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Subject[PATCH v4] PM / devfreq: Add possible_frequencies device attribute
Date
Some devices use freq_table instead of OPP. For those devices, the
available_frequencies sysfs file shows up empty. So, add a
possible_frequencies attribute/syfs file that list all the possible
frequencies.

For devices that use OPP, the output of this file will match
available_frequencies. It may change in the future to show all OPP
frequencies -- even the disabled ones.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
---
Documentation/ABI/testing/sysfs-class-devfreq | 15 +++++++++++++++
drivers/devfreq/devfreq.c | 26 ++++++++++++++++++++++++++
2 files changed, 41 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index ee39aca..a461e67 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -72,6 +72,21 @@ Description:
This is a snapshot of available frequencies and not limited
by the min/max frequency restrictions.

+What: /sys/class/devfreq/.../possible_frequencies
+Date: July 2014
+Contact: Saravana Kannan <skannan@codeaurora.org>
+Description:
+ The /sys/class/devfreq/.../possible_frequencies shows
+ the possible frequencies of the corresponding devfreq object.
+ This is a snapshot of possible frequencies and not limited by
+ the min/max frequency restrictions. Unlike
+ available_frequencies, this is also does not require the
+ devfreq device to use OPP for listing its possible
+ frequencies. When OPP is used, this behaves the same way as
+ available_frequencies. It maybe improved in the future to
+ list all possible OPP frequencies even if some of them are
+ disabled at run-time.
+
What: /sys/class/devfreq/.../available_governors
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 9f90369..65eed38 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -994,6 +994,31 @@ static ssize_t available_frequencies_show(struct device *d,
}
static DEVICE_ATTR_RO(available_frequencies);

+static ssize_t possible_frequencies_show(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(d);
+ unsigned int i = 0;
+ ssize_t count = 0;
+
+ if (!df->profile->freq_table)
+ return available_frequencies_show(d, attr, buf);
+
+ for (i = 0; i < df->profile->max_state; i++)
+ count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+ "%u ", df->profile->freq_table[i]);
+
+ /* Truncate the trailing space */
+ if (count)
+ count--;
+
+ count += sprintf(&buf[count], "\n");
+
+ return count;
+}
+static DEVICE_ATTR_RO(possible_frequencies);
+
static ssize_t trans_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1041,6 +1066,7 @@ static struct attribute *devfreq_attrs[] = {
&dev_attr_available_governors.attr,
&dev_attr_cur_freq.attr,
&dev_attr_available_frequencies.attr,
+ &dev_attr_possible_frequencies.attr,
&dev_attr_target_freq.attr,
&dev_attr_polling_interval.attr,
&dev_attr_min_freq.attr,
--
1.8.2.1
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