Merge tag 'gpio-v5.7-1' 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 development for the v5.7 kernel cycle.

  Core and userspace API:

   - The userspace API KFIFOs have been imoproved with locks that do not
     block interrupts. This makes us better at getting events to
     userspace without blocking or disturbing new events arriving in the
     same time. This was reviewed by the KFIFO maintainer Stefani. This
     is a generic improvement which paves the road for similar
     improvements in other subsystems.

   - We provide a new ioctl() for monitoring changes in the line
     information, such as when multiple clients are taking lines and
     giving them back, possibly reconfiguring them in the process: we
     can now monitor that and not get stuck with stale static
     information.

   - An example tool 'gpio-watch' is provided to showcase this
     functionality.

   - Timestamps for events are switched to ktime_get_ns() which is
     monotonic. We previously had a 'realtime' stamp which could move
     forward and *backward* in time, which probably would just cause
     silent bugs and weird behaviour. In the long run we see two
     relevant timestamps: ktime_get_ns() or the timestamp sometimes
     provided by the GPIO hardware itself, if that exists.

   - Device Tree overlay support for GPIO hogs. On systems that load
     overlays, these overlays can now contain hogs, and will then be
     respected.

   - Handle pin control interaction with nonexisting pin ranges in the
     GPIO library core instead of in the individual drivers.

  New drivers:

   - New driver for the Mellanox BlueField 2 GPIO controller.

  Driver improvements:

   - Introduce the BGPIOF_NO_SET_ON_INPUT flag to the generic MMIO GPIO
     library and use this flag in the MT7621 driver.

   - Texas Instruments OMAP CPU power management improvements, such as
     blocking of idle on pending GPIO interrupts"

* tag 'gpio-v5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (59 commits)
  Revert "gpio: eic-sprd: Use devm_platform_ioremap_resource()"
  pinctrl: Unconditionally assign .request()/.free()
  gpio: Unconditionally assign .request()/.free()
  gpio: export of_pinctrl_get to modules
  pinctrl: Define of_pinctrl_get() dummy for !PINCTRL
  gpio: Rename variable in core APIs
  gpio: Avoid using pin ranges with !PINCTRL
  gpiolib: Remove unused gpio_chip parameter from gpio_set_bias()
  gpiolib: Pass gpio_desc to gpio_set_config()
  gpiolib: Introduce gpiod_set_config()
  tools: gpio: Fix out-of-tree build regression
  gpio: gpiolib: fix a doc warning
  gpio: tegra186: Add Tegra194 pin ranges for GG.0 and GG.1
  gpio: tegra186: Add support for pin ranges
  gpio: Support GPIO controllers without pin-ranges
  ARM: integrator: impd1: Use GPIO_LOOKUP() helper macro
  gpio: brcmstb: support gpio-line-names property
  tools: gpio: Fix typo in gpio-utils
  tools: gpio-hammer: Apply scripts/Lindent and retain good changes
  gpiolib: gpio_name_to_desc: factor out !name check
  ...

include/uapi/linux/gpio.h

@@ -18,7 +18,7 @@
  * struct gpiochip_info - Information about a certain GPIO chip
  * @name: the Linux kernel name of this GPIO chip
  * @label: a functional name for this GPIO chip, such as a product
- * number, may be NULL
+ * number, may be empty
  * @lines: number of GPIO lines on this chip
  */
 struct gpiochip_info {
@@ -44,10 +44,10 @@ struct gpiochip_info {
  * @flags: various flags for this line
  * @name: the name of this GPIO line, such as the output pin of the line on the
  * chip, a rail or a pin header name on a board, as specified by the gpio
- * chip, may be NULL
+ * chip, may be empty
  * @consumer: a functional name for the consumer of this GPIO line as set by
- * whatever is using it, will be NULL if there is no current user but may
- * also be NULL if the consumer doesn't set this up
+ * whatever is using it, will be empty if there is no current user but may
+ * also be empty if the consumer doesn't set this up
  */
 struct gpioline_info {
 	__u32 line_offset;
@@ -59,6 +59,34 @@ struct gpioline_info {
 /* Maximum number of requested handles */
 #define GPIOHANDLES_MAX 64
 
+/* Possible line status change events */
+enum {
+	GPIOLINE_CHANGED_REQUESTED = 1,
+	GPIOLINE_CHANGED_RELEASED,
+	GPIOLINE_CHANGED_CONFIG,
+};
+
+/**
+ * struct gpioline_info_changed - Information about a change in status
+ * of a GPIO line
+ * @info: updated line information
+ * @timestamp: estimate of time of status change occurrence, in nanoseconds
+ * and GPIOLINE_CHANGED_CONFIG
+ * @event_type: one of GPIOLINE_CHANGED_REQUESTED, GPIOLINE_CHANGED_RELEASED
+ *
+ * Note: struct gpioline_info embedded here has 32-bit alignment on its own,
+ * but it works fine with 64-bit alignment too. With its 72 byte size, we can
+ * guarantee there are no implicit holes between it and subsequent members.
+ * The 20-byte padding at the end makes sure we don't add any implicit padding
+ * at the end of the structure on 64-bit architectures.
+ */
+struct gpioline_info_changed {
+	struct gpioline_info info;
+	__u64 timestamp;
+	__u32 event_type;
+	__u32 padding[5]; /* for future use */
+};
+
 /* Linerequest flags */
 #define GPIOHANDLE_REQUEST_INPUT	(1UL << 0)
 #define GPIOHANDLE_REQUEST_OUTPUT	(1UL << 1)
@@ -176,6 +204,8 @@ struct gpioevent_data {
 
 #define GPIO_GET_CHIPINFO_IOCTL _IOR(0xB4, 0x01, struct gpiochip_info)
 #define GPIO_GET_LINEINFO_IOCTL _IOWR(0xB4, 0x02, struct gpioline_info)
+#define GPIO_GET_LINEINFO_WATCH_IOCTL _IOWR(0xB4, 0x0b, struct gpioline_info)
+#define GPIO_GET_LINEINFO_UNWATCH_IOCTL _IOWR(0xB4, 0x0c, __u32)
 #define GPIO_GET_LINEHANDLE_IOCTL _IOWR(0xB4, 0x03, struct gpiohandle_request)
 #define GPIO_GET_LINEEVENT_IOCTL _IOWR(0xB4, 0x04, struct gpioevent_request)