Imx7 SPI Problem

Technical Support
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1

Hi all,

I am trying to get SPI working, I have changed my top level device tree file with the following settings:

&ecspi3 {
	status = "okay";

	mcp2515: can@0 {
		compatible = "microchip,mcp2515";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_can_int>;
		reg = <0>;
		clocks = <&clk16m>;
		interrupt-parent = <&gpio5>;
		interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
		spi-max-frequency = <10000000>;
		status = "disabled";
	};

	spidev0: spidev@0 {
		compatible = "toradex,evalspi";
		reg = <0>;
		spi-max-frequency = <23000000>;
		status = "okay";
	};
};

I then compiled the spidev_test.c program with the cross compiler. When I run the compiled code on my platform I do not get any output on the SPI lines. The output when I run the code looks like this:

root@colibri-imx7-emmc:~# ./spitest1 -D /dev/spidev2.0 -p "1234"
spi mode: 0x0
bits per word: 8
max speed: 500000 Hz (500 KHz)
RX | 00 00 00 00 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __  | ....
root@colibri-imx7-emmc:~#

The output from dmesg with reference to SPI looks like this:

[ 1.039537] spi_imx 30840000.ecspi:
dma setup error -19, use pio [
1.048391] spi_imx 30840000.ecspi: probed

I am expecxting to see SPI activity on pins 86,88,90,92, but there is nothing.

Does anybody have any tips on this topic?

2

Hi @eoin_oc

You have two devices on the same chip select (mcp2515 and spidev0 both reg=<0>;). I guess this should be different. Also you should define the chip selects similar to what we do here (line 86+):

http://git.toradex.com/cgit/linux-toradex.git/tree/arch/arm/boot/dts/imx7-colibri-aster.dtsi?h=toradex_4.14-2.3.x-imx
Further I guess you should set the pinctrl in ecspi3 as in the example above and not on the device itself. Also please test what happens if you only add a spidev and no mcp2515.

Regards,
Stefan

3

Thanks for the tips, i will try that,it is tricky to figure out as I have no idea what reg stands for?
It seems that this variable is named very poorly

4

Thanks for the feedback! Unfortunately Toradex has no influence on the naming convention in the devicetree.