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SubjectRe: platform/i2c busses: pm runtime and system sleep
On Thu, Feb 17, 2011 at 20:55, Rabin Vincent <rabin@rab.in> wrote:
> This will solve the platform vs AMBA bus, but shouldn't we really be
> aiming for consistent behaviour between these and the other busses such
> as I2C and SPI, which are also usually commonly used on the same
> platforms and are using GENERIC_PM_OPS?
>
> Should we be auditing all platform drivers and then switch platform to
> the GENERIC_PM_OPS?
>
> Or should the two points (1) and (2) be not handled in the bus at all
> and be left to individual drivers (in which case we should audit i2c and
> spi and change GENERIC_PM_OPS)?

How about something like the below? If we have something like this, we
can just switch platform to GENERIC_PM_OPS and add the
pm_runtime_want_interaction() (or something better named) call to the
i2c and spi drivers using runtime PM.

diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c
index 42f97f9..c2a3b63 100644
--- a/drivers/base/power/generic_ops.c
+++ b/drivers/base/power/generic_ops.c
@@ -87,7 +87,10 @@ static int __pm_generic_call(struct device *dev, int event)
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int (*callback)(struct device *);

- if (!pm || pm_runtime_suspended(dev))
+ if (!pm)
+ return 0;
+
+ if (device_want_interaction(dev) && pm_runtime_suspended(dev))
return 0;

switch (event) {
@@ -185,7 +188,7 @@ static int __pm_generic_resume(struct device *dev,
int event)
return 0;

ret = callback(dev);
- if (!ret && pm_runtime_enabled(dev)) {
+ if (!ret && device_want_interaction(dev) && pm_runtime_enabled(dev)) {
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 42615b4..2b8a099 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1069,6 +1069,30 @@ void pm_runtime_allow(struct device *dev)
EXPORT_SYMBOL_GPL(pm_runtime_allow);

/**
+ * pm_runtime_want_interaction - Enable interaction between system sleep
+ * and runtime PM callbacks at the bus/subsystem
+ * level.
+ * @dev: Device to handle
+ *
+ * Set the power.want_interaction flage, which tells the generic PM subsystem
+ * ops that the following actions should be done during system suspend/resume:
+ *
+ * - If the device has been runtime suspended, the driver's
+ * suspend() handler will not be invoked.
+ *
+ * - If the device has a resume() pm callback, and the resume()
+ * callback returns success on system resume, the device's
+ * runtime PM status will be set to active.
+ */
+void pm_runtime_want_interaction(struct device *dev)
+{
+ spin_lock_irq(&dev->power.lock);
+ dev->power.want_interaction = 1;
+ spin_unlock_irq(&dev->power.lock);
+}
+EXPORT_SYMBOL_GPL(pm_runtime_want_interaction);
+
+/**
* pm_runtime_no_callbacks - Ignore run-time PM callbacks for a device.
* @dev: Device to handle.
*
diff --git a/include/linux/pm.h b/include/linux/pm.h
index dd9c7ab..b9bcfb9 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -450,6 +450,7 @@ struct dev_pm_info {
unsigned int irq_safe:1;
unsigned int use_autosuspend:1;
unsigned int timer_autosuspends:1;
+ unsigned int want_interaction:1;
enum rpm_request request;
enum rpm_status runtime_status;
int runtime_error;
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index d34f067..a0e081b 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -44,6 +44,7 @@ extern void pm_runtime_irq_safe(struct device *dev);
extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);
extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev);
+static void pm_runtime_want_system_sleep_interaction(struct device *dev);

static inline bool pm_children_suspended(struct device *dev)
{
@@ -66,6 +67,11 @@ static inline void pm_runtime_put_noidle(struct device *dev)
atomic_add_unless(&dev->power.usage_count, -1, 0);
}

+static inline bool device_want_interaction(struct device *dev)
+{
+ return dev->power.want_interaction;
+}
+
static inline bool device_run_wake(struct device *dev)
{
return dev->power.run_wake;
@@ -122,6 +128,7 @@ static inline bool pm_children_suspended(struct
device *dev) { return false; }
static inline void pm_suspend_ignore_children(struct device *dev, bool en) {}
static inline void pm_runtime_get_noresume(struct device *dev) {}
static inline void pm_runtime_put_noidle(struct device *dev) {}
+static inline bool device_want_interaction(struct device *dev) {
return false; }
static inline bool device_run_wake(struct device *dev) { return false; }
static inline void device_set_run_wake(struct device *dev, bool enable) {}
static inline bool pm_runtime_suspended(struct device *dev) { return false; }
@@ -132,6 +139,7 @@ static inline int
pm_generic_runtime_suspend(struct device *dev) { return 0; }
static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
static inline void pm_runtime_no_callbacks(struct device *dev) {}
static inline void pm_runtime_irq_safe(struct device *dev) {}
+static inline void pm_runtime_want_system_sleep_interaction(struct
device *dev) {}

static inline void pm_runtime_mark_last_busy(struct device *dev) {}
static inline void __pm_runtime_use_autosuspend(struct device *dev,

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