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drivers/rtc/rtc-s3c.c: support clock gating
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Add support for clock gating.  Power consumption can be reduced by setting
rtc_clk disabled state except for when RTC related registers are accessed.

Signed-off-by: Donggeun Kim <dg77.kim@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: KyungMin Park <kyungmin.park@samsung.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ben Dooks <ben@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Donggeun Kim authored and Linus Torvalds committed Jul 26, 2011
1 parent 955dbea commit cefe4fb
Showing 1 changed file with 26 additions and 1 deletion.
27 changes: 26 additions & 1 deletion drivers/rtc/rtc-s3c.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,23 +57,27 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
{
struct rtc_device *rdev = id;

clk_enable(rtc_clk);
rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);

if (s3c_rtc_cpu_type == TYPE_S3C64XX)
writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);

clk_disable(rtc_clk);
return IRQ_HANDLED;
}

static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
{
struct rtc_device *rdev = id;

clk_enable(rtc_clk);
rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);

if (s3c_rtc_cpu_type == TYPE_S3C64XX)
writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);

clk_disable(rtc_clk);
return IRQ_HANDLED;
}

Expand All @@ -84,12 +88,14 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)

pr_debug("%s: aie=%d\n", __func__, enabled);

clk_enable(rtc_clk);
tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;

if (enabled)
tmp |= S3C2410_RTCALM_ALMEN;

writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);
clk_disable(rtc_clk);

return 0;
}
Expand All @@ -103,6 +109,7 @@ static int s3c_rtc_setfreq(struct device *dev, int freq)
if (!is_power_of_2(freq))
return -EINVAL;

clk_enable(rtc_clk);
spin_lock_irq(&s3c_rtc_pie_lock);

if (s3c_rtc_cpu_type == TYPE_S3C2410) {
Expand All @@ -114,6 +121,7 @@ static int s3c_rtc_setfreq(struct device *dev, int freq)

writel(tmp, s3c_rtc_base + S3C2410_TICNT);
spin_unlock_irq(&s3c_rtc_pie_lock);
clk_disable(rtc_clk);

return 0;
}
Expand All @@ -125,6 +133,7 @@ static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
unsigned int have_retried = 0;
void __iomem *base = s3c_rtc_base;

clk_enable(rtc_clk);
retry_get_time:
rtc_tm->tm_min = readb(base + S3C2410_RTCMIN);
rtc_tm->tm_hour = readb(base + S3C2410_RTCHOUR);
Expand Down Expand Up @@ -157,6 +166,7 @@ static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
rtc_tm->tm_year += 100;
rtc_tm->tm_mon -= 1;

clk_disable(rtc_clk);
return rtc_valid_tm(rtc_tm);
}

Expand All @@ -165,6 +175,7 @@ static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
void __iomem *base = s3c_rtc_base;
int year = tm->tm_year - 100;

clk_enable(rtc_clk);
pr_debug("set time %04d.%02d.%02d %02d:%02d:%02d\n",
1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
Expand All @@ -182,6 +193,7 @@ static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
writeb(bin2bcd(tm->tm_mday), base + S3C2410_RTCDATE);
writeb(bin2bcd(tm->tm_mon + 1), base + S3C2410_RTCMON);
writeb(bin2bcd(year), base + S3C2410_RTCYEAR);
clk_disable(rtc_clk);

return 0;
}
Expand All @@ -192,6 +204,7 @@ static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
void __iomem *base = s3c_rtc_base;
unsigned int alm_en;

clk_enable(rtc_clk);
alm_tm->tm_sec = readb(base + S3C2410_ALMSEC);
alm_tm->tm_min = readb(base + S3C2410_ALMMIN);
alm_tm->tm_hour = readb(base + S3C2410_ALMHOUR);
Expand Down Expand Up @@ -243,6 +256,7 @@ static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
else
alm_tm->tm_year = -1;

clk_disable(rtc_clk);
return 0;
}

Expand All @@ -252,6 +266,7 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
void __iomem *base = s3c_rtc_base;
unsigned int alrm_en;

clk_enable(rtc_clk);
pr_debug("s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
alrm->enabled,
1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
Expand Down Expand Up @@ -282,13 +297,15 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)

s3c_rtc_setaie(dev, alrm->enabled);

clk_disable(rtc_clk);
return 0;
}

static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned int ticnt;

clk_enable(rtc_clk);
if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);
ticnt &= S3C64XX_RTCCON_TICEN;
Expand All @@ -298,6 +315,7 @@ static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
}

seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt ? "yes" : "no");
clk_disable(rtc_clk);
return 0;
}

Expand Down Expand Up @@ -360,6 +378,7 @@ static void s3c_rtc_enable(struct platform_device *pdev, int en)
if (s3c_rtc_base == NULL)
return;

clk_enable(rtc_clk);
if (!en) {
tmp = readw(base + S3C2410_RTCCON);
if (s3c_rtc_cpu_type == TYPE_S3C64XX)
Expand Down Expand Up @@ -399,6 +418,7 @@ static void s3c_rtc_enable(struct platform_device *pdev, int en)
base + S3C2410_RTCCON);
}
}
clk_disable(rtc_clk);
}

static int __devexit s3c_rtc_remove(struct platform_device *dev)
Expand All @@ -410,7 +430,6 @@ static int __devexit s3c_rtc_remove(struct platform_device *dev)

s3c_rtc_setaie(&dev->dev, 0);

clk_disable(rtc_clk);
clk_put(rtc_clk);
rtc_clk = NULL;

Expand Down Expand Up @@ -530,6 +549,8 @@ static int __devinit s3c_rtc_probe(struct platform_device *pdev)

s3c_rtc_setfreq(&pdev->dev, 1);

clk_disable(rtc_clk);

return 0;

err_nortc:
Expand All @@ -555,6 +576,7 @@ static int ticnt_save, ticnt_en_save;

static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
clk_enable(rtc_clk);
/* save TICNT for anyone using periodic interrupts */
ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);
if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
Expand All @@ -569,6 +591,7 @@ static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)
else
dev_err(&pdev->dev, "enable_irq_wake failed\n");
}
clk_disable(rtc_clk);

return 0;
}
Expand All @@ -577,6 +600,7 @@ static int s3c_rtc_resume(struct platform_device *pdev)
{
unsigned int tmp;

clk_enable(rtc_clk);
s3c_rtc_enable(pdev, 1);
writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
if (s3c_rtc_cpu_type == TYPE_S3C64XX && ticnt_en_save) {
Expand All @@ -588,6 +612,7 @@ static int s3c_rtc_resume(struct platform_device *pdev)
disable_irq_wake(s3c_rtc_alarmno);
wake_en = false;
}
clk_disable(rtc_clk);

return 0;
}
Expand Down

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