bus: simple-pm-bus: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231109202830.4124591-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

bus: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20230803-dt-header-cleanups-for-soc-v2-16-d8de2cc88bff@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers: bus: simple-pm-bus: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

drivers: bus: simple-pm-bus: Use clocks

Simple Power-Managed bus controller may need functional clock(s)
to be enabled before child devices connected to the bus can be
accessed. Get the clock(s) as a bulk and enable/disable the
clock(s) when the bus is being power managed.

One example is that Freescale i.MX8qxp pixel link MSI bus controller
needs MSI clock and AHB clock to be enabled before accessing child
devices.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
Tested-by: Maxim Kochetkov <fido_max@inbox.ru>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20221226031417.1056745-1-victor.liu@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "drivers: bus: simple-pm-bus: Use clocks"

This reverts commit 882cf4c913d730a74175db039d941005b883de38 as it
breaks the build in linux-next.

Link: https://lore.kernel.org/r/20221114181752.08a850f0@canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Liu Ying <victor.liu@nxp.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: bus: simple-pm-bus: Use clocks

Simple Power-Managed bus controller may need functional clock(s)
to be enabled before child devices connected to the bus can be
accessed. Get the clock(s) as a bulk and enable/disable the
clock(s) when the bus is being power managed.

One example is that Freescale i.MX8qxp pixel link MSI bus controller
needs MSI clock and AHB clock to be enabled before accessing child
devices.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20221017074039.4181843-2-victor.liu@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: bus: simple-pm-bus: Add support for probing simple bus only devices

fw_devlink could end up creating device links for bus only devices.
However, bus only devices don't get probed and can block probe() or
sync_state() [1] call backs of other devices. To avoid this, probe these
devices using the simple-pm-bus driver.

However, there are instances of devices that are not simple buses (they get
probed by their specific drivers) that also list the "simple-bus" (or other
bus only compatible strings) in their compatible property to automatically
populate their child devices. We still want these devices to get probed by
their specific drivers. So, we make sure this driver only probes devices
that are only buses.

[1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/

Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default")
Cc: stable <stable@vger.kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Tested-by: Saravana Kannan <saravanak@google.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210929000735.585237-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: bus: simple-pm-bus: Fix compatibility with simple-bus for auxdata

After converting am335x to probe devices with simple-pm-bus I noticed
that we are not passing auxdata for of_platform_populate() like we do
with simple-bus.

While device tree using SoCs should no longer need platform data, there
are still quite a few drivers that still need it as can be seen with
git grep OF_DEV_AUXDATA. We want to have simple-pm-bus be usable as a
replacement for simple-bus also for cases where OF_DEV_AUXDATA is still
needed.

Let's fix the issue by passing auxdata as platform data to simple-pm-bus.
That way the SoCs needing this can pass the auxdata with OF_DEV_AUXDATA.
And let's pass the auxdata for omaps to fix the issue for am335x.

As an alternative solution, adding simple-pm-bus handling directly to
drivers/of/platform.c was considered, but we would still need simple-pm-bus
device driver. So passing auxdata as platform data seems like the simplest
solution.

Fixes: 5a230524f879 ("ARM: dts: Use simple-pm-bus for genpd for am3 l4_wkup")
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers: bus: Add Simple Power-Managed Bus Driver

Add a driver for transparent busses that don't need a real driver, but
where the bus controller is part of a PM domain, or under the control of
a functional clock. Typically, the bus controller's PM domain and/or
clock must be enabled for child devices connected to the bus (either
on-SoC or externally) to function.

Hence the sole purpose of this driver is to enable its clock and PM
domain (if exist(s)), which are specified in the DT and managed from
platform and PM domain code, and to probe for child devices.

Due to the child-parent relationship with devices connected to the bus,
PM domain and clock state transitions are handled in the correct order.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>