Linux: AM5718 SPI read issue

dark hou

Intellectual 940 points

Tool/software: Linux

Hi Ti:

We want to use SPI4 to read data from slave device.

But we can't read ay data from slave. (SPI write is ok)

We use spi4 as our master.

    {GPMC_A8, (M8 | PIN_INPUT_PULLUP)},   /* spi4_sclk */
   {GPMC_A9, (M8 | PIN_INPUT | SLEWCONTROL)},   /* spi4_d1 */
   {GPMC_A10, (M8 | PIN_INPUT | SLEWCONTROL)},   /* spi4_d0*/
    {GPMC_A13, (M8 | PIN_INPUT | SLEWCONTROL)},   /* spi4_cs2 */

And our device tree setting is below.

&mcspi4 {
   status = "okay";

   sony_oled: sony_oled@0 {
       compatible = "oled,sony_ecx336";

       reg = <0>;
       spi-max-frequency = <1000000>;
       spi-tx-bus-width = <1>;
       spi-rx-bus-width = <1>;
   };
};

Can you help us to check what's going on?

DarkHou

over 8 years ago

0 Pavel Botev over 8 years ago

TI__Guru**** 170625 points

Hi DarkHou,

Do you use AM571x TI board or custom board?

Do you use AM57x TI PSDK? If yes, which version?

Which pin exactly you are using for data read, spi4_d0 or spi4_d1? Make sure data read pin is properly muxed, you can check that from user space using devmem2 or omapconf tool, reading the corresponding Control Module register.

Check also with scope if you have data bits coming on that pin from the slave SPI module.

Regards,
Pavel

0 dark hou over 8 years ago in reply to Pavel Botev

Intellectual 940 points

Hi Pavel:
I use custom board.
I use AM57x TI Linux SDK (04.01.00.06)

We use spi4_d0 as output pin.
spi4_d1 is input pin (read data from slave)

We observe spi4_d1 has data but driver doesn't read anything.

DarkHou

0 Pavel Botev over 8 years ago in reply to dark hou

TI__Guru**** 170625 points

DarkHou,

Do you mean u-boot driver or kernel driver? How exactly you test SPI read/write functionality?

Please provide full console log and AM571x McSPI register dump for analysis.

Regards.
Pavel

0 Yordan Kovachev over 7 years ago in reply to Pavel Botev

TI__Guru**** 161600 points

Closing this.

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Linux: AM5718 SPI read issue