linux-kernel - [PATCH v2 2/3] devfreq: add clearing transitions stats

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Date:   Wed,  4 Dec 2019 16:00:17 +0100
From:   Kamil Konieczny <k.konieczny@...sung.com>
To:     k.konieczny@...sung.com
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Subject: [PATCH v2 2/3] devfreq: add clearing transitions stats

Add clearing transition table and time in states devfreq statistics
by writing to trans_stat file in devfreq sysfs.

Signed-off-by: Kamil Konieczny <k.konieczny@...sung.com>
---
Changes in v2:
 instead of creating new sysfs file, add new functionality to trans_stat
 and clear stats when anything is writen to it

 drivers/devfreq/devfreq.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 0e2030403e4a..901af3b66a76 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1478,7 +1478,27 @@ static ssize_t trans_stat_show(struct device *dev,
 					devfreq->total_trans);
 	return len;
 }
-static DEVICE_ATTR_RO(trans_stat);
+
+static ssize_t trans_stat_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct devfreq *df = to_devfreq(dev);
+	unsigned int cnt = df->profile->max_state;
+
+	if (cnt == 0)
+		return count;
+
+	mutex_lock(&df->lock);
+	memset(df->time_in_state, 0, cnt * sizeof(u64));
+	memset(df->trans_table, 0, cnt * cnt * sizeof(int));
+	df->last_stat_updated = get_jiffies_64();
+	df->total_trans = 0;
+	mutex_unlock(&df->lock);
+
+	return count;
+}
+static DEVICE_ATTR_RW(trans_stat);
 
 static struct attribute *devfreq_attrs[] = {
 	&dev_attr_name.attr,
-- 
2.24.0