diff --git a/tools/power/x86/intel-speed-select/isst-config.c b/tools/power/x86/intel-speed-select/isst-config.c
index 346f8271b00f..fb83f74f15a4 100644
--- a/tools/power/x86/intel-speed-select/isst-config.c
+++ b/tools/power/x86/intel-speed-select/isst-config.c
@@ -803,8 +803,10 @@ static int isst_fill_platform_info(void)
 	const char *pathname = "/dev/isst_interface";
 	int fd;
 
-	if (is_clx_n_platform())
+	if (is_clx_n_platform()) {
+		isst_platform_info.api_version = 1;
 		goto set_platform_ops;
+	}
 
 	fd = open(pathname, O_RDWR);
 	if (fd < 0)
@@ -824,7 +826,7 @@ static int isst_fill_platform_info(void)
 	}
 
 set_platform_ops:
-	if (isst_set_platform_ops()) {
+	if (isst_set_platform_ops(isst_platform_info.api_version)) {
 		fprintf(stderr, "Failed to set platform callbacks\n");
 		exit(0);
 	}
diff --git a/tools/power/x86/intel-speed-select/isst-core.c b/tools/power/x86/intel-speed-select/isst-core.c
index fcab70ef5704..674097289ebf 100644
--- a/tools/power/x86/intel-speed-select/isst-core.c
+++ b/tools/power/x86/intel-speed-select/isst-core.c
@@ -16,9 +16,16 @@ static struct isst_platform_ops		*isst_ops;
 		}	\
 	} while (0)
 
-int isst_set_platform_ops(void)
+int isst_set_platform_ops(int api_version)
 {
-	isst_ops = mbox_get_platform_ops();
+	switch (api_version) {
+	case 1:
+		isst_ops = mbox_get_platform_ops();
+		break;
+	default:
+		isst_ops = NULL;
+		break;
+	}
 
 	if (!isst_ops)
 		return -1;
diff --git a/tools/power/x86/intel-speed-select/isst.h b/tools/power/x86/intel-speed-select/isst.h
index 8192e683ac92..6839ad2d2b9d 100644
--- a/tools/power/x86/intel-speed-select/isst.h
+++ b/tools/power/x86/intel-speed-select/isst.h
@@ -185,6 +185,7 @@ struct isst_platform_ops {
 	int (*get_disp_freq_multiplier)(void);
 	int (*get_trl_max_levels)(void);
 	char *(*get_trl_level_name)(int level);
+	void (*update_platform_param)(enum isst_platform_param param, int value);
 	int (*is_punit_valid)(struct isst_id *id);
 	int (*read_pm_config)(struct isst_id *id, int *cp_state, int *cp_cap);
 	int (*get_config_levels)(struct isst_id *id, struct isst_pkg_ctdp *pkg_ctdp);
@@ -226,15 +227,10 @@ extern void set_cpu_mask_from_punit_coremask(struct isst_id *id,
 					     size_t core_cpumask_size,
 					     cpu_set_t *core_cpumask,
 					     int *cpu_cnt);
-extern int isst_send_mbox_command(unsigned int cpu, unsigned char command,
-				  unsigned char sub_command,
-				  unsigned int write,
-				  unsigned int req_data, unsigned int *resp);
-
 extern int isst_send_msr_command(unsigned int cpu, unsigned int command,
 				 int write, unsigned long long *req_resp);
 
-extern int isst_set_platform_ops(void);
+extern int isst_set_platform_ops(int api_version);
 extern void isst_update_platform_param(enum isst_platform_param, int vale);
 extern int isst_get_disp_freq_multiplier(void);
 extern int isst_get_trl_max_levels(void);