Quoting Ajit Kumar Pandey (2021-10-12 03:36:08)

At present 48MHz clk support is only enabled for RV architecture
using "is-rv" device property initialized from boot loader. This
limit 48MHz fixed clock gate support to RV platform unless we add
similar device property in boot loader for other architecture.

Add Kernel config option to enable 48MHz fixed clk gate registration
with clock framework. This enahanced flexibility to enable 48MHz fch
clock support on any platforms by simply enabling kernel config. Also
replace RV with FIXED as generic naming convention across platforms.

What do we do if I enable CLK_FIXED_FCH in Kconfig but don't populate
the 48MHz clk? It's always present so this isn't actually a problem?
Why does the bootloader set an 'is-rv' property at all?