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Reference LCD panel linux device drivers for RFBI mode on AM437x

Manan Patel1
Intellectual 390 points

Hi,

We're going to use 16-bit parallel interface in RFBI mode. We are using an LCD controller with a remote FB.

Are there any reference panel-* drivers that describe the usage of rfbi.c ? I found some drivers that are not yet in the Linux SDK but seem to be useful...

https://gitorious.org/linux-omap-dss2/linux/source/4f4dd663c306bdefc4e3ea21ea52bc079db362d6:drivers/video/omap2/displays/panel-n8x0.c

Thanks,

Manan.

  • 0
    Intellectual 390 points

    Update - 

    On going through a lot of driver code, mainly in the drivers/video/omap2/dss/rfbi.c and comparing with a previous version of rfbi.c, it seems that the functions in rfbi driver either need to be interfaced using "EXPORT" or an "omap_dss_ops *rfbi_ops" must be added to omap_dss_device struct so that they can be pointed to in the panel/display driver. I'm not sure why these "ops" are not available for panel drivers to use. Is my understanding correct? Is there a detailed document on drivers for RFBI that can help me confirm?

    Thanks,

    Manan.

  • 0 in reply to Manan Patel1
    TI__Guru**** 393215 points

    Hi Manan,

    I will ask the factory team to comment on this.

  • 0 in reply to Biser Gatchev-XID
    Intellectual 390 points

    Gentle Reminder...

    Thanks,

    Manan.

  • 0 in reply to Manan Patel1
    TI__Guru**** 393215 points

    This thread will be updated when there is feedback from the factory team. This may take some time, depending on their schedules/priorities.

  • 0 in reply to Biser Gatchev-XID
    Intellectual 390 points

    Hello Biser,

    We're beginning to work on the rfbi panel drivers and we're running into some issues where we need to modify some dss/rfbi.c code.

    I just wanted to know the status of these drivers from the display sub-system team. It is important for us to know that we are not working on something that's outdated and not supported anymore.

    Thanks,

    Manan.

  • 0 in reply to Manan Patel1
    TI__Guru*** 125430 points

    I'm not aware of any work related to RFBI having occurred for 2+ years.  I bumped into this with a customer a couple years ago on OMAP4 on kernel 3.0.  Even back then the code was a bit rough around the edges.  At the time the customer managed to muddle through and get things working.  I expect with the passage of many kernel versions that this task will be much harder.

    I think you are pretty close to the mark when you mentioned "outdated and not supported".  I'm sure that's not the answer you're looking for, but I imagine it's better to hear it now than later...

  • 0 in reply to Brad Griffis
    Intellectual 390 points

    Brad,

    Thanks for your reply.

    It does seem like a significantly difficult task to get an rfbi driver to work now compared to a dpi driver. We'll review the effort and take a decision on whether to switch or not.

    Would like to mention though that a lot of smaller LCDs support solely 8080 interface and would be great if these drivers were supported.

    Thanks,

    Manan.