Provide a dummy implementation of soc_device_match(), to allow compiling
drivers that may be used on SoCs both with and without CONFIG_SOC_BUS,
and for compile testing.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
We keep running into cases where device drivers want to know the exact
version of the a SoC they are currently running on. In the past, this has
usually been done through a vendor specific API that can be called by a
driver, or by directly accessing some kind of version register that is
not part of the device itself but that belongs to a global register area
of the chip.
Common reasons for doing this include:
- A machine is not using devicetree or similar for passing data about
on-chip devices, but just announces their presence using boot-time
platform devices, and the machine code itself does not care about the
revision.
- There is existing firmware or boot loaders with existing DT binaries
with generic compatible strings that do not identify the particular
revision of each device, but the driver knows which SoC revisions
include which part.
- A prerelease version of a chip has some quirks and we are using the same
version of the bootloader and the DT blob on both the prerelease and the
final version. An update of the DT binding seems inappropriate because
that would involve maintaining multiple copies of the dts and/or
bootloader.
This patch introduces the soc_device_match() interface that is meant to
work like of_match_node() but instead of identifying the version of a
device, it identifies the SoC itself using a vendor-agnostic interface.
Unlike of_match_node(), we do not do an exact string compare but instead
use glob_match() to allow wildcards in strings.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Traditionally, any System-on-Chip based platform creates a flat list
of platform_devices directly under /sys/devices/platform.
In order to give these some better structure, this introduces a new
bus type for soc_devices that are registered with the new
soc_device_register() function. All devices that are on the same
chip should then be registered as child devices of the soc device.
The soc bus also exports a few standardised device attributes which
allow user space to query the specific type of soc.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Geert Uytterhoeven
Arnd Bergmann
Lee Jones