Thread (18 messages) 18 messages, 4 authors, 2020-03-10

Re: [PATCH 1/2] arm64: change ARCH_SPRD Kconfig to tristate

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2020-03-10 09:52:24
Also in: linux-serial, lkml

Hi Orson,

On Tue, Mar 10, 2020 at 10:41 AM Orson Zhai [off-list ref] wrote:
On Mon, Mar 9, 2020 at 6:32 PM Geert Uytterhoeven [off-list ref] wrote:
quoted
On Mon, Mar 9, 2020 at 9:32 AM Chunyan Zhang [off-list ref] wrote:
quoted
On Mon, 9 Mar 2020 at 16:03, Geert Uytterhoeven [off-list ref] wrote:
quoted
On Thu, Mar 5, 2020 at 11:33 AM Chunyan Zhang [off-list ref] wrote:
quoted
From: Chunyan Zhang <redacted>

The default value of Kconfig for almost all sprd drivers are the same with
ARCH_SPRD, making these drivers built as modules as default would be easier
if we can set ARCH_SPRD as 'm', so this patch change ARCH_SPRD to tristate.

Signed-off-by: Chunyan Zhang <redacted>
Can you actually boot a kernel on a Spreadtrum platform when all platform
and driver support is modular?
Yes, even if all drivers are modular.
Cool. No hard dependencies on e.g. regulators that are turned off when
unused?
quoted
But I hope serial can be builtin, then I can have a console to see
kernel output before loading modules.
No dependency on the clock driver?
Oh, I see you have a hack in the serial driver, to assume default
values when the serial port's parent clock is not found.  That may
limit use of the other serial ports, depending on the actual serial
hardware.
There is an function named "sprd_uart_is_console()" in the driver
code. So the hack could be only applied when the
port is identified as console. And other ports might return
PROBE_DEFER until the clock is ready.

Could it work out of the limitation?
Yes, that could work.  You also have only a single SPRD_DEFAULT_SOURCE_CLK,
which makes it simple to handle.
For other SoCs, there may be a variation of possible values, depending on
SoC and/or board.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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