diff --git a/sys/arm/allwinner/a10_gpio.c b/sys/arm/allwinner/a10_gpio.c
index b93bbc9d0b9a..a5321062cc78 100644
--- a/sys/arm/allwinner/a10_gpio.c
+++ b/sys/arm/allwinner/a10_gpio.c
@@ -474,8 +474,8 @@ a10_gpio_attach(device_t dev)
 	}
 	sc->sc_gpio_npins = i;
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	a10_gpio_sc = sc;
 
diff --git a/sys/arm/broadcom/bcm2835/bcm2835_gpio.c b/sys/arm/broadcom/bcm2835/bcm2835_gpio.c
index 98813853e2da..a8903ee82eab 100644
--- a/sys/arm/broadcom/bcm2835/bcm2835_gpio.c
+++ b/sys/arm/broadcom/bcm2835/bcm2835_gpio.c
@@ -747,8 +747,9 @@ bcm_gpio_attach(device_t dev)
 
 	bcm_gpio_sysctl_init(sc);
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
+
 	return (bus_generic_attach(dev));
 
 fail:
diff --git a/sys/arm/freescale/imx/imx_gpio.c b/sys/arm/freescale/imx/imx_gpio.c
index 95e24ca0378e..b36548943210 100644
--- a/sys/arm/freescale/imx/imx_gpio.c
+++ b/sys/arm/freescale/imx/imx_gpio.c
@@ -435,8 +435,8 @@ imx51_gpio_attach(device_t dev)
  		    "imx_gpio%d.%d", device_get_unit(dev), i);
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/freescale/vybrid/vf_gpio.c b/sys/arm/freescale/vybrid/vf_gpio.c
index 686e05c5b915..b83a877c56b9 100644
--- a/sys/arm/freescale/vybrid/vf_gpio.c
+++ b/sys/arm/freescale/vybrid/vf_gpio.c
@@ -146,8 +146,8 @@ vf_gpio_attach(device_t dev)
 		    "vf_gpio%d.%d", device_get_unit(dev), i);
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/lpc/lpc_gpio.c b/sys/arm/lpc/lpc_gpio.c
index b2310cb0a2d2..d9536a7012e1 100644
--- a/sys/arm/lpc/lpc_gpio.c
+++ b/sys/arm/lpc/lpc_gpio.c
@@ -192,8 +192,8 @@ lpc_gpio_attach(device_t dev)
 
 	lpc_gpio_sc = sc;
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/rockchip/rk30xx_gpio.c b/sys/arm/rockchip/rk30xx_gpio.c
index 2a3288fd1063..fc24947c6562 100644
--- a/sys/arm/rockchip/rk30xx_gpio.c
+++ b/sys/arm/rockchip/rk30xx_gpio.c
@@ -504,8 +504,8 @@ rk30_gpio_attach(device_t dev)
 	}
 	sc->sc_gpio_npins = i;
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	rk30_gpio_sc = sc;
 
diff --git a/sys/arm/samsung/exynos/exynos5_pad.c b/sys/arm/samsung/exynos/exynos5_pad.c
index c956e86612c2..d00eddca5589 100644
--- a/sys/arm/samsung/exynos/exynos5_pad.c
+++ b/sys/arm/samsung/exynos/exynos5_pad.c
@@ -559,8 +559,8 @@ pad_attach(device_t dev)
 		    "pad%d.%d", device_get_unit(dev), i);
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/ti/ti_gpio.c b/sys/arm/ti/ti_gpio.c
index 83e06105dff6..eb0c880214d3 100644
--- a/sys/arm/ti/ti_gpio.c
+++ b/sys/arm/ti/ti_gpio.c
@@ -800,8 +800,8 @@ ti_gpio_attach(device_t dev)
 	}
 
 	/* Finish of the probe call */
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/xilinx/zy7_gpio.c b/sys/arm/xilinx/zy7_gpio.c
index 77dc640b0b26..ac73c9f4ad36 100644
--- a/sys/arm/xilinx/zy7_gpio.c
+++ b/sys/arm/xilinx/zy7_gpio.c
@@ -329,8 +329,8 @@ zy7_gpio_attach(device_t dev)
 	/* Completely reset. */
 	zy7_gpio_hw_reset(sc);
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/arm/xscale/ixp425/avila_gpio.c b/sys/arm/xscale/ixp425/avila_gpio.c
index 8be99489507a..48f970d7f4bd 100644
--- a/sys/arm/xscale/ixp425/avila_gpio.c
+++ b/sys/arm/xscale/ixp425/avila_gpio.c
@@ -318,8 +318,9 @@ avila_gpio_attach(device_t dev)
 		sc->sc_valid |= 1 << p->pin;
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
+
 	return (bus_generic_attach(dev));
 #undef N
 }
diff --git a/sys/arm/xscale/ixp425/cambria_gpio.c b/sys/arm/xscale/ixp425/cambria_gpio.c
index 18472cd41978..baa34838f842 100644
--- a/sys/arm/xscale/ixp425/cambria_gpio.c
+++ b/sys/arm/xscale/ixp425/cambria_gpio.c
@@ -447,8 +447,9 @@ cambria_gpio_attach(device_t dev)
 		cambria_gpio_pin_setflags(dev, pin, p->flags);
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
+
 	return (bus_generic_attach(dev));
 }
 
diff --git a/sys/mips/atheros/ar71xx_gpio.c b/sys/mips/atheros/ar71xx_gpio.c
index d0a52ca0bbe7..0e1633229cb2 100644
--- a/sys/mips/atheros/ar71xx_gpio.c
+++ b/sys/mips/atheros/ar71xx_gpio.c
@@ -441,8 +441,9 @@ ar71xx_gpio_attach(device_t dev)
 			ar71xx_gpio_pin_set(dev, j, 1);
 		}
 	}
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
+
 	return (bus_generic_attach(dev));
 }
 
diff --git a/sys/mips/cavium/octeon_gpio.c b/sys/mips/cavium/octeon_gpio.c
index 788f0aa48a60..26b42eaca87c 100644
--- a/sys/mips/cavium/octeon_gpio.c
+++ b/sys/mips/cavium/octeon_gpio.c
@@ -441,8 +441,9 @@ octeon_gpio_attach(device_t dev)
 		}
 	}
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
+
 	return (bus_generic_attach(dev));
 }
 
diff --git a/sys/mips/rt305x/rt305x_gpio.c b/sys/mips/rt305x/rt305x_gpio.c
index 1d685187ec17..5f7defbcc4e5 100644
--- a/sys/mips/rt305x/rt305x_gpio.c
+++ b/sys/mips/rt305x/rt305x_gpio.c
@@ -511,9 +511,8 @@ rt305x_gpio_attach(device_t dev)
 	}
 #endif
 
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
-
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 
 	return (bus_generic_attach(dev));
 }
diff --git a/sys/powerpc/wii/wii_gpio.c b/sys/powerpc/wii/wii_gpio.c
index 78f627471779..b9ecccb39809 100644
--- a/sys/powerpc/wii/wii_gpio.c
+++ b/sys/powerpc/wii/wii_gpio.c
@@ -182,8 +182,8 @@ wiigpio_attach(device_t dev)
 		    "GPIO_PIN_INPUT" : "GPIO_PIN_OUTPUT");
 #endif
 	}
-	device_add_child(dev, "gpioc", device_get_unit(dev));
-	device_add_child(dev, "gpiobus", device_get_unit(dev));
+	device_add_child(dev, "gpioc", -1);
+	device_add_child(dev, "gpiobus", -1);
 	/*
 	 * We will be responsible for powering off the system.
 	 */