nuc900/rtc: change the waiting for device ready implement
- add an mdelay(1) to the polling loop to cause less frequent access to
the hardware register.
- change the return value from ENODEV to EPERM if the loop timed out. I
think the 'Operation not permitted' description is more suitable for the
meaning of 'check_rtc_access_enable()' function, it just be used to
judge rtc access operation is permitted or not.
Signed-off-by: Wan ZongShun <mcuos.com@gmail.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>
diff --git a/drivers/rtc/rtc-nuc900.c b/drivers/rtc/rtc-nuc900.c
index a351bd5..21d1330 100644
--- a/drivers/rtc/rtc-nuc900.c
+++ b/drivers/rtc/rtc-nuc900.c
@@ -85,22 +85,21 @@
static int *check_rtc_access_enable(struct nuc900_rtc *nuc900_rtc)
{
- unsigned int i;
+ unsigned int i, timeout = 0x1000;
__raw_writel(INIRRESET, nuc900_rtc->rtc_reg + REG_RTC_INIR);
mdelay(10);
__raw_writel(AERPOWERON, nuc900_rtc->rtc_reg + REG_RTC_AER);
- for (i = 0; i < 1000; i++) {
- if (__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_AER) & AERRWENB)
- return 0;
- }
+ while (!(__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_AER) & AERRWENB)
+ && timeout--)
+ mdelay(1);
- if ((__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_AER) & AERRWENB) == 0x0)
- return ERR_PTR(-ENODEV);
+ if (!timeout)
+ return ERR_PTR(-EPERM);
- return ERR_PTR(-EPERM);
+ return 0;
}
static void nuc900_rtc_bcd2bin(unsigned int timereg,