[PATCH 4.9 20/97] rtc: mt6397: fix alarm register overwrite

Greg Kroah-Hartman
2020-01-22T09:53:22Z

From: Ran Bi <ran.bi@mediatek.com>

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>

---
drivers/rtc/rtc-mt6397.c | 47 +++++++++++++++++++++++++++++++++--------------
1 file changed, 33 insertions(+), 14 deletions(-)

--- 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_t
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 dev
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 devi
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,