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Original question:

AM623: AM6234 EQEP Driver AND Touch Screen Cannot be touched and be controlled

AM623: Need EQEP Linux driver for AM62x

Gene Friesen
Intellectual 330 points
Part Number: AM623

Like tansai in a previous post, we also need an EQEP driver for AM62x Linux.

Our use case is to interface a pair of rotary encoders to be used as audio volume controls.

Your on-line AM62x Software Build Sheet 08-05-00-21 suggested that you would support EQEP with SDK9.0.

 https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/08_05_00_21/exports/docs/build_sheet/am62x-sw-buildsheet.html

SDK9.0 actually does include two files called ti-eqep.c and ti-eqep.yaml.

  • Can these files be used to implement a Linux EQEP driver?
  • If so, what are the “magic” lines of code needed in the Linux device tree to bring up the EQEP?

Thanks

  • 0
    TI__Guru 65237 points

    Hi Gene,

    I've assigned your request to the respective domain expert. Will get back shortly.

    Regards, Andreas

  • 0
    TI__Guru* 93345 points

    Hello Gene,

    Help me get this prioritized

    Thank you for posting. Can you please have your TI representative reach out to me over email with your timeframe of need, size of opportunity, and any other details that would help me get this prioritized with our development team?

    More details

    We do not support EQEP on AM62x or AM64x yet (as of SDK 9.0). Apologies that we do not have an updated software buildsheet out yet, the team is still working on the SDK 9.0 SW buildsheet.

    As per the discussion on Tansai's thread here, the ti-eqep.c driver was created for AM335x, and it is pretty bare bones. For some more background from one of our developers:

    "

    “Beagle folks use driver to detect the position:

    commit f213729f679619e70669c2b440886929595d26e5

    Author: David Lechner <david@lechnology.com>

    Date:   Sun Sep 1 17:58:24 2019 -0500

        counter: new TI eQEP driver

        This adds a new counter driver for the Texas Instruments Enhanced

        Quadrature Encoder Pulse (eQEP) module.

        Only very basic functionality is currently implemented - only enough to

        be able to read the position. The actual device has many more features

        which can be added to the driver on an as-needed basis.

        It is not possible to read the QEPA/B signal values in hardware, so

        that feature is omitted.

    Note, eQEP has much more features such as strobe event, index event, different counter mode (up, down quad, dir) etc.
    So, would be good to get what exactly is end customer requirements so that we can prioritize and test those features first.”

    "

    What else do I need from you? 

    Please look through the feature list of the existing AM335x driver. If there are specific features / settings / etc that you need on top of the basic position functionality, let me know what those features are so I can bring them up with the developers.

    If your team does any additional development on the EQEP driver in the near term, I would be happy to pass your code changes back to our developers as well.

    Regards,

    Nick