gpiolib-acpi: Only defer request_irq for GpioInt ACPI event handlers

Commit 78d3a92edbfb ("gpiolib-acpi: Register GpioInt ACPI event handlers
from a late_initcall") deferred the entire acpi_gpiochip_request_interrupt
call for each event resource.

This means it also delays the gpiochip_request_own_desc(..., "ACPI:Event")
call. This is a problem if some AML code reads the GPIO pin before we
run the deferred acpi_gpiochip_request_interrupt, because in that case
acpi_gpio_adr_space_handler() will already have called
gpiochip_request_own_desc(..., "ACPI:OpRegion") causing the call from
acpi_gpiochip_request_interrupt to fail with -EBUSY and we will fail to
register an event handler.

acpi_gpio_adr_space_handler is prepared for acpi_gpiochip_request_interrupt
already having claimed the pin, but the other way around does not work.

One example of a problem this causes, is the event handler for the OTG
ID pin on a Prowise PT301 tablet not registering, keeping the port stuck
in whatever mode it was in during boot and e.g. only allowing charging
after a reboot.

This commit fixes this by only deferring the request_irq call and the
initial run of edge-triggered IRQs instead of deferring all of
acpi_gpiochip_request_interrupt.

Cc: stable@vger.kernel.org
Fixes: 78d3a92edbfb ("gpiolib-acpi: Register GpioInt ACPI event ...")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 84 insertions, 60 deletions

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 55b72fbe1631..7f93954c58ea 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -19,11 +19,28 @@
 
 #include "gpiolib.h"
 
+/**
+ * struct acpi_gpio_event - ACPI GPIO event handler data
+ *
+ * @node:         list-entry of the events list of the struct acpi_gpio_chip
+ * @handle:       handle of ACPI method to execute when the IRQ triggers
+ * @handler:      irq_handler to pass to request_irq when requesting the IRQ
+ * @pin:          GPIO pin number on the gpio_chip
+ * @irq:          Linux IRQ number for the event, for request_ / free_irq
+ * @irqflags:     flags to pass to request_irq when requesting the IRQ
+ * @irq_is_wake:  If the ACPI flags indicate the IRQ is a wakeup source
+ * @is_requested: True if request_irq has been done
+ * @desc:         gpio_desc for the GPIO pin for this event
+ */
 struct acpi_gpio_event {
         struct list_head node;
         acpi_handle handle;
+        irq_handler_t handler;
         unsigned int pin;
         unsigned int irq;
+        unsigned long irqflags;
+        bool irq_is_wake;
+        bool irq_requested;
         struct gpio_desc *desc;
 };
 
@@ -49,10 +66,10 @@ struct acpi_gpio_chip {
 
 /*
  * For gpiochips which call acpi_gpiochip_request_interrupts() before late_init
- * (so builtin drivers) we register the ACPI GpioInt event handlers from a
+ * (so builtin drivers) we register the ACPI GpioInt IRQ handlers from a
  * late_initcall_sync handler, so that other builtin drivers can register their
  * OpRegions before the event handlers can run.  This list contains gpiochips
- * for which the acpi_gpiochip_request_interrupts() has been deferred.
+ * for which the acpi_gpiochip_request_irqs() call has been deferred.
  */
 static DEFINE_MUTEX(acpi_gpio_deferred_req_irqs_lock);
 static LIST_HEAD(acpi_gpio_deferred_req_irqs_list);
@@ -133,8 +150,42 @@ bool acpi_gpio_get_irq_resource(struct acpi_resource *ares,
 }
 EXPORT_SYMBOL_GPL(acpi_gpio_get_irq_resource);
 
-static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
-                                                   void *context)
+static void acpi_gpiochip_request_irq(struct acpi_gpio_chip *acpi_gpio,
+                                      struct acpi_gpio_event *event)
+{
+        int ret, value;
+
+        ret = request_threaded_irq(event->irq, NULL, event->handler,
+                                   event->irqflags, "ACPI:Event", event);
+        if (ret) {
+                dev_err(acpi_gpio->chip->parent,
+                        "Failed to setup interrupt handler for %d\n",
+                        event->irq);
+                return;
+        }
+
+        if (event->irq_is_wake)
+                enable_irq_wake(event->irq);
+
+        event->irq_requested = true;
+
+        /* Make sure we trigger the initial state of edge-triggered IRQs */
+        value = gpiod_get_raw_value_cansleep(event->desc);
+        if (((event->irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
+            ((event->irqflags & IRQF_TRIGGER_FALLING) && value == 0))
+                event->handler(event->irq, event);
+}
+
+static void acpi_gpiochip_request_irqs(struct acpi_gpio_chip *acpi_gpio)
+{
+        struct acpi_gpio_event *event;
+
+        list_for_each_entry(event, &acpi_gpio->events, node)
+                acpi_gpiochip_request_irq(acpi_gpio, event);
+}
+
+static acpi_status acpi_gpiochip_alloc_event(struct acpi_resource *ares,
+                                             void *context)
 {
         struct acpi_gpio_chip *acpi_gpio = context;
         struct gpio_chip *chip = acpi_gpio->chip;
@@ -143,8 +194,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
         struct acpi_gpio_event *event;
         irq_handler_t handler = NULL;
         struct gpio_desc *desc;
-        unsigned long irqflags;
-        int ret, pin, irq, value;
+        int ret, pin, irq;
 
         if (!acpi_gpio_get_irq_resource(ares, &agpio))
                 return AE_OK;
@@ -175,8 +225,6 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 
         gpiod_direction_input(desc);
 
-        value = gpiod_get_value_cansleep(desc);
-
         ret = gpiochip_lock_as_irq(chip, pin);
         if (ret) {
                 dev_err(chip->parent, "Failed to lock GPIO as interrupt\n");
@@ -189,64 +237,42 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
                 goto fail_unlock_irq;
         }
 
-        irqflags = IRQF_ONESHOT;
+        event = kzalloc(sizeof(*event), GFP_KERNEL);
+        if (!event)
+                goto fail_unlock_irq;
+
+        event->irqflags = IRQF_ONESHOT;
         if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
                 if (agpio->polarity == ACPI_ACTIVE_HIGH)
-                        irqflags |= IRQF_TRIGGER_HIGH;
+                        event->irqflags |= IRQF_TRIGGER_HIGH;
                 else
-                        irqflags |= IRQF_TRIGGER_LOW;
+                        event->irqflags |= IRQF_TRIGGER_LOW;
         } else {
                 switch (agpio->polarity) {
                 case ACPI_ACTIVE_HIGH:
-                        irqflags |= IRQF_TRIGGER_RISING;
+                        event->irqflags |= IRQF_TRIGGER_RISING;
                         break;
                 case ACPI_ACTIVE_LOW:
-                        irqflags |= IRQF_TRIGGER_FALLING;
+                        event->irqflags |= IRQF_TRIGGER_FALLING;
                         break;
                 default:
-                        irqflags |= IRQF_TRIGGER_RISING |
-                                    IRQF_TRIGGER_FALLING;
+                        event->irqflags |= IRQF_TRIGGER_RISING |
+                                           IRQF_TRIGGER_FALLING;
                         break;
                 }
         }
 
-        event = kzalloc(sizeof(*event), GFP_KERNEL);
-        if (!event)
-                goto fail_unlock_irq;
-
         event->handle = evt_handle;
+        event->handler = handler;
         event->irq = irq;
+        event->irq_is_wake = agpio->wake_capable == ACPI_WAKE_CAPABLE;
         event->pin = pin;
         event->desc = desc;
 
-        ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
-                                   "ACPI:Event", event);
-        if (ret) {
-                dev_err(chip->parent,
-                        "Failed to setup interrupt handler for %d\n",
-                        event->irq);
-                goto fail_free_event;
-        }
-
-        if (agpio->wake_capable == ACPI_WAKE_CAPABLE)
-                enable_irq_wake(irq);
-
         list_add_tail(&event->node, &acpi_gpio->events);
 
-        /*
-         * Make sure we trigger the initial state of the IRQ when using RISING
-         * or FALLING.  Note we run the handlers on late_init, the AML code
-         * may refer to OperationRegions from other (builtin) drivers which
-         * may be probed after us.
-         */
-        if (((irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
-            ((irqflags & IRQF_TRIGGER_FALLING) && value == 0))
-                handler(event->irq, event);
-
         return AE_OK;
 
-fail_free_event:
-        kfree(event);
 fail_unlock_irq:
         gpiochip_unlock_as_irq(chip, pin);
 fail_free_desc:
@@ -283,6 +309,9 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
         if (ACPI_FAILURE(status))
                 return;
 
+        acpi_walk_resources(handle, "_AEI",
+                            acpi_gpiochip_alloc_event, acpi_gpio);
+
         mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
         defer = !acpi_gpio_deferred_req_irqs_done;
         if (defer)
@@ -293,8 +322,7 @@ void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
         if (defer)
                 return;
 
-        acpi_walk_resources(handle, "_AEI",
-                            acpi_gpiochip_request_interrupt, acpi_gpio);
+        acpi_gpiochip_request_irqs(acpi_gpio);
 }
 EXPORT_SYMBOL_GPL(acpi_gpiochip_request_interrupts);
 
@@ -331,10 +359,13 @@ void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
         list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
                 struct gpio_desc *desc;
 
-                if (irqd_is_wakeup_set(irq_get_irq_data(event->irq)))
-                        disable_irq_wake(event->irq);
+                if (event->irq_requested) {
+                        if (event->irq_is_wake)
+                                disable_irq_wake(event->irq);
+
+                        free_irq(event->irq, event);
+                }
 
-                free_irq(event->irq, event);
                 desc = event->desc;
                 if (WARN_ON(IS_ERR(desc)))
                         continue;
@@ -1200,23 +1231,16 @@ bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
         return con_id == NULL;
 }
 
-/* Run deferred acpi_gpiochip_request_interrupts() */
-static int acpi_gpio_handle_deferred_request_interrupts(void)
+/* Run deferred acpi_gpiochip_request_irqs() */
+static int acpi_gpio_handle_deferred_request_irqs(void)
 {
         struct acpi_gpio_chip *acpi_gpio, *tmp;
 
         mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
         list_for_each_entry_safe(acpi_gpio, tmp,
                                  &acpi_gpio_deferred_req_irqs_list,
-                                 deferred_req_irqs_list_entry) {
-                acpi_handle handle;
-
-                handle = ACPI_HANDLE(acpi_gpio->chip->parent);
-                acpi_walk_resources(handle, "_AEI",
-                                    acpi_gpiochip_request_interrupt, acpi_gpio);
-
-                list_del_init(&acpi_gpio->deferred_req_irqs_list_entry);
-        }
+                                 deferred_req_irqs_list_entry)
+                acpi_gpiochip_request_irqs(acpi_gpio);
 
         acpi_gpio_deferred_req_irqs_done = true;
         mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);
@@ -1224,4 +1248,4 @@ static int acpi_gpio_handle_deferred_request_interrupts(void)
         return 0;
 }
 /* We must use _sync so that this runs after the first deferred_probe run */
-late_initcall_sync(acpi_gpio_handle_deferred_request_interrupts);
+late_initcall_sync(acpi_gpio_handle_deferred_request_irqs);