SK-AM62A-LP: Partial I/O wakeup sources

Hi,

I have assigned your query to our expert. He is out of office for the holidays. Expect a response post New year when he returns.

Apologies for the delay.

Best Regards,

Suren

Hi Sathiya,

Currently, looks like the only wakeup sources for Partial I/O are here at the bottom of this .dtsi file:

https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62a.dtsi?h=ti-linux-6.1.y-wip

And the overlay file says the same where the MCU GPIO pins are for MCU Only: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=ti-linux-6.1.y-cicd#n329

Best Regards,

Anshu

Hi Anshu,

I got it that I can't use a GPIO for Partial I/O wakeup.

I have another query.

Anshu Madwesh said:

https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62a.dtsi?h=ti-linux-6.1.y-wip

How can I enable other Partial I/O wakeup sources (mcu_mcan1, mcu_uart0 & wkup_uart0) mentioned in the below link?

ethtool -s can0 wol p

echo enabled > /sys/class/tty/ttyS0/device/power/wakeup

Hi Anshu,

Wishing you a Happy 2024.
I'm mindful of your absence and don't want to disrupt your time off, but if you have a moment when you're back or available, I would greatly appreciate any guidance or updates on the matter.

Hi Sathiya,

Thank you for the wishes and hope you have a nice New Year.

I haven't gotten a chance to work with Partial IO yet, so I'm still trying to understand how it works.

Sathiya Narayanan said:

But if I type something in ttyUSB2 or ttyUSB3, the device is not turning on.

Can you provide any other details about this? Like what have you connected to the EVM?

Best Regards,
Anshu

Anshu Madwesh said:

Can you provide any other details about this? Like what have you connected to the EVM?

I am using a Linux PC to access serial consoles.

Hi Sathiya,

Thanks for the information. Can you confirm that the device tree overlays to support the wakeup peripherals is enabled?

Here is the link to the documentation for enabling dts overlays: https://software-dl.ti.com/processor-sdk-linux/esd/AM62AX/09_01_00/exports/docs/linux/How_to_Guides/Target/How_to_enable_DT_overlays_in_linux.html#howto-dt-overlays

Best Regards,
Anshu

Hello Anshu,

Anshu Madwesh said:

Can you confirm that the device tree overlays to support the wakeup peripherals is enabled?

Yes, the wakeup source device tree overlay is enabled.
k3-am62x-sk-lpm-wkup-sources.dtso

Using this overlay, I can able to use the following,

• waking up from deep sleep using gpio1_10
• waking up from deep sleep using mcugpio0_16
• waking up from deep sleep using mcu_uart0
• waking up from partial I/O using can0

I can't do the following,

• waking up from partial I/O using mcu_uart0
• waking up from partial I/O using wkup_uart0

Hi Sathiya,

I will discuss this internally and get back to you with an update. Please allow a few days for a response.

Best Regards,
Anshu

HI Anshu,

Is there any update on this?

Hi Sathiya,

What revision of SK-AM62A-LP are you using? I'll check internally again to make sure it can fully support Partial I/O.

After speaking with the development team, Partial I/O should wakeup on level change and if mcan0 wakeup is working, then so should the two uart wakeups.

Best Regards,
Anshu

Hi Anshu,

Anshu Madwesh said:

What revision of SK-AM62A-LP are you using?

I am using E3 version(PROC135E3) of board.

Hi Sathiya,

That revision should work.

Just to confirm, after "echo enabled > /sys/class/tty/ttyS0/device/power/wakeup" in the EVM terminal, when you try sending a signal through /dev/ttyS0 (for MCU_UART) or /dev/ttyS1 (for WKUP_UART), there is no response?

You may have to run this script to enable all the serial ports for wakeup: https://software-dl.ti.com/processor-sdk-linux/esd/AM62AX/09_01_00/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Power_Management/pm_wakeup_sources.html#main-uart

Thanks,
Anshu

Hi Anshu,

Anshu Madwesh said:

Just to confirm, after "echo enabled > /sys/class/tty/ttyS0/device/power/wakeup" in the EVM terminal, when you try sending a signal through /dev/ttyS0 (for MCU_UART) or /dev/ttyS1 (for WKUP_UART), there is no response?

Yes.

Anshu Madwesh said:

You may have to run this script to enable all the serial ports for wakeup

I did it before itself. No response through both MCU_UART and WKUP_UART.

Hi Sathiya,

I apologize for the confusion. What I meant was using /dev/ttyUSB3 on host machine to wakeup via MCU_UART0, not /dev/ttyS0. Try that and let me know if anything changes.

Best Regards,

Anshu

Hi Anshu,

Anshu Madwesh said:

What I meant was using /dev/ttyUSB3

I understood. I meant ttyUSB3 as MCU_UART.

Hi Sathiya,

After further discussions with the development team, MCU_UART0 may not have power supplied to the peripheral when the device is in Partial IO. If you have a way to measure voltage, look for a resistor in the schematics that is connected to VCC_3V3_SYS and measure the voltage across the resistor after poweroff. For example,

VCC_3V3_SYS is supposed to be the power supply for MCU_UART0. So if the R150 measure 0V after poweroff, then it shows that VCC_3V3_SYS is off and thus MCU_UART0 is off.

This might be the reason why UART wakeup is not working. Internal discussions will continue and will update this thread with any new information. Apologies for any confusion this may have caused.

Best Regards,
Anshu

Yeah, LD3 is off. Now how am i supposed to use MCU_UART0 for wakeup?

And one more thing, can you go into more detail with mcu_mcan1 also?

Hi Sathiya, 

Sathiya Narayanan said:

Now how am i supposed to use MCU_UART0 for wakeup?

Until a solution is found, MCU_UART0 wakeup for Partial IO cannot be used.

Sathiya Narayanan said:

can you go into more detail with mcu_mcan1 also?

What information are you looking for? It should be working correctly.

Best Regards,

Anshu

Anshu Madwesh said:

It should be working correctly.

Only mcu_mcan0 is enumerated as can0 in Linux. mcu_mcan1 is not shown in the Linux.

Hi Sathiya,

Thank you for the information. I will check internally on how the mcan1 wakeup was verified and will update this thread accordingly.

Thanks,

Anshu

Hi Sathiya,

I encountered into the same issue on my end where Linux didn't recognize MCAN1.

There are conflicting signals (MCU_GPIO0_16 and MCU_MCAN1_RX) trying attach to the same pin. Both are defined in the same overlay file. I raised this issue to the development team and we'll see what comments they have. Until a solution is found, MCAN1 wakeup may not work.

Thank you for your patience,
Anshu

Hi Madwesh,

Anshu Madwesh said:

Just a quick work around to get MCAN1 wakeup working, remove the 'mcu_gpio_key' node and its Pinmux node from the dts overlay.

This is working.

Hello Madwesh,

Out of necessity I am asking this question.
Is there any provision to connect a press button for system ON/OFF?
Here I am referring graceful shutdown as a system OFF. And I want the system to go into Partial I/O mode when turned off as it is consuming low power.

Hi Sathiya,

I am not aware of any documentation for connecting a press button for system on/off, but it should be possible. Please make a new thread for that topic and the correct hardware expert can provide help.

Best Regards,

Anshu