soc: imx95: a55: initialize lpuart clock

Initialize lpuart clock to avoid it is not initialized.

Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>

Author: JiafeiPan

soc/nxp/imx/imx9/imx95/a55/CMakeLists.txt

@@ -2,4 +2,5 @@
 
 zephyr_include_directories(.)
 zephyr_sources_ifdef(CONFIG_ARM_MMU mmu_regions.c)
+zephyr_sources_ifdef(CONFIG_ARM_MMU soc.c)
 set(SOC_LINKER_SCRIPT ${ZEPHYR_BASE}/include/zephyr/arch/arm64/scripts/linker.ld CACHE INTERNAL "")

soc/nxp/imx/imx9/imx95/a55/soc.c

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <zephyr/init.h>
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/firmware/scmi/clk.h>
+#include <zephyr/dt-bindings/clock/imx95_clock.h>
+#include <soc.h>
+
+#define FREQ_24M_HZ 24000000 /* 24 MHz */
+
+static int soc_clk_init(void)
+{
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(lpuart1), okay) ||                                             \
+	DT_NODE_HAS_STATUS(DT_NODELABEL(lpuart3), okay)
+	const struct device *clk_dev = DEVICE_DT_GET(DT_NODELABEL(scmi_clk));
+	struct scmi_protocol *proto = clk_dev->data;
+	struct scmi_clock_rate_config clk_cfg = {0};
+	uint32_t clk_id;
+	struct scmi_clock_config cfg;
+	int ret;
+
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(lpuart1), okay)
+	clk_id = IMX95_CLK_LPUART1;
+#elif DT_NODE_HAS_STATUS(DT_NODELABEL(lpuart3), okay)
+	clk_id = IMX95_CLK_LPUART3;
+#endif
+
+	ret = scmi_clock_parent_set(proto, clk_id, IMX95_CLK_24M);
+	if (ret) {
+		return ret;
+	}
+
+	cfg.attributes = SCMI_CLK_CONFIG_ENABLE_DISABLE(true);
+	cfg.clk_id = clk_id;
+	ret = scmi_clock_config_set(proto, &cfg);
+	if (ret) {
+		return ret;
+	}
+
+	clk_cfg.flags = SCMI_CLK_RATE_SET_FLAGS_ROUNDS_AUTO;
+	clk_cfg.clk_id = clk_id;
+	clk_cfg.rate[0] = FREQ_24M_HZ; /* 24 MHz*/
+	clk_cfg.rate[1] = 0;
+
+	ret = scmi_clock_rate_set(proto, &clk_cfg);
+	if (ret) {
+		return ret;
+	}
+#endif
+
+	return 0;
+}
+
+static int soc_init(void)
+{
+	return soc_clk_init();
+}
+/*
+ * Because platform is using ARM SCMI, drivers like scmi, mbox etc are
+ * initialized during PRE_KERNEL_1, so common init hooks can't be used, SoC
+ * early init and board early init should run during PRE_KERNEL_2 instead.
+ */
+SYS_INIT(soc_init, PRE_KERNEL_2, 0);