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
  ...

Documentation/driver-api/gpio/board.rst

@@ -193,3 +193,27 @@ And the table can be added to the board code as follows::
 
 The line will be hogged as soon as the gpiochip is created or - in case the
 chip was created earlier - when the hog table is registered.
+
+Arrays of pins
+--------------
+In addition to requesting pins belonging to a function one by one, a device may
+also request an array of pins assigned to the function.  The way those pins are
+mapped to the device determines if the array qualifies for fast bitmap
+processing.  If yes, a bitmap is passed over get/set array functions directly
+between a caller and a respective .get/set_multiple() callback of a GPIO chip.
+
+In order to qualify for fast bitmap processing, the array must meet the
+following requirements:
+- pin hardware number of array member 0 must also be 0,
+- pin hardware numbers of consecutive array members which belong to the same
+  chip as member 0 does must also match their array indexes.
+
+Otherwise fast bitmap processing path is not used in order to avoid consecutive
+pins which belong to the same chip but are not in hardware order being processed
+separately.
+
+If the array applies for fast bitmap processing path, pins which belong to
+different chips than member 0 does, as well as those with indexes different from
+their hardware pin numbers, are excluded from the fast path, both input and
+output.  Moreover, open drain and open source pins are excluded from fast bitmap
+output processing.

Documentation/driver-api/gpio/consumer.rst

@@ -109,9 +109,11 @@ For a function using multiple GPIOs all of those can be obtained with one call::
 					   enum gpiod_flags flags)
 
 This function returns a struct gpio_descs which contains an array of
-descriptors::
+descriptors.  It also contains a pointer to a gpiolib private structure which,
+if passed back to get/set array functions, may speed up I/O proocessing::
 
 	struct gpio_descs {
+		struct gpio_array *info;
 		unsigned int ndescs;
 		struct gpio_desc *desc[];
 	}
@@ -323,29 +325,37 @@ The following functions get or set the values of an array of GPIOs::
 
 	int gpiod_get_array_value(unsigned int array_size,
 				  struct gpio_desc **desc_array,
-				  int *value_array);
+				  struct gpio_array *array_info,
+				  unsigned long *value_bitmap);
 	int gpiod_get_raw_array_value(unsigned int array_size,
 				      struct gpio_desc **desc_array,
-				      int *value_array);
+				      struct gpio_array *array_info,
+				      unsigned long *value_bitmap);
 	int gpiod_get_array_value_cansleep(unsigned int array_size,
 					   struct gpio_desc **desc_array,
-					   int *value_array);
+					   struct gpio_array *array_info,
+					   unsigned long *value_bitmap);
 	int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
 					   struct gpio_desc **desc_array,
-					   int *value_array);
+					   struct gpio_array *array_info,
+					   unsigned long *value_bitmap);
 
-	void gpiod_set_array_value(unsigned int array_size,
-				   struct gpio_desc **desc_array,
-				   int *value_array)
-	void gpiod_set_raw_array_value(unsigned int array_size,
-				       struct gpio_desc **desc_array,
-				       int *value_array)
-	void gpiod_set_array_value_cansleep(unsigned int array_size,
-					    struct gpio_desc **desc_array,
-					    int *value_array)
-	void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
-						struct gpio_desc **desc_array,
-						int *value_array)
+	int gpiod_set_array_value(unsigned int array_size,
+				  struct gpio_desc **desc_array,
+				  struct gpio_array *array_info,
+				  unsigned long *value_bitmap)
+	int gpiod_set_raw_array_value(unsigned int array_size,
+				      struct gpio_desc **desc_array,
+				      struct gpio_array *array_info,
+				      unsigned long *value_bitmap)
+	int gpiod_set_array_value_cansleep(unsigned int array_size,
+					   struct gpio_desc **desc_array,
+					   struct gpio_array *array_info,
+					   unsigned long *value_bitmap)
+	int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
+					       struct gpio_desc **desc_array,
+					       struct gpio_array *array_info,
+					       unsigned long *value_bitmap)
 
 The array can be an arbitrary set of GPIOs. The functions will try to access
 GPIOs belonging to the same bank or chip simultaneously if supported by the
@@ -356,8 +366,9 @@ accessed sequentially.
 The functions take three arguments:
 	* array_size	- the number of array elements
 	* desc_array	- an array of GPIO descriptors
-	* value_array	- an array to store the GPIOs' values (get) or
-			  an array of values to assign to the GPIOs (set)
+	* array_info	- optional information obtained from gpiod_array_get()
+	* value_bitmap	- a bitmap to store the GPIOs' values (get) or
+			  a bitmap of values to assign to the GPIOs (set)
 
 The descriptor array can be obtained using the gpiod_get_array() function
 or one of its variants. If the group of descriptors returned by that function
@@ -366,16 +377,25 @@ the struct gpio_descs returned by gpiod_get_array()::
 
 	struct gpio_descs *my_gpio_descs = gpiod_get_array(...);
 	gpiod_set_array_value(my_gpio_descs->ndescs, my_gpio_descs->desc,
-			      my_gpio_values);
+			      my_gpio_descs->info, my_gpio_value_bitmap);
 
 It is also possible to access a completely arbitrary array of descriptors. The
 descriptors may be obtained using any combination of gpiod_get() and
 gpiod_get_array(). Afterwards the array of descriptors has to be setup
-manually before it can be passed to one of the above functions.
+manually before it can be passed to one of the above functions.  In that case,
+array_info should be set to NULL.
 
 Note that for optimal performance GPIOs belonging to the same chip should be
 contiguous within the array of descriptors.
 
+Still better performance may be achieved if array indexes of the descriptors
+match hardware pin numbers of a single chip.  If an array passed to a get/set
+array function matches the one obtained from gpiod_get_array() and array_info
+associated with the array is also passed, the function may take a fast bitmap
+processing path, passing the value_bitmap argument directly to the respective
+.get/set_multiple() callback of the chip.  That allows for utilization of GPIO
+banks as data I/O ports without much loss of performance.
+
 The return value of gpiod_get_array_value() and its variants is 0 on success
 or negative on error. Note the difference to gpiod_get_value(), which returns
 0 or 1 on success to convey the GPIO value. With the array functions, the GPIO

Documentation/driver-api/gpio/driver.rst

@@ -374,7 +374,28 @@ When implementing an irqchip inside a GPIO driver, these two functions should
 typically be called in the .startup() and .shutdown() callbacks from the
 irqchip.
 
-When using the gpiolib irqchip helpers, these callback are automatically
+When using the gpiolib irqchip helpers, these callbacks are automatically
+assigned.
+
+
+Disabling and enabling IRQs
+---------------------------
+When a GPIO is used as an IRQ signal, then gpiolib also needs to know if
+the IRQ is enabled or disabled. In order to inform gpiolib about this,
+a driver should call::
+
+	void gpiochip_disable_irq(struct gpio_chip *chip, unsigned int offset)
+
+This allows drivers to drive the GPIO as an output while the IRQ is
+disabled. When the IRQ is enabled again, a driver should call::
+
+	void gpiochip_enable_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 .irq_disable() and .irq_enable() callbacks from the
+irqchip.
+
+When using the gpiolib irqchip helpers, these callbacks are automatically
 assigned.
 
 Real-Time compliance for GPIO IRQ chips

Documentation/driver-api/gpio/index.rst

@@ -38,7 +38,7 @@ Device tree support
 Device-managed API
 ==================
 
-.. kernel-doc:: drivers/gpio/devres.c
+.. kernel-doc:: drivers/gpio/gpiolib-devres.c
    :export:
 
 sysfs helpers