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Subject[PATCH 12/15] sh: TMU: Basic runtime PM support
Date

Modify the SH TMU clock source/clock event device driver to support
runtime PM at a basic level (i.e. device clocks can be disabled and
enabled, but domain power must be on, because the devices have to
be marked as "irq safe").

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
drivers/clocksource/sh_tmu.c | 80 ++++++++++++++++++++++++++++++++++---------
1 file changed, 65 insertions(+), 15 deletions(-)

Index: linux/drivers/clocksource/sh_tmu.c
===================================================================
--- linux.orig/drivers/clocksource/sh_tmu.c
+++ linux/drivers/clocksource/sh_tmu.c
@@ -45,6 +45,7 @@ struct sh_tmu_priv {
struct clock_event_device ced;
struct clocksource cs;
bool cs_enabled;
+ unsigned int enable_count;
};

static DEFINE_RAW_SPINLOCK(sh_tmu_lock);
@@ -109,7 +110,7 @@ static void sh_tmu_start_stop_ch(struct
raw_spin_unlock_irqrestore(&sh_tmu_lock, flags);
}

-static int sh_tmu_enable(struct sh_tmu_priv *p)
+static int __sh_tmu_enable(struct sh_tmu_priv *p)
{
int ret;

@@ -137,7 +138,18 @@ static int sh_tmu_enable(struct sh_tmu_p
return 0;
}

-static void sh_tmu_disable(struct sh_tmu_priv *p)
+static int sh_tmu_enable(struct sh_tmu_priv *p)
+{
+ if (p->enable_count++ > 0)
+ return 0;
+
+ pm_runtime_get_sync(&p->pdev->dev);
+ dev_pm_syscore_device(&p->pdev->dev, true);
+
+ return __sh_tmu_enable(p);
+}
+
+static void __sh_tmu_disable(struct sh_tmu_priv *p)
{
/* disable channel */
sh_tmu_start_stop_ch(p, 0);
@@ -149,6 +161,20 @@ static void sh_tmu_disable(struct sh_tmu
clk_disable(p->clk);
}

+static void sh_tmu_disable(struct sh_tmu_priv *p)
+{
+ if (WARN_ON(p->enable_count == 0))
+ return;
+
+ if (--p->enable_count > 0)
+ return;
+
+ __sh_tmu_disable(p);
+
+ dev_pm_syscore_device(&p->pdev->dev, false);
+ pm_runtime_put(&p->pdev->dev);
+}
+
static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
int periodic)
{
@@ -205,11 +231,15 @@ static int sh_tmu_clocksource_enable(str
struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
int ret;

+ if (WARN_ON(p->cs_enabled))
+ return 0;
+
ret = sh_tmu_enable(p);
if (!ret) {
__clocksource_updatefreq_hz(cs, p->rate);
p->cs_enabled = true;
}
+
return ret;
}

@@ -217,7 +247,8 @@ static void sh_tmu_clocksource_disable(s
{
struct sh_tmu_priv *p = cs_to_sh_tmu(cs);

- WARN_ON(!p->cs_enabled);
+ if (WARN_ON(!p->cs_enabled))
+ return;

sh_tmu_disable(p);
p->cs_enabled = false;
@@ -227,19 +258,26 @@ static void sh_tmu_clocksource_suspend(s
{
struct sh_tmu_priv *p = cs_to_sh_tmu(cs);

- if (p->cs_enabled)
- sh_tmu_disable(p);
+ if (!p->cs_enabled)
+ return;

- pm_genpd_syscore_poweroff(&p->pdev->dev);
+ if (--p->enable_count == 0) {
+ __sh_tmu_disable(p);
+ pm_genpd_syscore_poweroff(&p->pdev->dev);
+ }
}

static void sh_tmu_clocksource_resume(struct clocksource *cs)
{
struct sh_tmu_priv *p = cs_to_sh_tmu(cs);

- pm_genpd_syscore_poweron(&p->pdev->dev);
- if (p->cs_enabled)
- sh_tmu_enable(p);
+ if (!p->cs_enabled)
+ return;
+
+ if (p->enable_count++ == 0) {
+ pm_genpd_syscore_poweron(&p->pdev->dev);
+ __sh_tmu_enable(p);
+ }
}

static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
@@ -434,6 +472,8 @@ static int sh_tmu_setup(struct sh_tmu_pr
ret = PTR_ERR(p->clk);
goto err1;
}
+ p->cs_enabled = false;
+ p->enable_count = 0;

return sh_tmu_register(p, (char *)dev_name(&p->pdev->dev),
cfg->clockevent_rating,
@@ -447,18 +487,17 @@ static int sh_tmu_setup(struct sh_tmu_pr
static int __devinit sh_tmu_probe(struct platform_device *pdev)
{
struct sh_tmu_priv *p = platform_get_drvdata(pdev);
+ struct sh_timer_config *cfg = pdev->dev.platform_data;
int ret;

if (!is_early_platform_device(pdev)) {
- struct sh_timer_config *cfg = pdev->dev.platform_data;
-
- if (cfg->clocksource_rating || cfg->clockevent_rating)
- dev_pm_syscore_device(&pdev->dev, true);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
}

if (p) {
dev_info(&pdev->dev, "kept as earlytimer\n");
- return 0;
+ goto out;
}

p = kmalloc(sizeof(*p), GFP_KERNEL);
@@ -471,8 +510,19 @@ static int __devinit sh_tmu_probe(struct
if (ret) {
kfree(p);
platform_set_drvdata(pdev, NULL);
+ pm_runtime_idle(&pdev->dev);
+ return ret;
}
- return ret;
+ if (is_early_platform_device(pdev))
+ return 0;
+
+ out:
+ if (cfg->clockevent_rating || cfg->clocksource_rating)
+ pm_runtime_irq_safe(&pdev->dev);
+ else
+ pm_runtime_idle(&pdev->dev);
+
+ return 0;
}

static int __devexit sh_tmu_remove(struct platform_device *pdev)


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