serial: mpc512x: cleanup clock API use
cleanup the clock API use of the UART driver which is shared among the
MPC512x and the MPC5200 platforms
- get, prepare, and enable the MCLK during port allocation; disable,
unprepare and put the MCLK upon port release; hold a reference to the
clock over the period of use; check for and propagate enable errors
- fix a buffer overflow for clock names with two digit PSC index numbers
- stick with the PPC_CLOCK 'psc%d_mclk' name for clock lookup, only
switch to a fixed string later after device tree based clock lookup
will have become available
to achieve support for MPC512x which is neutral to MPC5200, the
modification was done as follows
- introduce "clock alloc" and "clock release" routines in addition to
the previous "clock enable/disable" routine in the psc_ops struct
- make the clock allocation a part of the port request (resource
allocation), and make clock release a part of the port release, such
that essential resources get allocated early
- just enable/disable the clock from within the .clock() callback
without any allocation or preparation as the former implementation
did, since this routine is called from within the startup and shutdown
callbacks
- all of the above remains a NOP for the MPC5200 platform (no callbacks
are provided on that platform)
- implementation note: the clock gets enabled upon allocation already
just in case the clock is not only required for bitrate generation but
for register access as well
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
1 file changed