device_tree binding for "amba bus"

[Stephen Neuendorffer]

Grant,

I've taken a quick look at the arm trace buffer driver
(arch/arm/kernel/etm.c).
This driver uses the amba bus driver (drivers/amba/bus.c).
It appears that this driver does three things:

1) ensures that the clock named "apb_pclk" is running.
2) ensures that the regulator named "vcore" is on.
3) queries the core to verify that a hardcoded register has the correct
value.

None of this seems terribly interesting enough to justify a bus that has
a
small number of users:

drivers/tty/serial/amba-pl010.c, line 788
drivers/tty/serial/amba-pl011.c, line 1477
drivers/input/serio/ambakmi.c, line 197
drivers/watchdog/sp805_wdt.c, line 359
drivers/rtc/rtc-pl031.c, line 478
drivers/rtc/rtc-pl030.c, line 183
drivers/char/hw_random/nomadik-rng.c, line 97
drivers/mmc/host/mmci.c, line 1049
drivers/video/amba-clcd.c, line 538
drivers/gpio/pl061.c, line 344
drivers/spi/amba-pl022.c, line 2284
drivers/dma/amba-pl08x.c, line 2062
drivers/dma/pl330.c, line 841
sound/arm/aaci.c, line 1125
arch/arm/kernel/etm.c:
line 421
line 625

And at the very least the hardcoded nature of the names seems, well...
hardcoded.

Any thoughts about how to abstract this in a device tree?
(My thoughts: devices need to reference a clock, devices need to
reference a regulator,
and it seems to me that the register check could be pulled out into a
single call that the
devices that care about it can do themselves during probe() )

Steve


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