From e7e034e18a0ab6bafb2425c3242cac311164f4d6 Mon Sep 17 00:00:00 2001 From: Haojian Zhuang Date: Mon, 4 Feb 2013 14:28:54 -0800 Subject: [PATCH] drivers/rtc/rtc-pl031.c: fix the missing operation on enable 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 08378e3cc21c..10c1a3454e48 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 */ @@ -320,7 +321,7 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id) struct pl031_local *ldata; struct pl031_vendor_data *vendor = id->data; struct rtc_class_ops *ops = &vendor->ops; - unsigned long time; + unsigned long time, data; ret = amba_request_regions(adev, NULL); if (ret) @@ -345,10 +346,11 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id) dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev)); dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev)); + data = readl(ldata->base + RTC_CR); /* Enable the clockwatch on ST Variants */ if (vendor->clockwatch) - 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 -- GitLab