diff --git a/drivers/st/scmi-msg/clock.h b/drivers/st/scmi-msg/clock.h
new file mode 100644
index 0000000..a637934
--- /dev/null
+++ b/drivers/st/scmi-msg/clock.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2019, Linaro Limited
+ */
+
+#ifndef SCMI_MSG_CLOCK_H
+#define SCMI_MSG_CLOCK_H
+
+#include <stdint.h>
+
+#include <lib/utils_def.h>
+
+#define SCMI_PROTOCOL_VERSION_CLOCK	0x20000U
+
+/*
+ * Identifiers of the SCMI Clock Management Protocol commands
+ */
+enum scmi_clock_command_id {
+	SCMI_CLOCK_ATTRIBUTES = 0x003,
+	SCMI_CLOCK_DESCRIBE_RATES = 0x004,
+	SCMI_CLOCK_RATE_SET = 0x005,
+	SCMI_CLOCK_RATE_GET = 0x006,
+	SCMI_CLOCK_CONFIG_SET = 0x007,
+};
+
+/* Protocol attributes */
+#define SCMI_CLOCK_CLOCK_COUNT_MASK			GENMASK(15, 0)
+#define SCMI_CLOCK_MAX_PENDING_TRANSITIONS_MASK		GENMASK(23, 16)
+
+#define SCMI_CLOCK_PROTOCOL_ATTRIBUTES(_max_pending, _clk_count) \
+	((((_max_pending) << 16) & SCMI_CLOCK_MAX_PENDING_TRANSITIONS_MASK) | \
+	 (((_clk_count) & SCMI_CLOCK_CLOCK_COUNT_MASK)))
+
+struct scmi_clock_attributes_a2p {
+	uint32_t clock_id;
+};
+
+#define SCMI_CLOCK_NAME_LENGTH_MAX	16U
+
+struct scmi_clock_attributes_p2a {
+	int32_t status;
+	uint32_t attributes;
+	char clock_name[SCMI_CLOCK_NAME_LENGTH_MAX];
+};
+
+/*
+ * Clock Rate Get
+ */
+
+struct scmi_clock_rate_get_a2p {
+	uint32_t clock_id;
+};
+
+struct scmi_clock_rate_get_p2a {
+	int32_t status;
+	uint32_t rate[2];
+};
+
+/*
+ * Clock Rate Set
+ */
+
+/* If set, set the new clock rate asynchronously */
+#define SCMI_CLOCK_RATE_SET_ASYNC_POS			0
+/* If set, do not send a delayed asynchronous response */
+#define SCMI_CLOCK_RATE_SET_NO_DELAYED_RESPONSE_POS	1
+/* Round up, if set, otherwise round down */
+#define SCMI_CLOCK_RATE_SET_ROUND_UP_POS		2
+/* If set, the platform chooses the appropriate rounding mode */
+#define SCMI_CLOCK_RATE_SET_ROUND_AUTO_POS		3
+
+#define SCMI_CLOCK_RATE_SET_ASYNC_MASK \
+		BIT(SCMI_CLOCK_RATE_SET_ASYNC_POS)
+#define SCMI_CLOCK_RATE_SET_NO_DELAYED_RESPONSE_MASK \
+		BIT(SCMI_CLOCK_RATE_SET_NO_DELAYED_RESPONSE_POS)
+#define SCMI_CLOCK_RATE_SET_ROUND_UP_MASK \
+		BIT(SCMI_CLOCK_RATE_SET_ROUND_UP_POS)
+#define SCMI_CLOCK_RATE_SET_ROUND_AUTO_MASK \
+		BIT(SCMI_CLOCK_RATE_SET_ROUND_AUTO_POS)
+
+struct scmi_clock_rate_set_a2p {
+	uint32_t flags;
+	uint32_t clock_id;
+	uint32_t rate[2];
+};
+
+struct scmi_clock_rate_set_p2a {
+	int32_t status;
+};
+
+/*
+ * Clock Config Set
+ */
+
+#define SCMI_CLOCK_CONFIG_SET_ENABLE_POS	0
+
+#define SCMI_CLOCK_CONFIG_SET_ENABLE_MASK \
+	BIT(SCMI_CLOCK_CONFIG_SET_ENABLE_POS)
+
+struct scmi_clock_config_set_a2p {
+	uint32_t clock_id;
+	uint32_t attributes;
+};
+
+struct scmi_clock_config_set_p2a {
+	int32_t status;
+};
+
+/*
+ * Clock Describe Rates
+ */
+
+#define SCMI_CLOCK_RATE_FORMAT_RANGE			1U
+#define SCMI_CLOCK_RATE_FORMAT_LIST			0U
+
+#define SCMI_CLOCK_DESCRIBE_RATES_REMAINING_MASK	GENMASK_32(31, 16)
+#define SCMI_CLOCK_DESCRIBE_RATES_REMAINING_POS		16
+
+#define SCMI_CLOCK_DESCRIBE_RATES_FORMAT_MASK		BIT(12)
+#define SCMI_CLOCK_DESCRIBE_RATES_FORMAT_POS		12
+
+#define SCMI_CLOCK_DESCRIBE_RATES_COUNT_MASK		GENMASK_32(11, 0)
+
+#define SCMI_CLOCK_DESCRIBE_RATES_NUM_RATES_FLAGS(_count, _fmt, _rem_rates) \
+	( \
+		((_count) & SCMI_CLOCK_DESCRIBE_RATES_COUNT_MASK) | \
+		(((_rem_rates) << SCMI_CLOCK_DESCRIBE_RATES_REMAINING_POS) & \
+		 SCMI_CLOCK_DESCRIBE_RATES_REMAINING_MASK) | \
+		(((_fmt) << SCMI_CLOCK_DESCRIBE_RATES_FORMAT_POS) & \
+		 SCMI_CLOCK_DESCRIBE_RATES_FORMAT_MASK) \
+	)
+
+struct scmi_clock_rate {
+	uint32_t low;
+	uint32_t high;
+};
+
+struct scmi_clock_describe_rates_a2p {
+	uint32_t clock_id;
+	uint32_t rate_index;
+};
+
+struct scmi_clock_describe_rates_p2a {
+	int32_t status;
+	uint32_t num_rates_flags;
+	struct scmi_clock_rate rates[];
+};
+
+#endif /* SCMI_MSG_CLOCK_H */