[PATCH 00/13] Discover and probe dependencies

Tomeu Vizoso
2015-06-17T13:42:58Z

Hi,

this is another attempt at preventing deferred probe from obscuring why your
devices aren't probing and from delaying to the end of the boot process the
probe of the device you care the most.

The major differences with my previous approach [0] are:

* Dependencies are probed before the target is probed, so we don't have nested
probe() calls, avoiding a series of deadlock situations.

* Dependencies could be stored and reused for other purposes such as for
passing resources to drivers ala devm_probe, or for warning when a device is
going to be unbound and has dependencies active, etc.

* I have tried to keep it firmware-agnostic. The previous approach (on-demand
probing) could be done like this as well, but would require adding fwnode
APIs to all affected subsystems first.

I have only implemented the class.get_dependencies() callback for the GPIO
subsystem and for the host1x bus because that's all that was needed on my Tegra
Chromebook to avoid deferred probes, but if this approach is deemed worthwhile
I will add more implementations so that deferred probes are avoided on the
other boards I have access to.

[0] http://thread.gmane.org/gmane.linux.kernel.gpio/8465

Thanks,

Tomeu

Tomeu Vizoso (13):
gpiolib: Fix docs for gpiochip_add_pingroup_range
driver-core: defer all probes until late_initcall
ARM: tegra: Add gpio-ranges property
pinctrl: tegra: Only set the gpio range if needed
driver core: fix docbook for device_private.device
of/platform: Set fwnode field for new devices
driver-core: Add class.get_dependencies() callback
gpio: sysfs: implement class.get_dependencies()
gpu: host1x: implement class.get_dependencies()
driver-core: add for_each_class()
device property: add fwnode_get_parent()
device property: add fwnode_get_name()
driver-core: probe dependencies before probing

arch/arm/boot/dts/tegra114.dtsi | 1 +
arch/arm/boot/dts/tegra124.dtsi | 1 +
arch/arm/boot/dts/tegra20.dtsi | 1 +
arch/arm/boot/dts/tegra30.dtsi | 1 +
drivers/base/base.h | 4 +-
drivers/base/class.c | 16 +++++
drivers/base/dd.c | 128 +++++++++++++++++++++++++++++++++++++++-
drivers/base/property.c | 38 ++++++++++++
drivers/gpio/gpiolib-sysfs.c | 81 +++++++++++++++++++++++++
drivers/gpio/gpiolib.c | 2 +-
drivers/gpu/host1x/dev.c | 47 +++++++++++++++
drivers/of/platform.c | 1 +
drivers/pinctrl/pinctrl-tegra.c | 19 +++++-
include/acpi/acpi_bus.h | 5 ++
include/linux/acpi.h | 5 ++
include/linux/device.h | 6 ++
include/linux/fwnode.h | 5 ++
include/linux/property.h | 4 ++
18 files changed, 361 insertions(+), 4 deletions(-)

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2.4.1