driverBackgroundInformation
The drivers are written in the Video4Linux2 (V4L2) framework and have full device tree support.
Three main components are necessary for a V4L2 driver:
- Host driver: tegra_vi2 - This driver has originally been developed by Avionic Design for the Meerkat Nvidia TK1 platform and was ported to the TX1 by the HPMM research group
- Sensor (subdevice) driver: tc358840 - Based on the predecessor TC358743, this driver was developed by the HPMM research group and is getting into Linux Media
- Video buffer driver: tegra_vi2_vidq - The videobuf2 API is used with contiguous DMA buffers
Fig.2: Hardware and software components for using HDMI2CSI with a Nvidia Jetson TX1 host processor
The hardware-specific device configuration is handled in the Device Tree source file. It consists of two parts:
- The two TC358840 subdevices as I2C nodes
i2c7: i2c@546c0000 {
/* HDMI IN A (4K) */
tc358840xbg@0f {
...
};
/* HDMI IN B (Full HD) */
tc358840xbg@1f {
...
};
};
- and the video interface of the TX1 (in short: VI2) with two ports
host1x {
vi {
...
/* HDMI IN A */
port@0 {
...
};
/* HDMI IN B */
port@2 {
...
};
};
};
};