rtc: mt6397: fix alarm register overwrite

commit 653997eeecef95c3ead4fba1b2d27e6a5854d6cd upstream.

Alarm registers high byte was reserved for other functions.
This add mask in alarm registers operation functions.
This also fix error condition in interrupt handler.

Fixes: fc2979118f3f ("rtc: mediatek: Add MT6397 RTC driver")

Signed-off-by: Ran Bi <ran.bi@mediatek.com>
Signed-off-by: Hsin-Hsiung Wang <hsin-hsiung.wang@mediatek.com>
Link: https://lore.kernel.org/r/1576057435-3561-6-git-send-email-hsin-hsiung.wang@mediatek.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c
index 1a61fa56f3ad77bad999d234778e8d953fc1ad5a..494a7fbd512b7bec00035d6e1e09dcdc4e24768d 100644 (file)
--- a/drivers/rtc/rtc-mt6397.c
+++ b/drivers/rtc/rtc-mt6397.c
@@ -55,6 +55,14 @@
 
 #define RTC_AL_SEC             0x0018
 
+#define RTC_AL_SEC_MASK                0x003f
+#define RTC_AL_MIN_MASK                0x003f
+#define RTC_AL_HOU_MASK                0x001f
+#define RTC_AL_DOM_MASK                0x001f
+#define RTC_AL_DOW_MASK                0x0007
+#define RTC_AL_MTH_MASK                0x000f
+#define RTC_AL_YEA_MASK                0x007f
+
 #define RTC_PDN2               0x002e
 #define RTC_PDN2_PWRON_ALARM   BIT(4)
 
@@ -111,7 +119,7 @@ static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
                irqen = irqsta & ~RTC_IRQ_EN_AL;
                mutex_lock(&rtc->lock);
                if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
-                                irqen) < 0)
+                                irqen) == 0)
                        mtk_rtc_write_trigger(rtc);
                mutex_unlock(&rtc->lock);
 
@@ -233,12 +241,12 @@ static int mtk_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
        alm->pending = !!(pdn2 & RTC_PDN2_PWRON_ALARM);
        mutex_unlock(&rtc->lock);
 
-       tm->tm_sec = data[RTC_OFFSET_SEC];
-       tm->tm_min = data[RTC_OFFSET_MIN];
-       tm->tm_hour = data[RTC_OFFSET_HOUR];
-       tm->tm_mday = data[RTC_OFFSET_DOM];
-       tm->tm_mon = data[RTC_OFFSET_MTH];
-       tm->tm_year = data[RTC_OFFSET_YEAR];
+       tm->tm_sec = data[RTC_OFFSET_SEC] & RTC_AL_SEC_MASK;
+       tm->tm_min = data[RTC_OFFSET_MIN] & RTC_AL_MIN_MASK;
+       tm->tm_hour = data[RTC_OFFSET_HOUR] & RTC_AL_HOU_MASK;
+       tm->tm_mday = data[RTC_OFFSET_DOM] & RTC_AL_DOM_MASK;
+       tm->tm_mon = data[RTC_OFFSET_MTH] & RTC_AL_MTH_MASK;
+       tm->tm_year = data[RTC_OFFSET_YEAR] & RTC_AL_YEA_MASK;
 
        tm->tm_year += RTC_MIN_YEAR_OFFSET;
        tm->tm_mon--;
@@ -259,14 +267,25 @@ static int mtk_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
        tm->tm_year -= RTC_MIN_YEAR_OFFSET;
        tm->tm_mon++;
 
-       data[RTC_OFFSET_SEC] = tm->tm_sec;
-       data[RTC_OFFSET_MIN] = tm->tm_min;
-       data[RTC_OFFSET_HOUR] = tm->tm_hour;
-       data[RTC_OFFSET_DOM] = tm->tm_mday;
-       data[RTC_OFFSET_MTH] = tm->tm_mon;
-       data[RTC_OFFSET_YEAR] = tm->tm_year;
-
        mutex_lock(&rtc->lock);
+       ret = regmap_bulk_read(rtc->regmap, rtc->addr_base + RTC_AL_SEC,
+                              data, RTC_OFFSET_COUNT);
+       if (ret < 0)
+               goto exit;
+
+       data[RTC_OFFSET_SEC] = ((data[RTC_OFFSET_SEC] & ~(RTC_AL_SEC_MASK)) |
+                               (tm->tm_sec & RTC_AL_SEC_MASK));
+       data[RTC_OFFSET_MIN] = ((data[RTC_OFFSET_MIN] & ~(RTC_AL_MIN_MASK)) |
+                               (tm->tm_min & RTC_AL_MIN_MASK));
+       data[RTC_OFFSET_HOUR] = ((data[RTC_OFFSET_HOUR] & ~(RTC_AL_HOU_MASK)) |
+                               (tm->tm_hour & RTC_AL_HOU_MASK));
+       data[RTC_OFFSET_DOM] = ((data[RTC_OFFSET_DOM] & ~(RTC_AL_DOM_MASK)) |
+                               (tm->tm_mday & RTC_AL_DOM_MASK));
+       data[RTC_OFFSET_MTH] = ((data[RTC_OFFSET_MTH] & ~(RTC_AL_MTH_MASK)) |
+                               (tm->tm_mon & RTC_AL_MTH_MASK));
+       data[RTC_OFFSET_YEAR] = ((data[RTC_OFFSET_YEAR] & ~(RTC_AL_YEA_MASK)) |
+                               (tm->tm_year & RTC_AL_YEA_MASK));
+
        if (alm->enabled) {
                ret = regmap_bulk_write(rtc->regmap,
                                        rtc->addr_base + RTC_AL_SEC,