drivers/rtc/rtc-pl031.c: configure correct wday for 2000-01-01
Rajkumar Kasirajan [Fri, 18 May 2012 00:03:24 +0000 (17:03 -0700)]
The reset date of the ST Micro version of PL031 is 2000-01-01.  The
correct weekday for 2000-01-01 is saturday, but pl031 is initialized to
sunday.  This may lead to alarm malfunction, so configure the correct
wday if RTC_DR indicates reset.

Signed-off-by: Rajkumar Kasirajan <rajkumar.kasirajan@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Mattias Wallin <mattias.wallin@stericsson.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-pl031.c

index 684ef4b..f027c06 100644 (file)
@@ -312,6 +312,7 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
        int ret;
        struct pl031_local *ldata;
        struct rtc_class_ops *ops = id->data;
+       unsigned long time;
 
        ret = amba_request_regions(adev, NULL);
        if (ret)
@@ -343,6 +344,23 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
                writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
                       ldata->base + RTC_CR);
 
+       /*
+        * On ST PL031 variants, the RTC reset value does not provide correct
+        * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
+        */
+       if (ldata->hw_designer == AMBA_VENDOR_ST) {
+               if (readl(ldata->base + RTC_YDR) == 0x2000) {
+                       time = readl(ldata->base + RTC_DR);
+                       if ((time &
+                            (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
+                           == 0x02120000) {
+                               time = time | (0x7 << RTC_WDAY_SHIFT);
+                               writel(0x2000, ldata->base + RTC_YLR);
+                               writel(time, ldata->base + RTC_LR);
+                       }
+               }
+       }
+
        ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
                                        THIS_MODULE);
        if (IS_ERR(ldata->rtc)) {