Free Electrons the top #18 contributor to the 3.11 kernel

The 3.11 Linux kernel has now been released by Linus Torvalds, and as usual as thousands of patches coming from a large number of companies and contributors. For this release, Free Electrons has contributed a total of 128 patches (yes, exactly 2^7), which makes Free Electrons the 18th contributor in the list of companies contributing to the kernel, according to, before Broadcom and Cisco, and after ARM and Oracle. It is also the first time that six different engineers from Free Electrons contribute code to the Linux kernel in a single release!

As usual, most of our contributions were centered around support for the Marvell Armada 370 and XP SOCs, the Allwinner SOCs and the Crystalfontz i.MX28 platforms:

  • Added support for the PCIe controllers of the Armada 370 and Armada XP platforms, and used it for the already supported Kirkwood platform. Supporting PCIe has been a very long process, which got started in December 2012, required long discussions with various kernel maintainers and multiple iterations of the patch series. Armada 370/XP was the first ARM platform to add Device Tree based PCIe support, and therefore this required many discussions to sort out the Device Tree bindings for PCIe controllers. This work was done by Thomas Petazzoni.
  • Enable an additional USB interface on the OpenBlocks AX3 platform, which is available as part of the mini-PCIe connector inside the device. This work was done by Thomas Petazzoni.
  • Cleaned up all the Kirkwood platform Device Tree files to assign the pin muxing configurations to the appropriate devices. This work was done by Thomas Petazzoni.
  • Made various cleanups and improvements in the Armada 370/XP platform code (in arch/arm/mach-mvebu) to make it possible to support different base address for the internal registers depending on the board being used. Many hardcoded physical addresses were removed, as well as the static virtual to physical mapping. This work was done by Thomas Petazzoni.
  • Cleaned up many ARM platforms to remove their unneeded ->init_irq() callback, and also the ->map_io() callback which we changed to default to calling debug_ll_io_init() when not provided. This work was done by Maxime Ripard.
  • Extended the ssd1307fb driver that we contributed a few releases ago to also support the SSD1306 device. The SSD1306 and SSD1307 are OLED screens controlled over I2C that are used on Crystalfontz i.MX28 platforms. We also optimized significantly the communication with the SSD130x devices. This work was done by Maxime Ripard.
  • Added an Ethernet driver for the Allwinner SOCs. The work was initially done by Stefan Roese, and our engineer Maxime Ripard did all the final cleanup, development of an MDIO driver, and integration with all the Device Tree files of the Allwinner platforms.
  • Added support for the Allwinner I2C controller, by re-using and extending the existing i2c-mv64xxx driver used on Marvell platforms, since the hardware block was very similar. The Allwinner Device Tree files were also updated to add the I2C controllers. This work was done by Maxime Ripard.
  • Added basic support for the Allwinner A10s SOC: pin muxing information and Device Tree information. This work was done by Maxime Ripard.
  • Added support for the Olimex A10s-Olinuxino-micro, a new hardware platform manufactured by Olimex that uses the Allwinner A10s SOC. This work was done by Maxime Ripard.
  • Implemented a “Device Bus” driver for the Marvell SOCs, that allows to configure the access to NOR flash and other devices connected to the memory bus. It has been used to enabled NOR support on the Armada XP DB development platform. This work was done by Ezequiel Garcia.
  • Fixed a few bugs in the IIO subsystem, and a build failure on AT91 platform when CONFIG_PHYLIB was not enabled. This work was done by Alexandre Belloni.
  • Fixed the ARM low-level code that handles compatibility with ATAG bootloaders, to properly convert 32 bits memory sizes passed by the bootloader into 64 bits cells of the Device Tree, when LPAE is used. This work was done by Gregory Clement.
  • Michael Opdenacker made a few improvements and fixes to the documentation.

For the upcoming 3.12, we already have 131 patches lined up, and a few more will probably show up after this blog post is written. Over the last release cycles, Free Electrons has become a regular contributor to ARM support in the Linux kernel, and we’re looking forward to doing more contributions in the future.

The details of our 3.11 contributions is:

Author: Thomas Petazzoni

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

Leave a Reply

Your email address will not be published. Required fields are marked *