Merge tag 'md/3.17' of git://neil.brown.name/md

[cascardo/linux.git] / Documentation / cpu-freq / core.txt

diff --git a/Documentation/cpu-freq/core.txt b/Documentation/cpu-freq/core.txt
index 0060d76..70933ea 100644 (file)
--- a/Documentation/cpu-freq/core.txt
+++ b/Documentation/cpu-freq/core.txt
@@ -20,6 +20,7 @@ Contents:
 ---------
 1.  CPUFreq core and interfaces
 2.  CPUFreq notifiers
+3.  CPUFreq Table Generation with Operating Performance Point (OPP)
 
 1. General Information
 =======================
@@ -92,3 +93,31 @@ values:
 cpu    - number of the affected CPU
 old    - old frequency
 new    - new frequency
+
+3. CPUFreq Table Generation with Operating Performance Point (OPP)
+==================================================================
+For details about OPP, see Documentation/power/opp.txt
+
+dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
+       cpufreq_frequency_table_cpuinfo which is provided with the list of
+       frequencies that are available for operation. This function provides
+       a ready to use conversion routine to translate the OPP layer's internal
+       information about the available frequencies into a format readily
+       providable to cpufreq.
+
+       WARNING: Do not use this function in interrupt context.
+
+       Example:
+        soc_pm_init()
+        {
+               /* Do things */
+               r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
+               if (!r)
+                       cpufreq_frequency_table_cpuinfo(policy, freq_table);
+               /* Do other things */
+        }
+
+       NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
+       addition to CONFIG_PM_OPP.
+
+dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table