diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
index cfc0a5cd3c7d..4ce28d901b9a 100644
--- a/drivers/platform/x86/acerhdf.c
+++ b/drivers/platform/x86/acerhdf.c
@@ -92,9 +92,9 @@ static unsigned int fanstate = ACERHDF_FAN_AUTO;
 static char force_bios[16];
 static char force_product[16];
 static unsigned int prev_interval;
-struct thermal_zone_device *thz_dev;
-struct thermal_cooling_device *cl_dev;
-struct platform_device *acerhdf_dev;
+static struct thermal_zone_device *thz_dev;
+static struct thermal_cooling_device *cl_dev;
+static struct platform_device *acerhdf_dev;
 
 module_param(kernelmode, uint, 0);
 MODULE_PARM_DESC(kernelmode, "Kernel mode fan control on / off");
@@ -406,7 +406,7 @@ static int acerhdf_get_crit_temp(struct thermal_zone_device *thermal,
 }
 
 /* bind callback functions to thermalzone */
-struct thermal_zone_device_ops acerhdf_dev_ops = {
+static struct thermal_zone_device_ops acerhdf_dev_ops = {
 	.bind = acerhdf_bind,
 	.unbind = acerhdf_unbind,
 	.get_temp = acerhdf_get_ec_temp,
@@ -481,7 +481,7 @@ err_out:
 }
 
 /* bind fan callbacks to fan device */
-struct thermal_cooling_device_ops acerhdf_cooling_ops = {
+static struct thermal_cooling_device_ops acerhdf_cooling_ops = {
 	.get_max_state = acerhdf_get_max_state,
 	.get_cur_state = acerhdf_get_cur_state,
 	.set_cur_state = acerhdf_set_cur_state,