Hello,
I am attempting to set up an ADIS16448 imu on a Nvidia Jetson TK1 over SPI. I have been following the guide here to configure the Jetson TK1 for spidev.
After following this guide, I have verified that I can communicate out over the SPI interface on the TK1 using the configured spidev interface by tweaking the ioctl commands as shown in the code sample from the tutorial.
I have compiled the kernel modules and made sure that they are loaded:
username@host:~$ lsmod
Module Size Used by
dm_crypt 12216 0
bnep 11872 2
rfcomm 46483 0
rtc_as3722 3212 0
bluetooth 279594 10 bnep,rfcomm
rfkill 14634 3 bluetooth
parport_pc 28658 0
parport 27466 1 parport_pc
adis16400 10748 0
adis_lib 5597 1 adis16400
nvhost_vi 2908 0
The tutorial linked above has the following snippet from the device tree:
spi@7000d400 {
compatible = "nvidia,tegra114-spi";
reg = <0x7000d400 0x200>;
interrupts = <0x0 0x3b 0x4>;
nvidia,dma-request-selector = <0x7 0xf>;
nvidia,memory-clients = <0xe>;
#address-cells = <0x1>;
#size-cells = <0x0>;
status = "okay";
spi-max-frequency = <0x17d7840>;
spi0_0 {
#address-cells = <0x1>;
#size-cells = <0x0>;
compatible = "spidev";
reg = <0x0>;
spi-max-frequency = <0x17d7840>;
spi-cpha;
nvidia,enable-hw-based-cs;
nvidia,cs-setup-clk-count = <0x1e>;
nvidia,cs-hold-clk-count = <0x1e>;
nvidia,rx-clk-tap-delay = <0x1f>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
where spi0_0 corresponds to the spidev device that presents itself as /dev/spidev0.0
My guess is that I need to join the IMU to this same spi bus, but I am unsure how. I have attempted to follow this similar issue that deals with the same concepts on the beaglebone, but the device tree is so vastly different that I am uncertain whether I am doing it right.
By adding the spi0_1 entry (as seen below), I was able to get your IIO driver to present itself. Note that when I have it configured like this, the spidev device seems to be unable to access the chip select line (as verified by my logic analyzer). I believe that both devices want to use reg = <0x0> for their chip select.
spi@7000d400 {
compatible = "nvidia,tegra114-spi";
reg = <0x7000d400 0x200>;
interrupts = <0x0 0x3b 0x4>;
nvidia,dma-request-selector = <0x7 0xf>;
nvidia,memory-clients = <0xe>;
#address-cells = <0x1>;
#size-cells = <0x0>;
status = "okay";
spi-max-frequency = <0x17d7840>;
spi0_0 {
#address-cells = <0x1>;
#size-cells = <0x0>;
compatible = "spidev";
reg = <0x1>;
spi-max-frequency = <0x17d7840>;
spi-cpha;
nvidia,enable-hw-based-cs;
nvidia,cs-setup-clk-count = <0x1e>;
nvidia,cs-hold-clk-count = <0x1e>;
nvidia,rx-clk-tap-delay = <0x1f>;
nvidia,tx-clk-tap-delay = <0x0>;
};
spi0_1{
#address-cells = <0x1>;
#size-cells = <0x0>;
compatible = "adi,adis16400";
reg = <0x0>;
spi-cpha;
spi-cpol;
spi-max-frequency = <0x17d7840>;
nvidia,enable-hw-based-cs;
nvidia,cs-setup-clk-count = <0x10>;
nvidia,cs-hold-clk-count = <0x10>;
nvidia,rx-clk-tap-delay = <0x28>;
nvidia,tx-clk-tap-delay = <0x0>;
};
};
My issue is that when I add the spi0_1 piece, the device shows up under the IIO but when I attempt to read values, they all return "0". I am new to the concept of device trees, so I believe that I am close, but I just need to tweak these entries somehow.
Any info on how to get data out of the device from this stage would be helpful =)
Thank you,
Curtis