i.MX8M DVFS support

[prajna_nayak]

Hi,

We are using i.MX8M custom board with Linux 4.9.51_ga release. I want to enable the Dynamic Voltage Frequency Scaling(DVFS) property in it. I have added the below in dts file for the same:

************************************************************************************

reg_gpio_dvfs: regulator-gpio {
   compatible = "regulator-gpio";
   pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_dvfs>;
    regulator-min-microvolt = <900000>;
    regulator-max-microvolt = <1000000>;
    regulator-name = "gpio_dvfs";
    regulator-type = "voltage";
    gpios = <&gpio1 13 GPIO_ACTIVE_HIGH>;
    states = <900000 0x1 1000000 0x0>;
};
.....
pinctrl_dvfs: dvfsgrp {
   fsl,pins = <
      MX8MQ_IOMUXC_GPIO1_IO13_GPIO1_IO13 0x16
   >;
};
......
&A53_0 {
   operating-points = <
   /* kHz uV */
   1500000 1000000
   1300000 1000000
   1000000 900000
   800000 900000
   >;
   dc-supply = <&reg_gpio_dvfs>;
};

**********************************************************************************************

Is there any other change that needs to be done? with this change in dts and 'ondemand' CPU frequency governer, the board hangs.

Can somebody help in solving this issue?

Thanks in advance.

Regards,

Prajna

[diegoadrian]

Hello,

Are you using our BSP as a reference? This is because several drivers use the information of the DVFS, one of them is the DDR driver. This is because your configuration of your DTS is the same as our i.MX8MQ board. 

Best regards,

Diego.