linux-kernel - [PATCH v2 4/8] PM / devfreq: Show the all available frequencies

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Date:   Thu, 21 Sep 2017 09:33:48 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     myungjoo.ham@...sung.com, kyungmin.park@...sung.com,
        cw00.choi@...sung.com
Cc:     rafael.j.wysocki@...el.com, chanwoo@...nel.org,
        inki.dae@...sung.com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/8] PM / devfreq: Show the all available frequencies

The commit a76caf55e5b35 ("thermal: Add devfreq cooling") allows
the devfreq device to use the cooling device. When the cooling down
are required, the devfreq_cooling.c disables the OPP entry with
the dev_pm_opp_disable(). In result, 'available_frequencies'[1]
sysfs node never came to show the all available frequencies.
[1] /sys/class/devfreq/.../available_frequencies

So, this patch uses the 'freq_table' in the 'struct devfreq_dev_profile'
in order to show the all available frequencies.
- If 'freq_table' is NULL, devfreq core initializes them by using OPP values.
- If 'freq_table' is initialized, devfreq core just uses the 'freq_table'.

Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
---
 drivers/devfreq/devfreq.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 799a0cf75d39..1c4b377cacfb 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1185,22 +1185,26 @@ static ssize_t available_frequencies_show(struct device *d,
 					  char *buf)
 {
 	struct devfreq *df = to_devfreq(d);
-	struct device *dev = df->dev.parent;
-	struct dev_pm_opp *opp;
 	ssize_t count = 0;
-	unsigned long freq = 0;
+	unsigned long *freq_table;
+	int i, max_state;
 
-	do {
-		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
-		if (IS_ERR(opp))
-			break;
+	mutex_lock(&df->lock);
 
-		dev_pm_opp_put(opp);
-		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-				   "%lu ", freq);
-		freq++;
-	} while (1);
+	freq_table = df->profile->freq_table;
+	max_state = df->profile->max_state;
 
+	if (freq_table[0] < freq_table[max_state - 1]) {
+		for (i = 0; i < max_state; i++)
+			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+					"%lu ", freq_table[i]);
+	} else {
+		for (i = max_state - 1; i >= 0 ; i--)
+			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+					"%lu ", freq_table[i]);
+	}
+
+	mutex_unlock(&df->lock);
 	/* Truncate the trailing space */
 	if (count)
 		count--;
-- 
1.9.1