diff --git a/sys/dev/acpica/acpi_perf.c b/sys/dev/acpica/acpi_perf.c
index df0fa9a29b6..5134bbaaa4d 100644
--- a/sys/dev/acpica/acpi_perf.c
+++ b/sys/dev/acpica/acpi_perf.c
@@ -161,7 +161,8 @@ acpi_perf_identify(driver_t *driver, device_t parent)
 	 * We probe this child now so that other devices that depend
 	 * on it (i.e., for info about supported states) will see it.
 	 */
-	if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_perf", -1)) != NULL)
+	if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_perf",
+	    device_get_unit(parent))) != NULL)
 		device_probe_and_attach(dev);
 	else
 		device_printf(parent, "add acpi_perf child failed\n");
diff --git a/sys/dev/acpica/acpi_throttle.c b/sys/dev/acpica/acpi_throttle.c
index 883b5d34de0..a9cc2d77ecf 100644
--- a/sys/dev/acpica/acpi_throttle.c
+++ b/sys/dev/acpica/acpi_throttle.c
@@ -157,7 +157,8 @@ acpi_throttle_identify(driver_t *driver, device_t parent)
 	obj = (ACPI_OBJECT *)buf.Pointer;
 	if ((obj->Processor.PblkAddress && obj->Processor.PblkLength >= 4) ||
 	    ACPI_SUCCESS(AcpiEvaluateObject(handle, "_PTC", NULL, NULL))) {
-		if (BUS_ADD_CHILD(parent, 0, "acpi_throttle", -1) == NULL)
+		if (BUS_ADD_CHILD(parent, 0, "acpi_throttle",
+		    device_get_unit(parent)) == NULL)
 			device_printf(parent, "add throttle child failed\n");
 	}
 	AcpiOsFree(obj);
diff --git a/sys/dev/amdtemp/amdtemp.c b/sys/dev/amdtemp/amdtemp.c
index 21227a47c51..c1d696d070a 100644
--- a/sys/dev/amdtemp/amdtemp.c
+++ b/sys/dev/amdtemp/amdtemp.c
@@ -263,7 +263,8 @@ amdtemp_identify(driver_t *driver, device_t parent)
 		return;
 
 	if (amdtemp_match(parent, NULL)) {
-		child = device_add_child(parent, "amdtemp", -1);
+		child = device_add_child(parent, "amdtemp",
+		    device_get_unit(parent));
 		if (child == NULL)
 			device_printf(parent, "add amdtemp child failed\n");
 	}
diff --git a/sys/dev/coretemp/coretemp.c b/sys/dev/coretemp/coretemp.c
index bdc71b284ac..251fb08b4c1 100644
--- a/sys/dev/coretemp/coretemp.c
+++ b/sys/dev/coretemp/coretemp.c
@@ -133,7 +133,7 @@ coretemp_identify(driver_t *driver, device_t parent)
 	 * We add a child for each CPU since settings must be performed
 	 * on each CPU in the SMP case.
 	 */
-	child = device_add_child(parent, "coretemp", -1);
+	child = device_add_child(parent, "coretemp", device_get_unit(parent));
 	if (child == NULL)
 		device_printf(parent, "add coretemp child failed\n");
 }
diff --git a/sys/dev/cpufreq/cpufreq_dt.c b/sys/dev/cpufreq/cpufreq_dt.c
index 3beffeb7063..4ab021a97d3 100644
--- a/sys/dev/cpufreq/cpufreq_dt.c
+++ b/sys/dev/cpufreq/cpufreq_dt.c
@@ -309,7 +309,8 @@ cpufreq_dt_identify(driver_t *driver, device_t parent)
 	if (device_find_child(parent, "cpufreq_dt", -1) != NULL)
 		return;
 
-	if (BUS_ADD_CHILD(parent, 0, "cpufreq_dt", -1) == NULL)
+	if (BUS_ADD_CHILD(parent, 0, "cpufreq_dt", device_get_unit(parent))
+	    == NULL)
 		device_printf(parent, "add cpufreq_dt child failed\n");
 }
 
diff --git a/sys/kern/kern_cpu.c b/sys/kern/kern_cpu.c
index 2f44405aef3..380849974a3 100644
--- a/sys/kern/kern_cpu.c
+++ b/sys/kern/kern_cpu.c
@@ -1103,7 +1103,7 @@ cpufreq_register(device_t dev)
 	}
 
 	/* Add the child device and possibly sysctls. */
-	cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", -1);
+	cf_dev = BUS_ADD_CHILD(cpu_dev, 0, "cpufreq", device_get_unit(cpu_dev));
 	if (cf_dev == NULL)
 		return (ENOMEM);
 	device_quiet(cf_dev);
diff --git a/sys/x86/cpufreq/est.c b/sys/x86/cpufreq/est.c
index 258a9c493d0..cdca2fdfec5 100644
--- a/sys/x86/cpufreq/est.c
+++ b/sys/x86/cpufreq/est.c
@@ -946,7 +946,7 @@ est_identify(driver_t *driver, device_t parent)
 	 * We add a child for each CPU since settings must be performed
 	 * on each CPU in the SMP case.
 	 */
-	child = BUS_ADD_CHILD(parent, 10, "est", -1);
+	child = BUS_ADD_CHILD(parent, 10, "est", device_get_unit(parent));
 	if (child == NULL)
 		device_printf(parent, "add est child failed\n");
 }
diff --git a/sys/x86/cpufreq/hwpstate_amd.c b/sys/x86/cpufreq/hwpstate_amd.c
index ee67da43de5..3193cbd908c 100644
--- a/sys/x86/cpufreq/hwpstate_amd.c
+++ b/sys/x86/cpufreq/hwpstate_amd.c
@@ -341,7 +341,8 @@ hwpstate_identify(driver_t *driver, device_t parent)
 	if (resource_disabled("hwpstate", 0))
 		return;
 
-	if (BUS_ADD_CHILD(parent, 10, "hwpstate", -1) == NULL)
+	if (BUS_ADD_CHILD(parent, 10, "hwpstate", device_get_unit(parent))
+	    == NULL)
 		device_printf(parent, "hwpstate: add child failed\n");
 }
 
diff --git a/sys/x86/cpufreq/hwpstate_intel.c b/sys/x86/cpufreq/hwpstate_intel.c
index e3d17aa0bd1..1ed1056024c 100644
--- a/sys/x86/cpufreq/hwpstate_intel.c
+++ b/sys/x86/cpufreq/hwpstate_intel.c
@@ -352,11 +352,9 @@ intel_hwpstate_identify(driver_t *driver, device_t parent)
 	if ((cpu_power_eax & CPUTPM1_HWP) == 0)
 		return;
 
-	if (BUS_ADD_CHILD(parent, 10, "hwpstate_intel", -1) == NULL)
-		return;
-
-	if (bootverbose)
-		device_printf(parent, "hwpstate registered\n");
+	if (BUS_ADD_CHILD(parent, 10, "hwpstate_intel", device_get_unit(parent))
+	    == NULL)
+		device_printf(parent, "hwpstate_intel: add child failed\n");
 }
 
 static int
diff --git a/sys/x86/cpufreq/p4tcc.c b/sys/x86/cpufreq/p4tcc.c
index 89bfef3f693..4370da81cf0 100644
--- a/sys/x86/cpufreq/p4tcc.c
+++ b/sys/x86/cpufreq/p4tcc.c
@@ -135,7 +135,8 @@ p4tcc_identify(driver_t *driver, device_t parent)
 	 * of the IA32 Intel Architecture Software Developer's Manual,
 	 * Volume 3, for more info.
 	 */
-	if (BUS_ADD_CHILD(parent, 10, "p4tcc", -1) == NULL)
+	if (BUS_ADD_CHILD(parent, 10, "p4tcc", device_get_unit(parent))
+	    == NULL)
 		device_printf(parent, "add p4tcc child failed\n");
 }
 
diff --git a/sys/x86/cpufreq/powernow.c b/sys/x86/cpufreq/powernow.c
index da559855738..977798ab2f7 100644
--- a/sys/x86/cpufreq/powernow.c
+++ b/sys/x86/cpufreq/powernow.c
@@ -876,7 +876,8 @@ pn_identify(driver_t *driver, device_t parent)
 	}
 	if (device_find_child(parent, "powernow", -1) != NULL)
 		return;
-	if (BUS_ADD_CHILD(parent, 10, "powernow", -1) == NULL)
+	if (BUS_ADD_CHILD(parent, 10, "powernow", device_get_unit(parent))
+	    == NULL)
 		device_printf(parent, "powernow: add child failed\n");
 }
 
diff --git a/sys/x86/cpufreq/smist.c b/sys/x86/cpufreq/smist.c
index 309b725d31a..129ec2d4884 100644
--- a/sys/x86/cpufreq/smist.c
+++ b/sys/x86/cpufreq/smist.c
@@ -310,7 +310,8 @@ smist_identify(driver_t *driver, device_t parent)
 
 	if (device_find_child(parent, "smist", -1) != NULL)
 		return;
-	if (BUS_ADD_CHILD(parent, 30, "smist", -1) == NULL)
+	if (BUS_ADD_CHILD(parent, 30, "smist", device_get_unit(parent))
+	    == NULL)
 		device_printf(parent, "smist: add child failed\n");
 }