From 0a89b55364e0a4fd4be9bc2c9a697f9b027eb395 Mon Sep 17 00:00:00 2001 From: Wan ZongShun Date: Tue, 10 Aug 2010 18:02:05 -0700 Subject: [PATCH] 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 Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-nuc900.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/rtc/rtc-nuc900.c b/drivers/rtc/rtc-nuc900.c index a351bd5d8176..21d13309fb20 100644 --- a/drivers/rtc/rtc-nuc900.c +++ b/drivers/rtc/rtc-nuc900.c @@ -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); 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, -- 2.20.1