Cannot Find SPI driver in /dev for Colibri i.MX7D

Technical Support
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1

We’re trying to access our SPI device driver for a Colibri i.MX7D. When looking in /dev, on the device, the SPI driver is not listed as one of the drivers in the device tree. I found a similar community forum post to this one regarding the issue where someone had a similar question to this about a Colibri i.MX7 board:

Unable to find SPI node in /dev directory

The post mentioned that in order for the SPI driver to work the CAN driver needs to be disabled. There’s also a link to imx7-colibri-eval-v3.dtsi that opens the file in the section where the modification is needed.

What exactly must be done to the file?

In the spidev0: spidev@0 section there is the line: status = “disabled”. Does this just need to be changed to status = “enabled”? I’ve viewed the spi-imx.c file and it appears that the spi_imx_dt_ids structure is defined and setup properly, but I don’t see spi anywhere in the /dev folder on our device. I’ve rebuilt the imx7-colibri-eval-v3.dtsi file and copied the corresponding imx7d-colibri-eval-v3.dtb file, after modification, to the device but I still don’t see the spi driver in the list of devices.

What needs to be done to make this work?

2

In the spidev0: spidev@0 section there is the line: status = “disabled”. Does this just need to be changed to status = “enabled”?

Yes. The diff of the kernel source would be as below for enabling spidev on iMX7.

diff --git a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
index 1db5aa5365b2..28a8bc7ad44c 100644
--- a/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
+++ b/arch/arm/boot/dts/imx7-colibri-eval-v3.dtsi
@@ -101,14 +101,14 @@
                interrupt-parent = <&gpio5>;
                interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
                spi-max-frequency = <10000000>;
-               status = "okay";
+               status = "disabled";
        };
 
        spidev0: spidev@0 {
                compatible = "toradex,evalspi";
                reg = <0>;
                spi-max-frequency = <23000000>;
-               status = "disabled";
+               status = "okay";
        };
 };

The “status” property for mcp258x0 needs to be changed to “disabled” and for spidev it needs to be changed to “okay”.

3

Thank you sanchayan.tx! This is exactly what we needed to make this work. spidev is now showing up in /dev when the embedded Linux OS is loaded.

Is there a document somewhere on your website that specifies the function calls that we must make from user space in an application to access the spi-imx device driver to read from and write to a device? Function calls like open() and ioctl(). I’m not familiar with embedded Linux device drivers, but do have familiarity with Windows CE and vxworks.

Is there a document somewhere on your website that describes how to make the calls to access the SPI device driver?

Thank You again for all of your help

4

The documentation is included in the kernel source. Please see the spidev document and spidev test code.

5

Perfect! We appreciate your help with everything. :).

Thanks Again.