Merge tag 'gpio-v3.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO update from Linus Walleij:
 "This is the bulk of GPIO changes for the v3.17 development cycle, and
  this time we got a lot of action going on and it will continue:

   - The core GPIO library implementation has been split up in three
     different files:
     - gpiolib.c for the latest and greatest and shiny GPIO library code
       using GPIO descriptors only
     - gpiolib-legacy.c for the old integer number space API that we are
       phasing out gradually
     - gpiolib-sysfs.c for the sysfs interface that we are not entirely
       happy with, but has to live on for ABI compatibility

   - Add a flags argument to *gpiod_get* functions, with some
     backward-compatibility macros to ease transitions.  We should have
     had the flags there from the beginning it seems, now we need to
     clean up the mess.  There is a plan on how to move forward here
     devised by Alexandre Courbot and Mark Brown

   - Split off a special <linux/gpio/machine.h> header for the board
     gpio table registration, as per example from the regulator
     subsystem

   - Start to kill off the return value from gpiochip_remove() by
     removing the __must_check attribute and removing all checks inside
     the drivers/gpio directory.  The rationale is: well what were we
     supposed to do if there is an error code? Not much: print an error
     message.  And gpiolib already does that.  So make this function
     return void eventually

   - Some cleanups of hairy gpiolib code, make some functions not to be
     used outside the library private and make sure they are not
     exported, remove gpiod_lock/unlock_as_irq() as the existing
     function is for driver-internal use and fine as it is, delete
     gpio_ensure_requested() as it is not meaningful anymore

   - Support the GPIOF_ACTIVE_LOW flag from gpio_request_one() function
     calls, which is logical since this is already supported when
     referencing GPIOs from e.g. device trees

   - Switch STMPE, intel-mid, lynxpoint and ACPI (!) to use the gpiolib
     irqchip helpers cutting down on GPIO irqchip boilerplate a bit more

   - New driver for the Zynq GPIO block

   - The usual incremental improvements around a bunch of drivers

   - Janitorial syntactic and semantic cleanups by Jingoo Han, and
     Rickard Strandqvist especially"

* tag 'gpio-v3.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (37 commits)
  MAINTAINERS: update GPIO include files
  gpio: add missing includes in machine.h
  gpio: add flags argument to gpiod_get*() functions
  MAINTAINERS: Update Samsung pin control entry
  gpio / ACPI: Move event handling registration to gpiolib irqchip helpers
  gpio: lynxpoint: Convert to use gpiolib irqchip
  gpio: split gpiod board registration into machine header
  gpio: remove gpio_ensure_requested()
  gpio: remove useless check in gpiolib_sysfs_init()
  gpiolib: Export gpiochip_request_own_desc and gpiochip_free_own_desc
  gpio: move gpio_ensure_requested() into legacy C file
  gpio: remove gpiod_lock/unlock_as_irq()
  gpio: make gpiochip_get_desc() gpiolib-private
  gpio: simplify gpiochip_export()
  gpio: remove export of private of_get_named_gpio_flags()
  gpio: Add support for GPIOF_ACTIVE_LOW to gpio_request_one functions
  gpio: zynq: Clear pending interrupt when enabling a IRQ
  gpio: drop retval check enforcing from gpiochip_remove()
  gpio: remove all usage of gpio_remove retval in driver/gpio
  devicetree: Add Zynq GPIO devicetree bindings documentation
  ...

1 files changed, 23 insertions, 2 deletions

diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt
index fa9a0a8b3734..18790c237977 100644
--- a/Documentation/gpio/driver.txt
+++ b/Documentation/gpio/driver.txt
@@ -157,13 +157,34 @@ Locking IRQ usage
 Input GPIOs can be used as IRQ signals. When this happens, a driver is requested
 to mark the GPIO as being used as an IRQ:
 
-	int gpiod_lock_as_irq(struct gpio_desc *desc)
+	int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
 
 This will prevent the use of non-irq related GPIO APIs until the GPIO IRQ lock
 is released:
 
-	void gpiod_unlock_as_irq(struct gpio_desc *desc)
+	void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
 
 When implementing an irqchip inside a GPIO driver, these two functions should
 typically be called in the .startup() and .shutdown() callbacks from the
 irqchip.
+
+
+Requesting self-owned GPIO pins
+-------------------------------
+
+Sometimes it is useful to allow a GPIO chip driver to request its own GPIO
+descriptors through the gpiolib API. Using gpio_request() for this purpose
+does not help since it pins the module to the kernel forever (it calls
+try_module_get()). A GPIO driver can use the following functions instead
+to request and free descriptors without being pinned to the kernel forever.
+
+	int gpiochip_request_own_desc(struct gpio_desc *desc, const char *label)
+
+	void gpiochip_free_own_desc(struct gpio_desc *desc)
+
+Descriptors requested with gpiochip_request_own_desc() must be released with
+gpiochip_free_own_desc().
+
+These functions must be used with care since they do not affect module use
+count. Do not use the functions to request gpio descriptors not owned by the
+calling driver.