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power management with OMAP35x

ranchu
Guru 20755 points
Other Parts Discussed in Thread: OMAP3530

Hello,

Where can I find documentation for PM in linux for the OMAP3530 ?

I see in documentation of each OMAP based soc, different capabilities in PSP, so I'm not sure which capabilities are supported...

I found the following file but it seems to refer to old PSP (debugfs is used intsead of sysfs, Is it still correct ?)

http://processors.wiki.ti.com/index.php/UserGuidePowerMgmt_PSP_03.00.00.05

I also found the following link which talks about other capabilities, Is it relevant to OMAP35x too ?
http://processors.wiki.ti.com/index.php/AM335x_Power_Management_Standby_User's_Guide

Is standby mode supported for OMAP35x as described in the above link for AM335X ?

Another question, how can I know the precise PSP version in my SDK (RDK 4.1.0.2). It is not mention in release notes.

Thanks!
Ran

  • 0
    TI__Guru 65405 points

    Hi Ran,

    The standby mode is supported for OMAP35x and description in the Power management standby guide for AM335x also refers to OMAP35x.

    The precise PSP version of your SDK could by found in the kernel folder name (something like linux-2.6.32-psp03.00.01.06 in DVSDK 4.01.00.09 for example).

    BR

    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    Guru 20755 points

    Hi Cvetolin,

    Thanks for the quick response.
    I see other description for standby (which is same as "off mode", right ?) in the following link, so I'm not sure which is relevant or updated .
    http://processors.wiki.ti.com/index.php/AM37x_Power_Management_User_Guide

    mkdir /debug
mount -t debugfs debugfs /debug
echo 1 > /debug/pm_debug/sleep_while_idle
echo 1 > /debug/pm_debug/enable_off_mode
echo mem > /sys/power/state

    As to PSP version I checked the folder, but there is no version in it (maybe the 04.01.00.02 is the PSP version ?)
    DVRRDK_04.01.00.02/ti_tools/linux_lsp/kernel/linux-dvr-rdk

    Thanks
    Ran

     

  • 0 in reply to ranchu
    TI__Guru 65405 points

    Hi Ran,

    There are some differences between off mode and standby but you can find more detailed description in the OMAP 35x TRM section 4 Power, Reset and Clock Management and 4.12 PRCM Basic Programming Model.

    About the PSP version in your SDK it is 4.01.00.02.

    BR

    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    Guru 20755 points

    Hi Tsvetolin,

    I would like to verify the following if I may:

    According to PSP documentation:

    http://processors.wiki.ti.com/index.php/UserGuidePowerMgmt_PSP_04.02.00.07

    1. Standby mode is not mentioned in this page. Does it mean it is not supported (in software) ?

    2. I also see that in off-mode the transition back to normal, as done only from UART, is this right ? "Important The idle and off states are entered only upon timing out of the uart terminals"

    Thanks, Ran

  • 0 in reply to ranchu
    TI__Guru 65405 points

    Hi Ran,

    I'm not familiar with this specific PSP but the standby mode should be supported because it is described in the menuconfig -> Power management support section of the linked user guide.

    BR

    Tsvetolin Shulev

  • 0 in reply to Cvetolin Shulev-XID
    Guru 20755 points

    Hi Tvestolin,

    I'm trying to figure out how to use the PM mechanism, but the PSP does not give me the full details of this subject:

    What the meaning of the following text in the link above ":
    Important
    The idle and off states are entered only upon timing out of the uart terminals.By default their sleep time-out values are 0 which means never time-out."

    1. Is the IDLE entered only upon timing of uart sleep ?
    2. Are there other triggers entering to IDLE ? 
    3. How is the exit from idle done (can't find description for it in this PSP link

      http://processors.wiki.ti.com/index.php/UserGuidePowerMgmt_PSP_04.02.00.07

      ) ?
    4.  Is it the same IDLE mode known in software and OS or is it different PM IDLE mode terminology ?isn't it the same IDLE when the SW just enters simple timer sleep ?
    5. If it is the same simple IDLE from SW, than isn't it problematic that we suspend all interfaces (LCD?) on sleep ?


      Thanks, Ran