gpio: generic: add request function pointer

gpiolib will require all gpio drivers to expicitly set the request
function pointer in the future. To encourage gpio driver developers
to adhere to this standard gpio-generic.c now sets this function
pointer.
Signed-off-by: NAnthony Fee <anthony.fee@emutex.com>
Acked-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-generic.c

@@ -388,6 +388,14 @@ static int bgpio_setup_direction(struct bgpio_chip *bgc,
 	return 0;
 }
 
+static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
+{
+	if (gpio_pin < chip->ngpio)
+		return 0;
+
+	return -EINVAL;
+}
+
 int bgpio_remove(struct bgpio_chip *bgc)
 {
 	return gpiochip_remove(&bgc->gc);
@@ -413,6 +421,7 @@ int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
 	bgc->gc.label = dev_name(dev);
 	bgc->gc.base = -1;
 	bgc->gc.ngpio = bgc->bits;
+	bgc->gc.request = bgpio_request;
 
 	ret = bgpio_setup_io(bgc, dat, set, clr);
 	if (ret)