How to enter i.MX6SX to low power mode.

[satoshishimoda]

Hi community,

I have a question about i.MX6SX power modes.

Please see Table 10-1, there are 4 power modes for i.MX6SX.

RUN, System IDLE, Low Power IDLE, and SUSPEND (STOP).

However, I did not understand how to enter to these modes.

I think CPU enter System IDLE automatically if there is no task, and I should set VSTBY bit in CCM_CLPCR register to enter SUSPEND(STOP), right?

Then, would you let me know how to enter to Low Power IDLE?

Best Regards,

Satoshi Shimoda

[igorpadykov · Accepted solution]

Hi Satoshi

procedure for entering low power modes is described in

sect.19.5.3 Power modes i.MX6SX RM http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6SXRM.pdf

AN4050 describes steps for “Dormant mode” or “Suspend" modes and System Idle mode.

Codes examples are described in attached Linux Manual Chapter 22 Low-level Power Management (PM) Driver.

Unfortunately "Low Power IDLE" is not implemented in linux, one will have to look at examples of

“Suspend" mode and System Idle mode and develop own procedure making combination of these

codes based on Table 10-1.

Best regards

igor

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[satoshishimoda]

Hi Igor,

> Unfortunately "Low Power IDLE" is not implemented in linux, one will have to look at examples of

> “Suspend" mode and System Idle mode and develop own procedure making combination of these

> codes based on Table 10-1.

I understand corresponding of power modes as following image.

But you said "Low Power IDLE" is not implemented in linux, so I feel the above image is wrong.

Would you let me know the correct corresponding?

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

unfortunately I do not understand you:

where did you find that table ? Is it from

official nxp documentation ?

Best regards

igor

[satoshishimoda]

Hi Igor,

> where did you find that table ? Is it from

> official nxp documentation ?

No, its just my understand.

So if it is wrong, please correct my understanding.

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

Table 21-1 SUSPEND (STOP) corresponds to SUSPEND (STOP)  (not Low Power IDLE) Table 10-1

Best regards

igor

[satoshishimoda]

Hi Igor,

Thank you for your quick reply.

OK, I understand I can refer RUN and SUSPEND (STOP) in Table 21-1 to RUN and SUSPEND (STOP) in Table 10-1.

Then, how about Low Power IDLE?

You said "one will have to look at examples of　“Suspend" mode and System Idle mode", but I feel I have to understand what Low power IDLE is wrong from RUN and SUSPEND (STOP).

I thought, System idle in Table 10-1 corresponds to WAIT in Chapter 19.5.3, and Low Power IDLE in Table 10-1 corresponds STOP in Chapter 19.5.3, but if it is wrong also, I don't find what register should be set to enter Low Power IDLE because chapter 10 of IMX6SXRM does not mention how to enter Low Power IDLE.

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

briefly not all power modes described in RM Table 10-1. Power Modes

are implemented in Linux. For example Low Power IDLE is not implemented.

If customer wishes to add its support to Linux it may be suggested to apply

to Professional Services or direct such request through local marketing

NXP Professional Services|NXP

Best regards

igor

[satoshishimoda]

Hi Igor,

> Power Modes are implemented in Linux. For example Low Power IDLE is not implemented.

Yes, I understand it and I did not request about software code.

I just want to hardware information to use Low Power IDLE.

I feel it is not enough hardware information in reference manual chapter 10 to use Low Power IDLE by creating software by our selves.

Best Regards,

Satoshi Shimoda

[igorpadykov]

Hi Satoshi

reference manual does not provide detailed information how

to enter each low power modes. Such detailed info is provided

with software example. Suggest to request such practical example

contacting local marketing.

Best regards

igor