mailbox/riscv-sbi-mpxy: Add ACPI support

Add ACPI support for the RISC-V SBI message proxy (MPXY) based
mailbox driver.

Acked-by: Jassi Brar <[e-mail]>
Signed-off-by: Sunil V L <[e-mail]>
Signed-off-by: Anup Patel <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Paul Walmsley <[e-mail]>

drivers/mailbox/riscv-sbi-mpxy-mbox.c

···
  * Copyright (C) 2025 Ventana Micro Systems Inc.
  */
 
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/init.h>
+#include <linux/irqchip/riscv-imsic.h>
 #include <linux/mailbox_controller.h>
 #include <linux/mailbox/riscv-rpmi-message.h>
 #include <linux/minmax.h>
···
 		 * explicitly configure here.
 		 */
 		if (!dev_get_msi_domain(dev)) {
+			struct fwnode_handle *fwnode = dev_fwnode(dev);
+
 			/*
 			 * The device MSI domain for OF devices is only set at the
 			 * time of populating/creating OF device. If the device MSI
···
 			 * then we need to set it explicitly before using any platform
 			 * MSI functions.
 			 */
-			if (dev_of_node(dev))
+			if (is_of_node(fwnode)) {
 				of_msi_configure(dev, dev_of_node(dev));
+			} else if (is_acpi_device_node(fwnode)) {
+				struct irq_domain *msi_domain;
+
+				msi_domain = irq_find_matching_fwnode(imsic_acpi_get_fwnode(dev),
+								      DOMAIN_BUS_PLATFORM_MSI);
+				dev_set_msi_domain(dev, msi_domain);
+			}
 
 			if (!dev_get_msi_domain(dev))
 				return -EPROBE_DEFER;
···
 		return rc;
 	}
 
+#ifdef CONFIG_ACPI
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (adev)
+		acpi_dev_clear_dependencies(adev);
+#endif
+
 	dev_info(dev, "mailbox registered with %d channels\n",
 		 mbox->channel_count);
 	return 0;
···
 };
 MODULE_DEVICE_TABLE(of, mpxy_mbox_of_match);
 
+static const struct acpi_device_id mpxy_mbox_acpi_match[] = {
+	{ "RSCV0005" },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, mpxy_mbox_acpi_match);
+
 static struct platform_driver mpxy_mbox_driver = {
 	.driver = {
 		.name = "riscv-sbi-mpxy-mbox",
 		.of_match_table = mpxy_mbox_of_match,
+		.acpi_match_table = mpxy_mbox_acpi_match,
 	},
 	.probe = mpxy_mbox_probe,
 	.remove = mpxy_mbox_remove,