOMINAL_TIMING, rtc, RTC_CCR); + } + rtc->initialized = true; +} + static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct armada38x_rtc *rtc = dev_get_drvdata(dev); @@ -237,6 +257,9 @@ static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm) if (ret) goto out; + if (!rtc->initialized) + armada38x_rtc_reset(rtc); + spin_lock_irqsave(&rtc->lock, flags); rtc_delayed_write(time, rtc, RTC_TIME); spin_unlock_irqrestore(&rtc->lock, flags); |