Components of the Versatile Express platform (configuration
microcontrollers on motherboard and daughterboards in particular)
talk to each other over a custom configuration bus. They
provide miscellaneous functions (from clock generator control
to energy sensors) which are represented as platform devices
(and Device Tree nodes). The transactions on the bus can
be generated by different "bridges" in the system, some
of which are universal for the whole platform (for the price
of high transfer latencies), others restricted to a subsystem
(but much faster).
Until now drivers for such functions were using custom "func"
API, which is being replaced in this patch by regmap calls.
This required:
* a rework (and move to drivers/bus directory, as suggested
by Samuel and Arnd) of the config bus core, which is much
simpler now and uses device model infrastructure (class)
to keep track of the bridges; non-DT case (soon to be
retired anyway) is simply covered by a special device
registration function
* the new config-bus driver also takes over device population,
so there is no need for special matching table for
of_platform_populate nor "simple-bus" hack in the arm64
model dtsi file (relevant bindings documentation has
been updated); this allows all the vexpress devices
fit into normal device model, making it possible
to remove plenty of early inits and other hacks in
the near future
* adaptation of the syscfg bridge implementation in the
sysreg driver, again making it much simpler; there is
a special case of the "energy" function spanning two
registers, where they should be both defined in the tree
now, but backward compatibility is maintained in the code
* modification of the relevant drivers:
* hwmon - just a straight-forward API change
* power/reset driver - API change
* regulator - API change plus error handling
simplification
* osc clock driver - this one required larger rework
in order to turn in into a standard platform driver
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Mike Turquette <mturquette@linaro.org>
The way the VE motherboard Device Trees were constructed
enforced naming and structure of daughterboard files. This
patch makes it possible to simply include the motherboard
description anywhere in the main Device Tree and retires
the "arm,v2m-timer" alias - any of the motherboard SP804
timers will be used instead.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Versatile Express platform has an elaborated configuration system,
consisting of microcontrollers residing on the mother- and
daughterboards known as Motherboard/Daughterboard Configuration
Controller (MCC and DCC). The controllers are responsible for
the platform initialization (reset generation, flash programming,
FPGA bitfiles loading etc.) but also control clock generators,
voltage regulators, gather environmental data like temperature,
power consumption etc. Even the video output switch (FPGA) is
controlled that way.
Those devices are _not_ visible in the main address space and
the usual communication channel uses some kind of a bridge in
the peripheral block sending commands (requests) to the
controllers and receiving responses. It can take up to
500 microseconds for a transaction to be completed, therefore
it is important to provide a non-blocking interface to it.
This patch adds an abstraction of this infrastructure. Bridge
drivers can register themselves with the framework. Then,
a driver of a device can request an abstract "function" - the
request will be redirected to a bridge referred by thedd
"arm,vexpress,config-bridge" property of the device tree node.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
This patch adds generic Versatile Express DT machine description,
Device Tree description for the motherboard and documentation for
the bindings.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Pawel Moll