Set SPI mode to slave

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hi, how can I set SPI mode to slave on Jetson nano?
I only found discussions about jetson xavier nx.
Any solutions for Jetson nano? Thanks!

3

Modify the device tree to add compatible = “nvidia,tegra210-spi-slave”, and configure the SPI pinmux by jetson-io

4

Hi, I got syntax error when adding compatible = “nvidia,tegra210-spi-slave”.

My step is (follow here):
1.

$ sudo /opt/nvidia/jetson-io/config-by-function.py -o dtbo spi1
Configuration saved to /boot/tegra210-p3448-0000-p3449-0000-b00-user-custom.dtbo.

$ dtc -I dtb -O dts -o my-overlay.dts /boot/tegra210-p3448-0000-p3449-0000-b00-user-custom.dtbo
my-overlay.dts: Warning (unit_address_vs_reg): Node /fragment@0 has a unit name, but no reg property
my-overlay.dts: Warning (unit_address_vs_reg): Node /local_fixups/fragment@0 has a unit name, but no reg property

  1. Modify my-overlay.dts as

/dts-v1/;

/ {
overlay-name = “User Custom [2021-03-09-150612]”;
compatible = “nvidia,p3449-0000-b00+p3448-0000-b00”, “nvidia,p3449-0000-a02+p3448-0000-a02”, “nvidia,tegra210-spi-slave”;

fragment@0 {
target = <0xffffffff>;

  __overlay__ {
  	pinctrl-names = "default";
  	pinctrl-0 = <0x1>;

  	header-40pin-pinmux {
  		linux,phandle = <0x1>;
  		phandle = <0x1>;

  		pin3 {
  			nvidia,function = "i2c2";
  			nvidia,pins = "gen2_i2c_sda_pj3";
  			nvidia,pull = <0x0>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  			nvidia,io-high-voltage = <0x1>;
  		};

  		pin5 {
  			nvidia,function = "i2c2";
  			nvidia,pins = "gen2_i2c_scl_pj2";
  			nvidia,pull = <0x0>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  			nvidia,io-high-voltage = <0x1>;
  		};

  		pin8 {
  			nvidia,function = "uartb";
  			nvidia,pins = "uart2_tx_pg0";
  			nvidia,pull = <0x0>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x0>;
  		};

  		pin10 {
  			nvidia,function = "uartb";
  			nvidia,pins = "uart2_rx_pg1";
  			nvidia,pull = <0x2>;
  			nvidia,tristate = <0x1>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin19 {
  			nvidia,function = "spi1";
  			nvidia,pins = "spi1_mosi_pc0";
  			nvidia,pull = <0x1>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin21 {
  			nvidia,function = "spi1";
  			nvidia,pins = "spi1_miso_pc1";
  			nvidia,pull = <0x1>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin23 {
  			nvidia,function = "spi1";
  			nvidia,pins = "spi1_sck_pc2";
  			nvidia,pull = <0x1>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin24 {
  			nvidia,function = "spi1";
  			nvidia,pins = "spi1_cs0_pc3";
  			nvidia,pull = <0x2>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin26 {
  			nvidia,function = "spi1";
  			nvidia,pins = "spi1_cs1_pc4";
  			nvidia,pull = <0x2>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  		};

  		pin27 {
  			nvidia,function = "i2c1";
  			nvidia,pins = "gen1_i2c_sda_pj0";
  			nvidia,pull = <0x0>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  			nvidia,io-high-voltage = <0x1>;
  		};

  		pin28 {
  			nvidia,function = "i2c1";
  			nvidia,pins = "gen1_i2c_scl_pj1";
  			nvidia,pull = <0x0>;
  			nvidia,tristate = <0x0>;
  			nvidia,enable-input = <0x1>;
  			nvidia,io-high-voltage = <0x1>;
  		};
  	};
  };

};

symbols {
hdr40_pinmux = “/fragment@0/overlay/header-40pin-pinmux”;
};

fixups {
pinmux = “/fragment@0:target:0”;
};

local_fixups {

  fragment@0 {

  	__overlay__ {
  		pinctrl-0 = <0x0>;
  	};
  };

};
};

$ dtc -O dtb -o my-overlay.dtbo -@ my-overlay.dts
Error: my-overlay.dts:5.101-102 syntax error
FATAL ERROR: Unable to parse input tree

Where did I do wrong?

5

You need add it under the spi@xxxx scope.

6

Do I need to add spi@xxxx by myself?
I didn’t find it in my-overlay.dts

7

I would suggest to use full kernel source to build it instead using dtc.

https://docs.nvidia.com/jetson/l4t/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/kernel_custom.html#