Are there examples of device tree for a SPI slave device?

[codan-soea]

Hello

I am trying to create a device tree for a SPI slave device for Linux OpenWRT 6.6.58, my SPI device will be interfaced to Lima module
via SPI. I have used "target/linux/ath79/dts/qca9531_8dev_lima.dts" as template. However, I found that by just putting another client
as follows will not work.

&spi {
status = "okay";

/* Winbond W25Q256 SPI flash */
flash@0 {
    .....
    };

    /* more clients */
    bmi160: bmi160@1 {
	compatible = "bosch,bmi160";
	reg = <1>;
	spi-max-frequency = <7500000>;
     };

};

I am wondering are there device tree examples of how to connect a SPI slave to Lima module. Thanks!

[mantas-p]

Hi, you probably need to describe how CS (chip select) is connected - see https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=target/linux/ath79/dts/ar9342_mikrotik_routerboard-911g.dtsi#l158

[codan-soea]

Thanks. I have tried that, pls see my device tree for SPI slaves below, that but not working. My success criteria is that I have made reading of chip ID (I modified the driver so that it will try to read 5 times) and I know it is not reading correct chip ID.

&spi {
status = "okay";
cs-gpios = <0>, <&gpio 0 GPIO_ACTIVE_LOW>, <&gpio 1 GPIO_ACTIVE_LOW>;
......

bmi160: bmi160@1 {
	compatible = "bosch,bmi160";
	gpio-controller;
	#gpio-cells = <2>;
	reg = <1>;
	spi-max-frequency = <7500000>;
	
	vdd-supply = <&vdd_3v3>;  // Power supply for the BMI160 sensor
	vddio-supply = <&vddio_2v5>; // I/O supply if required

        	interrupt-names = "INT1";
        	mount-matrix = "0", "1", "0",
                       "-1", "0", "0",
                       "0", "0", "1";
};

.....

};

and my SPI Chip selects lines are connected to the Lima SoC as shown below:

And I believe my issue is with SPI CS lines are not driven correctly. Thanks!

[mantas-p]

GPIO[0-3] have JTAG interface by default, you need to disable it to use these pins as GPIO. See: https://github.com/openwrt/openwrt/blob/207bfee855320dc938f39e179b1d2e3b008140cb/target/linux/ath79/dts/qca9531_glinet_gl-xe300.dts#L36

[codan-soea]

Thanks, I think I have put it in leds block before, but I will try again.

• leds {

•   compatible = "gpio-leds";
  

•   pinctrl-names = "default";
  

•   pinctrl-0 = <&jtag_disable_pins>;
  

• };