From 6ec37f6672820465afae0a1dee6d52b11248f7cd Mon Sep 17 00:00:00 2001 From: Haojian Zhuang Date: Mon, 4 Feb 2013 14:28:54 -0800 Subject: drivers/rtc/rtc-pl031.c: fix the missing operation on enable commit e7e034e18a0ab6bafb2425c3242cac311164f4d6 upstream. The RTC control register should be enabled in the process of initializing. Without this patch, I failed to enable RTC in Hisilicon Hi3620 SoC. The register mapping section in RTC is always read as zero. So I doubt that ST guys may already enable this register in bootloader. So they won't meet this issue. Signed-off-by: Haojian Zhuang Cc: Srinidhi Kasagar Cc: Linus Walleij Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/rtc/rtc-pl031.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c index 1e80a48057e5..73816d886598 100644 --- a/drivers/rtc/rtc-pl031.c +++ b/drivers/rtc/rtc-pl031.c @@ -44,6 +44,7 @@ #define RTC_YMR 0x34 /* Year match register */ #define RTC_YLR 0x38 /* Year data load register */ +#define RTC_CR_EN (1 << 0) /* counter enable bit */ #define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */ #define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */ @@ -312,7 +313,7 @@ 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; + unsigned long time, data; ret = amba_request_regions(adev, NULL); if (ret) @@ -339,10 +340,11 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id) dev_dbg(&adev->dev, "designer ID = 0x%02x\n", ldata->hw_designer); dev_dbg(&adev->dev, "revision = 0x%01x\n", ldata->hw_revision); + data = readl(ldata->base + RTC_CR); /* Enable the clockwatch on ST Variants */ if (ldata->hw_designer == AMBA_VENDOR_ST) - writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN, - ldata->base + RTC_CR); + data |= RTC_CR_CWEN; + writel(data | RTC_CR_EN, ldata->base + RTC_CR); /* * On ST PL031 variants, the RTC reset value does not provide correct -- cgit v1.2.3