Merge tag 'gpio-v4.7-1' 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 kernel cycle v4.7:

  Core infrastructural changes:

   - Support for natively single-ended GPIO driver stages.

     This means that if the hardware has registers to configure open
     drain or open source configuration, we use that rather than (as we
     did before) try to emulate it by switching the line to an input to
     get high impedance.

     This is also documented throughly in Documentation/gpio/driver.txt
     for those of you who did not understand one word of what I just
     wrote.

   - Start to do away with the unnecessarily complex and unitelligible
     ARCH_REQUIRE_GPIOLIB and ARCH_WANT_OPTIONAL_GPIOLIB, another
     evolutional artifact from the time when the GPIO subsystem was
     unmaintained.

     Archs can now just select GPIOLIB and be done with it, cleanups to
     arches will trickle in for the next kernel.  Some minor archs ACKed
     the changes immediately so these are included in this pull request.

   - Advancing the use of the data pointer inside the GPIO device for
     storing driver data by switching the PowerPC, Super-H Unicore and
     a few other subarches or subsystem drivers in ALSA SoC, Input,
     serial, SSB, staging etc to use it.

   - The initialization now reads the input/output state of the GPIO
     lines, so that each GPIO descriptor knows - if this callback is
     implemented - whether the line is input or output.  This also
     reflects nicely in userspace "lsgpio".

   - It is now possible to name GPIO producer names, line names, from
     the device tree.  (Platform data has been supported for a while).
     I bet we will get a similar mechanism for ACPI one of those days.
     This makes is possible to get sensible producer names for e.g.
     GPIO rails in "lsgpio" in userspace.

  New drivers:

   - New driver for the Loongson1.

   - The XLP driver now supports Broadcom Vulcan ARM64.

   - The IT87 driver now supports IT8620 and IT8628.

   - The PCA953X driver now supports Galileo Gen2.

  Driver improvements:

   - MCP23S08 was switched to use the gpiolib irqchip helpers and now
     also suppors level-triggered interrupts.

   - 74x164 and RCAR now supports the .set_multiple() callback

   - AMDPT was converted to use generic GPIO.

   - TC3589x, TPS65218, SX150X, F7188X, MENZ127, VX855, WM831X, WM8994
     support the new single ended callback for open drain and in some
     cases open source.

   - Implement the .get_direction() callback for a few more drivers like
     PL061, Xgene.

  Cleanups:

   - Paul Gortmaker combed through the drivers and de-modularized those
     who are not really modules.

   - Move the GPIO poweroff DT bindings to the power subdir where they
     belong.

   - Rename gpio-generic.c to gpio-mmio.c, which is much more to the
     point.  That's what it is handling, nothing more, nothing less"

* tag 'gpio-v4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (126 commits)
  MIPS: do away with ARCH_[WANT_OPTIONAL|REQUIRE]_GPIOLIB
  gpio: zevio: make it explicitly non-modular
  gpio: timberdale: make it explicitly non-modular
  gpio: stmpe: make it explicitly non-modular
  gpio: sodaville: make it explicitly non-modular
  pinctrl: sh-pfc: Let gpio_chip.to_irq() return zero on error
  gpio: dwapb: Add ACPI device ID for DWAPB GPIO controller on X-Gene platforms
  gpio: dt-bindings: add wd,mbl-gpio bindings
  gpio: of: make it possible to name GPIO lines
  gpio: make gpiod_to_irq() return negative for NO_IRQ
  gpio: xgene: implement .get_direction()
  gpio: xgene: Enable ACPI support for X-Gene GFC GPIO driver
  gpio: tegra: Implement gpio_get_direction callback
  gpio: set up initial state from .get_direction()
  gpio: rename gpio-generic.c into gpio-mmio.c
  gpio: generic: fix GPIO_GENERIC_PLATFORM is set to module case
  gpio: dwapb: add gpio-signaled acpi event support
  gpio: dwapb: convert device node to fwnode
  gpio: dwapb: remove name from dwapb_port_property
  gpio/qoriq: select IRQ_DOMAIN
  ...

1 files changed, 24 insertions, 1 deletions

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index bee976f82788..50882e09289b 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -20,6 +20,18 @@ struct gpio_device;
 #ifdef CONFIG_GPIOLIB
 
 /**
+ * enum single_ended_mode - mode for single ended operation
+ * @LINE_MODE_PUSH_PULL: normal mode for a GPIO line, drive actively high/low
+ * @LINE_MODE_OPEN_DRAIN: set line to be open drain
+ * @LINE_MODE_OPEN_SOURCE: set line to be open source
+ */
+enum single_ended_mode {
+	LINE_MODE_PUSH_PULL,
+	LINE_MODE_OPEN_DRAIN,
+	LINE_MODE_OPEN_SOURCE,
+};
+
+/**
  * struct gpio_chip - abstract a GPIO controller
  * @label: a functional name for the GPIO device, such as a part
  *	number or the name of the SoC IP-block implementing it.
@@ -38,7 +50,15 @@ struct gpio_device;
  * @set: assigns output value for signal "offset"
  * @set_multiple: assigns output values for multiple signals defined by "mask"
  * @set_debounce: optional hook for setting debounce time for specified gpio in
- *      interrupt triggered gpio chips
+ *	interrupt triggered gpio chips
+ * @set_single_ended: optional hook for setting a line as open drain, open
+ *	source, or non-single ended (restore from open drain/source to normal
+ *	push-pull mode) this should be implemented if the hardware supports
+ *	open drain or open source settings. The GPIOlib will otherwise try
+ *	to emulate open drain/source by not actively driving lines high/low
+ *	if a consumer request this. The driver may return -ENOTSUPP if e.g.
+ *	it supports just open drain but not open source and is called
+ *	with LINE_MODE_OPEN_SOURCE as mode argument.
  * @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
  *	implementation may not sleep
  * @dbg_show: optional routine to show contents in debugfs; default code
@@ -130,6 +150,9 @@ struct gpio_chip {
 	int			(*set_debounce)(struct gpio_chip *chip,
 						unsigned offset,
 						unsigned debounce);
+	int			(*set_single_ended)(struct gpio_chip *chip,
+						unsigned offset,
+						enum single_ended_mode mode);
 
 	int			(*to_irq)(struct gpio_chip *chip,
 						unsigned offset);