This suspend/resume operations works analogous to the
cpufreq_{suspend,resume}() calls in the CPUFreq subsystem.
Signed-off-by: Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/devfreq.h | 10 ++++
2 files changed, 142 insertions(+)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 3904ebc..7e71c19 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -32,6 +32,8 @@ enum devfreq_flag_bits {
DEVFREQ_BIT_STOP_POLLING,
/* Bit set if DevFreq device was suspended in devfreq_suspend_device(). */
DEVFREQ_BIT_SUSPENDED,
+ /* Bit set if DevFreq device should be resumed in devfreq_resume(). */
+ DEVFREQ_BIT_RESUME,
};
static struct class *devfreq_class;
@@ -49,6 +51,8 @@ static LIST_HEAD(devfreq_governor_list);
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);
+static bool devfreq_suspended = false;
+
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device devfreq.
@@ -832,6 +836,9 @@ int devfreq_suspend_device(struct devfreq *devfreq)
if (!devfreq->governor)
return 0;
+ if (devfreq_suspended)
+ return -EBUSY;
+
ret = devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_SUSPEND, NULL);
@@ -860,6 +867,9 @@ int devfreq_resume_device(struct devfreq *devfreq)
if (!devfreq->governor)
return 0;
+ if (devfreq_suspended)
+ return -EBUSY;
+
ret = devfreq->governor->event_handler(devfreq,
DEVFREQ_GOV_RESUME, NULL);
@@ -871,6 +881,128 @@ int devfreq_resume_device(struct devfreq *devfreq)
EXPORT_SYMBOL(devfreq_resume_device);
/**
+ * devfreq_suspend() - Suspend DevFreq governors
+ *
+ * Called during system wide Suspend/Hibernate cycles for suspending governors
+ * in the same fashion as cpufreq_suspend().
+ */
+void devfreq_suspend(void)
+{
+ struct devfreq *devfreq;
+ struct devfreq_freqs freqs;
+ unsigned long freq;
+ int ret;
+
+ devfreq_suspended = true;
+
+ mutex_lock(&devfreq_list_lock);
+
+ /*
+ * Suspend all the devices that were not previously suspended through
+ * devfreq_suspend_device(). In devfreq_resume() we then resume exactly
+ * these devices.
+ */
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ if (test_bit(DEVFREQ_BIT_SUSPENDED, &devfreq->flags))
+ continue;
+
+ ret = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_SUSPEND, NULL);
+ if (ret < 0) {
+ dev_err(&devfreq->dev, "%s: governor suspend failed\n", __func__);
+ continue;
+ }
+
+ __set_bit(DEVFREQ_BIT_RESUME, &devfreq->flags);
+ }
+
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ if (!devfreq->suspend_freq)
+ continue;
+
+ if (devfreq->profile->get_cur_freq)
+ devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq);
+ else
+ freq = devfreq->previous_freq;
+
+ devfreq->resume_freq = freq;
+
+ freqs.old = devfreq->resume_freq;
+ freqs.new = devfreq->suspend_freq;
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
+
+ freq = devfreq->suspend_freq;
+ ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0);
+
+ if (ret < 0) {
+ dev_err(&devfreq->dev, "%s: setting suspend frequency failed\n", __func__);
+ freqs.new = devfreq->resume_freq;
+ devfreq->resume_freq = 0;
+ } else
+ freqs.new = freq;
+
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+ }
+
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_resume() - Resume DevFreq governors
+ *
+ * Called during system wide Suspend/Hibernate cycle for resuming governors that
+ * are suspended with devfreq_suspend().
+ */
+void devfreq_resume(void)
+{
+ struct devfreq *devfreq;
+ struct devfreq_freqs freqs;
+ unsigned long freq;
+ int ret;
+
+ mutex_lock(&devfreq_list_lock);
+
+ /*
+ * If a suspend OPP was set during devfreq_suspend(), then try to
+ * restore the DevFreq here to the original OPP.
+ */
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ if (!devfreq->resume_freq)
+ continue;
+
+ freqs.old = devfreq->suspend_freq;
+ freqs.new = devfreq->resume_freq;
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
+
+ freq = devfreq->resume_freq;
+ ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0);
+
+ if (ret < 0) {
+ dev_err(&devfreq->dev, "%s: setting resume frequency failed\n", __func__);
+ freqs.new = devfreq->suspend_freq;
+ } else
+ freqs.new = freq;
+
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+ devfreq->resume_freq = 0;
+ }
+
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ if (!test_bit(DEVFREQ_BIT_RESUME, &devfreq->flags))
+ continue;
+
+ ret = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_RESUME, NULL);
+ if (ret < 0)
+ dev_err(&devfreq->dev, "%s: governor resume failed\n", __func__);
+
+ __clear_bit(DEVFREQ_BIT_RESUME, &devfreq->flags);
+ }
+
+ mutex_unlock(&devfreq_list_lock);
+
+ devfreq_suspended = false;
+}
+
+/**
* devfreq_add_governor() - Add devfreq governor
* @governor: the devfreq governor to be added
*/
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index d6bf9a3..a98fa0f 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -173,6 +173,9 @@ struct devfreq {
unsigned int turbo_refcount;
+ unsigned long suspend_freq; /* freq during devfreq suspend */
+ unsigned long resume_freq; /* freq restored after suspend cycle */
+
unsigned long previous_freq;
struct devfreq_dev_status last_status;
@@ -216,6 +219,10 @@ extern int devfreq_turbo_put(struct devfreq *devfreq);
extern int devfreq_suspend_device(struct devfreq *devfreq);
extern int devfreq_resume_device(struct devfreq *devfreq);
+/* Suspend/resume the entire Devfreq subsystem. */
+void devfreq_suspend(void);
+void devfreq_resume(void);
+
/* Helper functions for devfreq user device driver with OPP. */
extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
unsigned long *freq, u32 flags);
@@ -425,6 +432,9 @@ static inline int devfreq_update_stats(struct devfreq *df)
{
return -EINVAL;
}
+
+static inline void devfreq_suspend(void) {}
+static inline void devfreq_resume(void) {}
#endif /* CONFIG_PM_DEVFREQ */
#endif /* __LINUX_DEVFREQ_H__ */
--
2.7.3
--
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