At present only root nodes in the device tree are scanned for devices.
But some devices can have children. For example a SPI bus may have
several children for each of its chip selects.
Add a function which scans subnodes and binds devices for each one. This
can be used for the root node scan also, so change it.
A device can call this function in its bind() or probe() methods to bind
its children.
Signed-off-by: Simon Glass <sjg@chromium.org>
Each device that was bound from a device tree has an node that caused it to
be bound. Add functions that find and return a device based on a device tree
offset.
Signed-off-by: Simon Glass <sjg@chromium.org>
In U-Boot it is pretty common to number devices from 0 and access them
on the command line using this numbering. While it may come to pass that
we will move away from this numbering, the possibility seems remote at
present.
Given that devices within a uclass will have an implied numbering, it
makes sense to build this into driver model as a core feature. The cost
is fairly small in terms of code and data space.
With each uclass having numbered devices we can ask for SPI port 0 or
serial port 1 and receive a single device.
Devices typically request a sequence number using aliases in the device
tree. These are resolved when the device is probed, to deal with conflicts.
Sequence numbers need not be sequential and holes are permitted.
At present there is no support for sequence numbers using static platform
data. It could easily be added to 'struct driver_info' if needed, but it
seems better to add features as we find a use for them, and the use of -1
to mean 'no sequence' makes the default value somewhat painful.
Signed-off-by: Simon Glass <sjg@chromium.org>
Driver model currently only operates after relocation is complete. In this
state U-Boot typically has a small amount of memory available. In adding
support for driver model prior to relocation we must try to use as little
memory as possible.
In addition, on some machines the memory has not be inited and/or the CPU
is not running at full speed or the data cache is off. These can reduce
execution performance, so the less initialisation that is done before
relocation the better.
An immediately-obvious improvement is to only initialise drivers which are
actually going to be used before relocation. On many boards the only such
driver is a serial UART, so this provides a very large potential benefit.
Allow drivers to mark themselves as 'pre-reloc' which means that they will
be initialised prior to relocation. This can be done either with a driver
flag or with a 'dm,pre-reloc' device tree property.
To support this, the various dm scanning function now take a 'pre_reloc_only'
parameter which indicates that only drivers marked pre-reloc should be
bound.
Signed-off-by: Simon Glass <sjg@chromium.org>
Rather than reusing the 'reg' property, use an explicit property for the
expected ping value used in testing.
Signed-off-by: Simon Glass <sjg@chromium.org>
using UBI and DM together leads in compiler error, as
both define a "struct device", so rename "struct device"
in include/dm/device.h to "struct udevice", as we use
linux code (MTD/UBI/UBIFS some USB code,...) and cannot
change the linux "struct device"
Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Marek Vasut <marex@denx.de>
Add some tests of driver model functionality. Coverage includes:
- basic init
- binding of drivers to devices using platform_data
- automatic probing of devices when referenced
- availability of platform data to devices
- lifecycle from bind to probe to remove to unbind
- renumbering within a uclass when devices are probed/removed
- calling driver-defined operations
- deactivation of drivers when removed
- memory leak across creation and destruction of drivers/uclasses
- uclass init/destroy methods
- automatic probe/remove of children/parents when needed
This function is enabled for sandbox, using CONFIG_DM_TEST.
Signed-off-by: Simon Glass <sjg@chromium.org>
