.ngpio                  = 24,
                        .direction_input        = s3c24xx_gpiolib_banka_input,
                        .direction_output       = s3c24xx_gpiolib_banka_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [1] = {
                        .owner                  = THIS_MODULE,
                        .label                  = "GPIOB",
                        .ngpio                  = 16,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [2] = {
                        .owner                  = THIS_MODULE,
                        .label                  = "GPIOC",
                        .ngpio                  = 16,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [3] = {
                        .owner                  = THIS_MODULE,
                        .label                  = "GPIOD",
                        .ngpio                  = 16,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [4] = {
                        .label                  = "GPIOE",
                        .owner                  = THIS_MODULE,
                        .ngpio                  = 16,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [5] = {
                        .owner                  = THIS_MODULE,
                        .label                  = "GPIOF",
                        .ngpio                  = 8,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
        [6] = {
                        .owner                  = THIS_MODULE,
                        .label                  = "GPIOG",
                        .ngpio                  = 10,
-                       .direction_input        = s3c24xx_gpiolib_input,
-                       .direction_output       = s3c24xx_gpiolib_output,
-                       .set                    = s3c24xx_gpiolib_set,
-                       .get                    = s3c24xx_gpiolib_get,
                },
        },
 };
 
+static __init void s3c24xx_gpiolib_add(struct s3c24xx_gpio_chip *chip)
+{
+       struct gpio_chip *gc = &chip->chip;
+
+       BUG_ON(!chip->base);
+       BUG_ON(!gc->label);
+       BUG_ON(!gc->ngpio);
+
+       if (!gc->direction_input)
+               gc->direction_input = s3c24xx_gpiolib_input;
+       if (!gc->direction_output)
+               gc->direction_output = s3c24xx_gpiolib_output;
+       if (!gc->set)
+               gc->set = s3c24xx_gpiolib_set;
+       if (!gc->get)
+               gc->get = s3c24xx_gpiolib_get;
+
+       /* gpiochip_add() prints own failure message on error. */
+       gpiochip_add(gc);
+}
+
 static __init int s3c24xx_gpiolib_init(void)
 {
        struct s3c24xx_gpio_chip *chip = gpios;
        int gpn;
 
        for (gpn = 0; gpn < ARRAY_SIZE(gpios); gpn++, chip++)
-               gpiochip_add(&chip->chip);
+               s3c24xx_gpiolib_add(chip);
 
        return 0;
 }