soc: sophgo: sg2044: Add support for SG2044 TOP syscon device

The SG2044 TOP device provide PLL clock function in its area.
Add a mfd definition for it.

Link: https://lore.kernel.org/r/20250418020325.421257-3-inochiama@gmail.com
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
Signed-off-by: Chen Wang <wangchen20@iscas.ac.cn>

Author: inochisa

drivers/soc/Kconfig

@@ -23,6 +23,7 @@ source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/renesas/Kconfig"
 source "drivers/soc/rockchip/Kconfig"
 source "drivers/soc/samsung/Kconfig"
+source "drivers/soc/sophgo/Kconfig"
 source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/tegra/Kconfig"
 source "drivers/soc/ti/Kconfig"

drivers/soc/Makefile

@@ -29,6 +29,7 @@ obj-y				+= qcom/
 obj-y				+= renesas/
 obj-y				+= rockchip/
 obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
+obj-y				+= sophgo/
 obj-y				+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-y				+= ti/

drivers/soc/sophgo/Kconfig

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Sophgo SoC drivers
+#
+
+if ARCH_SOPHGO || COMPILE_TEST
+menu "Sophgo SoC drivers"
+
+config SOPHGO_SG2044_TOPSYS
+	tristate "Sophgo SG2044 TOP syscon driver"
+	select MFD_CORE
+	help
+	  This is the core driver for the Sophgo SG2044 TOP system
+	  controller device. This driver provide PLL clock device
+	  for the SoC.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called sg2044-topsys.
+
+endmenu
+endif

drivers/soc/sophgo/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_SOPHGO_SG2044_TOPSYS)	+= sg2044-topsys.o

drivers/soc/sophgo/sg2044-topsys.c

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sophgo SG2044 multi-function system controller driver
+ *
+ * Copyright (C) 2025 Inochi Amaoto <inochiama@gmail.com>
+ */
+
+#include <linux/mfd/core.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/resource.h>
+
+static const struct mfd_cell sg2044_topsys_subdev[] = {
+	{
+		.name = "sg2044-pll",
+	},
+};
+
+static int sg2044_topsys_probe(struct platform_device *pdev)
+{
+	return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
+				    sg2044_topsys_subdev,
+				    ARRAY_SIZE(sg2044_topsys_subdev),
+				    NULL, 0, NULL);
+}
+
+static const struct of_device_id sg2044_topsys_of_match[] = {
+	{ .compatible = "sophgo,sg2044-top-syscon" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sg2044_topsys_of_match);
+
+static struct platform_driver sg2044_topsys_driver = {
+	.probe = sg2044_topsys_probe,
+	.driver = {
+		.name = "sg2044-topsys",
+		.of_match_table = sg2044_topsys_of_match,
+	},
+};
+module_platform_driver(sg2044_topsys_driver);
+
+MODULE_AUTHOR("Inochi Amaoto <inochiama@gmail.com>");
+MODULE_DESCRIPTION("Sophgo SG2044 multi-function system controller driver");
+MODULE_LICENSE("GPL");