RE: [PATCH 3/6] clk: renesas: r7s9210: Add SPIBSC clock

[Chris Brandt <Chris.Brandt@xxxxxxxxxxx>]

Hi Geert,

On Tue, Dec 3, 2019, Geert Uytterhoeven wrote:
> > +static const unsigned int r7s9210_crit_mod_clks[] __initconst = {
> > +       MOD_CLK_ID_10(83),      /* SPIBSC */
> 
> This is only a critical clock if XIP is in use, right?

Correct.


> Can we do better, and only mark it critical if we detect the FLASH is used in
> XIP mode?
> E.g. by using for_each_compatible_node(..., "mtd-rom"), and checking if any
> of the corresponding register blocks matches the SPIBSC FLASH memory window?

Well...technically...you don't need the "mtd-rom" partition when using the AXFS
file system. But, we can make a rule that you have to use it regardless.

Instead, I think it would be better if we could flag the clock as critical 
in a board-specific .dts like we're going to do with the RZ/A1 MSTP driver.

Can we add something like  "clock-critical = <83>;" to the cpg-mssr driver?

What do you think?

Chris