drivers/rtc/rtc-pl031.c: configure correct wday for 2000-01-01

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>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c
index 684ef4bbfce4..f027c063fb20 100644
--- a/drivers/rtc/rtc-pl031.c
+++ b/drivers/rtc/rtc-pl031.c
@@ -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)) {