Linux 4.4, Free Electrons contributions

Linux 4.4 is the latest releaseLinux 4.4 has been released, a week later than the normal schedule in order to allow kernel developers to recover from the Christmas/New Year period. As usual, LWN has covered the 4.4 cycle merge window, in two articles: part 1 and part 2. This time around, KernelNewbies has a nice overview of the Linux 4.4 changes. With 112 patches merged, we are the 20th contributing company by number of patches according to the statistics.

Besides our contributions in terms of patches, some of our engineers have also become over time maintainers of specific areas of the Linux kernel. Recently, conducted a study of how the patches merged in 4.4 went into the kernel, which shows the chain of maintainers who pushed the patches up to Linus Torvalds. Free Electrons engineers had the following role in this chain of maintainers:

  • As a co-maintainer of the Allwinner (sunxi) ARM support, Maxime Ripard has submitted a pull request with one patch to the clock maintainers, and pull requests with a total of 124 patches to the ARM SoC maintainers.
  • As a maintainer of the RTC subsystem, Alexandre Belloni has submitted pull requests with 30 patches directly to Linus Torvalds.
  • As a co-maintainer of the AT91 ARM support, Alexandre Belloni has submitted pull requests with 46 patches to the ARM SoC maintainers.
  • As a co-maintainer of the Marvell EBU ARM support, Gregory Clement has submitted pull requests with a total of 33 patches to the ARM SoC maintainers.

Our contributions for the 4.4 kernel were centered around the following topics:

  • Alexandre Belloni continued some general improvements to support for the AT91 ARM processors, with fixes and cleanups in the at91-reset, at91-poweroff, at91_udc, atmel-st, at91_can drivers and some clock driver improvements.
  • Alexandre Belloni also wrote a driver for the RV8803 RTC from Microcrystal.
  • Antoine Ténart added PWM support for the Marvell Berlin platform and enabled the use of cpufreq on this platform.
  • Antoine Ténart did some improvements in the pxa3xx_nand driver, still in preparation to the addition of support for the Marvell Berlin NAND controller.
  • Boris Brezillon did a number of improvements to the sunxi_nand driver, used for the NAND controller found on the Allwinner SoCs. Boris also merged a few patches doing cleanups and improvements to the MTD subsystem itself.
  • Boris Brezillon enabled the cryptographic accelerator on more Marvell EBU platforms by submitting the corresponding Device Tree descriptions, and he also fixed a few bugs found in the driver
  • Maxime Ripard reworked the interrupt handling of per-CPU interrupts on Marvell EBU platforms especially in the mvneta network driver. This was done in preparation to enable RSS support in the mvneta driver.
  • Maxime Ripard added support for the Allwinner R8 and the popular C.H.I.P platform.
  • Maxime Ripard enabled audio support on a number of Allwinner platforms, by adding the necessary clock code and Device Tree descriptions, and also several fixes/improvements to the ALSA driver.

The details of our contributions for 4.4:

About Thomas Petazzoni

Thomas Petazzoni is an embedded Linux and kernel engineer at Free Electrons. He is a lead developer of Buildroot and also a contributor to the Linux kernel. More details...
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