Re: [PATCH] spi: meson-spicc: save pow2 datarate between messages

[Neil Armstrong]

On 10/08/2022 14:37, Mark Brown wrote:
> On Wed, Aug 10, 2022 at 11:17:14AM +0200, Neil Armstrong wrote:
> > On 09/08/2022 17:27, Mark Brown wrote:
> > > On Tue, Aug 09, 2022 at 05:20:19PM +0200, Neil Armstrong wrote:
>
> > > When you say the value set by the clock framework does that mean that
> > > the clock driver is adjusting hardware inside the SPI controller IP
> > > block which is then getting reset by the SPI driver without the SPI
> > > driver knowing about it?  That seems like a bad idea as you're finding
> > > here.
>
> > The SPI driver is explicitely triggering a reset at the end of each message
> > to get back to a clean HW state, but it does reset the content of the "legacy"
> > registers containing the power of 2 divider value, the new registers configuring
> > the new clock divider path (only on newer SoCs) doesn't get cleared.
>
> Sure, but that doesn't really address the concern - is this something
> that the clk driver programmed or is this the driver forgetting to
> restore a register that it programmed itself?  The commit message sounds
> like the former which is a much bigger problem.

It's what is programmed by the Clock Framework yes, it was designed as-is
so the Clock Framework takes the most accurate clock path but the reset case
wasn't taken in account.

Neil