Tegra the chipset is supported by Nvidia, but even then they are not a paragon of cooperation with the Linux community. They have their own non-mainlined driver

Tegra the chipset is supported by Nvidia, but even then they are not a paragon of cooperation with the Linux community. They have their own non-mainlined driver, while the mainlined one (tegra) is done by someone else. They did contribute somewhat to the "tegra" driver at least.