The second result seems more reasonable for SPI usage.
Please make sure your pinmux configured as following.
spi1_sck_pz3 {
nvidia,pins = "spi1_sck_pz3";
nvidia,function = "spi1";
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_DISABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
spi1_miso_pz4 {
nvidia,pins = "spi1_miso_pz4";
nvidia,function = "spi1";
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_ENABLE>;
nvidia,enable-input = <TEGRA_PIN_ENABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
spi1_mosi_pz5 {
nvidia,pins = "spi1_mosi_pz5";
nvidia,function = "spi1";
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_DISABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
spi1_cs0_pz6 {
nvidia,pins = "spi1_cs0_pz6";
nvidia,function = "spi1";
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_DISABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
spi1_cs1_pz7 {
nvidia,pins = "spi1_cs1_pz7";
nvidia,function = "spi1";
nvidia,pull = <TEGRA_PIN_PULL_NONE>;
nvidia,tristate = <TEGRA_PIN_DISABLE>;
nvidia,enable-input = <TEGRA_PIN_DISABLE>;
nvidia,io-high-voltage = <TEGRA_PIN_DISABLE>;
nvidia,lpdr = <TEGRA_PIN_DISABLE>;
};
Could you connect MOSI/MISO and refer to the Step4-Step6 of the following thread to verify loopback test?
Jetson Nano SPI Bus Not Working - #10 by KevinFFF