In order to take full advantage of the LDO bypass mode (How to Enable LDO Bypass Based on i.MX6 Android ICS), I would like to control the VDD_ARM and VDD_SOC through the PF100 regulator in the cpufreq driver.
The table lists the operation setpoints for LDO bypass mode: 0.925V for up to 396MHz, 1.150V up to 792MHz.
The current driver only controls the internal LDO, thus only works for "LDO enabled" mode.
This code gets the LDO regulators here:
linux/imx6q-cpufreq.c at master · torvalds/linux · GitHub
Question:
How can I get the actual PF100 voltage regulator in code? regulator_get(cpu_dev, "sw1ab")?
Why does the cpufreq driver use devm_regulator_get_optional() and not regulator_get()?
Where do I find the name of PF0100 SW1AB? The i.MX6 Linux Reference Chapter 23 explains the PF100 Regulator driver, and chapter 23.3.1 describes the regulator APIs. In the code I found the following table:
linux/pfuze100-regulator.c at master · torvalds/linux · GitHub
When I print the regulator names, they are listed in this exact order:
root@h5:/sys/class/regulator # cat regulator.0/name regulator-dummy root@h5:/sys/class/regulator # cat regulator.1/name vdd1p1 root@h5:/sys/class/regulator # cat regulator.2/name vdd3p0 root@h5:/sys/class/regulator # cat regulator.3/name vdd2p5 root@h5:/sys/class/regulator # cat regulator.4/name vddarm root@h5:/sys/class/regulator # cat regulator.5/name vddpu root@h5:/sys/class/regulator # cat regulator.6/name vddsoc root@h5:/sys/class/regulator # cat regulator.7/name usb_otg_vbus root@h5:/sys/class/regulator # cat regulator.8/name usb_h1_vbus root@h5:/sys/class/regulator # cat regulator.9/name SW1AB root@h5:/sys/class/regulator # cat regulator.10/name SW1C
已解决! 转到解答。
Hi Igor
Yes I know that, but I think I understood "the magic" now: In the DTS I can configure which regulator should be used.
As an example, imx6sx-sdb.dts uses sw1a of PFUZE0100 for arm-supply, which in turn the cpufreq driver will use to regulate the voltage of the ARM. Is this assumption correct?
linux-imx.git - i.MX Linux Kernel
Hi Michael
ldo bypass is used by default in latest nxp bsps, one can look at "ldo-bypass" property in dts files
linux-imx.git - i.MX Linux Kernel
for using internal LDO special imx6q-sabresd-ldo.dts is used. Cpu freq driver
is described in attached Linux Manual sect.2.3.3 CPU Frequency Scaling (CPUFREQ).
Full documentation can be found in
https://www.nxp.com/webapp/Download?colCode=L4.9.11_1.0.0_LINUX_DOCS
Best regards
igor
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Hi Igor
Yes I know that, but I think I understood "the magic" now: In the DTS I can configure which regulator should be used.
As an example, imx6sx-sdb.dts uses sw1a of PFUZE0100 for arm-supply, which in turn the cpufreq driver will use to regulate the voltage of the ARM. Is this assumption correct?
linux-imx.git - i.MX Linux Kernel