linux-kernel - [PATCH v7 16/19] PM / devfreq: Add new interrupt

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Message-Id: <20191029220019.26773-17-digetx@gmail.com>
Date:   Wed, 30 Oct 2019 01:00:16 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Peter Geis <pgwipeout@...il.com>
Cc:     linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v7 16/19] PM / devfreq: Add new interrupt_driven flag for governors

Currently interrupt-driven governors (like NVIDIA Tegra30 ACTMON governor)
are used to set polling_ms=0 in order to avoid periodic polling of device
status by devfreq core. This means that polling interval can't be changed
by userspace for such governors.

The new governor flag allows interrupt-driven governors to convey that
devfreq core shouldn't perform polling of device status and thus generic
devfreq polling interval could be supported by these governors now.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/devfreq/devfreq.c  | 14 +++++++++-----
 drivers/devfreq/governor.h |  3 +++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index b905963cea7d..0ef972264841 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -410,7 +410,8 @@ static void devfreq_monitor(struct work_struct *work)
 void devfreq_monitor_start(struct devfreq *devfreq)
 {
 	INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
-	if (devfreq->profile->polling_ms)
+	if (devfreq->profile->polling_ms &&
+	    !devfreq->governor->interrupt_driven)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 }
@@ -474,7 +475,8 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 		goto out;
 
 	if (!delayed_work_pending(&devfreq->work) &&
-			devfreq->profile->polling_ms)
+			devfreq->profile->polling_ms &&
+				!devfreq->governor->interrupt_driven)
 		queue_delayed_work(devfreq_wq, &devfreq->work,
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
@@ -518,8 +520,9 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 
 	/* if current delay is zero, start polling with new delay */
 	if (!cur_delay) {
-		queue_delayed_work(devfreq_wq, &devfreq->work,
-			msecs_to_jiffies(devfreq->profile->polling_ms));
+		if (!devfreq->governor->interrupt_driven)
+			queue_delayed_work(devfreq_wq, &devfreq->work,
+				msecs_to_jiffies(devfreq->profile->polling_ms));
 		goto out;
 	}
 
@@ -528,7 +531,8 @@ void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay)
 		mutex_unlock(&devfreq->lock);
 		cancel_delayed_work_sync(&devfreq->work);
 		mutex_lock(&devfreq->lock);
-		if (!devfreq->stop_polling)
+		if (!devfreq->stop_polling &&
+		    !devfreq->governor->interrupt_driven)
 			queue_delayed_work(devfreq_wq, &devfreq->work,
 				msecs_to_jiffies(devfreq->profile->polling_ms));
 	}
diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
index bbe5ff9fcecf..dc7533ccc3db 100644
--- a/drivers/devfreq/governor.h
+++ b/drivers/devfreq/governor.h
@@ -31,6 +31,8 @@
  * @name:		Governor's name
  * @immutable:		Immutable flag for governor. If the value is 1,
  *			this govenror is never changeable to other governor.
+ * @interrupt_driven:	Devfreq core won't schedule polling work for this
+ *			governor if value is set to 1.
  * @get_target_freq:	Returns desired operating frequency for the device.
  *			Basically, get_target_freq will run
  *			devfreq_dev_profile.get_dev_status() to get the
@@ -49,6 +51,7 @@ struct devfreq_governor {
 
 	const char name[DEVFREQ_NAME_LEN];
 	const unsigned int immutable;
+	const unsigned int interrupt_driven;
 	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
 	int (*event_handler)(struct devfreq *devfreq,
 				unsigned int event, void *data);
-- 
2.23.0