linux/Documentation/driver-api
Linus Torvalds 114b5f8f7e This is the bulk of GPIO changes for the v4.20 series:
Core changes:
 
 - A patch series from Hans Verkuil to make it possible to
   enable/disable IRQs on a GPIO line at runtime and drive GPIO
   lines as output without having to put/get them from scratch.
   The irqchip callbacks have been improved so that they can
   use only the fastpatch callbacks to enable/disable irqs
   like any normal irqchip, especially the gpiod_lock_as_irq()
   has been improved to be callable in fastpath context.
   A bunch of rework had to be done to achieve this but it is
   a big win since I never liked to restrict this to slowpath.
   The only call requireing slowpath was try_module_get() and
   this is kept at the .request_resources() slowpath callback.
   In the GPIO CEC driver this is a big win sine a single
   line is used for both outgoing and incoming traffic, and
   this needs to use IRQs for incoming traffic while actively
   driving the line for outgoing traffic.
 
 - Janusz Krzysztofik improved the GPIO array API to pass a
   "cookie" (struct gpio_array) and a bitmap for setting or
   getting multiple GPIO lines at once. This improvement
   orginated in a specific need to speed up an OMAP1 driver and
   has led to a much better API and real performance gains
   when the state of the array can be used to bypass a lot
   of checks and code when we want things to go really fast.
   The previous code would minimize the number of calls
   down to the driver callbacks assuming the CPU speed was
   orders of magnitude faster than the I/O latency, but this
   assumption was wrong on several platforms: what we needed
   to do was to profile and improve the speed on the hot
   path of the array functions and this change is now
   completed.
 
 - Clean out the painful and hard to grasp BNF experiments
   from the device tree bindings. Future approaches are looking
   into using JSON schema for this purpose. (Rob Herring
   is floating a patch series.)
 
 New drivers:
 
 - The RCAR driver now supports r8a774a1 (RZ/G2M).
 
 - Synopsys GPIO via CREGs driver.
 
 Major improvements:
 
 - Modernization of the EP93xx driver to use irqdomain and
   other contemporary concepts.
 
 - The ingenic driver has been merged into the Ingenic pin
   control driver and removed from the GPIO subsystem.
 
 - Debounce support in the ftgpio010 driver.
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Merge tag 'gpio-v4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "This is the bulk of GPIO changes for the v4.20 series:

  Core changes:

   - A patch series from Hans Verkuil to make it possible to
     enable/disable IRQs on a GPIO line at runtime and drive GPIO lines
     as output without having to put/get them from scratch.

     The irqchip callbacks have been improved so that they can use only
     the fastpatch callbacks to enable/disable irqs like any normal
     irqchip, especially the gpiod_lock_as_irq() has been improved to be
     callable in fastpath context.

     A bunch of rework had to be done to achieve this but it is a big
     win since I never liked to restrict this to slowpath. The only call
     requireing slowpath was try_module_get() and this is kept at the
     .request_resources() slowpath callback. In the GPIO CEC driver this
     is a big win sine a single line is used for both outgoing and
     incoming traffic, and this needs to use IRQs for incoming traffic
     while actively driving the line for outgoing traffic.

   - Janusz Krzysztofik improved the GPIO array API to pass a "cookie"
     (struct gpio_array) and a bitmap for setting or getting multiple
     GPIO lines at once.

     This improvement orginated in a specific need to speed up an OMAP1
     driver and has led to a much better API and real performance gains
     when the state of the array can be used to bypass a lot of checks
     and code when we want things to go really fast.

     The previous code would minimize the number of calls down to the
     driver callbacks assuming the CPU speed was orders of magnitude
     faster than the I/O latency, but this assumption was wrong on
     several platforms: what we needed to do was to profile and improve
     the speed on the hot path of the array functions and this change is
     now completed.

   - Clean out the painful and hard to grasp BNF experiments from the
     device tree bindings. Future approaches are looking into using JSON
     schema for this purpose. (Rob Herring is floating a patch series.)

  New drivers:

   - The RCAR driver now supports r8a774a1 (RZ/G2M).

   - Synopsys GPIO via CREGs driver.

  Major improvements:

   - Modernization of the EP93xx driver to use irqdomain and other
     contemporary concepts.

   - The ingenic driver has been merged into the Ingenic pin control
     driver and removed from the GPIO subsystem.

   - Debounce support in the ftgpio010 driver"

* tag 'gpio-v4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (116 commits)
  gpio: Clarify kerneldoc on gpiochip_set_chained_irqchip()
  gpio: Remove unused 'irqchip' argument to gpiochip_set_cascaded_irqchip()
  gpio: Drop parent irq assignment during cascade setup
  mmc: pwrseq_simple: Fix incorrect handling of GPIO bitmap
  gpio: fix SNPS_CREG kconfig dependency warning
  gpiolib: Initialize gdev field before is used
  gpio: fix kernel-doc after devres.c file rename
  gpio: fix doc string for devm_gpiochip_add_data() to not talk about irq_chip
  gpio: syscon: Fix possible NULL ptr usage
  gpiolib: Show correct direction from the beginning
  pinctrl: msm: Use init_valid_mask exported function
  gpiolib: Add init_valid_mask exported function
  GPIO: add single-register GPIO via CREG driver
  dt-bindings: Document the Synopsys GPIO via CREG bindings
  gpio: mockup: use device properties instead of platform_data
  gpio: Slightly more helpful debugfs
  gpio: omap: Remove set but not used variable 'dev'
  gpio: omap: drop omap_gpio_list
  Accept partial 'gpio-line-names' property.
  gpio: omap: get rid of the conditional PM runtime calls
  ...
2018-10-23 08:45:05 +01:00
..
80211 cfg80211: remove unused function ieee80211_data_from_8023() 2017-09-21 11:42:02 +02:00
dmaengine dmaengine: Fix spelling for parenthesis in dmatest documentation 2018-03-26 10:40:37 -06:00
firmware Documentation: update firmware loader fallback reference 2018-07-07 17:45:25 +02:00
fpga docs: fpga: document fpga manager flags 2018-09-30 08:49:55 -07:00
gpio gpio: fix kernel-doc after devres.c file rename 2018-10-10 13:49:15 +02:00
iio docs: driver-api: add iio hw consumer section 2018-01-10 10:30:06 +00:00
pm PM / core: Direct DPM_FLAG_LEAVE_SUSPENDED handling 2018-01-03 00:30:00 +01:00
soundwire Documentation: soundwire: Add more documentation 2018-05-11 21:47:02 +05:30
usb usb: typec: Bus type for alternate modes 2018-07-02 17:42:36 +02:00
basics.rst docs: refcount_t documentation 2017-12-11 14:37:11 -07:00
clk.rst This time we have a good set of changes to the core framework that do some 2018-06-09 12:06:24 -07:00
conf.py doc-rst: make driver-api folder buildable stand-alone 2016-10-26 17:25:00 -06:00
device_connection.rst Documentation: driver-api: fix device_connection.rst kernel-doc error 2018-04-27 17:17:34 -06:00
device_link.rst driver core: Add flag to autoremove device link on supplier unbind 2018-07-09 12:14:31 +02:00
device-io.rst docs: Convert the deviceio template to RST 2017-01-31 17:31:21 -07:00
dma-buf.rst dma-fence: Polish kernel-doc for dma-fence.c 2018-07-04 12:18:37 +02:00
edac.rst edac.rst: move concepts dictionary from edac.h 2016-12-15 08:58:12 -02:00
frame-buffer.rst
hsi.rst docs: split up serial-interfaces.rst 2016-09-06 09:14:52 -06:00
i2c.rst Merge branch 'i2c/for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-07-12 10:04:56 -07:00
index.rst SCSI misc on 20180610 2018-06-10 13:01:12 -07:00
infrastructure.rst dma-mapping: move all DMA mapping code to kernel/dma 2018-06-14 08:50:37 +02:00
input.rst
libata.rst libata: remove ata_sff_data_xfer_noirq() 2018-07-11 10:45:28 -07:00
message-based.rst docs: Don't format internal MPT docs 2016-09-06 09:15:48 -06:00
misc_devices.rst docs-rst: core_api: move driver-specific stuff to drivers_api 2017-04-02 14:17:43 -06:00
miscellaneous.rst docs: driver-api: Remove trailing blank line 2017-08-07 14:27:45 -06:00
mtdnand.rst mtd: rawnand: Deprecate ->chip_delay 2018-10-03 11:12:25 +02:00
pci.rst Documentation: fix docs build error after source file removed 2017-12-03 15:11:45 -07:00
pinctl.rst pinctrl/gpio: Unify namespace for cross-calls 2017-09-22 11:02:10 +02:00
rapidio.rst docs-rst: convert rapidio book to ReST 2017-05-16 08:44:16 -03:00
regulator.rst docs: Convert the regulator docbook to RST 2017-01-31 17:31:41 -07:00
s390-drivers.rst s390/docs: reword airq section 2018-02-02 10:47:15 +01:00
scsi.rst scsi: target: add driver-api document 2018-04-20 19:14:40 -04:00
slimbus.rst slimbus: stream: add stream support 2018-07-07 17:25:23 +02:00
sound.rst
spi.rst docs: split up serial-interfaces.rst 2016-09-06 09:14:52 -06:00
target.rst scsi: target: add driver-api document 2018-04-20 19:14:40 -04:00
uio-howto.rst docs: uio-howto.rst: use a code block to solve a warning 2018-05-10 15:42:43 -06:00
vme.rst docs: Update VME documentation to include kerneldoc comments 2017-03-17 15:10:49 +09:00
w1.rst There has been a fair amount of activity in the docs tree this time 2017-07-03 21:13:25 -07:00