RE: [PATCH 3/3] tty: serial: samsung: Remove unused artpec-8 specific code

Ravi Patel
2025-09-11T16:04:54Z

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: 11 September 2025 20:05
...
> Subject: Re: [PATCH 3/3] tty: serial: samsung: Remove unused artpec-8 specific code
>
> On 11/09/2025 16:29, Krzysztof Kozlowski wrote:
> >>> --- a/drivers/tty/serial/samsung_tty.c
> >>> +++ b/drivers/tty/serial/samsung_tty.c
> >>
> >>> @@ -2655,8 +2621,6 @@ static const struct of_device_id s3c24xx_uart_dt_match[] = {
> >>> .data = S5L_SERIAL_DRV_DATA },
> >>> { .compatible = "samsung,exynos850-uart",
> >>> .data = EXYNOS850_SERIAL_DRV_DATA },
> >>> - { .compatible = "axis,artpec8-uart",
> >>> - .data = ARTPEC8_SERIAL_DRV_DATA },
> >>> { .compatible = "google,gs101-uart",
> >>> .data = GS101_SERIAL_DRV_DATA },
> >>> { .compatible = "samsung,exynos8895-uart",
> >>> @@ -2828,8 +2792,6 @@ OF_EARLYCON_DECLARE(s5pv210, "samsung,s5pv210-uart",
> >>> s5pv210_early_console_setup);
> >>> OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",
> >>> s5pv210_early_console_setup);
> >>> -OF_EARLYCON_DECLARE(artpec8, "axis,artpec8-uart",
> >>> - s5pv210_early_console_setup);
> >>>
> >>> static int __init gs101_early_console_setup(struct earlycon_device *device,
> >>> const char *opt)
> >>
> >> Removing these breaks backwards-compatibility with existing DTBs,
> >> which lack the new "samsung,exynos8895-uart" fallback compatible value.
> >
> > This was just applied, so ABI break would be fine. It should be however
> > clearly expressed in the commit msg.
> >
> > I have a feeling that not much testing was happening in Samsung around
> > this patchset and only now - after I applied it - some things happen.
> > But it is damn too late, my tree is already closed which means this is
> > going to be the ABI.
>
> Ah, no, I mixed up patches with recent DTS for Artpec-8. This serial ABI
> was accepted three years ago (!!!), so you are Geert absolutely right -
> that's ABI break.

Thank you for your review.

The DTS patches for ARTPEC-8 is added recently (https://lore.kernel.org/linux-samsung-soc/20250901051926.59970-1-ravi.patel@samsung.com/)
Before that, there was no user (in DT) of "axis,artpec8-uart" compatible.
So I am not convinced of ABI break (considering patch #1 and #2 goes first with review comment fixes)

My intension here is to optimize the driver code (by removing kind of duplicated code)
And also preparation of upcoming ARTPEC-9 patch series where ARTPEC-9 uart is
exactly same as ARTPEC-8.

Please let me know if I misunderstood anything here.

Thanks,
Ravi

>
> Folks in Samsung, maybe try to organize some weekly sessions sharing
> knowledge after upstreaming reviews/feedbacks? I feel like you are
> repeating same mistakes.
>
> Best regards,
> Krzysztof