Before set_rate() pllv3 needs enable() to power the pll up.
Add enable() taking into account different power_bit and
different powerup_set, because some pll needs its power_bit to be
set or reset to be powered on.
Signed-off-by: NGiulio Benetti <giulio.benetti@benettiengineering.com>

div_mask is different for GENERIC and USB pll, so set it according.
Signed-off-by: NGiulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: NLukasz Majewski <lukma@denx.de>

Better to register the 2 clock as 2 different drivers because they work
slightly differently depending on power_bit and powerup_set bits coming
on next patches.
Signed-off-by: NGiulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: NLukasz Majewski <lukma@denx.de>

This patch brings the files from Linux kernel (linux-stable/linux-5.1.y
SHA1: 5752b50477da)to provide clocks support as it is used on the Linux
kernel with Common Clock Framework [CCF] setup.

The directory structure has been preserved. The ported code only supports
reading information from PLL, MUX, Divider, etc and enabling/disabling
the clocks USDHCx/ECSPIx depending on used bus. Moreover, it is agnostic
to the alias numbering as the information about the clock is read from the
device tree.

One needs to pay attention to the comments indicating necessary for U-Boot's
driver model changes.

If needed, the code can be extended to support the "set" part of the clock
management.
Signed-off-by: NLukasz Majewski <lukma@denx.de>