Add driver code for the SiFive FU540 PRCI IP block. This IP block
handles reset and clock control for the SiFive FU540 device and
implements SoC-level clock tree controls and dividers.
Based on code written by Wesley Terpstra <wesley@sifive.com>
found in commit 999529edf517ed75b56659d456d221b2ee56bb60 of:
https://github.com/riscv/riscv-linux
Boot and PLL rate change were tested on a SiFive HiFive Unleashed
board.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
