gpiolib: Introduce GPIO_LOOKUP_FLAGS_DEFAULT

Since GPIO library operates with enumerator when it's subject to handle
the GPIO lookup flags, it will be better to clearly see what default means.

Thus, introduce GPIO_LOOKUP_FLAGS_DEFAULT entry to describe
the default assumptions.

While here, replace 0 by newly introduced constant.

Signed-off-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Mika Westerberg <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

drivers/gpio/gpiolib-acpi.c

···
 			return PTR_ERR(desc);
 
 		if (info.gpioint && idx++ == index) {
+			unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 			char label[32];
 			int irq;
 
···
 				return irq;
 
 			snprintf(label, sizeof(label), "GpioInt() %d", index);
-			ret = gpiod_configure_flags(desc, label, 0, info.flags);
+			ret = gpiod_configure_flags(desc, label, lflags, info.flags);
 			if (ret < 0)
 				return ret;
 
···
 	u32 gpios[2];
 	int ret;
 
-	*lflags = 0;
+	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	*dflags = 0;
 	*name = NULL;
 

drivers/gpio/gpiolib-of.c

···
 		return ERR_PTR(-EINVAL);
 
 	xlate_flags = 0;
-	*lflags = 0;
+	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	*dflags = 0;
 
 	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);

drivers/gpio/gpiolib.c

···
 					    const char *label,
 					    enum gpiod_flags flags)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = gpiochip_get_desc(chip, hwnum);
 	int err;
 
···
 	if (err < 0)
 		return ERR_PTR(err);
 
-	err = gpiod_configure_flags(desc, label, 0, flags);
+	err = gpiod_configure_flags(desc, label, lflags, flags);
 	if (err) {
 		chip_err(chip, "setup of own GPIO %s failed\n", label);
 		gpiod_free_commit(desc);
···
 					       unsigned int idx,
 					       enum gpiod_flags flags)
 {
-	unsigned long lookupflags = 0;
+	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = NULL;
 	int status;
 	/* Maybe we have a device name, maybe not */
···
 					 enum gpiod_flags dflags,
 					 const char *label)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc;
-	unsigned long lflags = 0;
 	enum of_gpio_flags flags;
 	bool active_low = false;
 	bool single_ended = false;
···
 					 enum gpiod_flags dflags,
 					 const char *label)
 {
+	unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
 	struct gpio_desc *desc = ERR_PTR(-ENODEV);
-	unsigned long lflags = 0;
 	int ret;
 
 	if (!fwnode)

include/linux/gpio/machine.h

···
 	GPIO_TRANSITORY			= (1 << 3),
 	GPIO_PULL_UP			= (1 << 4),
 	GPIO_PULL_DOWN			= (1 << 5),
+
+	GPIO_LOOKUP_FLAGS_DEFAULT	= GPIO_ACTIVE_HIGH | GPIO_PERSISTENT,
 };
 
 /**