reset: npcm: register npcm8xx clock auxiliary bus device

Add NPCM8xx clock controller auxiliary bus device registration.

The NPCM8xx clock controller is registered as an aux device because the
reset and the clock controller share the same register region.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Tested-by: Benjamin Fair <benjaminfair@google.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20240912191038.981105-3-tmaimon77@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/reset/Kconfig

@@ -170,6 +170,7 @@ config RESET_MESON_AUDIO_ARB
 config RESET_NPCM
 	bool "NPCM BMC Reset Driver" if COMPILE_TEST
 	default ARCH_NPCM
+	select AUXILIARY_BUS
 	help
 	  This enables the reset controller driver for Nuvoton NPCM
 	  BMC SoCs.

drivers/reset/reset-npcm.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2019 Nuvoton Technology corporation.
 
+#include <linux/auxiliary_bus.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
@@ -10,11 +11,14 @@
 #include <linux/property.h>
 #include <linux/reboot.h>
 #include <linux/reset-controller.h>
+#include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
 #include <linux/of_address.h>
 
+#include <soc/nuvoton/clock-npcm8xx.h>
+
 /* NPCM7xx GCR registers */
 #define NPCM_MDLR_OFFSET	0x7C
 #define NPCM7XX_MDLR_USBD0	BIT(9)
@@ -89,6 +93,7 @@ struct npcm_rc_data {
 	const struct npcm_reset_info *info;
 	struct regmap *gcr_regmap;
 	u32 sw_reset_number;
+	struct device *dev;
 	void __iomem *base;
 	spinlock_t lock;
 };
@@ -372,6 +377,67 @@ static const struct reset_control_ops npcm_rc_ops = {
 	.status		= npcm_rc_status,
 };
 
+static void npcm_clock_unregister_adev(void *_adev)
+{
+	struct auxiliary_device *adev = _adev;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static void npcm_clock_adev_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+	struct npcm_clock_adev *rdev = to_npcm_clock_adev(adev);
+
+	kfree(rdev);
+}
+
+static struct auxiliary_device *npcm_clock_adev_alloc(struct npcm_rc_data *rst_data, char *clk_name)
+{
+	struct npcm_clock_adev *rdev;
+	struct auxiliary_device *adev;
+	int ret;
+
+	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
+	if (!rdev)
+		return ERR_PTR(-ENOMEM);
+
+	rdev->base = rst_data->base;
+
+	adev = &rdev->adev;
+	adev->name = clk_name;
+	adev->dev.parent = rst_data->dev;
+	adev->dev.release = npcm_clock_adev_release;
+	adev->id = 555u;
+
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		kfree(rdev);
+		return ERR_PTR(ret);
+	}
+
+	return adev;
+}
+
+static int npcm8xx_clock_controller_register(struct npcm_rc_data *rst_data, char *clk_name)
+{
+	struct auxiliary_device *adev;
+	int ret;
+
+	adev = npcm_clock_adev_alloc(rst_data, clk_name);
+	if (IS_ERR(adev))
+		return PTR_ERR(adev);
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(rst_data->dev, npcm_clock_unregister_adev, adev);
+}
+
 static int npcm_rc_probe(struct platform_device *pdev)
 {
 	struct npcm_rc_data *rc;
@@ -392,6 +458,7 @@ static int npcm_rc_probe(struct platform_device *pdev)
 	rc->rcdev.of_node = pdev->dev.of_node;
 	rc->rcdev.of_reset_n_cells = 2;
 	rc->rcdev.of_xlate = npcm_reset_xlate;
+	rc->dev = &pdev->dev;
 
 	ret = devm_reset_controller_register(&pdev->dev, &rc->rcdev);
 	if (ret) {
@@ -408,12 +475,19 @@ static int npcm_rc_probe(struct platform_device *pdev)
 			rc->restart_nb.priority = 192,
 			rc->restart_nb.notifier_call = npcm_rc_restart,
 			ret = register_restart_handler(&rc->restart_nb);
-			if (ret)
+			if (ret) {
 				dev_warn(&pdev->dev, "failed to register restart handler\n");
+				return ret;
+			}
 		}
 	}
 
-	return ret;
+	switch (rc->info->bmc_id) {
+	case BMC_NPCM8XX:
+		return npcm8xx_clock_controller_register(rc, "clk-npcm8xx");
+	default:
+		return 0;
+	}
 }
 
 static struct platform_driver npcm_rc_driver = {

include/soc/nuvoton/clock-npcm8xx.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SOC_NPCM8XX_CLOCK_H
+#define __SOC_NPCM8XX_CLOCK_H
+
+#include <linux/auxiliary_bus.h>
+#include <linux/container_of.h>
+
+struct npcm_clock_adev {
+	void __iomem *base;
+	struct auxiliary_device adev;
+};
+
+static inline struct npcm_clock_adev *to_npcm_clock_adev(struct auxiliary_device *_adev)
+{
+	return container_of(_adev, struct npcm_clock_adev, adev);
+}
+
+#endif