How to configure SPI1 as a slave?

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Xavier
1

Hi teams

I want to configure SPI1 as a slave device in Xavier. The current configuration is shown in the figure below. How should I modify it

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3

Add below for slave mode.

compatible = “nvidia,tegra186-spi-slave”;

4

hi ShaneCCC
Thanks to your reply
I have modifyed the compatible to “nvidia,tegra186-spi-slave”, bulid and flash the image, but the device node “/dev/spidev0.0” and “/dev/spidev0.1” ware disappeared. Is there anything else that should be modified?

5

Did you add it to the device tree?

6

Hi ShaneCCC
It’s my bad, I had replace compatible = “spidev” to compatible = “nvidia,tegra186-spi-slave”, so there is no device node. dose the spidev_test can be test slave mode?

7

You can configure one SPI control as slave and have loopback connect to another master SPI to test it.

8

In slave and master mode, what’s the correct value of pinmux, and where is the reference documentation for setting the pinmux? could you tell me, Thanks

9

When execute spidev_test on slave mode, it tips “Can’t send spi message: Invalid argument”, The error location corresponding to the source code is show in follow figure below.

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and dmesg print some fault message
[ 2860.180998] spi-tegra124-slave 3210000.spi: Tx is not supported in mode 0
[ 2860.181231] spi-tegra124-slave 3210000.spi: spi can not start transfer, err -22
[ 2860.181454] spi_master spi0: failed to transfer one message from queue

Is there a problem with the slave mode than i configured ?

10

Something like below example

connected -> SPI1_MOSI<-->SPI3_MISO, SPI1_CLK<-->SPI3_CLK, SP1_CS0 <--> SPI3_CS0  and SPI1_CS1->SPI3_CS1.

SPI1 has to be configured as Master and SPI3 has to be configured as slave in the dt and pinmux settings have to be updated. 
SPI1 DT:    
spi@3210000 {
        status = "okay";
        compatible = "nvidia,tegra186-spi";
        spi@0 {
            compatible = "spidev";
            reg = <0>;
            spi-max-frequency = <65000000>;
            controller-data {
                nvidia,enable-hw-based-cs;
            };
        };
    };

SPI3 DT
    spi@3230000 {
        status = "okay";
        compatible = "nvidia,tegra186-spi-slave";
        spi@0 {
            compatible = "spidev";
            reg = <0>;
            spi-max-frequency = <65000000>;
            controller-data {
                nvidia,enable-hw-based-cs;
            };
        };
     };

PINMUX settings are listed below for SPI1 and SP13 for loopback. (Note: SPI1 and SP3 have an internal loopback connection for Xavier)

SPI_1 pinmux settings:
PADCTL_UART_SPI1_MISO_0  (0x0243d020) =  0x440;
PADCTL_UART_SPI1_MOSI_0 (0x0243d058) =  0x440;
PADCTL_UART_SPI1_SCK_0 (0x0243d040) =  0x440;
PADCTL_UART_SPI1_CS0_0 (0x0243d010) =  0x448;
PADCTL_UART_SPI1_CS1_0 (0x0243d050) =  0x448;

SPI_3 pinmux settings:
PADCTL_UART_SPI3_MISO_0  (0x0243d008) =  0x440;
PADCTL_UART_SPI3_MOSI_0 (0x0243d060) =  0x440;
PADCTL_UART_SPI3_SCK_0 (0x0243d048) =  0x444;
PADCTL_UART_SPI3_CS0_0 (0x0243d018) =  0x448;
PADCTL_UART_SPI3_CS1_0 (0x0243d028) =  0x448;
11

Could you share the document “Jetson_AGX_Series_DevKit_Pinmux_Configuration_Template.xlsm” ?
I did’t found the download link, Thanks.

12

Check with below link.

https://developer.nvidia.com/embedded/dlc/jetson-agx-series-devkit-pinmux-configuration-template

13

Hi ShaneCCC
Now we use two Xavier communicate through SPI, Xavier A as Master and Xavier B as Slave, The connection line is as follows

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When Xavier A and Xavier B execute spidev_test there is no waveform signal on SPI1_SCK、SPI1_CSO、SPI1_MISO、SPI1_MOSI, Xavier A and Xavier B can not receive any data, What’s the problem?

14

It could be the pinmux setting not correct.
Please have devmem2 to read them to confirm.