1a46712aa9
Pull GPIO updates from Linus Walleij:
"This is the bulk of GPIO changes for kernel v4.6. There is quite a
lot of interesting stuff going on.
The patches to other subsystems and arch-wide are ACKed as far as
possible, though I consider things like per-arch <asm/gpio.h> as
essentially a part of the GPIO subsystem so it should not be needed.
Core changes:
- The gpio_chip is now a *real device*. Until now the gpio chips
were just piggybacking the parent device or (gasp) floating in
space outside of the device model.
We now finally make GPIO chips devices. The gpio_chip will create
a gpio_device which contains a struct device, and this gpio_device
struct is kept private. Anything that needs to be kept private
from the rest of the kernel will gradually be moved over to the
gpio_device.
- As a result of making the gpio_device a real device, we have added
resource management, so devm_gpiochip_add_data() will cut down on
overhead and reduce code lines. A huge slew of patches convert
almost all drivers in the subsystem to use this.
- Building on making the GPIO a real device, we add the first step of
a new userspace ABI: the GPIO character device. We take small
steps here, so we first add a pure *information* ABI and the tool
"lsgpio" that will list all GPIO devices on the system and all
lines on these devices.
We can now discover GPIOs properly from userspace. We still have
not come up with a way to actually *use* GPIOs from userspace.
- To encourage people to use the character device for the future, we
have it always-enabled when using GPIO. The old sysfs ABI is still
opt-in (and can be used in parallel), but is marked as deprecated.
We will keep it around for the foreseeable future, but it will not
be extended to cover ever more use cases.
Cleanup:
- Bjorn Helgaas removed a whole slew of per-architecture <asm/gpio.h>
includes.
This dates back to when GPIO was an opt-in feature and no shared
library even existed: just a header file with proper prototypes was
provided and all semantics were up to the arch to implement. These
patches make the GPIO chip even more a proper device and cleans out
leftovers of the old in-kernel API here and there.
Still some cruft is left but it's very little now.
- There is still some clamping of return values for .get() going on,
but we now return sane values in the vast majority of drivers and
the errorpath is sanitized. Some patches for powerpc, blackfin and
unicore still drop in.
- We continue to switch the ARM, MIPS, blackfin, m68k local GPIO
implementations to use gpiochip_add_data() and cut down on code
lines.
- MPC8xxx is converted to use the generic GPIO helpers.
- ATH79 is converted to use the generic GPIO helpers.
New drivers:
- WinSystems WS16C48
- Acces 104-DIO-48E
- F81866 (a F7188x variant)
- Qoric (a MPC8xxx variant)
- TS-4800
- SPI serializers (pisosr): simple 74xx shift registers connected to
SPI to obtain a dirt-cheap output-only GPIO expander.
- Texas Instruments TPIC2810
- Texas Instruments TPS65218
- Texas Instruments TPS65912
- X-Gene (ARM64) standby GPIO controller"
* tag 'gpio-v4.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (194 commits)
Revert "Share upstreaming patches"
gpio: mcp23s08: Fix clearing of interrupt.
gpiolib: Fix comment referring to gpio_*() in gpiod_*()
gpio: pca953x: Fix pca953x_gpio_set_multiple() on 64-bit
gpio: xgene: Fix kconfig for standby GIPO contoller
gpio: Add generic serializer DT binding
gpio: uapi: use 0xB4 as ioctl() major
gpio: tps65912: fix bad merge
Revert "gpio: lp3943: Drop pin_used and lp3943_gpio_request/lp3943_gpio_free"
gpio: omap: drop dev field from gpio_bank structure
gpio: mpc8xxx: Slightly update the code for better readability
gpio: mpc8xxx: Remove *read_reg and *write_reg from struct mpc8xxx_gpio_chip
gpio: mpc8xxx: Fixup setting gpio direction output
gpio: mcp23s08: Add support for mcp23s18
dt-bindings: gpio: altera: Fix altr,interrupt-type property
gpio: add driver for MEN 16Z127 GPIO controller
gpio: lp3943: Drop pin_used and lp3943_gpio_request/lp3943_gpio_free
gpio: timberdale: Switch to devm_ioremap_resource()
gpio: ts4800: Add IMX51 dependency
gpiolib: rewrite gpiodev_add_to_list
...
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.