soc: st: Add STM32MP2 SYSCFG driver

Add trivial SYSCFG driver for ST STM32MP25xx, which binds drivers
to its subnodes. This is currently used to bind USB PHY drivers to
subnodes described in the SYSCFG DT node.

Signed-off-by: Marek Vasut <marex@nabladev.com>
Tested-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20260902124018.606544-2-marex@nabladev.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

drivers/soc/Kconfig

@@ -24,6 +24,7 @@ source "drivers/soc/renesas/Kconfig"
 source "drivers/soc/rockchip/Kconfig"
 source "drivers/soc/samsung/Kconfig"
 source "drivers/soc/sophgo/Kconfig"
+source "drivers/soc/st/Kconfig"
 source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/tegra/Kconfig"
 source "drivers/soc/ti/Kconfig"

drivers/soc/Makefile

@@ -30,6 +30,7 @@ obj-y				+= renesas/
 obj-y				+= rockchip/
 obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
 obj-y				+= sophgo/
+obj-y				+= st/
 obj-y				+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-y				+= ti/

drivers/soc/st/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "ST SoC drivers"
+
+config SOC_STM32MP2
+	tristate "STM32MP2 SoC family support"
+	depends on ARCH_STM32 || COMPILE_TEST
+	default ARCH_STM32 && ARM64
+	select SOC_BUS
+	help
+	  If you say yes here, you get support for the ST STM32MP2 family
+
+endmenu

drivers/soc/st/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_SOC_STM32MP2) += stm32mp2-syscfg.o

drivers/soc/st/stm32mp2-syscfg.c

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2026 Marek Vasut
+ */
+
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+static int stm32mp2_syscfg_probe(struct platform_device *pdev)
+{
+	return devm_of_platform_populate(&pdev->dev);
+}
+
+static const struct of_device_id stm32mp2_syscfg_ids[] = {
+	{ .compatible = "st,stm32mp23-syscfg" },
+	{ .compatible = "st,stm32mp25-syscfg" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, stm32mp2_syscfg_ids);
+
+static struct platform_driver stm32mp2_syscfg_driver = {
+	.driver = {
+		.name	= "stm32mp2_syscfg",
+		.of_match_table = stm32mp2_syscfg_ids,
+	},
+	.probe = stm32mp2_syscfg_probe,
+};
+module_platform_driver(stm32mp2_syscfg_driver);
+
+MODULE_AUTHOR("Marek Vasut <marex@nabladev.com>");
+MODULE_DESCRIPTION("ST STM32MP2 SYSCFG driver");
+MODULE_LICENSE("GPL");