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 <skan...@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 <skan...@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 <n...@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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