[PATCH v2 11/12] soc: starfive: Add socinfo driver for JHB100 SoC

[Changhuang Liang <changhuang.liang@starfivetech.com>]

Add socinfo driver for JHB100 SoC. Currently available for distinguishing
between the two reversions, A0 and A1.

Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
---
 MAINTAINERS                                   |  5 ++
 drivers/soc/Kconfig                           |  1 +
 drivers/soc/Makefile                          |  1 +
 drivers/soc/starfive/Kconfig                  |  6 ++
 drivers/soc/starfive/Makefile                 |  2 +
 drivers/soc/starfive/socinfo/Kconfig          | 11 +++
 drivers/soc/starfive/socinfo/Makefile         |  2 +
 drivers/soc/starfive/socinfo/jhb100-socinfo.c | 80 +++++++++++++++++++
 8 files changed, 108 insertions(+)
 create mode 100644 drivers/soc/starfive/Kconfig
 create mode 100644 drivers/soc/starfive/Makefile
 create mode 100644 drivers/soc/starfive/socinfo/Kconfig
 create mode 100644 drivers/soc/starfive/socinfo/Makefile
 create mode 100644 drivers/soc/starfive/socinfo/jhb100-socinfo.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6f6aac7cea95..66175f453d20 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25613,6 +25613,11 @@ S:	Maintained
 F:	drivers/reset/starfive/reset-starfive-jhb1*
 F:	include/dt-bindings/reset/starfive,jhb1*.h
 
+STARFIVE JHB100 SOCINFO DRIVER
+M:	Changhuang Liang <changhuang.liang@starfivetech.com>
+S:	Maintained
+F:	drivers/soc/starfive/
+
 STARFIVE JHB100 SYSCON
 M:	Changhuang Liang <changhuang.liang@starfivetech.com>
 S:	Maintained
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index a2d65adffb80..b3b01fc38139 100644
--- a/drivers/soc/Kconfig
+++ b/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/starfive/Kconfig"
 source "drivers/soc/sunxi/Kconfig"
 source "drivers/soc/tegra/Kconfig"
 source "drivers/soc/ti/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index c9e689080ceb..009f85ff891a 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -30,6 +30,7 @@ obj-y				+= renesas/
 obj-y				+= rockchip/
 obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
 obj-y				+= sophgo/
+obj-y				+= starfive/
 obj-y				+= sunxi/
 obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-y				+= ti/
diff --git a/drivers/soc/starfive/Kconfig b/drivers/soc/starfive/Kconfig
new file mode 100644
index 000000000000..04b020083d3e
--- /dev/null
+++ b/drivers/soc/starfive/Kconfig
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "StarFive SoC (System On Chip) specific Drivers"
+
+source "drivers/soc/starfive/socinfo/Kconfig"
+
+endmenu
diff --git a/drivers/soc/starfive/Makefile b/drivers/soc/starfive/Makefile
new file mode 100644
index 000000000000..ca1e609b8104
--- /dev/null
+++ b/drivers/soc/starfive/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y += socinfo/
diff --git a/drivers/soc/starfive/socinfo/Kconfig b/drivers/soc/starfive/socinfo/Kconfig
new file mode 100644
index 000000000000..92bbab62895b
--- /dev/null
+++ b/drivers/soc/starfive/socinfo/Kconfig
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config STARFIVE_JHB100_SOCINFO
+	bool "StarFive JHB100 SoC Information"
+	depends on ARCH_STARFIVE || COMPILE_TEST
+	select SOC_BUS
+	default y
+	help
+	  Include support for the SoC bus socinfo for the StarFive JHB100 SoC
+	  platforms to provide information about the SoC family and variant
+	  to user space.
diff --git a/drivers/soc/starfive/socinfo/Makefile b/drivers/soc/starfive/socinfo/Makefile
new file mode 100644
index 000000000000..26c2bdf1de3b
--- /dev/null
+++ b/drivers/soc/starfive/socinfo/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_STARFIVE_JHB100_SOCINFO)	+= jhb100-socinfo.o
diff --git a/drivers/soc/starfive/socinfo/jhb100-socinfo.c b/drivers/soc/starfive/socinfo/jhb100-socinfo.c
new file mode 100644
index 000000000000..9c5826d7c253
--- /dev/null
+++ b/drivers/soc/starfive/socinfo/jhb100-socinfo.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 StarFive Technology Co., Ltd.
+ *
+ * Author: Changhuang Liang <changhuang.liang@starfivetech.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/init.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/sys_soc.h>
+
+#define JHB100_REV_ID			0x38
+#define JHB100_REV_ID_CHAR		GENMASK(3, 2)
+#define JHB100_REV_ID_NUM		GENMASK(1, 0)
+
+static int __init starfive_socinfo_init(void)
+{
+	struct soc_device_attribute *attrs;
+	struct soc_device *soc_dev;
+	const char *machine = NULL;
+	struct device_node *np;
+	struct regmap *regmap;
+	char rev_char;
+	u32 rev_id;
+	int ret;
+
+	np = of_find_compatible_node(NULL, NULL, "starfive,jhb100-sys0-syscon");
+	if (!of_device_is_available(np)) {
+		of_node_put(np);
+		return -ENODEV;
+	}
+
+	regmap = syscon_node_to_regmap(np);
+	if (IS_ERR(regmap)) {
+		of_node_put(np);
+		return PTR_ERR(regmap);
+	}
+
+	ret = regmap_read(regmap, JHB100_REV_ID, &rev_id);
+	if (ret) {
+		of_node_put(np);
+		return ret;
+	}
+
+	of_node_put(np);
+
+	rev_char = (char)FIELD_GET(JHB100_REV_ID_CHAR, rev_id) + 'A';
+	rev_id = (u32)FIELD_GET(JHB100_REV_ID_NUM, rev_id);
+
+	attrs = kzalloc_obj(*attrs);
+	if (!attrs)
+		return -ENOMEM;
+
+	np = of_find_node_by_path("/");
+	of_property_read_string(np, "model", &machine);
+	if (machine)
+		attrs->machine = kstrdup(machine, GFP_KERNEL);
+	of_node_put(np);
+
+	attrs->revision = kasprintf(GFP_KERNEL, "%c%u", rev_char, rev_id);
+	attrs->family = "JH";
+	attrs->soc_id = "JHB100";
+
+	soc_dev = soc_device_register(attrs);
+	if (IS_ERR(soc_dev)) {
+		kfree(attrs->revision);
+		kfree(attrs->machine);
+		kfree(attrs);
+		return PTR_ERR(soc_dev);
+	}
+
+	pr_info("StarFive %s SoC rev(%s)\n", attrs->soc_id, attrs->revision);
+
+	return 0;
+}
+
+early_initcall(starfive_socinfo_init);
-- 
2.25.1