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Blackfin RTC driver: the frequency function is in units of Hz, not units of seconds, so lock our driver down to 1 Hz 

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Frysinger 2008-02-06 01:38:47 -08:00 committed by Linus Torvalds
parent 8f26795a22
commit 5c236343eb
1 changed files with 17 additions and 7 deletions
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24
drivers/rtc/rtc-bfin.c
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@ -72,7 +72,7 @@ struct bfin_rtc {
#define SEC_BITS_OFF 0 #define SEC_BITS_OFF 0
/* Some helper functions to convert between the common RTC notion of time /* Some helper functions to convert between the common RTC notion of time
* and the internal Blackfin notion that is stored in 32bits. * and the internal Blackfin notion that is encoded in 32bits.
*/ */
static inline u32 rtc_time_to_bfin(unsigned long now) static inline u32 rtc_time_to_bfin(unsigned long now)
{ {
@ -112,6 +112,11 @@ static inline void rtc_bfin_to_tm(u32 rtc_bfin, struct rtc_time *tm)
* If anyone can point out the obvious solution here, i'm listening :). This * If anyone can point out the obvious solution here, i'm listening :). This
* shouldn't be an issue on an SMP or preempt system as this function should * shouldn't be an issue on an SMP or preempt system as this function should
* only be called with the rtc lock held. * only be called with the rtc lock held.
*
* Other options:
* - disable PREN so the sync happens at 32.768kHZ ... but this changes the
* inc rate for all RTC registers from 1HZ to 32.768kHZ ...
* - use the write complete IRQ
*/ */
static void rtc_bfin_sync_pending(void) static void rtc_bfin_sync_pending(void)
{ {
@ -356,12 +361,18 @@ static int bfin_rtc_proc(struct device *dev, struct seq_file *seq)
return 0; return 0;
} }
/**
* bfin_irq_set_freq - make sure hardware supports requested freq
* @dev: pointer to RTC device structure
* @freq: requested frequency rate
*
* The Blackfin RTC can only generate periodic events at 1 per
* second (1 Hz), so reject any attempt at changing it.
*/
static int bfin_irq_set_freq(struct device *dev, int freq) static int bfin_irq_set_freq(struct device *dev, int freq)
{ {
struct bfin_rtc *rtc = dev_get_drvdata(dev);
stampit(); stampit();
rtc->rtc_dev->irq_freq = freq; return -ENOTTY;
return 0;
} }
static struct rtc_class_ops bfin_rtc_ops = { static struct rtc_class_ops bfin_rtc_ops = {
@ -394,14 +405,13 @@ static int __devinit bfin_rtc_probe(struct platform_device *pdev)
ret = PTR_ERR(rtc->rtc_dev); ret = PTR_ERR(rtc->rtc_dev);
goto err; goto err;
} }
rtc->rtc_dev->irq_freq = 0; rtc->rtc_dev->irq_freq = 1;
rtc->rtc_dev->max_user_freq = (2 << 16); /* stopwatch is an unsigned 16 bit reg */
platform_set_drvdata(pdev, rtc); platform_set_drvdata(pdev, rtc);
return 0; return 0;
err: err:
kfree(rtc); kfree(rtc);
return ret; return ret;
} }