Re: [PATCH v2 1/2] dt-bindings: clock: mediatek: replace unusable clock

From: Alexandre Mergnat
Date: Fri May 26 2023 - 04:54:18 EST

On 25/05/2023 19:51, Conor Dooley wrote:
On Thu, May 25, 2023 at 04:50:27PM +0200, Alexandre Mergnat wrote:
The “mcu_pm_bclk_ck_cg” clock is used by co-processors and should not be
added to the kernel driver, otherwise the CPU just halt and the board is
rebooted by the wathdog.

Instead, add the "aes_top0_bclk_ck_cg" missing clock to prevent
re-shuffling index and then preserve the ABI.

How does this preserve the ABI exactly? Please describe exactly what you
mean by that.

I mean that reduce the impact of the change compared to the v1 where I've changed the index of the following defines to be clean.

Also, what about any other users of these definitions, outside of Linux?

The clock driver and bindings are only a couple of kernel versions old, I'm pretty sure no one is using it. Also, if someone use CLK_IFR_MCU_PM_BK define, I'm wondering how his CPU is working since Mediatek told me that shouldn't be used, and after some try, I confirm.

I've a question: If something is wrong in the binding, you don't fix it to avoid ABI change ?

TBH, I just try to clean the binding. I can fix the driver index issue (patch 2/2) without fixing the binding if you prefer. But IMHO, keep an unusable define isn't great...