i3c: dw: Add shutdown support to dw_i3c_master driver

Add shutdown handler to the Synopsys DesignWare I3C master driver,
ensuring the device is gracefully disabled during system shutdown.

The shutdown handler cancels any pending hot-join work and disables
interrupts.

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
Link: https://lore.kernel.org/r/20250730151207.4113708-1-manikanta.guntupalli@amd.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Author: Manikanta Guntupalli

drivers/i3c/master/dw-i3c-master.c

@@ -1737,6 +1737,28 @@ static const struct dev_pm_ops dw_i3c_pm_ops = {
 	SET_RUNTIME_PM_OPS(dw_i3c_master_runtime_suspend, dw_i3c_master_runtime_resume, NULL)
 };
 
+static void dw_i3c_shutdown(struct platform_device *pdev)
+{
+	struct dw_i3c_master *master = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pm_runtime_resume_and_get(master->dev);
+	if (ret < 0) {
+		dev_err(master->dev,
+			"<%s> cannot resume i3c bus master, err: %d\n",
+			__func__, ret);
+		return;
+	}
+
+	cancel_work_sync(&master->hj_work);
+
+	/* Disable interrupts */
+	writel((u32)~INTR_ALL, master->regs + INTR_STATUS_EN);
+	writel((u32)~INTR_ALL, master->regs + INTR_SIGNAL_EN);
+
+	pm_runtime_put_autosuspend(master->dev);
+}
+
 static const struct of_device_id dw_i3c_master_of_match[] = {
 	{ .compatible = "snps,dw-i3c-master-1.00a", },
 	{},
@@ -1752,6 +1774,7 @@ MODULE_DEVICE_TABLE(acpi, amd_i3c_device_match);
 static struct platform_driver dw_i3c_driver = {
 	.probe = dw_i3c_probe,
 	.remove = dw_i3c_remove,
+	.shutdown = dw_i3c_shutdown,
 	.driver = {
 		.name = "dw-i3c-master",
 		.of_match_table = dw_i3c_master_of_match,