spmi: Introduce device-managed functions

Utilize the managed resource (devres) framework and add the following
devm_* helpers for the SPMI driver:

- devm_spmi_controller_alloc()
- devm_spmi_controller_add()

[[e-mail]: Rename to spmi-devres for module niceness, slap on
GPL module license]

Signed-off-by: Fei Shao <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/spmi/Makefile

···
 #
 # Makefile for kernel SPMI framework.
 #
-obj-$(CONFIG_SPMI)	+= spmi.o
+obj-$(CONFIG_SPMI)	+= spmi.o spmi-devres.o
 
 obj-$(CONFIG_SPMI_HISI3670)	+= hisi-spmi-controller.o
 obj-$(CONFIG_SPMI_MSM_PMIC_ARB)	+= spmi-pmic-arb.o

drivers/spmi/spmi-devres.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Google LLC.
+ */
+
+#include <linux/device.h>
+#include <linux/spmi.h>
+
+static void devm_spmi_controller_release(struct device *parent, void *res)
+{
+	spmi_controller_put(*(struct spmi_controller **)res);
+}
+
+struct spmi_controller *devm_spmi_controller_alloc(struct device *parent, size_t size)
+{
+	struct spmi_controller **ptr, *ctrl;
+
+	ptr = devres_alloc(devm_spmi_controller_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	ctrl = spmi_controller_alloc(parent, size);
+	if (!ctrl) {
+		devres_free(ptr);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	*ptr = ctrl;
+	devres_add(parent, ptr);
+
+	return ctrl;
+}
+EXPORT_SYMBOL_GPL(devm_spmi_controller_alloc);
+
+static void devm_spmi_controller_remove(struct device *parent, void *res)
+{
+	spmi_controller_remove(*(struct spmi_controller **)res);
+}
+
+int devm_spmi_controller_add(struct device *parent, struct spmi_controller *ctrl)
+{
+	struct spmi_controller **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_spmi_controller_remove, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = spmi_controller_add(ctrl);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = ctrl;
+	devres_add(parent, ptr);
+
+	return 0;
+
+}
+EXPORT_SYMBOL_GPL(devm_spmi_controller_add);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SPMI devres helpers");

include/linux/spmi.h

···
 int spmi_controller_add(struct spmi_controller *ctrl);
 void spmi_controller_remove(struct spmi_controller *ctrl);
 
+struct spmi_controller *devm_spmi_controller_alloc(struct device *parent, size_t size);
+int devm_spmi_controller_add(struct device *parent, struct spmi_controller *ctrl);
+
 /**
  * struct spmi_driver - SPMI slave device driver
  * @driver:	SPMI device drivers should initialize name and owner field of