imx6ull 's gpio_dvfs

changbaoma · ‎12-19-2019

Hi, Experts

below is imx6ull evk's Schematic

GPIO_DVFS & PMIC_STBY_REQ are used to select the voltage of VDD_ARM_SOC_IN. As i know PMIC_STBY_REQ is the dedicated pin, but i do know where and how this GPIO_DVFS is used in imx6ull BSP's kernel? and i can't even find out any description in dts?

Any suggest is appreciated！

igorpadykov · ‎12-19-2019

Hi changbao

one can check description in sect.2.5.3 CPU Frequency Scaling (CPUFREQ)

Linux Manual included in Linux 4.19.35_1.1.0 Documentation

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

changbaoma · ‎12-19-2019

Hi igorpadykov

Think you for your reply.

I have read through the Chapter 2.5.3 CPU Frequency Scaling (CPUFREQ) , but it do not answer my question. As i know GPIO_DVFS is a gpio, so i think this gpio must be controlled by a driver in somewhere in the kernel. So my question is how can i find this driver and code related to GPIO_DVFS?

BTW:

i noticed someone post in this community

https://community.nxp.com/message/1246207?commentID=1246207#comment-1246207

reg_gpio_dvfs: regulator-gpio {
   compatible = "regulator-gpio";
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_dvfs>;
   regulator-min-microvolt = <1300000>;
   regulator-max-microvolt = <1400000>;
   regulator-name = "gpio_dvfs";
   regulator-type = "voltage";
   gpios = <&gpio5 3 GPIO_ACTIVE_HIGH>; /* This gpio match the GPIO_DVFS in imx6ull evk */
   states = <1300000 0x1 1400000 0x0>;
};