Add sifive prci support for SiFive HiFive platform

[zongbox]

This driver initializes some necessary PLLs.

[zongbox]

Hi Paul, The register maps doesn't conflict in unleashed and unmatched, I'd like to distinguish the unleashed and unmatched in this driver, then do different initialization. If it is good to you, I would add the implementation above, and keep this original common name for this prci driver. I wanna do the similar thing for freedom-devicetree-tools.

[paul-walmsley-sifive]

Hi Paul, The register maps doesn't conflict in unleashed and unmatched, I'd like to distinguish the unleashed and unmatched in this driver, then do different initialization. If it is good to you, I would add the implementation above, and keep this original common name for this prci driver. I wanna do the similar thing for freedom-devicetree-tools.

Sure, whatever is easiest. It might be easiest to keep them separate, due to limitations in freedom-devicetree-tools. Whatever works for you.

My suggestion about "sifive,unmatched-prci0" was rather stupid, as @e-puerto reminded me. It should be something like "sifive,fu740-c000-prci0" instead. For that to work, the devicetree-overlay-generator will probably need to be modified to rewrite "sifive,ux00prci0" to "sifive,fu740-c000-prci0" if it sees that the SoC is an Almond (e.g., matching on /compatible = "SiFive,FU740-C000" or whatever)

[zongbox]

Changed in v2:

• Use pre-processor directive to separate the implementation for Unleashed and Unmatched by METAL_SIFIVE_FU540_C000_PRCI0 and METAL_SIFIVE_FU740_C000_PRCI0 macro, which are generated by freedom-devicetree-tools.
• The PRCI memory map of Unleashed is subset of Unmatched, so we can use this same driver for them, the freedom-devicetree-tools will generate the different register memory map offsets for them respectively.

[paul-walmsley-sifive]

Thanks Zong