gpio: acpi: normalize use of gpiochip_get_desc()

GPIO descriptors are changing from unique and permanent tokens to
allocated resources. Therefore gpiochip_get_desc() cannot be used as a
way to obtain a global GPIO descriptor anymore.

This patch updates the gpiolib ACPI support code to keep and use the
descriptor returned by a centralized call to gpiochip_get_desc().

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -25,10 +25,12 @@ struct acpi_gpio_event {
 	acpi_handle handle;
 	unsigned int pin;
 	unsigned int irq;
+	struct gpio_desc *desc;
 };
 
 struct acpi_gpio_connection {
 	struct list_head node;
+	unsigned int pin;
 	struct gpio_desc *desc;
 };
 
@@ -197,6 +199,7 @@ static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 	event->handle = evt_handle;
 	event->irq = irq;
 	event->pin = pin;
+	event->desc = desc;
 
 	ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 				   "ACPI:Event", event);
@@ -280,7 +283,7 @@ void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 		struct gpio_desc *desc;
 
 		free_irq(event->irq, event);
-		desc = gpiochip_get_desc(chip, event->pin);
+		desc = event->desc;
 		if (WARN_ON(IS_ERR(desc)))
 			continue;
 		gpio_unlock_as_irq(chip, event->pin);
@@ -406,24 +409,26 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 		struct gpio_desc *desc;
 		bool found;
 
-		desc = gpiochip_get_desc(chip, pin);
-		if (IS_ERR(desc)) {
-			status = AE_ERROR;
-			goto out;
-		}
-
 		mutex_lock(&achip->conn_lock);
 
 		found = false;
 		list_for_each_entry(conn, &achip->conns, node) {
-			if (conn->desc == desc) {
+			if (conn->pin == pin) {
 				found = true;
+				desc = conn->desc;
 				break;
 			}
 		}
 		if (!found) {
 			int ret;
 
+			desc = gpiochip_get_desc(chip, pin);
+			if (IS_ERR(desc)) {
+				status = AE_ERROR;
+				mutex_unlock(&achip->conn_lock);
+				goto out;
+			}
+
 			ret = gpiochip_request_own_desc(desc, "ACPI:OpRegion");
 			if (ret) {
 				status = AE_ERROR;
@@ -462,6 +467,7 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 				goto out;
 			}
 
+			conn->pin = pin;
 			conn->desc = desc;
 			list_add_tail(&conn->node, &achip->conns);
 		}