如何在rk3288平台上手动和通过内核调整CPU频率：打造定制化CPU频率控制方法——详解内核驱动的实现步骤

相关文件：

android5.1_sdk/kernel/arch/arm/boot/dts/firefly-rk3288.dts

android5.1_sdk/kernel/arch/arm/mach-rockchip/dvfs.c

dvfs.c：struct cpufreq_frequency_table 有三个数组变量rk3288v[012]_arm_pvtm_table会列出CPU动态的频率，只需要屏蔽其他频率只剩下固定的频率即可，此处定频为1GHZ示范如下：

...
static struct cpufreq_frequency_table rk3288v0_arm_pvtm_table[] = {
    /*..other freq..*/
    {.frequency = 1008000, .index = 14741},
    {.frequency = CPUFREQ_TABLE_END, .index = 1},
};
...

firefly-rk3288.dts：也是屏蔽只剩下固定的频率即可。 

...
&clk_core_dvfs_table {
    support-pvtm = <0>;
    pvtm-operating-points = <
        /*KHz        uV         pvtm margin*/
        /*----other freq-----*/
        1008000     1050000     25000
        >;
    status = "okay";
};
....

 重新编译内核：make bootimage -j8 && ./mkimage.sh