reset: spacemit: Extract common K1 reset code

Extract the common reset controller code from the K1 driver into
separate reset-spacemit-common.{c,h} files to prepare for additional
SpacemiT SoCs that share the same reset controller architecture.

The common code includes handlers for reset assert and deassert
operations and probing for auxiliary bus devices.

Changes during extraction:
- Module ownership: Use dev->driver->owner instead of THIS_MODULE in
  spacemit_reset_controller_register() to correctly reference the
  calling driver's module.
- Rename spacemit_reset_ids to spacemit_k1_reset_ids.
- Define new namespace "RESET_SPACEMIT" for the exported common
  functions (spacemit_reset_probe) and update K1 driver to import it.

This prepares for additional SpacemiT SoCs (K3) that share the same reset
controller architecture.

Reviewed-by: Alex Elder <elder@riscstar.com>
Signed-off-by: Guodong Xu <guodong@riscstar.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Link: https://lore.kernel.org/spacemit/20260114092742-GYC7933267@gentoo.org/ [1]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/spacemit/Kconfig

@@ -1,10 +1,20 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-config RESET_SPACEMIT_K1
-	tristate "SpacemiT K1 reset driver"
+menu "Reset support for SpacemiT platforms"
 	depends on ARCH_SPACEMIT || COMPILE_TEST
-	depends on SPACEMIT_K1_CCU
+
+config RESET_SPACEMIT_COMMON
+	tristate
 	select AUXILIARY_BUS
+	help
+	  Common reset controller infrastructure for SpacemiT SoCs.
+	  This provides shared code and helper functions used by
+	  reset drivers for various SpacemiT SoC families.
+
+config RESET_SPACEMIT_K1
+	tristate "Support for SpacemiT K1 SoC"
+	depends on SPACEMIT_K1_CCU
+	select RESET_SPACEMIT_COMMON
 	default SPACEMIT_K1_CCU
 	help
 	  Support for reset controller in SpacemiT K1 SoC.
@@ -12,3 +22,4 @@ config RESET_SPACEMIT_K1
 	  unit (CCU) driver to provide reset control functionality
 	  for various peripherals and subsystems in the SoC.
 
+endmenu

drivers/reset/spacemit/Makefile

@@ -1,2 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RESET_SPACEMIT_COMMON)	+= reset-spacemit-common.o
+
 obj-$(CONFIG_RESET_SPACEMIT_K1)		+= reset-spacemit-k1.o

drivers/reset/spacemit/reset-spacemit-common.c

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/* SpacemiT reset controller driver - common implementation */
+
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/module.h>
+
+#include <soc/spacemit/ccu.h>
+
+#include "reset-spacemit-common.h"
+
+static int spacemit_reset_update(struct reset_controller_dev *rcdev,
+				 unsigned long id, bool assert)
+{
+	struct ccu_reset_controller *controller;
+	const struct ccu_reset_data *data;
+	u32 mask;
+	u32 val;
+
+	controller = container_of(rcdev, struct ccu_reset_controller, rcdev);
+	data = &controller->data->reset_data[id];
+	mask = data->assert_mask | data->deassert_mask;
+	val = assert ? data->assert_mask : data->deassert_mask;
+
+	return regmap_update_bits(controller->regmap, data->offset, mask, val);
+}
+
+static int spacemit_reset_assert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	return spacemit_reset_update(rcdev, id, true);
+}
+
+static int spacemit_reset_deassert(struct reset_controller_dev *rcdev,
+				   unsigned long id)
+{
+	return spacemit_reset_update(rcdev, id, false);
+}
+
+static const struct reset_control_ops spacemit_reset_control_ops = {
+	.assert		= spacemit_reset_assert,
+	.deassert	= spacemit_reset_deassert,
+};
+
+static int spacemit_reset_controller_register(struct device *dev,
+					      struct ccu_reset_controller *controller)
+{
+	struct reset_controller_dev *rcdev = &controller->rcdev;
+
+	rcdev->ops = &spacemit_reset_control_ops;
+	rcdev->owner = dev->driver->owner;
+	rcdev->of_node = dev->of_node;
+	rcdev->nr_resets = controller->data->count;
+
+	return devm_reset_controller_register(dev, &controller->rcdev);
+}
+
+int spacemit_reset_probe(struct auxiliary_device *adev,
+			 const struct auxiliary_device_id *id)
+{
+	struct spacemit_ccu_adev *rdev = to_spacemit_ccu_adev(adev);
+	struct ccu_reset_controller *controller;
+	struct device *dev = &adev->dev;
+
+	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
+	if (!controller)
+		return -ENOMEM;
+	controller->data = (const struct ccu_reset_controller_data *)id->driver_data;
+	controller->regmap = rdev->regmap;
+
+	return spacemit_reset_controller_register(dev, controller);
+}
+EXPORT_SYMBOL_NS_GPL(spacemit_reset_probe, "RESET_SPACEMIT");
+
+MODULE_DESCRIPTION("SpacemiT reset controller driver - common code");
+MODULE_LICENSE("GPL");

drivers/reset/spacemit/reset-spacemit-common.h

@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * SpacemiT reset controller driver - common definitions
+ */
+
+#ifndef _RESET_SPACEMIT_COMMON_H_
+#define _RESET_SPACEMIT_COMMON_H_
+
+#include <linux/auxiliary_bus.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/types.h>
+
+struct ccu_reset_data {
+	u32 offset;
+	u32 assert_mask;
+	u32 deassert_mask;
+};
+
+struct ccu_reset_controller_data {
+	const struct ccu_reset_data *reset_data;	/* array */
+	size_t count;
+};
+
+struct ccu_reset_controller {
+	struct reset_controller_dev rcdev;
+	const struct ccu_reset_controller_data *data;
+	struct regmap *regmap;
+};
+
+#define RESET_DATA(_offset, _assert_mask, _deassert_mask)	\
+	{							\
+		.offset		= (_offset),			\
+		.assert_mask	= (_assert_mask),		\
+		.deassert_mask	= (_deassert_mask),		\
+	}
+
+/* Common probe function */
+int spacemit_reset_probe(struct auxiliary_device *adev,
+			 const struct auxiliary_device_id *id);
+
+#endif /* _RESET_SPACEMIT_COMMON_H_ */

drivers/reset/spacemit/reset-spacemit-k1.c

@@ -1,41 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0-only
 
-/* SpacemiT reset controller driver */
+/* SpacemiT K1 reset controller driver */
 
-#include <linux/auxiliary_bus.h>
-#include <linux/container_of.h>
-#include <linux/device.h>
 #include <linux/module.h>
-#include <linux/regmap.h>
-#include <linux/reset-controller.h>
-#include <linux/types.h>
 
-#include <soc/spacemit/k1-syscon.h>
 #include <dt-bindings/clock/spacemit,k1-syscon.h>
+#include <soc/spacemit/k1-syscon.h>
 
-struct ccu_reset_data {
-	u32 offset;
-	u32 assert_mask;
-	u32 deassert_mask;
-};
-
-struct ccu_reset_controller_data {
-	const struct ccu_reset_data *reset_data;	/* array */
-	size_t count;
-};
-
-struct ccu_reset_controller {
-	struct reset_controller_dev rcdev;
-	const struct ccu_reset_controller_data *data;
-	struct regmap *regmap;
-};
-
-#define RESET_DATA(_offset, _assert_mask, _deassert_mask)	\
-	{							\
-		.offset		= (_offset),			\
-		.assert_mask	= (_assert_mask),		\
-		.deassert_mask	= (_deassert_mask),		\
-	}
+#include "reset-spacemit-common.h"
 
 static const struct ccu_reset_data k1_mpmu_resets[] = {
 	[RESET_WDT]	= RESET_DATA(MPMU_WDTPCR,		BIT(2), 0),
@@ -214,91 +186,30 @@ static const struct ccu_reset_controller_data k1_apbc2_reset_data = {
 	.count		= ARRAY_SIZE(k1_apbc2_resets),
 };
 
-static int spacemit_reset_update(struct reset_controller_dev *rcdev,
-				 unsigned long id, bool assert)
-{
-	struct ccu_reset_controller *controller;
-	const struct ccu_reset_data *data;
-	u32 mask;
-	u32 val;
-
-	controller = container_of(rcdev, struct ccu_reset_controller, rcdev);
-	data = &controller->data->reset_data[id];
-	mask = data->assert_mask | data->deassert_mask;
-	val = assert ? data->assert_mask : data->deassert_mask;
-
-	return regmap_update_bits(controller->regmap, data->offset, mask, val);
-}
-
-static int spacemit_reset_assert(struct reset_controller_dev *rcdev,
-				 unsigned long id)
-{
-	return spacemit_reset_update(rcdev, id, true);
-}
-
-static int spacemit_reset_deassert(struct reset_controller_dev *rcdev,
-				   unsigned long id)
-{
-	return spacemit_reset_update(rcdev, id, false);
-}
-
-static const struct reset_control_ops spacemit_reset_control_ops = {
-	.assert		= spacemit_reset_assert,
-	.deassert	= spacemit_reset_deassert,
-};
-
-static int spacemit_reset_controller_register(struct device *dev,
-					      struct ccu_reset_controller *controller)
-{
-	struct reset_controller_dev *rcdev = &controller->rcdev;
-
-	rcdev->ops = &spacemit_reset_control_ops;
-	rcdev->owner = THIS_MODULE;
-	rcdev->of_node = dev->of_node;
-	rcdev->nr_resets = controller->data->count;
-
-	return devm_reset_controller_register(dev, &controller->rcdev);
-}
-
-static int spacemit_reset_probe(struct auxiliary_device *adev,
-				const struct auxiliary_device_id *id)
-{
-	struct spacemit_ccu_adev *rdev = to_spacemit_ccu_adev(adev);
-	struct ccu_reset_controller *controller;
-	struct device *dev = &adev->dev;
-
-	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
-	if (!controller)
-		return -ENOMEM;
-	controller->data = (const struct ccu_reset_controller_data *)id->driver_data;
-	controller->regmap = rdev->regmap;
-
-	return spacemit_reset_controller_register(dev, controller);
-}
-
 #define K1_AUX_DEV_ID(_unit) \
 	{ \
 		.name = "spacemit_ccu.k1-" #_unit "-reset", \
 		.driver_data = (kernel_ulong_t)&k1_ ## _unit ## _reset_data, \
 	}
 
-static const struct auxiliary_device_id spacemit_reset_ids[] = {
+static const struct auxiliary_device_id spacemit_k1_reset_ids[] = {
 	K1_AUX_DEV_ID(mpmu),
 	K1_AUX_DEV_ID(apbc),
 	K1_AUX_DEV_ID(apmu),
 	K1_AUX_DEV_ID(rcpu),
 	K1_AUX_DEV_ID(rcpu2),
 	K1_AUX_DEV_ID(apbc2),
-	{ },
+	{ /* sentinel */ }
 };
-MODULE_DEVICE_TABLE(auxiliary, spacemit_reset_ids);
+MODULE_DEVICE_TABLE(auxiliary, spacemit_k1_reset_ids);
 
 static struct auxiliary_driver spacemit_k1_reset_driver = {
 	.probe          = spacemit_reset_probe,
-	.id_table       = spacemit_reset_ids,
+	.id_table       = spacemit_k1_reset_ids,
 };
 module_auxiliary_driver(spacemit_k1_reset_driver);
 
+MODULE_IMPORT_NS("RESET_SPACEMIT");
 MODULE_AUTHOR("Alex Elder <elder@kernel.org>");
-MODULE_DESCRIPTION("SpacemiT reset controller driver");
+MODULE_DESCRIPTION("SpacemiT K1 reset controller driver");
 MODULE_LICENSE("GPL");