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RTC: sa1100: Update the sa1100 RTC driver.
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Since PIE interrupts are now emulated, this patch removes the previous
code that used the hardware counters.

The removal of read_callback() also fixes a wrong user space behaviour
of this driver, which was not returning the right value to read().

[john.stultz: Merge fixups]

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
CC: rtc-linux@googlegroups.com
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Marcelo Roberto Jimenez authored and John Stultz committed Mar 9, 2011
1 parent a417493 commit 416f0e8
Showing 1 changed file with 3 additions and 108 deletions.
111 changes: 3 additions & 108 deletions drivers/rtc/rtc-sa1100.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,6 @@
#define RTC_DEF_TRIM 0

static const unsigned long RTC_FREQ = 1024;
static unsigned long timer_freq;
static struct rtc_time rtc_alarm;
static DEFINE_SPINLOCK(sa1100_rtc_lock);

Expand Down Expand Up @@ -156,97 +155,11 @@ static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

static int sa1100_irq_set_freq(struct device *dev, int freq)
{
if (freq < 1 || freq > timer_freq) {
return -EINVAL;
} else {
struct rtc_device *rtc = (struct rtc_device *)dev;

rtc->irq_freq = freq;

return 0;
}
}

static int rtc_timer1_count;

static inline int sa1100_timer1_retrigger(struct rtc_device *rtc)
{
unsigned long diff;
unsigned long period = timer_freq / rtc->irq_freq;

spin_lock_irq(&sa1100_rtc_lock);

do {
OSMR1 += period;
diff = OSMR1 - OSCR;
/* If OSCR > OSMR1, diff is a very large number (unsigned
* math). This means we have a lost interrupt. */
} while (diff > period);
OIER |= OIER_E1;

spin_unlock_irq(&sa1100_rtc_lock);

return 0;
}

static irqreturn_t timer1_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = to_platform_device(dev_id);
struct rtc_device *rtc = platform_get_drvdata(pdev);

/*
* If we match for the first time, rtc_timer1_count will be 1.
* Otherwise, we wrapped around (very unlikely but
* still possible) so compute the amount of missed periods.
* The match reg is updated only when the data is actually retrieved
* to avoid unnecessary interrupts.
*/
OSSR = OSSR_M1; /* clear match on timer1 */

rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF);

if (rtc_timer1_count == 1)
rtc_timer1_count =
(rtc->irq_freq * ((1 << 30) / (timer_freq >> 2)));

/* retrigger. */
sa1100_timer1_retrigger(rtc);

return IRQ_HANDLED;
}

static int sa1100_rtc_read_callback(struct device *dev, int data)
{
if (data & RTC_PF) {
struct rtc_device *rtc = (struct rtc_device *)dev;

/* interpolate missed periods and set match for the next */
unsigned long period = timer_freq / rtc->irq_freq;
unsigned long oscr = OSCR;
unsigned long osmr1 = OSMR1;
unsigned long missed = (oscr - osmr1)/period;
data += missed << 8;
OSSR = OSSR_M1; /* clear match on timer 1 */
OSMR1 = osmr1 + (missed + 1)*period;
/* Ensure we didn't miss another match in the mean time.
* Here we compare (match - OSCR) 8 instead of 0 --
* see comment in pxa_timer_interrupt() for explanation.
*/
while ((signed long)((osmr1 = OSMR1) - OSCR) <= 8) {
data += 0x100;
OSSR = OSSR_M1; /* clear match on timer 1 */
OSMR1 = osmr1 + period;
}
}
return data;
}

static int sa1100_rtc_open(struct device *dev)
{
int ret;
struct rtc_device *rtc = (struct rtc_device *)dev;
struct platform_device *plat_dev = to_platform_device(dev);
struct rtc_device *rtc = platform_get_drvdata(plat_dev);

ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED,
"rtc 1Hz", dev);
Expand All @@ -260,19 +173,11 @@ static int sa1100_rtc_open(struct device *dev)
dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
goto fail_ai;
}
ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED,
"rtc timer", dev);
if (ret) {
dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1);
goto fail_pi;
}
rtc->max_user_freq = RTC_FREQ;
sa1100_irq_set_freq(dev, RTC_FREQ);
rtc_irq_set_freq(rtc, NULL, RTC_FREQ);

return 0;

fail_pi:
free_irq(IRQ_RTCAlrm, dev);
fail_ai:
free_irq(IRQ_RTC1Hz, dev);
fail_ui:
Expand All @@ -287,12 +192,10 @@ static void sa1100_rtc_release(struct device *dev)
OSSR = OSSR_M1;
spin_unlock_irq(&sa1100_rtc_lock);

free_irq(IRQ_OST1, dev);
free_irq(IRQ_RTCAlrm, dev);
free_irq(IRQ_RTC1Hz, dev);
}


static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
spin_lock_irq(&sa1100_rtc_lock);
Expand Down Expand Up @@ -359,7 +262,6 @@ static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)

static const struct rtc_class_ops sa1100_rtc_ops = {
.open = sa1100_rtc_open,
.read_callback = sa1100_rtc_read_callback,
.release = sa1100_rtc_release,
.read_time = sa1100_rtc_read_time,
.set_time = sa1100_rtc_set_time,
Expand All @@ -373,8 +275,6 @@ static int sa1100_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;

timer_freq = get_clock_tick_rate();

/*
* According to the manual we should be able to let RTTR be zero
* and then a default diviser for a 32.768KHz clock is used.
Expand All @@ -400,11 +300,6 @@ static int sa1100_rtc_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, rtc);

/* Set the irq_freq */
/*TODO: Find out who is messing with this value after we initialize
* it here.*/
rtc->irq_freq = RTC_FREQ;

/* Fix for a nasty initialization problem the in SA11xx RTSR register.
* See also the comments in sa1100_rtc_interrupt().
*
Expand Down

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