Device Tree Patches Posted For Review To Boot Linux On Apple A7 To A11 Devices

Device Tree patches have been posted to the Linux kernel mailing list for review and possible upstreaming to the mainline Linux kernel for booting Apple iPhones, iPads, and iPods that use the A7 to A11 SoCs.

The Device Tree (DT) patches for the many Apple A7 / A8 / A8X / A9 / A9X / A10 / A10X / A11 powered devices is out for review on the Linux kernel mailing list. This follows various other Linux kernel driver patches posted for review recently to fix various issues needed for enabling the Apple iPhones / iPads / iPod Touch / Apple TVs on Linux.

The DT support was worked out by open-source developer Konrad Dybcio and posted to the LKML by Nick Chan with additional modifications. Chan explained with the cover letter on the patch series:

"This series adds device trees for all A7-A11 SoC based iPhones, iPads, iPod touches and Apple TVs.

The following devices has been excluded from this series:
- All T2 devices (A10-based): bootloader does not work (yet)
- HomePod: Not tested, and it's also a different form factor

This series supports the following on all devices:
- SMP (spin-table)
- UART
- simple-framebuffer
- watchdog
- timer
- pinctrl
- AIC interrupts

The following is supported on A7-A10:
- gpio-keys
The buttons on A11 based devices like the iPhone X is a SMC subdevice, and cannot be supported in this way.

The following is supported on A10:
- cpufreq

A10(X) has performance and efficiency core pairs that act as single logical cores, and only one type of core can be active at a given time. This results in a core that suddenly have its capacity lowered in low p-states, so the frequencies of the low p-states must be adjusted."

Those interested in seeing these older Apple device/SoC support with the mainline Linux kernel can see this patch series now under review.