[PATCH 0/8] PinePhone automatic device tree selection

[André Przywara]

On 03/09/2020 06:07, Samuel Holland wrote:

Hi Samuel,

> This patch series implements a feature to automatically choose the
> right PinePhone device tree by probing the hardware. It then extends
> the functionality to pass the chosen DTB name to the boot command.
> Finally, I add device trees and a defconfig for the PinePhone.
> 
> I'm aware that Andre has concerns about updating the device tree files.
> It would be unfortunate for this to block new hardware support.

I agree that it shouldn't block it.

> Since
> the device trees are primarily maintained in the Linux repository, and
> only copied here, I believe compatibility concerns should be directed
> there, not here.

Sigh. I tried that there, multiple times, and was basically dismissed.
IIRC the main argument was that we (as the sunxi community) do not have
the resources to pull off something like compatible DTs. The DTs are
being created and written as we go, so maintaining forward compatibility
is not something the Linux maintainers wanted to subscribe to.
And while I see that's *some* extra effort, I argued that it's worth it,
even providing solutions. Otherwise I am afraid that we end up in the
embedded rabbit hole that we see today, where dozens of images are
traded around, even though there are generic distributions available.

We parted by agreeing on putting those necessary DT changes into U-Boot
instead. Commit ababb5920e899 is one example of this. I tried to prevent
further changes, but failed.

> In any case, the first 6 patches can be merged
> independently, so I request that they be merged even if patches 7-8 are
> not. I am mainly including the last two patches for ease of testing.

So I have some easy patches that improve DT compatibility, I guess we
can just apply them later. The most prominent issue is the change of the
RTC compatible name. This seems to cost us the RTC (bearable?) and, in
turn, the debouncing feature of the GPIO controller (through the newly
introduced clock in the RTC).
There seem to be more issues that popped up in testing. I guess we would
need to define some supported kernels, and test them. The effort for
this depends on how far back we want to support Linux kernels and with
what feature set. I ran a headless board fine here with Ubuntu's 18.04
original kernel, which is 4.15 based. I might concede to give this up,
if needed, to go back to only 4.19 (Debian), or maybe 4.18 (Ubuntu
18.04.2 HWE kernel).

I will have a look at the other patches later. It seems like you jump
through some hoops to be able to set fdtfile in U-Boot proper later? I
consider this conceptually dodgy ($fdtcontroladdr should be all you
need), but don't care enough, as it does not seem to break things.

Cheers,
Andre

> Samuel Holland (8):
>   sunxi: board: Use a more descriptive variable name
>   sunxi: board: Add a helper to get the SPL DT name
>   sunxi: board: Simplify Pine A64 DT selection logic
>   sunxi: board: Add PinePhone DT selection logic
>   sunxi: board: Save the chosen DT name in the SPL header
>   sunxi: board: Set fdtfile to match the DT chosen by SPL
>   sunxi: DT: A64: update device tree files
>   sunxi: a64: Add a defconfig for the PinePhone
> 
>  arch/arm/dts/Makefile                         |   4 +
>  arch/arm/dts/axp803.dtsi                      |  82 +--
>  arch/arm/dts/sun50i-a64-amarula-relic.dts     | 109 +++-
>  arch/arm/dts/sun50i-a64-bananapi-m64.dts      | 118 ++--
>  arch/arm/dts/sun50i-a64-cpu-opp.dtsi          |  75 +++
>  arch/arm/dts/sun50i-a64-nanopi-a64.dts        |  70 +--
>  .../dts/sun50i-a64-oceanic-5205-5inmfd.dts    |  31 +-
>  arch/arm/dts/sun50i-a64-olinuxino-emmc.dts    |  12 +-
>  arch/arm/dts/sun50i-a64-olinuxino.dts         | 113 ++--
>  arch/arm/dts/sun50i-a64-orangepi-win.dts      | 127 +++--
>  arch/arm/dts/sun50i-a64-pine64-lts.dts        |   7 +-
>  arch/arm/dts/sun50i-a64-pine64-plus.dts       |  52 +-
>  arch/arm/dts/sun50i-a64-pine64.dts            |  97 ++--
>  arch/arm/dts/sun50i-a64-pinebook-u-boot.dtsi  |  17 -
>  arch/arm/dts/sun50i-a64-pinebook.dts          | 237 ++++++--
>  arch/arm/dts/sun50i-a64-pinephone-1.0.dts     |  11 +
>  arch/arm/dts/sun50i-a64-pinephone-1.1.dts     |  30 +
>  arch/arm/dts/sun50i-a64-pinephone-1.2.dts     |  40 ++
>  arch/arm/dts/sun50i-a64-pinephone.dtsi        | 429 ++++++++++++++
>  arch/arm/dts/sun50i-a64-pinetab.dts           | 460 +++++++++++++++
>  arch/arm/dts/sun50i-a64-sopine-baseboard.dts  | 113 ++--
>  arch/arm/dts/sun50i-a64-sopine.dtsi           |  69 +--
>  arch/arm/dts/sun50i-a64-teres-i-u-boot.dtsi   |  41 --
>  arch/arm/dts/sun50i-a64-teres-i.dts           | 138 ++++-
>  arch/arm/dts/sun50i-a64.dtsi                  | 532 ++++++++++++++----
>  arch/arm/mach-sunxi/Kconfig                   |   7 +
>  board/sunxi/board.c                           |  97 +++-
>  configs/pinephone_defconfig                   |  12 +
>  include/dt-bindings/clock/sun50i-a64-ccu.h    |   4 +-
>  include/dt-bindings/clock/sun8i-de2.h         |   3 +
>  include/dt-bindings/reset/sun8i-de2.h         |   1 +
>  31 files changed, 2488 insertions(+), 650 deletions(-)
>  create mode 100644 arch/arm/dts/sun50i-a64-cpu-opp.dtsi
>  delete mode 100644 arch/arm/dts/sun50i-a64-pinebook-u-boot.dtsi
>  create mode 100644 arch/arm/dts/sun50i-a64-pinephone-1.0.dts
>  create mode 100644 arch/arm/dts/sun50i-a64-pinephone-1.1.dts
>  create mode 100644 arch/arm/dts/sun50i-a64-pinephone-1.2.dts
>  create mode 100644 arch/arm/dts/sun50i-a64-pinephone.dtsi
>  create mode 100644 arch/arm/dts/sun50i-a64-pinetab.dts
>  delete mode 100644 arch/arm/dts/sun50i-a64-teres-i-u-boot.dtsi
>  create mode 100644 configs/pinephone_defconfig
>