Looking for MIPI display driver of LG Nexus D-821 (which allegedly uses the same panel as we want fo

Discussion in 'Pyra OS (Debian GNU/Linux)' started by hns, Feb 10, 2014.

  1. hns

    hns Very Active Member

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    we are in the middle of making the display run on the OMAP5 EVM. Hardware is done and debugged and the display shows some mimimal reaction - but no images and no backlight.

    The chip inside the panel is the Renesas R63311 and the panel is a LH500WFT1-SD02. We have a datasheet but it appears to be incomplete. The usual path is to contact the supplier and we have already done that. But it may need much time (since such a request has to go through many hands) and not have a result (because someone in the middle of the chain thinks it is not important enough).

     


    We were told that the LCD panel we have choosen is the same as the one used in the LG Nexus 5 D821. Therefore, it would be great if we could find and study some Linux/Android kernel display driver to speed up getting it up.

    Since I am not familiar with Android source repositories, if someone knows where to find the authoritative sources of the above mentioned Nexus 5 model, that would be a great help for the Pyra project.
     
    Last edited by a moderator: Feb 10, 2014
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  2. aTc

    aTc Very Active Member

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  3. hns

    hns Very Active Member

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    Thanks! I have studied that but was not able to find a display driver that uses MIPI.

    The strange thing is that 

    https://github.com/CyanogenMod/android_kernel_lge_hammerhead/blob/cm-11.0/arch/arm/configs/cyanogenmod_hammerhead_defconfig

    configures some Chimei LVDS panel and not a MIPI.

    And the Renesas driver in

    https://github.com/CyanogenMod/android_kernel_lge_hammerhead/tree/cm-11.0/drivers/video/msm

    is not what we are looking for (different Renesas chip).

    So I am not sure if the LG is really the Hammerhead - and if Cyanogenmod supports it.
     
  4. EvilDragon

    EvilDragon Administrator Staff Member

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    Something really is weird here - the Google Nexus 5 definitely has a FullHD screen and not WXGA.

    The Google Nexus 4 has WXGA... but the Nexus 4 is "occam" or "mako" and not "hammerhead".
     
    Last edited by a moderator: Feb 10, 2014
  5. mcobit

    mcobit Advanced Member

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  6. Farox

    Farox Certified Guru

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  7. Mr_Loon

    Mr_Loon Can't Remember

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    From what I can see here the screen in the D820 & D821 are identical so if you can find drives for the D820 then they should also work.
     
  8. hns

    hns Very Active Member

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    Thanks for the additional links. Yes, the D820 and D821 are identical - so we need a driver for either one.

    But I was now able to find some real R63311 driver in the Xperia sources:

    https://github.com/CyanogenMod/android_kernel_sony_apq8064/tree/cm-10.2/drivers/video/msm

    There are some R63311 drivers for Sharp and JDC panels. I have a datasheet for the Sharp - but it is slightly different to our LG panel (and also incomplete).

    I will study these drivers tomorrow. It will be interesting what the differences are (which is an indication on how much the panel manufacturer can configure the controller).

    Anyways we are still hunting for the MIPI based kernel source for the LG Nexus 5 D820/1...
     
    Last edited by a moderator: Feb 11, 2014
  9. mclien

    mclien Very Active Member

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    I passed your call to bunnie from the novena Project. Maybe he's able to contribute something (data, sources, experience of getting them, wisdom)
     
  10. sidhurta

    sidhurta Newbie

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    @hns, were you ever able to get this to work?

    I am wanting to use the LG D820/D821 panel for my own project.

    Thanks.
     
    Last edited by a moderator: Jul 10, 2015
  11. hns

    hns Very Active Member

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    we have these drivers in use:

    http://git.goldelico.com/?p=gta04-kernel.git;a=tree;f=drivers/video/fbdev/omap2/displays-new;h=2226e954d9f26c3574dfb74555b3daa425bd4a22;hb=6279c688a570d02ba360c2f9a318bdd99795d32f

    So you must find the right controller chip (data sheet) and adapt some parameters to the specific glass.

    What has turned out to be very helpful is out panel-mipi-debug driver which allows to send arbitrary DCS and generic commands from user space:

    http://git.goldelico.com/?p=gta04-kernel.git;a=blob;f=drivers/video/fbdev/omap2/displays-new/panel-mipi-debug.c;h=9742012cd5c9ef9886cc31e3cfbb729bb3f68d57;hb=6279c688a570d02ba360c2f9a318bdd99795d32f

    Some panels are initialized by such scripts:

    http://git.goldelico.com/?p=gta04-kernel.git;a=tree;f=Letux/root;h=5b9c744989f67211f0d1377595a129044eaffa1b;hb=6279c688a570d02ba360c2f9a318bdd99795d32f

    Of course this is good only for development and for production systems, there should be a specific driver that initializes the panel during boot.
     
    levi likes this.

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