Tag: linux

Free seats in embedded Linux and kernel training sessions (Mar 2019)

Student penguinsAt Bootlin, we owe a lot to the Free Software community, and we’re doing our best to give back as much as we can.

One way of doing that is welcoming community contributors in our public training sessions organized in France. We’ve done that multiple times several years back, and this allowed us to meet very interesting people (who even had very valuable experience and points of view to share with the other course participants), while of course giving them extra knowledge that they can use for further contributions.

Here are the next sessions in which we can offer a free seat:

See our Free training seats page for practical details about how to apply.

Don’t hesitate to apply to this free seat. In past editions, we didn’t have so many people applying, and therefore you have a real chance to get selected!

Allwinner VPU support in mainline Linux end of the year status update

The end of 2018 is approaching, which is the right time to provide an update on where we stand with the Allwinner VPU support in Linux. The promise of our Kickstarter campaign was to deliver all funded stretch goals by the end of 2018. As we’ll explain below, all the goals have been met, and only the upstreaming process is not completely finished for some features.

With the Linux 4.20 release happening just a few days ago, the core of the Cedrus driver and the media Requests API that supports it are finally available through Linus Torvalds’ tree! They provide the required interface for hardware-accelerated MPEG-2 decoding on the A13, A20, A33 and H3 Allwinner SoCs.

Cedrus driver in staging

Discussions regarding the details of the stateless video decoding interface offered by the V4L2 API are still taking place, which explains why our driver was integrated as a staging media driver. It was also decided to hide the associated interface for MPEG-2 decoding from the public kernel headers for now. This way, the interface is not considered stable and can keep evolving as discussions are still taking place. Because the kernel has a policy of never breaking backward compatibility, these interfaces will hardly evolve once they are declared stable, so it is crucial to ensure they are ready when that happens. This is especially true given the level of complexity associated with video decoding and the various pitfalls paving that road.

Status of H264 and H265 decoding support

The code for H264 and H265 decoding is already developed and functional, has already been submitted for upstream inclusion but it hasn’t been merged yet. However, with the decoding interfaces considered unstable for now, it should become easier to bring-in H.264 and H.265 decoding support to mainline. Support for these two codecs in the API and our driver is still under review and we will continue sending new iterations for them, with the suggested changes and fixes as well as adaptations for the still-evolving decoding interface. More specifically, our series need to be updated to the latest proposal for identifying reference frames, which is now based on the timestamps of the buffers.

Platform support: H5, A64 and A10 on the horizon

Regarding the platforms supported by our driver, the patches for H5 and A64 support were accepted since our last update and they will make it to Linux 4.21! We are also looking to send out support for the A10, which was missing from our previous series (but shouldn’t cause any particular trouble).

DRM driver improvements

The adaptations for the DRM driver allowing to display the raw decoded frames from the VPU on older platforms were also finalized, with the first half of the series already queued for 4.21. Subsequent changes in the series are still waiting for more reviews as they affect common parts of the framework.

Conclusion

Overall, we are slowly closing down on this project and hoping to get the remaining pieces of our work integrated in mainline Linux as soon as possible, as there seems to be very few obstacles left in the way.

MIPI I3C support is now in upstream Linux

MIPI I3C specification publishedBack in August 2017, we wrote in a blog post about the first iteration of the Linux kernel subsystem we proposed to support the brand new MIPI I3C bus. Almost a year and half later, there are some really good news:

  • The Linux I3C support now has its own Git repository on kernel.org
  • The Linux I3C community has its mailing list.
  • Besides the first I3C controller driver we wrote for the Cadence I3C Master, Synopsys has contributed a second driver for their I3C master IP: i3c: master: Add driver for Synopsys DesignWare IP. This definitely helped show that there is interest in I3C beyond our contributions, and also helped validate that the subsystem was working fine for a different I3C controller.
  • The Linux I3C tree has been part of linux-next since November 6, 2018: linux-next: Tree for Nov 6.
  • The Linux I3C subsystem has received a Reviewed-by: Arnd Bergmann and later on a Acked-by: Greg Kroah-Hartman, which were two key approvals to move forward with the merging of I3C support.
  • I3C subsystem maintainer Boris Brezillon has therefore sent a pull request to get this subsystem merged in the upcoming 4.21 (or 5.0 ?) Linux kernel: [GIT PULL] i3c: Initial pull request, and this pull request has been merged by Linus Torvalds, so the I3C subsystem is now visible in Linus Git tree: drivers/i3c. The merge commit has been done on December 25, so it arrived as a very nice Christmas present!

It has been a long process, but we are proud and happy to have pioneered the support for I3C in the Linux kernel, from the design of the subsystem based on the I3C specifications all the way to its merging in the upstream Linux kernel and the creation of a small (but hopefully growing) community of developers around it.

Linux 4.19 released, Bootlin contributions

Penguin from Mylène Josserand
Drawing from Mylène Josserand,
based on a picture from Samuel Blanc under CC-BY-SA

With the 4.19 released last week by Greg Kroah-Hartman (and not Linus), it’s time to have a look at our contributions for this release.

As always, LWN.net did an interesting coverage of this release cycle merge window, highlighting the most important changes: the first half of the 4.19 merge window and the rest of the 4.19 merge window. For 4.19 only, Bootlin contributed a total of 295 patches, which puts us at the 10th place in the ranking of most contributing companies according to KPS.

Also according to LWN statistics, Bootlin’s engineer Boris Brezillon is the 16th most active developer in terms of commits for this release with a total of 85.

The main highlights of our contributions are:

Bootlin engineers are not only contributors, but also maintainers of various subsystems in the Linux kernel, which means they are involved in the process of reviewing, discussing and merging patches contributed to those subsystems:

  • Maxime Ripard, as the Allwinner platform co-maintainer, merged 93 patches from other contributors
  • Boris Brezillon, as the MTD/NAND maintainer, merged 38 patches from other contributors
  • Miquèl Raynal, as the NAND co-maintainer, merged 110 patches from other contributors
  • Alexandre Belloni, as the RTC and Microsemi maintainer and Atmel platform co-maintainer, merged 38 patches from other contributors
  • Grégory Clement, as the Marvell EBU co-maintainer, merged 16 patches from other contributors

Here is the commit by commit detail of our contributions to 4.19:

Linux 4.15 released, Bootlin contributions

Penguin from Mylène Josserand
Drawing from Mylène Josserand,
based on a picture from Samuel Blanc under CC-BY-SA

After a month of February busier than usual, with the renaming of our company from Free Electrons to Bootlin, our participation to FOSDEM and the welcoming of Maxime Chevallier, the latest addition to our engineering team, our article on the latest release of the Linux kernel arrives a bit late, more than a month after Linux 4.15 has been released by Linus Torvalds.

As usual, LWN.net did an interesting coverage of this release cycle merge window, highlighting the most important changes: The first half of the 4.15 merge window and The rest of the 4.15 merge window. Due to the now well-known Spectre and Meltdown vulnerabilities and the resulting effort to try to mitigate them, 4.15 required a -rc9, which happened the last time back in 2011 with the 3.1, Torvalds said.

According to Linux Kernel Patch statistics, Bootlin (now Bootlin) contributed 150 patches to this release, making it the 16th contributing company by number of commits.

The main highlights of our contributions are:

  • In the RTC subsystem, Alexandre Belloni made a number of improvements to various drivers, mainly making them use the nvmem subsystem where appropriate, and use the recently introduced rtc_register_device() API.
  • In the MTD subsystem, both Boris Brezillon and Miquèl Raynal made a number of contributions, mainly fixes.
  • For Marvell platforms
    • Antoine Ténart contributed a few fixes to the inside-secure crypto accelerator driver, used on Marvell Armada 3700 and Armada 7K/8K
    • Antoine Ténart also contributed fixes and improvements to the mvpp2 network driver, used for the Ethernet controller on the Marvell Armada 7K/8K. His improvements include preparation work to support Receive Side Scaling (RSS).
    • Antoine Ténart enabled more networking ports and features in some Armada 7K/8K boards, especially SFP ports on Armada 7040 DB and Armada 7040 DB.
    • Boris Brezillon contributed a few fixes to the Marvell CESA crypto accelerator driver, used on the older Orion, Kirkwood, Armada 370/XP/38x processors. He migrated the driver to use the skcipher interface of the Linux kernel crypto framework.
    • Grégory Clement enabled NAND support on Armada 7K, and contributed a number of fixes around MMC support for some Marvell boards.
    • Thomas Petazzoni contributed a few minor Device Tree enhancements for Marvell platforms: fixing MPP muxing on an older Kirkwood platform, enabling more PCIe ports on Armada 8040 DB, etc.
    • Miquèl Raynal contributed support for more advanced statistics in the mvpp2 network driver.
    • Miquèl Raynal added support for the extended UART for the Marvell Armada 3720 processor, both in the UART driver and in the Device Tree.
  • For the RaspberryPi platform, Boris Brezillon contributed a few fixes to the vc4 display driver, and added support for the new DRM_IOCTL_VC4_GEM_MADVISE ioctl, which can be used to ask the userspace applications to purge inactive buffers when allocations start to fail in the kernel.
  • For Allwinner platforms
    • Mylène Josserand contributed a fix for the Allwinner A83 clock driver, fixing I2C bus clocks.
    • Quentin Schulz contributed a few fixes to the sun4i-gpadc-iio.c driver, which is used for the ADCs on several Allwinner processors.
    • Maxime Ripard made a number of fixes to the sun8i-codec driver, fixing clock issues, left/right channels inversion, etc.
    • Maxime Ripard made a number of improvements to the sun4i DRM display driver.
    • Maxime Ripard improved the support for the A83 processor (described the UART1 controller, the MMC1 controller, added support for display clocks) and added the Device Tree for a new A83 device.
    • Maxime Ripard also did a number of cleanups and misc improvements in a significant number of Device Tree files for Allwinner platforms.
  • Thomas Petazzoni made a few fixes to the sh_eth network driver, used on several Renesas SuperH platform, as part of a recent project Bootlin did on SuperH 4.

Bootlin engineers are not only contributors, but also maintainers of various subsystems in the Linux kernel, which means they are involved in the process of reviewing, discussing and merging patches contributed to those subsystems:

  • Maxime Ripard, as the Allwinner platform co-maintainer, merged 108 patches from other contributors
  • Boris Brezillon, as the MTD/NAND maintainer, merged 34 patches from other contributors
  • Alexandre Belloni, as the RTC maintainer and Atmel platform co-maintainer, merged 50 patches from other contributors
  • Grégory Clement, as the Marvell EBU co-maintainer, merged 24 patches from other contributors

Here is the commit by commit detail of our contributons to 4.15:

Bootlin contributes Linux support for Microsemi MIPS SoC

VSC7513 Block Diagram
Microsemi VSC7513 Block Diagram
Earlier this month, Bootlin engineer Alexandre Belloni posted a patch series (in its second version) adding initial support for Microsemi Ocelot SoCs, the VSC7513 and VSC7514. These SoCs are used for switches, so the biggest part of the chip is a switch fabric, built around a MIPS core and a few basic peripherals. While Bootlin generally works on ARM platforms and has contributed support for numerous ARM processors in the Linux kernel, for this project we are contributing the support for a MIPS processor.

Alexandre’s initial patch series contains the basic support for the SoC:

All in all, this patch series only adds support to boot the platform up to a shell, with interrupts, pin-muxing, GPIOs and UARTs enabled. Additional features will be contributed later, especially support for the switch fabric in the form of a switchdev driver.

We are happy to be working on Microsemi platforms, and to bring the support for yet another hardware platform to the official Linux kernel.

Linux 4.14 released, Bootlin contributions

Penguin from Mylène Josserand
Drawing from Mylène Josserand,
based on a picture from Samuel Blanc under CC-BY-SA
Linux 4.14, which is going to become the next Long Term Supported version, has been released a week ago by Linus Torvalds. As usual, LWN.net did an interesting coverage of this release cycle merge window, highlighting the most important changes: The first half of the 4.14 merge window and The rest of the 4.14 merge window.

According to Linux Kernel Patch statistics, Bootlin contributed 111 patches to this release, making it the 24th contributing company by number of commits: a somewhat lower than usual contribution level from our side. At least, Bootlin cannot be blamed for trying to push more code into 4.14 because of its Long Term Support nature! 🙂

The main highlights of our contributions are:

  • On the RTC subsystem, Alexandre Belloni made as usual a number of fixes and improvements to various drivers, especially the ds1307 driver.
  • On the NAND subsystem, Boris Brezillon did a number of small improvements in various areas.
  • On the support for Marvell platforms
    • Antoine Ténart improved the ppv2 network driver used by the Marvell Armada 7K/8K SoCs: support for 10G speed and TSO support are the main highlights. In order to support 10G speed, Antoine added a driver in drivers/phy/ to configure the common PHYs in the Armada 7K/8K SoCs.
    • Thomas Petazzoni also improved the ppv2 network driver by adding support for TX interrupts and per-CPU RX interrupts.
    • Grégory Clement contributed some patches to enable NAND support on Armada 7K/8K, as well as a number of fixes in different areas (GPIO fix, clock handling fixes, etc.)
    • Miquèl Raynal contributed a fix for the Armada 3700 SPI controller driver.
  • On the support for Allwinner platforms
    • Maxime Ripard contributed the support for a new board, the BananaPI M2-Magic. Maxime also contributed a few fixes to the Allwinner DRM driver, and a few other misc fixes (clock, MMC, RTC, etc.).
    • Quentin Schulz contributed the support for the power button functionality of the AXP221 (PMIC used in several Allwinner platforms)
  • On the support for Atmel platforms, Quentin Schulz improved the clock drivers for this platform to properly support the Audio PLL, which allowed to fix the Atmel audio drivers. He also fixed suspend/resume support in the Atmel MMC driver to support the deep sleep mode of the SAMA5D2 processor.

In addition to making direct contributions, Bootlin is also involved in the Linux kernel development by having a number of its engineers act as Linux kernel maintainers. As part of this effort, Bootlin engineers have reviewed, merged and sent pull requests for a large number of contributions from other developers:

  • Boris Brezillon, as the NAND subsystem maintainer and MTD subsystem co-maintainer, merged 68 patches from other developers.
  • Alexandre Belloni, as the RTC subsystem maintainer and Atmel ARM platform co-maintainer, merged 32 patches from other developers.
  • Grégory Clement, as the Marvell ARM platform co-maintainer, merged 29 patches from other developers.
  • Maxime Ripard, as the Allwinner ARM platform co-maintainer, merged 18 patches from other developers.

This flow of patches from kernel maintainers to other kernel maintainers is also nicely described for the 4.14 release by the Patch flow into the mainline for 4.14 LWN.net article.

The detailed list of our contributions:

Linux 4.13 released, Bootlin contributions

Linux 4.13 was released last Sunday by Linus Torvalds, and the major new features of this release were described in details by LWN in a set of articles: part 1 and part 2.

This release gathers 13006 non-merge commits, amongst which 239 were made by Bootlin engineers. According to the LWN article on 4.13 statistics, this makes Bootlin the 13th contributing company by number of commits, the 10th by lines changed.

The most important contributions from Bootlin for this release have been:

  • In the RTC subsystem
    • Alexandre Belloni introduced a new method for registering RTC devices, with one step for the allocation, and one step for the registration itself, which allows to solve race conditions in a number of drivers.
    • Alexandre Belloni added support for exposing the non-volatile memory found in some RTC devices through the Linux kernel nvmem framework, making them usable from userspace. A few drivers were changed to use this new mechanism.
  • In the MTD/NAND subsystem
    • Boris Brezillon did a large number of fixes and minor improvements in the NAND subsystem, both in the core and in a few drivers.
    • Thomas Petazzoni contributed the support for on-die ECC, specifically with Micron NANDs. This allows to use the ECC calculation capabilities of the NAND chip itself, as opposed to using software ECC (calculated by the CPU) or ECC done by the NAND controller.
    • Thomas Petazzoni contributed a few improvements to the FSMC NAND driver, used on ST Spear platforms. The main improvement is to support the ->setup_data_interface() callback, which allows to configure optimal timings in the NAND controller.
  • Support for Allwinner ARM platforms
    • Alexandre Belloni improved the sun4i PWM driver to use the so-called atomic API and support hardware read out.
    • Antoine Ténart improved the sun4i-ss cryptographic engine driver to support the Allwinner A13 processor, in addition to the already supported A10.
    • Maxime Ripard contributed HDMI support for the Allwinner A10 processor (in the DRM subsystem) and a number of related changes to the Allwinner clock support.
    • Quentin Schulz improved the support for battery charging through the AXP20x PMIC, used on Allwinner platforms.
  • Support for Atmel ARM platforms
    • Alexandre Belloni added suspend/resume support for the Atmel SAMA5D2 clock driver. This is part of a larger effort to implement the backup mode for the SAMA5D2 processor.
    • Alexandre Belloni added suspend/resume support in the tcb_clksrc driver, used as for clocksource and clockevents on Atmel SAMA5D2.
    • Alexandre Belloni cleaned up a number of drivers, removing support for non-DT probing, which is possible now that the AVR32 architecture has been dropped. Indeed, the AVR32 processors used to share the same drivers as the Atmel ARM processors.
    • Alexandre Belloni added the core support for the backup mode on Atmel SAMA5D2, a suspend/resume state with significant power savings.
    • Boris Brezillon switched Atmel platforms to use the new binding for the EBI and NAND controllers.
    • Boris Brezillon added support for timing configuration in the Atmel NAND driver.
    • Quentin Schulz added suspend/resume support to the Bosch m_can driver, used on Atmel platforms.
  • Support for Marvell ARM platforms
    • Antoine Ténart contributed a completely new driver (3200+ lines of code) for the Inside Secure EIP197 cryptographic engine, used in the Marvell Armada 7K and 8K processors. He also subsequently contributed a number of fixes and improvements for this driver.
    • Antoine Ténart improved the existing mvmdio driver, used to communicate with Ethernet PHYs over MDIO on Marvell platforms to support the XSMI variant found on Marvell Armada 7K/8K, used to communicate with 10G capable PHYs.
    • Antoine Ténart contributed minimal support for 10G Ethernet in the mvpp2 driver, used on Marvell Armada 7K/8K. For now, the driver still relies on low-level initialization done by the bootloader, but additional changes in 4.14 and 4.15 will remove this limitation.
    • Grégory Clement added a new pinctrl driver to configure the pin-muxing on the Marvell Armada 37xx processors.
    • Grégory Clement did a large number of changes to the clock drivers used on the Marvell Armada 7K/8K processors to prepare the addition of pinctrl support.
    • Grégory Clement added support for Marvell Armada 7K/8K to the existing mvebu-gpio driver.
    • Thomas Petazzoni added support for the ICU, a specialized interrupt controller used on the Marvell Armada 7K/8K, for all devices located in the CP110 part of the processor.
    • Thomas Petazzoni removed a work-around to properly resume per-CPU interrupts on the older Marvell Armada 370/XP platforms.
  • Support for RaspberryPi platforms
    • Boris Brezillon added runtime PM support to the HDMI encoder driver used on RaspberryPi platforms, and contributed a few other fixes to the VC4 DRM driver.

It is worth mentioning that Miquèl Raynal, recently hired by Bootlin, sees his first kernel patch merged: nand: fix wrong default oob layout for small pages using soft ecc.

Bootlin engineers are not only contributors, but also maintainers of various subsystems in the Linux kernel, which means they are involved in the process of reviewing, discussing and merging patches contributed to those subsystems:

  • Maxime Ripard, as the Allwinner platform co-maintainer, merged 113 patches from other contributors
  • Boris Brezillon, as the MTD/NAND maintainer, merged 62 patches from other contributors
  • Alexandre Belloni, as the RTC maintainer and Atmel platform co-maintainer, merged 57 patches from other contributors
  • Grégory Clement, as the Marvell EBU co-maintainer, merged 47 patches from other contributors

Here is the commit by commit detail of our contributors to 4.13:

Bootlin proposes an I3C subsystem for the Linux kernel

MIPI I3C fact sheet, from the MIPI I3C white paper
MIPI I3C fact sheet, from the MIPI I3C white paper
At the end of 2016, the MIPI consortium has finalized the first version of its I3C specification, a new communication bus that aims at replacing older busses like I2C or SPI. According to the specification, I3C gets closer to SPI data rate while requiring less pins and adding interesting mechanisms like in-band interrupts, hotplug capability or automatic discovery of devices connected on the bus. In addition, I3C provides backward compatibility with I2C: I3C and legacy I2C devices can be connected on a common bus controlled by an I3C master.

For more details about I3C, we suggest reading the MIPI I3C Whitepaper, as unfortunately MIPI has not publicly released the specifications for this protocol.

For the last few months, Bootlin engineer Boris Brezillon has been working with Cadence to develop a Linux kernel subsystem to support this new bus, as well as Cadence’s I3C master controller IP. We have now posted the first version of our patch series to the Linux kernel mailing list for review, and we already received a large number of very useful comments from the kernel community.

Bootlin is proud to be pioneering the support for this new bus in the Linux kernel, and hopes to see other developers contribute to this subsystem in the near future!

Linux 4.12, Bootlin contributions

Linus Torvalds has released the 4.12 Linux kernel a week ago, in what is the second biggest kernel release ever by number of commits. As usual, LWN had a very nice coverage of the major new features and improvements: first part, second part and third part.

LWN has also published statistics about the Linux 4.12 development cycles, showing:

  • Bootlin as the #14 contributing company by number of commits, with 221 commits, between Broadcom (230 commits) and NXP (212 commits)
  • Bootlin as the #14 contributing company number of changed lines, with 16636 lines changed, just two lines less than Mellanox
  • Bootlin engineer and MTD NAND maintainer Boris Brezillon as the #17 most active contributor by number of lines changed.

Our most important contributions to this kernel release have been:

  • On Atmel AT91 and SAMA5 platforms:
    • Alexandre Belloni has continued to upstream the support for the SAMA5D2 backup mode, which is a very deep suspend to RAM state, offering very nice power savings. Alexandre touched the core code in arch/arm/mach-at91 as well as pinctrl and irqchip drivers
    • Boris Brezillon has converted the Atmel PWM driver to the atomic API of the PWM subsystem, implemented suspend/resume and did a number of fixes in the Atmel display controller driver, and also removed the no longer used AT91 Parallel ATA driver.
    • Quentin Schulz improved the suspend/resume hooks in the atmel-spi driver to support the SAMA5D2 backup mode.
  • On Allwinner platforms:
    • Mylène Josserand has made a number of improvements to the sun8i-codec audio driver that she contributed a few releases ago.
    • Maxime Ripard added devfreq support to dynamically change the frequency of the GPU on the Allwinner A33 SoC.
    • Quentin Schulz added battery charging and ADC support to the X-Powers AXP20x and AXP22x PMICs, found on Allwinner platforms.
    • Quentin Schulz added a new IIO driver to support the ADCs found on numerous Allwinner SoCs.
    • Quentin Schulz added support for the Allwinner A33 built-in thermal sensor, and used it to implement thermal throttling on this platform.
  • On Marvell platforms:
    • Antoine Ténart contributed Device Tree changes to describe the cryptographic engines found in the Marvell Armada 7K and 8K SoCs. For now only the Device Tree description has been merged, the driver itself will arrive in Linux 4.13.
    • Grégory Clement has contributed a pinctrl and GPIO driver for the Marvell Armada 3720 SoC (Cortex-A53 based)
    • Grégory Clement has improved the Device Tree description of the Marvell Armada 3720 and Marvell Armada 7K/8K SoCs and corresponding evaluation boards: SDHCI and RTC are now enabled on Armada 7K/8K, USB2, USB3 and RTC are now enabled on Armada 3720.
    • Thomas Petazzoni made a significant number of changes to the mvpp2 network driver, finally adding support for the PPv2.2 version of this Ethernet controller. This allowed to enable network support on the Marvell Armada 7K/8K SoCs.
    • Thomas Petazzoni contributed a number of fixes to the mv_xor_v2 dmaengine driver, used for the XOR engines on the Marvell Armada 7K/8K SoCs.
    • Thomas Petazzoni cleaned-up the MSI support in the Marvell pci-mvebu and pcie-aardvark PCI host controller drivers, which allowed to remove a no-longer used MSI kernel API.
  • On the ST SPEAr600 platform:
    • Thomas Petazzoni added support for the ADC available on this platform, by adding its Device Tree description and fixing a clock driver bug
    • Thomas did a number of small improvements to the Device Tree description of the SoC and its evaluation board
    • Thomas cleaned up the fsmc_nand driver, which is used for the NAND controller driver on this platform, removing lots of unused code
  • In the MTD NAND subsystem:
    • Boris Brezillon implemented a mechanism to allow vendor-specific initialization and detection steps to be added, on a per-NAND chip basis. As part of this effort, he has split into multiple files the vendor-specific initialization sequences for Macronix, AMD/Spansion, Micron, Toshiba, Hynix and Samsung NANDs. This work will allow in the future to more easily exploit the vendor-specific features of different NAND chips.
  • Other contributions:
    • Maxime Ripard added a display panel driver for the ST7789V LCD controller

In addition, several Bootlin engineers are also maintainers of various kernel subsystems. During this release cycle, they reviewed and merged a number of patches from kernel contributors:

  • Maxime Ripard, as the Allwinner co-maintainer, merged 94 patches
  • Boris Brezillon, as the NAND maintainer and MTD co-maintainer, merged 64 patches
  • Alexandre Belloni, as the RTC maintainer and Atmel co-maintainer, merged 38 patches
  • Grégory Clement, as the Marvell EBU co-maintainer, merged 32 patches

The details of all our contributions for this release: