Some interesting code updates were just recently put into the Linux 4.19 kernel merge window regarding “multi-function device” capabilities – mostly, this includes several new drivers and driver support, but perhaps most interesting is the ChromeOS EC CEC driver being added.
Google’s embedded controller for ChromeOS has been able to expose an HDMI CEC (Consumer Electronics Control) bus for interacting with HDMI-connected devices, which in turn is able to control them via supported commands. So now Linux kernel’s HDMI CEC support has been improved over the past few kernel cycles until now, which means that the ChromeOS EC support will be able to expose the HDMI CEC abilities utilizing the new driver added in this merge window.
On top of that, there is also update code for prep work to support HDMI CEC with the Intel DRM driver. Additionally, USB charging support has also been added to the Linux 4.19 kernel for ChromeOS EC driver.
For development on Intel drivers, the necessary IDs for Intel’s Icelake series of processors has been added to the intel-lpss driver (Low Power Subsystem) – this is great to see the Intel Linux driver development team stepping up their Icelake support on Linux, and with the Cannonlake CPU support having been addressed satisfactorily in the past, overall things are looking great for Intel processors on the Linux 4.19 kernel.
Finally, accessory detection for Madera devices was added, along with Cirrus Logic Madera Codec support for CS47L35, CS47L85, and CS47L90/91 drivers – which should be good news for Linux audiophiles and sound engineers.
The overall changelog summary is as follows, but you can find the entire changelog on the Git pull:
- Add Cirrus Logic Madera Codec (CS47L35, CS47L85 and CS47L90/91) driver
- Add ChromeOS EC CEC driver
- Add ROHM BD71837 PMIC driver
- Add support for Dialog Semi DA9063L PMIC variant to DA9063
- Add support for Intel Ice Lake to Intel-PLSS-PCI
- Add support for X-Powers AXP806 to AXP20x
- Add support for USB Charging to the ChromeOS Embedded Controller
- Add support for HDMI CEC to the ChromeOS Embedded Controller
- Add support for HDMI CEC to Intel HDMI
- Add support for accessory detection to Madera devices
- Allow individual pins to be configured via DT’ wlf,csnaddr-pd
- Provide legacy platform specific EEPROM/Watchdog commands; rave-sp
- Trivial renaming/spelling fixes; cros_ec, da9063-*
- Convert to Managed Resources (devm_*); da9063-*, ti_am335x_tscadc
- Transition to helper macros/functions; da9063-*
- Constify; kempld-core
- Improve error path/messages; wm8994-core
- Disable IRQs locally instead of relying on USB subsystem; dln2
- Remove unused code; rave-sp
- New exports; sec-core
- Fix possible false I2C transaction error; arizona-core
- Fix declared memory area size; hi655x-pmic
- Fix checksum type; rave-sp
- Fix incorrect default serial port configuration: rave-sp
- Fix incorrect coherent DMA mask for sub-devices; sm501