Commit d941effa authored by Dave Jones's avatar Dave Jones

[CPUFREQ] update Documentation

- the path to sysfs changed
- add the cpufreq_driver.owner requirement
- clarify another paragraph
parent 5fa458f6
...@@ -41,16 +41,17 @@ on what is necessary: ...@@ -41,16 +41,17 @@ on what is necessary:
1.1 Initialization 1.1 Initialization
------------------ ------------------
First of all, in an __initcall level 7 or later (preferrably First of all, in an __initcall level 7 (module_init()) or later
module_init() so that your driver is modularized) function check function check whether this kernel runs on the right CPU and the right
whether this kernel runs on the right CPU and the right chipset. If chipset. If so, register a struct cpufreq_driver with the CPUfreq core
so, register a struct cpufreq_driver with the CPUfreq core using using cpufreq_register_driver()
cpufreq_register_driver()
What shall this struct cpufreq_driver contain? What shall this struct cpufreq_driver contain?
cpufreq_driver.name - The name of this driver. cpufreq_driver.name - The name of this driver.
cpufreq_driver.owner - THIS_MODULE;
cpufreq_driver.init - A pointer to the per-CPU initialization cpufreq_driver.init - A pointer to the per-CPU initialization
function. function.
...@@ -76,8 +77,7 @@ cpufreq driver registers itself, the per-CPU initialization function ...@@ -76,8 +77,7 @@ cpufreq driver registers itself, the per-CPU initialization function
cpufreq_driver.init is called. It takes a struct cpufreq_policy cpufreq_driver.init is called. It takes a struct cpufreq_policy
*policy as argument. What to do now? *policy as argument. What to do now?
If necessary, activate the CPUfreq support on your CPU (unlock that If necessary, activate the CPUfreq support on your CPU.
register etc.).
Then, the driver must fill in the following values: Then, the driver must fill in the following values:
......
...@@ -132,7 +132,7 @@ the processor shall run at. ...@@ -132,7 +132,7 @@ the processor shall run at.
The preferred interface is located in the sysfs filesystem. If you The preferred interface is located in the sysfs filesystem. If you
mounted it at /sys, the cpufreq interface is located in a subdirectory mounted it at /sys, the cpufreq interface is located in a subdirectory
"cpufreq" within the cpu-device directory "cpufreq" within the cpu-device directory
(e.g. /sys/class/cpu/cpu0/cpufreq/ for the first CPU). (e.g. /sys/devices/system/cpu/cpu0/cpufreq/ for the first CPU).
cpuinfo_min_freq : this file shows the minimum operating cpuinfo_min_freq : this file shows the minimum operating
frequency the processor can run at(in kHz) frequency the processor can run at(in kHz)
......
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