About set points for the VDDARM/SOC voltage of DVFS and the Bus Frequence driver, for i.MX6UL LinuxBSP

[yuuki]

Dear all,

I investigate DVFS function of i.MX6UL.

In AN5170, The voltage levels of VDDARM and VDDSOC is shown in following Table1.

On the other hand, in i.MX Linux Reference Manual for i.MX6UL,
Dynamic Bus Frequency Driver has three set points.
- 1. High Frequency Setpoint
- 2. Audio Playback setpoint
- 3. Low Frequency setpoint

Does the table1 of AN5170 match those set points of  Dynamic Bus Frequency Driver?

     For example,
     When High Frequency Setpoint is set, the voltage of VDDSOC and VDDARM in 528MHz is used.

May I have advice?

Best Regards,
Yuuki

[igorpadykov · Accepted solution]

Hi Yuuki

voltage levels of VDDARM and VDDSOC affect cpu frequency - CPU Frequency

Scaling (CPUFREQ) Driver and does not affect Bus Frequency Driver

(it varies the AHB/DDR frequency).

CPU Frequency Scaling (CPUFREQ) Driver and Bus Frequency Driver are different drivers.

For Dynamic Bus Frequency Driver frequency values one can look at (attached)

linux-2.6-imx-imx_3.14.38_6ul_ga/include/linux/busfreq-imx.h and

Linux/Dcoumentation/...arm/imx/busfreq-imx.txt

Best regards

igor

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