Re: [PATCH v4 07/20] PM / devfreq: Show the related information according to governor type

From: MyungJoo Ham <myungjoo.ham@samsung.com>
Date: 2015-12-14 09:49:55
Also in: linux-pm, linux-samsung-soc, lkml

  
 This patch modifies the following sysfs entry of DEVFREQ framework
because the devfreq device using passive governor don't need the same
information of the devfreq device using rest governor.
- polling_interval    : passive gov don't use the sampling rate.
- available_governors : passive gov don't be changed on runtime in this version.
- trans_stat          : passive governor don't support trans_stat in this version.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
[linux.amoon: Tested on Odroid U3]
Tested-by: Anand Moon <redacted>
You have a major update that is not mendtioned in the commit message.
(add governor "type")
quoted hunk
---
 drivers/devfreq/devfreq.c                 | 31 +++++++++++++++++++++++++------
 drivers/devfreq/governor.h                |  7 +++++++
 drivers/devfreq/governor_passive.c        |  1 +
 drivers/devfreq/governor_performance.c    |  1 +
 drivers/devfreq/governor_powersave.c      |  1 +
 drivers/devfreq/governor_simpleondemand.c |  1 +
 drivers/devfreq/governor_userspace.c      |  1 +
 include/linux/devfreq.h                   |  2 ++
 8 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 78ea4cdaa82c..18ad956fec93 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -597,7 +597,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_init;
 	}
 
-	if (!strncmp(devfreq->governor_name, "passive", 7)) {
+	if (devfreq->governor->type == DEVFREQ_GOV_PASSIVE) {
 		struct devfreq *parent_devfreq =
 			((struct devfreq_passive_data *)data)->parent;
As mentioned in a previous reply, this code may be removed.
quoted hunk
 
@@ -963,13 +963,23 @@ static ssize_t available_governors_show(struct device *d,
 					struct device_attribute *attr,
 					char *buf)
 {
-	struct devfreq_governor *tmp_governor;
+	struct devfreq *devfreq = to_devfreq(d);
 	ssize_t count = 0;
 
 	mutex_lock(&devfreq_list_lock);
-	list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
+	if (devfreq->governor->type == DEVFREQ_GOV_PASSIVE) {
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				   "%s ", tmp_governor->name);
+					   "%s ", devfreq->governor->name);
+	} else {
+		struct devfreq_governor *tmp_governor;
+
+		list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
+			if (tmp_governor->type == DEVFREQ_GOV_PASSIVE)
+				continue;
+			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+					   "%s ", tmp_governor->name);
+		}
+	}
Uh no. As long as we do not have a list of all possible governors
for each device, let's stick with what we've defined in ABI documentation:
show all available governors "in the system".

You MAY have a device that may run both PASSIVE and USERSPACE.
quoted hunk
 	mutex_unlock(&devfreq_list_lock);
 
 	/* Truncate the trailing space */
@@ -1006,6 +1016,11 @@ static DEVICE_ATTR_RO(target_freq);
 static ssize_t polling_interval_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
+	struct devfreq *df = to_devfreq(dev);
+
+	if (df->governor->type == DEVFREQ_GOV_PASSIVE)
+		return sprintf(buf, "Not Supported.\n");
+
 	return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms);
 }
When polling interval is irrlevent with the governor,
you don't need to print "Not Supported". Instead,
printing "0" is enough, (polling_ms=0 == no polling)
which is what devfreq is doing now.
quoted hunk
 
@@ -1020,6 +1035,9 @@ static ssize_t polling_interval_store(struct device *dev,
 	if (!df->governor)
 		return -EINVAL;
 
+	if (df->governor->type == DEVFREQ_GOV_PASSIVE)
+		return -EINVAL;
+
Please simply return -EINVAL with governor's event_handler with DEVFREQ_GOV_INTERVAL
(I see the return value checking is missing at df->governor->event_handler().
You may want to add return value checking there to properly handle what you want.)
quoted hunk
 	ret = sscanf(buf, "%u", &value);
 	if (ret != 1)
 		return -EINVAL;
@@ -1137,11 +1155,12 @@ static ssize_t trans_stat_show(struct device *dev,
 	int i, j;
 	unsigned int max_state = devfreq->profile->max_state;
 
+	if (max_state == 0 || devfreq->governor->type == DEVFREQ_GOV_PASSIVE)
+		return sprintf(buf, "Not Supported.\n");
+
 	if (!devfreq->stop_polling &&
 			devfreq_update_status(devfreq, devfreq->previous_freq))
 		return 0;
-	if (max_state == 0)
-		return sprintf(buf, "Not Supported.\n");
We have no reason to always disable this for PASSIVE.
quoted hunk
 
 	len = sprintf(buf, "     From  :   To\n");
 	len += sprintf(buf + len, "           :");
diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
index fad7d6321978..43513a58f5bf 100644
--- a/drivers/devfreq/governor.h
+++ b/drivers/devfreq/governor.h
@@ -18,6 +18,13 @@
 
 #define to_devfreq(DEV)	container_of((DEV), struct devfreq, dev)
 
+/* Devfreq governor type */
+#define DEVFREQ_GOV_ONDEMAND			0x1
+#define DEVFREQ_GOV_PERFORMANCE			0x2
+#define DEVFREQ_GOV_POWERSAVE			0x3
+#define DEVFREQ_GOV_USERSPACE			0x4
+#define DEVFREQ_GOV_PASSIVE			0x4
Uh.. both USERSPACE AND PASSIVE are 0x4?

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