* [PATCH v3] PM / devfreq: Add possible_frequencies device attribute
[not found] <725805840.101171405558256488.JavaMail.weblogic@epmlwas01c>
@ 2014-07-18 3:32 ` Saravana Kannan
2014-07-19 0:15 ` [PATCH v4] " Saravana Kannan
1 sibling, 0 replies; 3+ messages in thread
From: Saravana Kannan @ 2014-07-18 3:32 UTC (permalink / raw)
To: linux-arm-kernel
On 07/16/2014 05:50 PM, MyungJoo Ham wrote:
> On Wed, Jul 16, 2014 at 12:01 PM, Saravana Kannan <skannan@codeaurora.org> wrote:
>> 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>
>
> Hi,
>
>
> Please add a documentation entry for this new ABI having a little justification and usage included.
Will do.
>
> Plus, I am considering to move trans_stat along with this entry to somewhere such as .../stat/*
> (you don't need to take care of this.)
Ok.
>
> Besides, as OPP seems becoming the standard as imagined when devfreq development started,
> soon, devfreq may require OPP unless the devfreq device has continuous frequencies.
I agree. Only one caveat with OPP is that if a device isn't using OPP to
do any voltage scaling, then it forces a voltage column with 0s. Also,
even if we make OPP mandatory, we'll still want trans_stats that
currently seem to depend on freq_table being populated. I was actually
planning on sending out more patches later that'll do a lot of stuff
automatically for devices with OPP. Like creating freq_table, etc.
-Saravana
--
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^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v4] PM / devfreq: Add possible_frequencies device attribute
[not found] <725805840.101171405558256488.JavaMail.weblogic@epmlwas01c>
2014-07-18 3:32 ` [PATCH v3] PM / devfreq: Add possible_frequencies device attribute Saravana Kannan
@ 2014-07-19 0:15 ` Saravana Kannan
1 sibling, 0 replies; 3+ messages in thread
From: Saravana Kannan @ 2014-07-19 0:15 UTC (permalink / raw)
To: linux-arm-kernel
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
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
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