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Linux/PROCESSOR-SDK-AM335X: McSPI CS control from GPIO

thanh tien
Prodigy 60 points
Part Number: PROCESSOR-SDK-AM335X


Tool/software: Linux

I want to control SPI0_CS0 by driver. Is this possible?

Currently, SPI0_CS0 is automatically controlled by controller according to PIN MUX definition:

http://processors.wiki.ti.com/images/8/82/TMDSSK3358_1.2A_PinMux_Description.zip

If it's possible, please tell me:

* Setting device tree

* How to do this in source code (driver/spi)

 

I'm using SDK Linux for am335x starter kit:

http://www.ti.com/tool/processor-sdk-am335x

Many thanks,

Thanh

  • 0
    TI__Guru**** 393215 points
    The software team have been notified. They will respond here.
  • 0
    TI__Genius 13505 points
    Hi Thanh,

    Can you clarify your question, maybe explain what you're trying to do?

    Are you wanting to explicitly control SPI CS0 in the driver to handle deal with a device's protocol (I know some devices want to see a CS toggle to start conversion, for example).

    Or, are you trying to assign a regular GPIO as an SPI chip select?

    Regards,
    Mike
  • 0 in reply to Michael Erdahl
    Prodigy 60 points

    Hi Mike,

    I'm trying to add a driver to support a device that has SPI protocol. And, for that device we must handle SPI by driver.

    For example, when sending a command to device, CS pin must be driven to low. That is device's protocol as you said.

    I just know there's a way to control CS via its assigned GPIO.

    However could you support for more clearification about implementation?  

    Regards,

    Thanh

  • 0 in reply to thanh tien
    TI__Genius 13505 points
    Hi Thanh,

    Sorry for the delay.

    I would like to help, but will be out of the office until 11/20. If you're still stuck then, I will be happy to help out.

    In the meantime, take a look at this blog post: dev.iachieved.it/.../
    This is assuming the Debian filesystem and cape manager provided by BeagleBoard.org, however the concepts will still apply.

    Regards,
    Mike