Thread (29 messages) 29 messages, 11 authors, 2019-04-02

Re: [PATCH v2 8/9] rtc: mt6397: fix alarm register overwrite

From: Sean Wang <sean.wang@kernel.org>
Date: 2019-03-11 20:50:37
Also in: linux-devicetree, linux-mediatek, linux-rtc, lkml

Hi,

On Sun, Mar 10, 2019 at 8:49 PM Hsin-Hsiung Wang
[off-list ref] wrote:
From: Ran Bi <redacted>

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")
add a  Cc: stable@vger.kernel.org  here to apply to all stable kernels
for the critical fixup patch.
quoted hunk ↗ jump to hunk
Signed-off-by: Ran Bi <redacted>
---
 drivers/rtc/rtc-mt6397.c | 47 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 14 deletions(-)
diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c
index e9a25ec..f85f1fc 100644
--- 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;
+
Why did we need an additional regmap_bulk_read here? I would suppose
data[RTC_OFFSET_*] & ~(RTC_AL_*_MASK) is always equal to 0.

It might be another fixup since change is not being mentioned in the
git message.
+       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,
--
1.9.1


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