BayLibre contributions to Linux 6.7

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Linux 6.7 was released on January 7th. LWN has great coverage of the 6.7 merge window (part 1, part 2).

Here is a summary of the contributions made by BayLibre engineers in this release:

Amlogic SoCs

BayLibre continues to maintain and improve support for Amlogic SoCs in the kernel. 

Jerome Brunet added support for the Libretech cottonwood board family.  The 2 boards are based on the same PCB with an RPi B form factor.  The “Alta” board uses an A311D SoC while the “Solitude” variant uses an S905D3 SoC.

He also fixed audio support for the U200 and added the onboard audio devices.  The U200 is a reference board manufactured by Amlogic with the Amlogic S905D2 ARM Cortex-A53 quad-core SoC.

In addition, Jerome extended the TDM maximum sample rate to 384kHz for the Meson AXG and made a fix for the HDMI audio driver.

Analog Devices

ADI has engaged BayLibre to improve and expand support for their devices in the upstream Linux kernel.  As part of this effort, David Lechner has made a number of improvements to the AD2S1210 driver that allowed it to be promoted to a proper Linux kernel driver after 13 years in staging.  The AD2S1210 is a resolver-to-digital converter that can measure rotational position and speed of a motor.  David also made fixes to the Industrial I/O (iio) subsystem.

MediaTek SoCs

BayLibre continued to support MediaTek SoCs during this kernel release.

Bernhard Rosenkränzer contributed full LVTS support (MCU thermal domain + AP thermal domain) to MediaTek MT8192 SoC. In addition, the patch series add suspend and resume support to LVTS Driver (all SoCs), and updated the documentation that describes the Calibration Data Offsets.

Alexandre Mergnat added IOMMU support to MT8365 SoC which includes System Power Manager, MultiMedia Memory Management Unit “M4U” (IOMMU), Smart Multimedia Interface “SMI”, Local arbiter “LARB”.

Markus Schneider-Pargmann added power management domain support for the Mediatek MT8365 which is included in v6.7. This work was based patches from Alexandre Bailon plus some redesigning of the driver.

Texas Instruments SoCs

BayLibre continues to provide upstream support for TI parts.

Julien Panis added support for TPS6593 PMIC on the SK-AM62A-LP starter kit which provides regulators (bucks and LDOs), but also GPIOs, a RTC, a watchdog, an ESM (Error Signal Monitor) which monitors the SoC error output signal, and a PFSM (Pre-configurable Finite State Machine) which manages the operational modes of the PMIC.

Summary of BayLibre contributions in Linux 6.7

  Lines added: 4482
Lines removed: 1329
Files changed: 109
      Commits: 75
Signed-off-by: 15
  Reviewed-by: 41
     Acked-by: 10
    Tested-by: 5

Our U-Boot contributions in 2023

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U-Boot is an important open source bootloader used in many embedded Linux systems. U-Boot has a fixed release interval of every 3 months.  BayLibre engineers contributed to each release in 2023:

U-Boot v2023.01

  • Alexandre Mergnat enabled the MT81813 Pumpkin board to boot via extlinux
  • Julien Masson made it possible to store boot splashscreen images on raw eMMC storage
  • Mattijs Korpershoek fixed a fastboot issue that occurred when changing hardware partitions
  • Mattijs also contributed a fix to ensure USB is detached on fastboot reboot commands

U-Boot v2023.04

  • Mattijs updated USB OTG support for Amlogic Meson S905X2 to use the U-Boot Driver Model

U-Boot v2023.07

  • Safae Ouajih added Android Boot image v3 and v4 support. This allows implementing modern (Android 11+) boot flows which are mandatory for Android Generic Kernel Image (GKI).
  • Mattijs continued improving support for the Khadas VIM3 board by fixing the reset logic in the serial driver.

U-Boot v2023.10

  • Julien Panis made a fix for SPI transfers on TI OMAP3 family SoCs.
  • Mattijs fixed a performance regression on Android fastboot writing over USB.

Future contributions

Mattijs reviewed 84 patches and tested 44 patches in 2023. Mattijs has now become a co-maintainer of the USB DFU subsystem in U-Boot and has sent pull requests for the upcoming U-Boot v2024.01 release.