iMX6 - PMIC SW1AB and SW1C standby voltage setting

[Ansari]

Hi,

We are using imx6Q sabresd platform for our development with Linux 3.14.28_1.0.0-GA BSP.

From the below board file we could see the following function "setup_pmic_voltages".

~/u-boot-imx/board/freescale/mx6sabresd/mx6sabresd.c

We understood that, after detection of PMIC

1. VGEN3 and VGEN5 voltages are increased to 2.8v and 3.0v respectively.

2. The SW1AB and SW1C standby voltages are set to 0.975v.

We would like to know, why the SW1AB and SW1C standby voltages are set to 0.975? and where this voltage will be used?

Regards,

Ansari

[igorpadykov]

Hi Abdul

uboot does not use low power modes, they are used in linux,

please refer to Chapter 22-25 attached Linux Manual from L3.14.28_1.0.0_iMX6QDLS_BUNDLE

Best regards

igor

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[Ansari]

Dear Igor,

Thank you for your input in our request.

We believe,  the SW1AB and SW1C standby registers(0x21 & 0x2F respectively) are not accessed in the below driver file.

~/linux-imx/drivers/regulator/pfuze100-regulator.c

Please let us know, in Linux kernel where the SW1AB and SW1C standby voltages used during the low power mode.

From the PFUZE100 data sheet, we understood as below

When the PMIC enters into standby mode(CPU request for standby mode), the regulator(SW1AB & SW1C) will use the set point as programmed by SW1xSTBY[5:0].  Is this correct?

Please correct us if we are wrong.

Regards,

Ansari

[igorpadykov]

Hi Abdul

Linux Manual shows used files.

>When the PMIC enters into standby mode(CPU request for standby mode), the regulator

>(SW1AB & SW1C) will use the set point as programmed by SW1xSTBY[5:0].  Is this correct?

yes.

Best regards

igor

[Ansari]

Hi Igor,

We are waiting for your valuable input on our issue.

Please help us to understand in better.

Regards,

Ansari

[igorpadykov]

Hi Abdul

Linux Manual shows used files and you can check sources

where these settings are configured.  Also one can add printfs to

check if they were modified or not.

Best regards

igor

[Ansari]

Dear Igor,

Thanks for your input.

>>When the PMIC enters into standby mode(CPU request for standby mode), the regulator

>>(SW1AB & SW1C) will use the set point as programmed by SW1xSTBY[5:0].  Is this correct?

>yes.

We believe, the SW1xSTBY[5:0] register values are not modified or updated in the Linux level and the standby set point values are maintained for 0.975v(which is set in u-boot level).

Please let us know, in Linux kernel where the SW1AB and SW1C standby voltages used during the low power mode or it is not required to update the SW1xSTBY register values.?

Please correct us, if we are wrong.

Regards,

Ansari