VDD_ARM_CAP on 3.14.28

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VDD_ARM_CAP on 3.14.28

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adrianmcgrath
Contributor III

Hello All

I've been looking through postings on this and other forums for fixes to behaviour described as instability. During this process I was pointed to this posting:

The reason i.MX6DQ VDD_ARM_CAP setting was changed by L3.10.53_1.1.0-ga.

I'm using Kernel 3.14.28 (Yocto Fido) and checked on the status of the VDD_ARM_CAP voltage setting as described by Satoshi Shimoda in Sept 2015. Satoshi highlights line 33 in arch/arm/boot/dts/imx6q.dtsi which refers to the following section:

operating-points = <

     /*     kHz               uV */

           1200000           1275000

           996000            1250000

           852000            1250000

           792000            1175000           <== Value updated to increase stability

           396000            975000

>;

So my question is do any of the other values in this (or a related) section need to be updated for improved stability if operating at the higher clock frequencies?

Many thanks in advance.

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art
NXP TechSupport
NXP TechSupport

The highest possible operating clock frequency of 1.2GHz (1200000kHz) is already listed here, so, no other values should be updated.


Have a great day,
Artur

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adrianmcgrath
Contributor III

Hi Artur

Thank you for your response.

From Satoshi's original question "operating-points" relates to VDD_ARM_CAP.

Would you be able to confirm what symbols in the datasheet the term "fsl,soc-operating-points" refers to?

i.e.

1) Does "operating-points" relate to other datasheet symbols as well as VDD_ARM_CAP?

2) Does "fsl,soc-operating-points" refer to datasheet symbols VDD_ARM_IN, VDD_ARM23_IN, VDD_SOC_IN or something else?

Many thanks

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