linux-kernel - [PATCH 4/7] i3c: mipi-i3c-hci: Add quirk to allow IBI while runtime suspended

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Message-ID: <20260129181841.130864-5-adrian.hunter@intel.com>
Date: Thu, 29 Jan 2026 20:18:38 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: alexandre.belloni@...tlin.com
Cc: Frank.Li@....com,
	linux-i3c@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: [PATCH 4/7] i3c: mipi-i3c-hci: Add quirk to allow IBI while runtime suspended

Some I3C controllers can be automatically runtime-resumed in order to
handle in-band interrupts (IBIs), meaning that runtime suspend does not
need to be blocked when IBIs are enabled.

For example, a PCI-attached controller in a low-power state may generate
a Power Management Event (PME) when the SDA line is pulled low to signal
the START condition of an IBI. The PCI subsystem will then runtime-resume
the device, allowing the IBI to be received without requiring the
controller to remain active.

Introduce a new quirk, HCI_QUIRK_RPM_IBI_ALLOWED, so that drivers can
opt-in to this capability via driver data.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 drivers/i3c/master/mipi-i3c-hci/core.c | 3 +++
 drivers/i3c/master/mipi-i3c-hci/hci.h  | 1 +
 2 files changed, 4 insertions(+)

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index e925584113d1..ec4dbe64c35e 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -959,6 +959,9 @@ static int i3c_hci_probe(struct platform_device *pdev)
 	if (hci->quirks & HCI_QUIRK_RPM_ALLOWED)
 		i3c_hci_rpm_enable(&pdev->dev);
 
+	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
+		hci->master.rpm_ibi_allowed = true;
+
 	return i3c_master_register(&hci->master, &pdev->dev, &i3c_hci_ops, false);
 }
 
diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
index 6035f74212db..819328a85b84 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci.h
+++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
@@ -146,6 +146,7 @@ struct i3c_hci_dev_data {
 #define HCI_QUIRK_OD_PP_TIMING		BIT(3)  /* Set OD and PP timings for AMD platforms */
 #define HCI_QUIRK_RESP_BUF_THLD		BIT(4)  /* Set resp buf thld to 0 for AMD platforms */
 #define HCI_QUIRK_RPM_ALLOWED		BIT(5)  /* Runtime PM allowed */
+#define HCI_QUIRK_RPM_IBI_ALLOWED	BIT(6)  /* IBI and Hot-Join allowed while runtime suspended */
 
 /* global functions */
 void mipi_i3c_hci_resume(struct i3c_hci *hci);
-- 
2.51.0