Re: [PATCH] spi: dw: assert reset before deasserting reset

[Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>]

Hi Niklas,

On Di, 2022-03-22 at 10:32 +0000, Niklas Cassel wrote:
[...]
>  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c?h=v5.17#n7035
> 

Thank you.

[...]
I see your point. Many drivers should probably change assert() +
udelay(x) + deassert() with a reset_control_reset(), since .reset()
implementation should have the correct delay for each SoC.
..but I guess often the manual for some hardware block states the how long
reset has to be held. So for that to work the delay in .reset() has to be
greater equal the longest reset time needed for all hardware in that SoC?

Yes, exactly. The reset-simple driver was prepared for this in commit
a9701376ed0f ("reset: simple: Add reset callback"), for example.
Several of the custom reset drivers also implement .reset() with a
fixed delay.

regards
Philipp