c07b3682cd
Pull LED updates from Jacek Anaszewski:
"LED triggers improvements make the biggest part of this pull request.
The most striking ones, that allowed for nice cleanups in the triggers
are:
- centralized handling of creation and removal of trigger sysfs
attributes via attribute group
- addition of module_led_trigger() helper
The other things that need to be mentioned:
New features and improvements to existing LED class drivers:
- lt3593: add DT support, switch to gpiod interface
- lm3692x: support LED sync configuration, change OF calls to fwnode
calls
- apu: modify PC Engines apu/apu2 driver to support apu3
Change in the drivers/net/can/led.c:
- mark led trigger as broken since it's in the way for the further
cleanups. It implements a subset of the netdev trigger and an Ack
is needed from someone who can actually test and confirm that the
netdev trigger works for can devices"
* tag 'leds-for-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds: (32 commits)
leds: ns2: Change unsigned to unsigned int
usb: simplify usbport trigger
leds: gpio trigger: simplifications from core changes
leds: backlight trigger: simplifications from core changes
leds: activity trigger: simplifications from core changes
leds: default-on trigger: make use of module_led_trigger()
leds: heartbeat trigger: simplifications from core changes
leds: oneshot trigger: simplifications from core changes
leds: transient trigger: simplifications from core changes
leds: timer trigger: simplifications from core changes
leds: netdev trigger: simplifications from core changes
leds: triggers: new function led_set_trigger_data()
leds: triggers: define module_led_trigger helper
leds: triggers: handle .trigger_data and .activated() in the core
leds: triggers: add device attribute support
leds: triggers: let struct led_trigger::activate() return an error code
leds: triggers: make the MODULE_LICENSE string match the actual license
leds: lm3692x: Support LED sync configuration
dt: bindings: lm3692x: Update binding for LED sync control
leds: lm3692x: Change DT calls to fwnode calls
...
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("hub_wq").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.