gpio / ACPI: register to ACPI events automatically

Instead of asking each driver to register to ACPI events we can just call
acpi_gpiochip_register_interrupts() for each chip that has an ACPI handle.
The function checks chip->to_irq and if it is set to NULL (a GPIO driver
that doesn't do interrupts) the function does nothing.

We also add the a new header drivers/gpio/gpiolib.h that is used for
functions internal to gpiolib and add ACPI GPIO chip registering functions
to that header.

Once that is done we can remove call to acpi_gpiochip_register_interrupts()
from its only user, pinctrl-baytrail.c

Signed-off-by: Mika Westerberg <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpiolib-acpi.c

···
  * gpio pins have acpi event methods and assigns interrupt handlers that calls
  * the acpi event methods for those pins.
  */
-void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
+static void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 {
 	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 	struct acpi_resource *res;
···
 				irq);
 	}
 }
-EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
 
 /**
  * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
···
  * The remaining ACPI event interrupts associated with the chip are freed
  * automatically.
  */
-void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
+static void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 {
 	acpi_handle handle;
 	acpi_status status;
···
 	acpi_detach_data(handle, acpi_gpio_evt_dh);
 	kfree(evt_pins);
 }
-EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
 
 struct acpi_gpio_lookup {
 	struct acpi_gpio_info info;
···
 	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
 }
 EXPORT_SYMBOL_GPL(acpi_get_gpiod_by_index);
+
+void acpi_gpiochip_add(struct gpio_chip *chip)
+{
+	acpi_gpiochip_request_interrupts(chip);
+}
+
+void acpi_gpiochip_remove(struct gpio_chip *chip)
+{
+	acpi_gpiochip_free_interrupts(chip);
+}

drivers/gpio/gpiolib.c

···
 #include <linux/acpi.h>
 #include <linux/gpio/driver.h>
 
+#include "gpiolib.h"
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/gpio.h>
 
···
 #endif
 
 	of_gpiochip_add(chip);
+	acpi_gpiochip_add(chip);
 
 	if (status)
 		goto fail;
···
 
 	gpiochip_remove_pin_ranges(chip);
 	of_gpiochip_remove(chip);
+	acpi_gpiochip_remove(chip);
 
 	for (id = 0; id < chip->ngpio; id++) {
 		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {

drivers/gpio/gpiolib.h

···
+/*
+ * Internal GPIO functions.
+ *
+ * Copyright (C) 2013, Intel Corporation
+ * Author: Mika Westerberg <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef GPIOLIB_H
+#define GPIOLIB_H
+
+#ifdef CONFIG_ACPI
+void acpi_gpiochip_add(struct gpio_chip *chip);
+void acpi_gpiochip_remove(struct gpio_chip *chip);
+#else
+static inline void acpi_gpiochip_add(struct gpio_chip *chip) { }
+static inline void acpi_gpiochip_remove(struct gpio_chip *chip) { }
+#endif
+
+#endif /* GPIOLIB_H */

drivers/pinctrl/pinctrl-baytrail.c

···
 #include <linux/gpio.h>
 #include <linux/irqdomain.h>
 #include <linux/acpi.h>
-#include <linux/acpi_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/seq_file.h>
 #include <linux/io.h>
···
 
 		irq_set_handler_data(hwirq, vg);
 		irq_set_chained_handler(hwirq, byt_gpio_irq_handler);
-
-		/* Register interrupt handlers for gpio signaled acpi events */
-		acpi_gpiochip_request_interrupts(gc);
 	}
 
 	pm_runtime_enable(dev);

include/linux/acpi_gpio.h

···
 
 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
 					  struct acpi_gpio_info *info);
-void acpi_gpiochip_request_interrupts(struct gpio_chip *chip);
-void acpi_gpiochip_free_interrupts(struct gpio_chip *chip);
-
 #else /* CONFIG_GPIO_ACPI */
 
 static inline struct gpio_desc *
···
 {
 	return ERR_PTR(-ENOSYS);
 }
-
-static inline void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) { }
-static inline void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) { }
 
 #endif /* CONFIG_GPIO_ACPI */