SK-TDA4VM: spidev is not showing under /dev

Kaviraj S

Part Number: SK-TDA4VM
Other Parts Discussed in Thread: SYSCONFIG

Hi TI,

I am in the process of enabling SPI in the 40 pin header on the SK-TDA4VM board.

But still I am facing issues in bring up the spidev under /dev or under /sys/class/spi*

Can you please help expecting your response as soon as possible.

Thanks,

Kaviraj

0 Kaviraj S over 3 years ago

Hi,

Any updates on this, I am waiting for the response

Also, I have gone through the following e2e links as well

Still, spidev is not showing up.

Thanks,

Kaviraj

0 Manisha Agrawal over 3 years ago in reply to Kaviraj S

Hi Kaviraj, is this issue still open for you?

0 Takuma Fujiwara over 3 years ago in reply to Manisha Agrawal

Hi Kaviraj,

The E2Es that you are referencing are for PSDK Linux and for the EVM board, not PSDK RTOS and SK board. I see other threads that seem to be using PSDK RTOS, but is this on Linux or RTOS? https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1201411/sk-tda4vm-spi-not-working-when-using-the-example-main_mcpsi_slave_mode-c-example-code-in-sk-tda4vm-board

For both cases, I will give my comments:

PSDK Linux case:

The reason why you are not seeing spi come up under /dev is probably because the pins from the SoC that are pinned out to the headers are different between SK and EVM boards.
Recommendation is to only use FAQs that you find as reference (not a working example) for SK board, as most, if not all, FAQs are written with a large, green EVM board instead of the small, blue SK board that you have.
Make sure all pins you are using are not taken by other systems by referencing the dts files: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-j721e-sk.dts?h=ti-linux-5.10.y. For example, PRG1_PRU1_GPO17 that can be configured as SPI that is sometimes used as an example on the EVM board is taken by the display subsystem on the SK board
If using the 40-pin headers, I will also recommend looking at the dts file for 40-pin header to see which pins are pinned out, and you can edit this file and compile a new dtb overlay with SPI enabled: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-j721e-sk-rpi-hdr-ehrpwm.dts?h=ti-linux-5.10.y
Customers have reported back that using the sysconfig tool and existing dts files were useful in finding out which pins are connected, and which can be configured as SPI: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1188254/sk-tda4vm-spidev-not-showing-under-dev

PSDK RTOS case:

TI does not claim support for PSDK RTOS with SK board (only EVM board supports RTOS), so most examples or tests are not validated on the SK board.
With the first bullet point in mind, for PSDK RTOS, you must make sure Linux does not have control of any of the pins you are using (i.e., the dts files that I linked in PSDK Linux case should not have defined any of the pins being used)
If all the pins used are from the dts file from 40-pin, then not apply the resulting dtbo should bring back control to PSDK RTOS. So uEnv.txt should not have "k3-j721e-sk-rpi-exp-header.dtbo" unlike: https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-sk-tda4vm/08_05_00/exports/docs/pi_hdr_programming.html
Otherwise, I have linked relevant documentations for enabling SPI on EVM using PSDK RTOS in this E2E: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1195309/tda4vm-i2c-not-running-properly?tisearch=e2e-sitesearch&keymatch=spi5%252520rtos# . Note: these are not examples for SK board so they should only be used as reference, and not as a working example

Regards,

Takuma

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