[PATCH RFC 1/2] dt-bindings: clock: Add SCMI clock rounding mode declarations

Peng Fan (OSS)
2026-03-06T06:18:54Z

From: Peng Fan <peng.fan@nxp.com>

The ARM System Control and Management Interface (SCMI) specification
(DEN0056E) defines the CLOCK_RATE_SET command, which allows clients to
specify how the platform should round the requested clock rate.

Bits[3:2] define the rounding behaviour:
- If Bit[3] is set, the platform autonomously selects the closest
achievable rate, ignoring Bit[2].
- If Bit[3] is clear, Bit[2] selects the direction:
0 = round down
1 = round up

Add dt-bindings definitions for these rounding modes so that device tree
agent nodes can specify the desired rounding behaviour to the firmware.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
include/dt-bindings/clock/scmi.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/include/dt-bindings/clock/scmi.h b/include/dt-bindings/clock/scmi.h
new file mode 100644
index 0000000000000000000000000000000000000000..bd97d5aba53d042659e8e00ed96c6a054a2f9d98
--- /dev/null
+++ b/include/dt-bindings/clock/scmi.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
+/*
+ * Copyright 2026 NXP
+ */
+
+#ifndef __SCMI_CLOCK_H
+#define __SCMI_CLOCK_H
+
+#define ROUND_DOWN 0
+#define ROUND_UP 1
+#define ROUND_AUTO 2
+
+#endif

--
2.37.1