[PATCH V2 04/10] i3c: mipi-i3c-hci: Allow for Multi-Bus Instances

[Adrian Hunter]

A MIPI I3C Host Controller with the Multi-Bus Instance capability supports
multiple I3C Buses (up to 15), with one instance of the HCI Register Set
and one instance of I3C Bus Controller Logic for each I3C Bus, in a single
hardware function (e.g. PCIe B/D/F).

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 range, but not necessarily
in separate contiguous sub-ranges. To avoid overlapping mappings, provide
base_regs from the parent mapping.

Allow the IRQ to be shared.

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
---


Changes in V2:

	None


 drivers/i3c/master/mipi-i3c-hci/core.c     | 21 +++++++++++++++++----
 include/linux/platform_data/mipi-i3c-hci.h | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 include/linux/platform_data/mipi-i3c-hci.h

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index 07fb91a12593..05b8df1cf86d 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 000000000000..ab7395f455f9
--- /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
-- 
2.51.0