How to apply Battery + 5V Power in kernel in i.MX23

[erickang]

Dear All,
I have a question for Battery + 5V operating in i.MX23.

I modified the boot stream to be operated with Low Battery and 5V power.
For this, I just enabled DCDC_4P2 for Low Battery and 5V Power in boot stream.
For your more understanding, I'll attached the modified boot stream file, power_prep/power_prep.c

But Kernel was used Battery when the Power source was "Low Battery + 5V".
So the board was power-off when I plug-out 5V USB Power Cable and the kernel was not operating on very low battery.

Could you tell me how to use 5V as power source when the power source is "Low Battery + 5V"?
And then I want to charge the Battery.

Best Regards,
Eric.

Original Attachment has been moved to: power_prep.c_2015.01.20.txt.zip

[igorpadykov]

Hi Eric

regarding :

"when the Power source was "Low Battery + 5V".

So the board was power-off when I plug-out 5V USB Power Cable and the

kernel was not operating on very low battery."

proccesor can not operate below Battery<2.6V,

IMX23RM Table 2-3. Recommended Power Supply Operating Conditions,

so without any suitable power (no battery, no 5V) board powers off.

In BSP you can charge battery using BSP battery charger device driver, refer

to attached Linux Manual Chapter 27 Battery Charger and Power Source Manager (PSM) Driver.

However BSP does not support transition from 5V to battery (note, it should be charged

up to this moment) and vice versa, you should add such support yourself using

attached AN4199 sect.4.2.1 Transition from Battery to 5 V Power Source,

4.2.2 Transition from 5 V Supply to Battery. One can detect 5V removal using

sect.3.2.2.4 Enabling 5 V Detection for DC-DC Control Logic.

Best regards

igor

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[erickang]

Thanks for your response.

My explain was wrong.

The board was power-off when I plug-out battery.

Ann I'll checked other guide.

[igorpadykov]

Hi Eric

for case 'plug-out battery" one needs to implement

AN4199 sect.4.2.1 Transition from Battery to 5 V Power Source

Best regards

igor

[erickang]

Dear Igor,

You means the current i.MX23 Kernel BSP just only supportted Battery Only and 5V only,

so User have to make the power source changes from 5V to Battery and from Battery to 5V.

Is that right?

Could you give me any detailed guidance if It's right?

I could find the relative issue in Community, but I couldn't find the correct solution.

Best Regards,

Eric.

[igorpadykov]

Hi Eric

current i.MX23 Freescale  BSP supports

only case Battery. 5V only is supported for i.MX28 :

L2.6.35_1.1.0_ER_SOURCE : i.MX28 Linux 2.6.35 Source Code

All other cases should be added by customer himself.

Best regards

igor