From: Adrian Hunter <adrian.hunter@intel.com>
Date: Tue, 6 Jan 2026 16:44:12 +0000 (+0200)
Subject: i3c: mipi-i3c-hci: Allow for Multi-Bus Instances
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b8460480f62e16751876a1f367dc14fb62867463;p=thirdparty%2Fkernel%2Flinux.git

i3c: mipi-i3c-hci: Allow for Multi-Bus Instances

Add support for MIPI I3C Host Controllers with the Multi-Bus Instance
capability.  These controllers can host multiple I3C buses (up to 15)
within a single hardware function (e.g., PCIe B/D/F), providing one
indepedent HCI register set and corresponding I3C bus controller logic
per bus.

A separate platform device will represent each instance, but it is
necessary to allow for shared resources.

Multi-bus instances share the same MMIO address space, but the ranges are
not guaranteed to be contiguous. To avoid overlapping mappings, pass
base_regs from the parent mapping to child devices.

Allow the IRQ to be shared among instances.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260106164416.67074-8-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index 3d6544a641887..6da5daf18166f 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -14,6 +14,7 @@
 #include <linux/interrupt.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
+#include <linux/platform_data/mipi-i3c-hci.h>
 #include <linux/platform_device.h>
 
 #include "hci.h"
@@ -737,15 +738,27 @@ static int i3c_hci_init(struct i3c_hci *hci)
 
 static int i3c_hci_probe(struct platform_device *pdev)
 {
+	const struct mipi_i3c_hci_platform_data *pdata = pdev->dev.platform_data;
 	struct i3c_hci *hci;
 	int irq, ret;
 
 	hci = devm_kzalloc(&pdev->dev, sizeof(*hci), GFP_KERNEL);
 	if (!hci)
 		return -ENOMEM;
-	hci->base_regs = devm_platform_ioremap_resource(pdev, 0);
-	if (IS_ERR(hci->base_regs))
-		return PTR_ERR(hci->base_regs);
+
+	/*
+	 * Multi-bus instances share the same MMIO address range, but not
+	 * necessarily in separate contiguous sub-ranges. To avoid overlapping
+	 * mappings, provide base_regs from the parent mapping.
+	 */
+	if (pdata)
+		hci->base_regs = pdata->base_regs;
+
+	if (!hci->base_regs) {
+		hci->base_regs = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(hci->base_regs))
+			return PTR_ERR(hci->base_regs);
+	}
 
 	platform_set_drvdata(pdev, hci);
 	/* temporary for dev_printk's, to be replaced in i3c_master_register */
@@ -759,7 +772,7 @@ static int i3c_hci_probe(struct platform_device *pdev)
 
 	irq = platform_get_irq(pdev, 0);
 	ret = devm_request_irq(&pdev->dev, irq, i3c_hci_irq_handler,
-			       0, NULL, hci);
+			       IRQF_SHARED, NULL, hci);
 	if (ret)
 		return ret;
 
diff --git a/include/linux/platform_data/mipi-i3c-hci.h b/include/linux/platform_data/mipi-i3c-hci.h
new file mode 100644
index 0000000000000..ab7395f455f94
--- /dev/null
+++ b/include/linux/platform_data/mipi-i3c-hci.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef INCLUDE_PLATFORM_DATA_MIPI_I3C_HCI_H
+#define INCLUDE_PLATFORM_DATA_MIPI_I3C_HCI_H
+
+#include <linux/compiler_types.h>
+
+/**
+ * struct mipi_i3c_hci_platform_data - Platform-dependent data for mipi_i3c_hci
+ * @base_regs: Register set base address (to support multi-bus instances)
+ */
+struct mipi_i3c_hci_platform_data {
+	void __iomem *base_regs;
+};
+
+#endif