linux-imx

LF-446 clk: imx: lpcg-scu: SW workaround for errata (e10858)

Back-to-back LPCG writes can be ignored by the LPCG register due to
a HW bug. The writes need to be seperated by at least 4 cycles of
the gated clock.

The workaround is implemented as follows:
1. For clocks running greater than or equal to 24MHz, a read
followed by the write will provide sufficient delay.
2. For clocks running below 24MHz, add a delay of 4 clock cylces
after the write to the LPCG register.

Signed-off-by: Peng Fan <peng.fan@nxp.com>