serial: mpc512x: setup the PSC FIFO clock as well

prepare and enable the FIFO clock upon PSC FIFO initialization,
check for and propagage errors when enabling the PSC FIFO clock,
disable and unprepare the FIFO clock upon PSC FIFO uninitialization

devm_{get,put}_clk() doesn't apply here, as the SoC provides a
single FIFO component which is shared among several PSC components,
thus the FIFO isn't associated with a device (while the PSCs are)

provide a fallback clock lookup approach in case the OF based clock
lookup for the PSC FIFO fails, this allows for successful operation in
the presence of an outdated device tree which lacks clock specs

Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: [email protected]
Acked-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Gerhard Sittig <[email protected]>
Signed-off-by: Anatolij Gustschin <[email protected]>

0 files changed, 0 insertions, 0 deletions