Since the Linux 2.6.36 kernel release in 2010, Samsung's involvement in the upstream kernel is up by 1.83 times according to data provided by the Linux Foundation. This increase in commits is more than any other company during the same time period and trailing behind are Texas Instruments, Broadcom, Wolfson, Nokia, Google, Atheros, AMD, and Intel.
This fast rate of Samsung's involvement within the upstream Linux kernel is largely about their large (and continually growing) mobile presence. Tizen hasn't really taken off yet but they have made a number of general improvements to the upstream Linux kernel plus other innovations like the Flash-Friendly File-System.
Samsung is also currently reported to be hiring around 20,000 software developers to work on other areas of Linux and open-source besides just the kernel. Other targets for Samsung reportedly include Cairo, UBoot, Xen, Hadoop, CloudStack, Wayland, GStreamer, FFmpeg, Linaro, Lighttpd, and Cassandra, among others.
More details on the recent growth statistics for Samsung's Linux involvement can be found at TizenExperts.com.