Commit 0a89b553 authored by Wan ZongShun's avatar Wan ZongShun Committed by Linus Torvalds
Browse files

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: default avatarWan ZongShun <>
Cc: Alessandro Zummo <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 5fc79d85
......@@ -85,22 +85,21 @@ static irqreturn_t nuc900_rtc_interrupt(int irq, void *_rtc)
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);
__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--)
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,
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