On 03/12/2021 17:22, Sam Protsenko wrote:

On Wed, 1 Dec 2021 at 12:54, Andy Shevchenko [off-list ref] wrote:

quoted

On Wed, Dec 1, 2021 at 12:42 AM Sam Protsenko
[off-list ref] wrote:

quoted

USI control is now extracted to dedicated USI driver. Remove USI related

the dedicated

quoted

code from serial driver to avoid conflicts and code duplication.

Would it break run-time bisectability?
If so, why is it not a problem?

It shouldn't. This patch is [3/5], and USI driver (which takes the
control over the USI registers) is [2/5]. As for Device Tree, the only
platform using "samsung,exynos850-uart" right now is Exynos Auto V9
SADK (serial node is declared in exynosautov9.dtsi). I don't have
Exynos Auto V9 datasheet, so I can't really add the USI node properly
there, nor I can test that. I guess it should be done separately from
this patch series.

Chanho, Krzysztof:

Guys, what are your thoughts on this? Basically with this patch series
applied, Exynos Auto V9 serial might become not functional. New USI
node should be added for UART case in Exynos Auto V9 dtsi (providing
correct sysreg, SW_CONF offset, clocks, etc), and serial node should
be encapsulated inside of that USI node. Also, USI node should be
referenced and enabled in SADK dts, providing also "clkreq-on"
property. More details can be found in [PATCH 1/5]. Do you think it's
ok to take this series as is, and add that later? Because otherwise we
might need to collaborate to add that Exynos Auto V9 enablement into
this patch series, which might take more time...

The patch in current state will probably break Exynos Auto v9 boards,
including the in-tree one, unless bootloader sets the USI to serial. The
trouble is that. Changing the Exynos Auto v9 DTSI in these series would
solve it only partially, because the kernel still won't be bisectable.

Breaking Auto v9 serial within a kernel is okay for me, because the
board was added recently, I don't expect products using it and it is
still development phase. This of course assuming that it's users agree,
so the question is to Chanho and other folks.

Best regards,
Krzysztof