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Martin Kepplinger

Latest posts by Martin Kepplinger (see all)

• PureOS Unaffected by ext4 Data Corruption Bug - January 2, 2024
• Purism and Linux 6.5 to 6.7 - December 22, 2023
• Purism and Linux 6.2 to 6.4 - July 13, 2023

Purism and Linux 5.9 and Linux 5.10

Following up on our report for Linux 5.8 this summarizes the progress on mainline support for the Librem 5 phone and its development kit during the 5.9 and 5.10 development cycles.

Librem 5 updates

One of the most notable additions is a first devicetree description for the phone. This is important to have upstream since it describes how the hardware is wired up. Without that, it’s impossible to boot a mainline kernel. We added descriptions for the various phone revisions themselves (up to the Dogwood board) and also for the MIPI DSI controller of the imx8mq SoC. From this point on, we’ll incrementally add the missing pieces, for example from the display stack, just like we’ve done for the devkit back in Linux 5.2.

• dt-bindings: arm: fsl: Add the Librem 5 phone
• arm64: dts: Add a device tree for the Librem 5 phone
• arm64: dts: imx8mq: Add NWL MIPI DSI controller

Librem 5 LCD panel

Speaking of the display stack: The phone includes a different LCD panel than the devkit and we had to add a driver for it:

• dt-binding: display: Require two resets on mantix panel
• drm/panel: mantix: Fix panel reset
• drm/panel: mantix: Don’t dereference NULL mode
• arm64: defconfig: re-sync DRM related defconfig bits
• drm/panel: Add panel driver for the Mantix MLAF057WE51-X DSI panel
• dt-bindings: Add Mantix MLAF057WE51-X panel bindings
• dt-bindings: vendor-prefixes: Add mantix vendor prefix
• drm/mxsfb: Make supported modifiers explicit

Devkit updates

Another milestone we reached (and had promised earlier) is that the devkits’ display now works with mainline Linux directly. All needed drivers are there and the hardware is described accurately in the devicetree upstream. It’s not only nice to be able to use a mainline kernel without (m)any patches, it’s important in order to keep the hardware supported for a long time. The hard parts had been done before and that’s how the final pieces for the display look like:

• arm64: dts: imx8mq-librem5-devkit: Enable the LCD panel
• arm64: defconfig: Enable imx8mq-librem5-devkit display stack
• dt-bindings: panel: rocktech,jh057n00900: Add myself as maintainer
• dt-bindings: panel: rocktech,jh057n00900: Modernize

Audio Codec

The wm8962 audio codec needed a small update to allow userspace to utilize hardware mono downmix for cases where mono output to a single speaker is desired only, like on a mobile phone:

• ASoC: wm8962: Export DAC/ADC monomix switches

Code review

During these rounds, we contributed 24 Reviewed-by: or Tested-by: tags to patches by other authors. Also, we would like to thank everybody who reviewed our patches and helped us, especially Sam in the DRM layer and Shawn and Krzysztof in the devicetree area. It’s supposed to be fun but we know it not always actually is, so that’s much appreciated.

Sources

Have a look at our Linux tree to see what is currently being worked on and tested (or help if you feel like joining the fun).

Discover the Librem 5

Purism believes building the Librem 5 is just one step on the road to launching a digital rights movement, where we—the-people stand up for our digital rights, where we place the control of your data and your family’s data back where it belongs: in your own hands.

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