[PATCH 0/7] i3c: mipi-i3c-hci-pci: Enable IBI while runtime suspended for Intel controllers

[PATCH 0/7] i3c: mipi-i3c-hci-pci: Enable IBI while runtime suspended for Intel controllers

[Adrian Hunter]

Hi

Here are patches related to enabling IBI while runtime suspended for Intel
controllers.

Intel LPSS I3C controllers can wake from runtime suspend to receive
in-band interrupts (IBIs).

It is non-trivial to implement because the parent PCI device has 2 I3C bus
instances (MIPI I3C HCI Multi-Bus Instance capability) represented by
platform devices with a separate driver, but the IBI-wakeup is shared by
both, which means runtime PM has to be managed by the parent PCI driver.

To make that work, the PCI driver handles runtime PM, but leverages the
mipi-i3c-hci platform driver's functionality for saving and restoring
controller state.


Adrian Hunter (7):
      i3c: mipi-i3c-hci-pci: Set d3hot_delay to 0 for Intel controllers
      i3c: master: Allow controller drivers to select runtime PM device
      i3c: master: Mark last_busy on IBI when runtime PM is allowed
      i3c: mipi-i3c-hci: Add quirk to allow IBI while runtime suspended
      i3c: mipi-i3c-hci: Allow parent to manage runtime PM
      i3c: mipi-i3c-hci-pci: Add optional ability to manage child runtime PM
      i3c: mipi-i3c-hci-pci: Enable IBI while runtime suspended for Intel controllers

 drivers/i3c/master.c                               |  14 +-
 drivers/i3c/master/mipi-i3c-hci/core.c             |  30 ++--
 drivers/i3c/master/mipi-i3c-hci/hci.h              |   7 +
 drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 158 ++++++++++++++++++++-
 include/linux/i3c/master.h                         |   2 +
 5 files changed, 194 insertions(+), 17 deletions(-)


Regards
Adrian

[PATCH 1/7] i3c: mipi-i3c-hci-pci: Set d3hot_delay to 0 for Intel controllers

[Adrian Hunter]

Set d3hot_delay to 0 for Intel controllers because a delay is not needed.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
index 0f05a15c14c7..bc83caad4197 100644
--- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
+++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
@@ -164,6 +164,7 @@ static int intel_i3c_init(struct mipi_i3c_hci_pci *hci)
 	dma_set_mask_and_coherent(&hci->pci->dev, DMA_BIT_MASK(64));
 
 	hci->pci->d3cold_delay = 0;
+	hci->pci->d3hot_delay = 0;
 
 	hci->private = host;
 	host->priv = priv;
-- 
2.51.0

[PATCH 2/7] i3c: master: Allow controller drivers to select runtime PM device

[Adrian Hunter]

Some I3C controller drivers need runtime PM to operate on a device other
than the parent device.  To support that, add an rpm_dev pointer to
struct i3c_master_controller so drivers can specify which device should
be used for runtime power management.

If a driver does not set rpm_dev explicitly, default to using the parent
device to maintain existing behaviour.

Update the runtime PM helpers to use rpm_dev instead of dev.parent.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master.c       | 9 ++++++---
 include/linux/i3c/master.h | 2 ++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 49fb6e30a68e..bcc493dc9d04 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -108,10 +108,10 @@ static struct i3c_master_controller *dev_to_i3cmaster(struct device *dev)
 
 static int __must_check i3c_master_rpm_get(struct i3c_master_controller *master)
 {
-	int ret = master->rpm_allowed ? pm_runtime_resume_and_get(master->dev.parent) : 0;
+	int ret = master->rpm_allowed ? pm_runtime_resume_and_get(master->rpm_dev) : 0;
 
 	if (ret < 0) {
-		dev_err(master->dev.parent, "runtime resume failed, error %d\n", ret);
+		dev_err(master->rpm_dev, "runtime resume failed, error %d\n", ret);
 		return ret;
 	}
 	return 0;
@@ -120,7 +120,7 @@ static int __must_check i3c_master_rpm_get(struct i3c_master_controller *master)
 static void i3c_master_rpm_put(struct i3c_master_controller *master)
 {
 	if (master->rpm_allowed)
-		pm_runtime_put_autosuspend(master->dev.parent);
+		pm_runtime_put_autosuspend(master->rpm_dev);
 }
 
 int i3c_bus_rpm_get(struct i3c_bus *bus)
@@ -2975,6 +2975,9 @@ int i3c_master_register(struct i3c_master_controller *master,
 	INIT_LIST_HEAD(&master->boardinfo.i2c);
 	INIT_LIST_HEAD(&master->boardinfo.i3c);
 
+	if (!master->rpm_dev)
+		master->rpm_dev = parent;
+
 	ret = i3c_master_rpm_get(master);
 	if (ret)
 		return ret;
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index af2bb48363ba..4be67a902dd8 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -501,6 +501,7 @@ struct i3c_master_controller_ops {
  *	 registered to the I2C subsystem to be as transparent as possible to
  *	 existing I2C drivers
  * @ops: master operations. See &struct i3c_master_controller_ops
+ * @rpm_dev: Runtime PM device
  * @secondary: true if the master is a secondary master
  * @init_done: true when the bus initialization is done
  * @hotjoin: true if the master support hotjoin
@@ -526,6 +527,7 @@ struct i3c_master_controller {
 	struct i3c_dev_desc *this;
 	struct i2c_adapter i2c;
 	const struct i3c_master_controller_ops *ops;
+	struct device *rpm_dev;
 	unsigned int secondary : 1;
 	unsigned int init_done : 1;
 	unsigned int hotjoin: 1;
-- 
2.51.0

[PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

[Adrian Hunter]

When an IBI can be received after the controller is
pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
device is auto‑suspended.  In such cases, the runtime PM core may not see
any recent activity and may suspend the device earlier than intended.

Mark the controller as last busy whenever an IBI is queued (when
rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
recent bus activity and avoids premature suspension.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index bcc493dc9d04..dcc07ebc50a2 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
  */
 void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
 {
+	struct i3c_master_controller *master = i3c_dev_get_master(dev);
+
 	if (!dev->ibi || !slot)
 		return;
 
+	if (master->rpm_ibi_allowed)
+		pm_runtime_mark_last_busy(master->rpm_dev);
+
 	atomic_inc(&dev->ibi->pending_ibis);
 	queue_work(dev->ibi->wq, &slot->work);
 }
-- 
2.51.0

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

[Adrian Hunter]

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@intel.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

[PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
where a single parent device hosts multiple I3C controller instances.  In
such designs, the parent - not the individual child instances - may need to
coordinate runtime PM so that all controllers enter low-power states
together, and all runtime suspend callbacks are invoked in a controlled
and synchronized manner.

For example, if the parent enables IBI-wakeup when transitioning into a
low-power state, every bus instance must remain able to receive IBIs up
until that point.  This requires deferring the individual controllers’
runtime suspend callbacks (which disable bus activity) until the parent
decides it is safe for all instances to suspend together.

To support this usage model:

  * Export the controller's runtime PM suspend/resume callbacks so that
    the parent can invoke them directly.

  * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
    parent device as the controller’s runtime PM device (rpm_dev).  When
    used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
    instance’s system-suspend callbacks from using
    pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
    PM is managed entirely by the parent.

  * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
    by parent-managed PM implementations.

The new quirk allows platforms with multi-bus parent-managed PM
infrastructure to correctly coordinate runtime PM across all I3C HCI
instances.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
 drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index ec4dbe64c35e..cb974b0f9e17 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
 	return 0;
 }
 
-static int i3c_hci_runtime_suspend(struct device *dev)
+int i3c_hci_runtime_suspend(struct device *dev)
 {
 	struct i3c_hci *hci = dev_get_drvdata(dev);
 	int ret;
@@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
 
-static int i3c_hci_runtime_resume(struct device *dev)
+int i3c_hci_runtime_resume(struct device *dev)
 {
 	struct i3c_hci *hci = dev_get_drvdata(dev);
 	int ret;
@@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
 
 static int i3c_hci_suspend(struct device *dev)
 {
@@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
 	struct i3c_hci *hci = dev_get_drvdata(dev);
 	int ret;
 
-	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
-		return 0;
+	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
+		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
+			return 0;
 
-	ret = pm_runtime_force_resume(dev);
-	if (ret)
-		return ret;
+		ret = pm_runtime_force_resume(dev);
+		if (ret)
+			return ret;
+	}
 
 	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
 	if (ret)
@@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
 	return i3c_hci_resume_common(dev, true);
 }
 
-#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
-
 static void i3c_hci_rpm_enable(struct device *dev)
 {
 	struct i3c_hci *hci = dev_get_drvdata(dev);
@@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
 	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
 		hci->master.rpm_ibi_allowed = true;
 
+	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
+		hci->master.rpm_dev = pdev->dev.parent;
+		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci.h
+++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
@@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
 #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 */
+#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
 
 /* global functions */
 void mipi_i3c_hci_resume(struct i3c_hci *hci);
@@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
 void amd_set_resp_buf_thld(struct i3c_hci *hci);
 void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
 
+#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
+
+int i3c_hci_runtime_suspend(struct device *dev);
+int i3c_hci_runtime_resume(struct device *dev);
+
 #endif
-- 
2.51.0

[PATCH 6/7] i3c: mipi-i3c-hci-pci: Add optional ability to manage child runtime PM

[Adrian Hunter]

Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
where a single parent device hosts multiple I3C controller instances.  In
such designs, the parent - not the individual child instances - may need to
coordinate runtime PM so that all controllers enter low-power states
together, and all runtime suspend callbacks are invoked in a controlled
and synchronized manner.

For example, if the parent enables IBI-wakeup when transitioning into a
low-power state, every bus instance must remain able to receive IBIs up
until that point.  This requires deferring the individual controllers’
runtime suspend callbacks (which disable bus activity) until the parent
decides it is safe for all instances to suspend together.

To support this usage model:

  * Add runtime PM and system PM callbacks in the PCI driver to invoke
    the mipi-i3c-hci driver’s runtime PM callbacks for each instance.

  * Introduce a driver-data flag, control_instance_pm, which opts into
    the new parent-managed PM behaviour.

  * Ensure the callbacks are only used when the corresponding instance is
    operational at suspend time.  This is reliable because the operational
    state cannot change while the parent device is undergoing a PM
    transition, and PCI always performs a runtime resume before system
    suspend on current configurations, so that suspend and resume alternate
    irrespective of whether it is runtime or system PM.

By that means, parent-managed runtime PM coordination for multi-instance
MIPI I3C HCI PCI devices is provided without altering existing behaviour on
platforms that do not require it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 .../master/mipi-i3c-hci/mipi-i3c-hci-pci.c    | 154 +++++++++++++++++-
 1 file changed, 150 insertions(+), 4 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
index bc83caad4197..f7f776300a0f 100644
--- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
+++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
@@ -9,6 +9,7 @@
 #include <linux/acpi.h>
 #include <linux/bitfield.h>
 #include <linux/debugfs.h>
+#include <linux/i3c/master.h>
 #include <linux/idr.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
@@ -20,16 +21,24 @@
 #include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
 
+#include "hci.h"
+
 /*
  * There can up to 15 instances, but implementations have at most 2 at this
  * time.
  */
 #define INST_MAX 2
 
+struct mipi_i3c_hci_pci_instance {
+	struct device *dev;
+	bool operational;
+};
+
 struct mipi_i3c_hci_pci {
 	struct pci_dev *pci;
 	void __iomem *base;
 	const struct mipi_i3c_hci_pci_info *info;
+	struct mipi_i3c_hci_pci_instance instance[INST_MAX];
 	void *private;
 };
 
@@ -40,6 +49,7 @@ struct mipi_i3c_hci_pci_info {
 	int id[INST_MAX];
 	u32 instance_offset[INST_MAX];
 	int instance_count;
+	bool control_instance_pm;
 };
 
 #define INTEL_PRIV_OFFSET		0x2b0
@@ -210,14 +220,148 @@ static const struct mipi_i3c_hci_pci_info intel_si_2_info = {
 	.instance_count = 1,
 };
 
-static void mipi_i3c_hci_pci_rpm_allow(struct device *dev)
+static int mipi_i3c_hci_pci_find_instance(struct mipi_i3c_hci_pci *hci, struct device *dev)
+{
+	for (int i = 0; i < INST_MAX; i++) {
+		if (!hci->instance[i].dev)
+			hci->instance[i].dev = dev;
+		if (hci->instance[i].dev == dev)
+			return i;
+	}
+
+	return -1;
+}
+
+#define HC_CONTROL			0x04
+#define HC_CONTROL_BUS_ENABLE		BIT(31)
+
+static bool __mipi_i3c_hci_pci_is_operational(struct device *dev)
+{
+	const struct mipi_i3c_hci_platform_data *pdata = dev->platform_data;
+	u32 hc_control = readl(pdata->base_regs + HC_CONTROL);
+
+	return hc_control & HC_CONTROL_BUS_ENABLE;
+}
+
+static bool mipi_i3c_hci_pci_is_operational(struct device *dev, bool update)
+{
+	struct mipi_i3c_hci_pci *hci = dev_get_drvdata(dev->parent);
+	int pos = mipi_i3c_hci_pci_find_instance(hci, dev);
+
+	if (pos < 0) {
+		dev_err(dev, "%s: I3C instance not found\n", __func__);
+		return false;
+	}
+
+	if (update)
+		hci->instance[pos].operational = __mipi_i3c_hci_pci_is_operational(dev);
+
+	return hci->instance[pos].operational;
+}
+
+struct mipi_i3c_hci_pci_pm_data {
+	struct device *dev[INST_MAX];
+	int dev_cnt;
+};
+
+static bool mipi_i3c_hci_pci_is_mfd(struct device *dev)
+{
+	return dev_is_platform(dev) && mfd_get_cell(to_platform_device(dev));
+}
+
+static int mipi_i3c_hci_pci_suspend_instance(struct device *dev, void *data)
+{
+	struct mipi_i3c_hci_pci_pm_data *pm_data = data;
+	int ret;
+
+	if (!mipi_i3c_hci_pci_is_mfd(dev) ||
+	    !mipi_i3c_hci_pci_is_operational(dev, true))
+		return 0;
+
+	ret = i3c_hci_runtime_suspend(dev);
+	if (ret)
+		return ret;
+
+	pm_data->dev[pm_data->dev_cnt++] = dev;
+
+	return 0;
+}
+
+static int mipi_i3c_hci_pci_resume_instance(struct device *dev, void *data)
 {
+	struct mipi_i3c_hci_pci_pm_data *pm_data = data;
+	int ret;
+
+	if (!mipi_i3c_hci_pci_is_mfd(dev) ||
+	    !mipi_i3c_hci_pci_is_operational(dev, false))
+		return 0;
+
+	ret = i3c_hci_runtime_resume(dev);
+	if (ret)
+		return ret;
+
+	pm_data->dev[pm_data->dev_cnt++] = dev;
+
+	return 0;
+}
+
+static int mipi_i3c_hci_pci_suspend(struct device *dev)
+{
+	struct mipi_i3c_hci_pci *hci = dev_get_drvdata(dev);
+	struct mipi_i3c_hci_pci_pm_data pm_data = {};
+	int ret;
+
+	if (!hci->info->control_instance_pm)
+		return 0;
+
+	ret = device_for_each_child_reverse(dev, &pm_data, mipi_i3c_hci_pci_suspend_instance);
+	if (ret) {
+		if (ret == -EAGAIN || ret == -EBUSY)
+			pm_runtime_mark_last_busy(&hci->pci->dev);
+		for (int i = 0; i < pm_data.dev_cnt; i++)
+			i3c_hci_runtime_resume(pm_data.dev[i]);
+	}
+
+	return ret;
+}
+
+static int mipi_i3c_hci_pci_resume(struct device *dev)
+{
+	struct mipi_i3c_hci_pci *hci = dev_get_drvdata(dev);
+	struct mipi_i3c_hci_pci_pm_data pm_data = {};
+	int ret;
+
+	if (!hci->info->control_instance_pm)
+		return 0;
+
+	ret = device_for_each_child(dev, &pm_data, mipi_i3c_hci_pci_resume_instance);
+	if (ret)
+		for (int i = 0; i < pm_data.dev_cnt; i++)
+			i3c_hci_runtime_suspend(pm_data.dev[i]);
+
+	return ret;
+}
+
+static void mipi_i3c_hci_pci_rpm_allow(struct mipi_i3c_hci_pci *hci)
+{
+	struct device *dev = &hci->pci->dev;
+
+	if (hci->info->control_instance_pm) {
+		pm_runtime_set_autosuspend_delay(dev, DEFAULT_AUTOSUSPEND_DELAY_MS);
+		pm_runtime_use_autosuspend(dev);
+	}
+
 	pm_runtime_put(dev);
 	pm_runtime_allow(dev);
 }
 
-static void mipi_i3c_hci_pci_rpm_forbid(struct device *dev)
+static void mipi_i3c_hci_pci_rpm_forbid(struct mipi_i3c_hci_pci *hci)
 {
+	struct device *dev = &hci->pci->dev;
+
+	if (hci->info->control_instance_pm)
+		pm_runtime_dont_use_autosuspend(dev);
+
 	pm_runtime_forbid(dev);
 	pm_runtime_get_sync(dev);
 }
@@ -299,7 +443,7 @@ static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
 
 	pci_set_drvdata(pci, hci);
 
-	mipi_i3c_hci_pci_rpm_allow(&pci->dev);
+	mipi_i3c_hci_pci_rpm_allow(hci);
 
 	return 0;
 
@@ -316,13 +460,15 @@ static void mipi_i3c_hci_pci_remove(struct pci_dev *pci)
 	if (hci->info->exit)
 		hci->info->exit(hci);
 
-	mipi_i3c_hci_pci_rpm_forbid(&pci->dev);
+	mipi_i3c_hci_pci_rpm_forbid(hci);
 
 	mfd_remove_devices(&pci->dev);
 }
 
 /* PM ops must exist for PCI to put a device to a low power state */
 static const struct dev_pm_ops mipi_i3c_hci_pci_pm_ops = {
+	RUNTIME_PM_OPS(mipi_i3c_hci_pci_suspend, mipi_i3c_hci_pci_resume, NULL)
+	SYSTEM_SLEEP_PM_OPS(mipi_i3c_hci_pci_suspend, mipi_i3c_hci_pci_resume)
 };
 
 static const struct pci_device_id mipi_i3c_hci_pci_devices[] = {
-- 
2.51.0

[PATCH 7/7] i3c: mipi-i3c-hci-pci: Enable IBI while runtime suspended for Intel controllers

[Adrian Hunter]

Intel LPSS I3C controllers can wake from runtime suspend to receive
in-band interrupts (IBIs), and they also implement the MIPI I3C HCI
Multi-Bus Instance capability.  When multiple I3C bus instances share the
same PCI wakeup, the PCI parent must coordinate runtime PM so that all
instances suspend together and their mipi-i3c-hci runtime suspend
callbacks are invoked in a consistent manner.

Enable IBI-based wakeup by setting HCI_QUIRK_RPM_IBI_ALLOWED for the
intel-lpss-i3c platform device.  Replace HCI_QUIRK_RPM_ALLOWED with
HCI_QUIRK_RPM_PARENT_MANAGED so that the mipi-i3c-hci core driver expects
runtime PM to be controlled by the PCI parent rather than by individual
instances.  For all Intel HCI PCI configurations, enable the corresponding
control_instance_pm flag in the PCI driver.

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

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index cb974b0f9e17..67ae7441ce97 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -992,7 +992,7 @@ static const struct acpi_device_id i3c_hci_acpi_match[] = {
 MODULE_DEVICE_TABLE(acpi, i3c_hci_acpi_match);
 
 static const struct platform_device_id i3c_hci_driver_ids[] = {
-	{ .name = "intel-lpss-i3c", HCI_QUIRK_RPM_ALLOWED },
+	{ .name = "intel-lpss-i3c", HCI_QUIRK_RPM_IBI_ALLOWED | HCI_QUIRK_RPM_PARENT_MANAGED },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(platform, i3c_hci_driver_ids);
diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
index f7f776300a0f..2f72cf48e36c 100644
--- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
+++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
@@ -200,6 +200,7 @@ static const struct mipi_i3c_hci_pci_info intel_mi_1_info = {
 	.id = {0, 1},
 	.instance_offset = {0, 0x400},
 	.instance_count = 2,
+	.control_instance_pm = true,
 };
 
 static const struct mipi_i3c_hci_pci_info intel_mi_2_info = {
@@ -209,6 +210,7 @@ static const struct mipi_i3c_hci_pci_info intel_mi_2_info = {
 	.id = {2, 3},
 	.instance_offset = {0, 0x400},
 	.instance_count = 2,
+	.control_instance_pm = true,
 };
 
 static const struct mipi_i3c_hci_pci_info intel_si_2_info = {
@@ -218,6 +220,7 @@ static const struct mipi_i3c_hci_pci_info intel_si_2_info = {
 	.id = {2},
 	.instance_offset = {0},
 	.instance_count = 1,
+	.control_instance_pm = true,
 };
 
 static int mipi_i3c_hci_pci_find_instance(struct mipi_i3c_hci_pci *hci, struct device *dev)
-- 
2.51.0

Re: [PATCH 1/7] i3c: mipi-i3c-hci-pci: Set d3hot_delay to 0 for Intel controllers

[Frank Li]

On Thu, Jan 29, 2026 at 08:18:35PM +0200, Adrian Hunter wrote:
> Set d3hot_delay to 0 for Intel controllers because a delay is not needed.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>
>  drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> index 0f05a15c14c7..bc83caad4197 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> @@ -164,6 +164,7 @@ static int intel_i3c_init(struct mipi_i3c_hci_pci *hci)
>  	dma_set_mask_and_coherent(&hci->pci->dev, DMA_BIT_MASK(64));
>
>  	hci->pci->d3cold_delay = 0;
> +	hci->pci->d3hot_delay = 0;
>
>  	hci->private = host;
>  	host->priv = priv;
> --
> 2.51.0
>

Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

[Frank Li]

On Thu, Jan 29, 2026 at 08:18:37PM +0200, Adrian Hunter wrote:
> When an IBI can be received after the controller is
> pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
> device is auto‑suspended.  In such cases, the runtime PM core may not see
> any recent activity and may suspend the device earlier than intended.
>
> Mark the controller as last busy whenever an IBI is queued (when
> rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
> recent bus activity and avoids premature suspension.

look like this can't resolve problem. pm_runtime_mark_last_busy() just
change dev->power.last_busy. If suspend before it, nothing happen.

irq use thread irq, in irq thread call pm_runtime_resume() if needs.

And this function call by irq handle, just put to work queue, what's impact
if do nothing here?

Frank

>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>  drivers/i3c/master.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index bcc493dc9d04..dcc07ebc50a2 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
>   */
>  void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
>  {
> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
> +
>  	if (!dev->ibi || !slot)
>  		return;
>
> +	if (master->rpm_ibi_allowed)
> +		pm_runtime_mark_last_busy(master->rpm_dev);
> +
>  	atomic_inc(&dev->ibi->pending_ibis);
>  	queue_work(dev->ibi->wq, &slot->work);
>  }
> --
> 2.51.0
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
> where a single parent device hosts multiple I3C controller instances.  In
> such designs, the parent - not the individual child instances - may need to
> coordinate runtime PM so that all controllers enter low-power states
> together, and all runtime suspend callbacks are invoked in a controlled
> and synchronized manner.
>
> For example, if the parent enables IBI-wakeup when transitioning into a
> low-power state,

Does your hardware support recieve IBI when runtime suspend?

Frank

> every bus instance must remain able to receive IBIs up
> until that point.  This requires deferring the individual controllers’
> runtime suspend callbacks (which disable bus activity) until the parent
> decides it is safe for all instances to suspend together.
>
> To support this usage model:
>
>   * Export the controller's runtime PM suspend/resume callbacks so that
>     the parent can invoke them directly.
>
>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
>     parent device as the controller’s runtime PM device (rpm_dev).  When
>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
>     instance’s system-suspend callbacks from using
>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
>     PM is managed entirely by the parent.
>
>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
>     by parent-managed PM implementations.
>
> The new quirk allows platforms with multi-bus parent-managed PM
> infrastructure to correctly coordinate runtime PM across all I3C HCI
> instances.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
>  2 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> index ec4dbe64c35e..cb974b0f9e17 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
>  	return 0;
>  }
>
> -static int i3c_hci_runtime_suspend(struct device *dev)
> +int i3c_hci_runtime_suspend(struct device *dev)
>  {
>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>  	int ret;
> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
>
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
>
> -static int i3c_hci_runtime_resume(struct device *dev)
> +int i3c_hci_runtime_resume(struct device *dev)
>  {
>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>  	int ret;
> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
>
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
>
>  static int i3c_hci_suspend(struct device *dev)
>  {
> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>  	int ret;
>
> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> -		return 0;
> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> +			return 0;
>
> -	ret = pm_runtime_force_resume(dev);
> -	if (ret)
> -		return ret;
> +		ret = pm_runtime_force_resume(dev);
> +		if (ret)
> +			return ret;
> +	}
>
>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
>  	if (ret)
> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
>  	return i3c_hci_resume_common(dev, true);
>  }
>
> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> -
>  static void i3c_hci_rpm_enable(struct device *dev)
>  {
>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
>  		hci->master.rpm_ibi_allowed = true;
>
> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
> +		hci->master.rpm_dev = pdev->dev.parent;
> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
>  #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 */
> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
>
>  /* global functions */
>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
>
> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> +
> +int i3c_hci_runtime_suspend(struct device *dev);
> +int i3c_hci_runtime_resume(struct device *dev);
> +
>  #endif
> --
> 2.51.0
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

On 29/01/2026 22:00, Frank Li wrote:
> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
>> where a single parent device hosts multiple I3C controller instances.  In
>> such designs, the parent - not the individual child instances - may need to
>> coordinate runtime PM so that all controllers enter low-power states
>> together, and all runtime suspend callbacks are invoked in a controlled
>> and synchronized manner.
>>
>> For example, if the parent enables IBI-wakeup when transitioning into a
>> low-power state,
> 
> Does your hardware support recieve IBI when runtime suspend?

When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
the clock is started and the IBI is received.

> 
> Frank
> 
>> every bus instance must remain able to receive IBIs up
>> until that point.  This requires deferring the individual controllers’
>> runtime suspend callbacks (which disable bus activity) until the parent
>> decides it is safe for all instances to suspend together.
>>
>> To support this usage model:
>>
>>   * Export the controller's runtime PM suspend/resume callbacks so that
>>     the parent can invoke them directly.
>>
>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
>>     parent device as the controller’s runtime PM device (rpm_dev).  When
>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
>>     instance’s system-suspend callbacks from using
>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
>>     PM is managed entirely by the parent.
>>
>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
>>     by parent-managed PM implementations.
>>
>> The new quirk allows platforms with multi-bus parent-managed PM
>> infrastructure to correctly coordinate runtime PM across all I3C HCI
>> instances.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
>>  2 files changed, 22 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
>> index ec4dbe64c35e..cb974b0f9e17 100644
>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
>>  	return 0;
>>  }
>>
>> -static int i3c_hci_runtime_suspend(struct device *dev)
>> +int i3c_hci_runtime_suspend(struct device *dev)
>>  {
>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>  	int ret;
>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
>>
>>  	return 0;
>>  }
>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
>>
>> -static int i3c_hci_runtime_resume(struct device *dev)
>> +int i3c_hci_runtime_resume(struct device *dev)
>>  {
>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>  	int ret;
>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
>>
>>  	return 0;
>>  }
>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
>>
>>  static int i3c_hci_suspend(struct device *dev)
>>  {
>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>  	int ret;
>>
>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>> -		return 0;
>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>> +			return 0;
>>
>> -	ret = pm_runtime_force_resume(dev);
>> -	if (ret)
>> -		return ret;
>> +		ret = pm_runtime_force_resume(dev);
>> +		if (ret)
>> +			return ret;
>> +	}
>>
>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
>>  	if (ret)
>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
>>  	return i3c_hci_resume_common(dev, true);
>>  }
>>
>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>> -
>>  static void i3c_hci_rpm_enable(struct device *dev)
>>  {
>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
>>  		hci->master.rpm_ibi_allowed = true;
>>
>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
>> +		hci->master.rpm_dev = pdev->dev.parent;
>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
>>  #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 */
>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
>>
>>  /* global functions */
>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
>>
>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>> +
>> +int i3c_hci_runtime_suspend(struct device *dev);
>> +int i3c_hci_runtime_resume(struct device *dev);
>> +
>>  #endif
>> --
>> 2.51.0
>>

Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

[Adrian Hunter]

On 29/01/2026 21:56, Frank Li wrote:
> On Thu, Jan 29, 2026 at 08:18:37PM +0200, Adrian Hunter wrote:
>> When an IBI can be received after the controller is
>> pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
>> device is auto‑suspended.  In such cases, the runtime PM core may not see
>> any recent activity and may suspend the device earlier than intended.
>>
>> Mark the controller as last busy whenever an IBI is queued (when
>> rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
>> recent bus activity and avoids premature suspension.
> 
> look like this can't resolve problem. pm_runtime_mark_last_busy() just
> change dev->power.last_busy. If suspend before it, nothing happen.

It should be effective.

rpm_suspend() recalculates the autosuspend expiry time based on
last_busy (see pm_runtime_autosuspend_expiration()) and restarts
the timer is it is in the future.

> 
> irq use thread irq, in irq thread call pm_runtime_resume() if needs.
> 
> And this function call by irq handle, just put to work queue, what's impact
> if do nothing here?

Just premature runtime suspension inconsistent with autosuspend_delay.

> 
> Frank
> 
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>> ---
>>  drivers/i3c/master.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
>> index bcc493dc9d04..dcc07ebc50a2 100644
>> --- a/drivers/i3c/master.c
>> +++ b/drivers/i3c/master.c
>> @@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
>>   */
>>  void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
>>  {
>> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
>> +
>>  	if (!dev->ibi || !slot)
>>  		return;
>>
>> +	if (master->rpm_ibi_allowed)
>> +		pm_runtime_mark_last_busy(master->rpm_dev);
>> +
>>  	atomic_inc(&dev->ibi->pending_ibis);
>>  	queue_work(dev->ibi->wq, &slot->work);
>>  }
>> --
>> 2.51.0
>>

Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

[Frank Li]

On Thu, Jan 29, 2026 at 10:42:32PM +0200, Adrian Hunter wrote:
> On 29/01/2026 21:56, Frank Li wrote:
> > On Thu, Jan 29, 2026 at 08:18:37PM +0200, Adrian Hunter wrote:
> >> When an IBI can be received after the controller is
> >> pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
> >> device is auto‑suspended.  In such cases, the runtime PM core may not see
> >> any recent activity and may suspend the device earlier than intended.
> >>
> >> Mark the controller as last busy whenever an IBI is queued (when
> >> rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
> >> recent bus activity and avoids premature suspension.
> >
> > look like this can't resolve problem. pm_runtime_mark_last_busy() just
> > change dev->power.last_busy. If suspend before it, nothing happen.
>
> It should be effective.
>
> rpm_suspend() recalculates the autosuspend expiry time based on
> last_busy (see pm_runtime_autosuspend_expiration()) and restarts
> the timer is it is in the future.
>
> >
> > irq use thread irq, in irq thread call pm_runtime_resume() if needs.
> >
> > And this function call by irq handle, just put to work queue, what's impact
> > if do nothing here?
>
> Just premature runtime suspension inconsistent with autosuspend_delay.


   CPU 0            CPU 1
1. rpm_suspend()    2. pm_runtime_mark_last_busy(master->rpm_dev)

if 2 happen before 1, it can extend suspend. 2 happen after 1, it should
do nothing.

Frank
>
> >
> > Frank
> >
> >>
> >> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >> ---
> >>  drivers/i3c/master.c | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> >> index bcc493dc9d04..dcc07ebc50a2 100644
> >> --- a/drivers/i3c/master.c
> >> +++ b/drivers/i3c/master.c
> >> @@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
> >>   */
> >>  void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
> >>  {
> >> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
> >> +
> >>  	if (!dev->ibi || !slot)
> >>  		return;
> >>
> >> +	if (master->rpm_ibi_allowed)
> >> +		pm_runtime_mark_last_busy(master->rpm_dev);
> >> +
> >>  	atomic_inc(&dev->ibi->pending_ibis);
> >>  	queue_work(dev->ibi->wq, &slot->work);
> >>  }
> >> --
> >> 2.51.0
> >>
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
> On 29/01/2026 22:00, Frank Li wrote:
> > On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
> >> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
> >> where a single parent device hosts multiple I3C controller instances.  In
> >> such designs, the parent - not the individual child instances - may need to
> >> coordinate runtime PM so that all controllers enter low-power states
> >> together, and all runtime suspend callbacks are invoked in a controlled
> >> and synchronized manner.
> >>
> >> For example, if the parent enables IBI-wakeup when transitioning into a
> >> low-power state,
> >
> > Does your hardware support recieve IBI when runtime suspend?
>
> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
> the clock is started and the IBI is received.

It align my assumption, why need complex solution.

SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
queue.

IBI work will try do transfer, which will call runtime resume(), then
transfer data.

What's issue?

Frank

>
> >
> > Frank
> >
> >> every bus instance must remain able to receive IBIs up
> >> until that point.  This requires deferring the individual controllers’
> >> runtime suspend callbacks (which disable bus activity) until the parent
> >> decides it is safe for all instances to suspend together.
> >>
> >> To support this usage model:
> >>
> >>   * Export the controller's runtime PM suspend/resume callbacks so that
> >>     the parent can invoke them directly.
> >>
> >>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
> >>     parent device as the controller’s runtime PM device (rpm_dev).  When
> >>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
> >>     instance’s system-suspend callbacks from using
> >>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
> >>     PM is managed entirely by the parent.
> >>
> >>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
> >>     by parent-managed PM implementations.
> >>
> >> The new quirk allows platforms with multi-bus parent-managed PM
> >> infrastructure to correctly coordinate runtime PM across all I3C HCI
> >> instances.
> >>
> >> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >> ---
> >>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
> >>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
> >>  2 files changed, 22 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> >> index ec4dbe64c35e..cb974b0f9e17 100644
> >> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> >> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> >> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
> >>  	return 0;
> >>  }
> >>
> >> -static int i3c_hci_runtime_suspend(struct device *dev)
> >> +int i3c_hci_runtime_suspend(struct device *dev)
> >>  {
> >>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>  	int ret;
> >> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
> >>
> >>  	return 0;
> >>  }
> >> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
> >>
> >> -static int i3c_hci_runtime_resume(struct device *dev)
> >> +int i3c_hci_runtime_resume(struct device *dev)
> >>  {
> >>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>  	int ret;
> >> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
> >>
> >>  	return 0;
> >>  }
> >> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
> >>
> >>  static int i3c_hci_suspend(struct device *dev)
> >>  {
> >> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
> >>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>  	int ret;
> >>
> >> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >> -		return 0;
> >> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
> >> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >> +			return 0;
> >>
> >> -	ret = pm_runtime_force_resume(dev);
> >> -	if (ret)
> >> -		return ret;
> >> +		ret = pm_runtime_force_resume(dev);
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >>
> >>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
> >>  	if (ret)
> >> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
> >>  	return i3c_hci_resume_common(dev, true);
> >>  }
> >>
> >> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >> -
> >>  static void i3c_hci_rpm_enable(struct device *dev)
> >>  {
> >>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
> >>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
> >>  		hci->master.rpm_ibi_allowed = true;
> >>
> >> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
> >> +		hci->master.rpm_dev = pdev->dev.parent;
> >> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
> >> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> >> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> >> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
> >>  #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 */
> >> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
> >>
> >>  /* global functions */
> >>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
> >> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
> >>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
> >>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
> >>
> >> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >> +
> >> +int i3c_hci_runtime_suspend(struct device *dev);
> >> +int i3c_hci_runtime_resume(struct device *dev);
> >> +
> >>  #endif
> >> --
> >> 2.51.0
> >>
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

On 29/01/2026 23:00, Frank Li wrote:
> On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
>> On 29/01/2026 22:00, Frank Li wrote:
>>> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
>>>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
>>>> where a single parent device hosts multiple I3C controller instances.  In
>>>> such designs, the parent - not the individual child instances - may need to
>>>> coordinate runtime PM so that all controllers enter low-power states
>>>> together, and all runtime suspend callbacks are invoked in a controlled
>>>> and synchronized manner.
>>>>
>>>> For example, if the parent enables IBI-wakeup when transitioning into a
>>>> low-power state,
>>>
>>> Does your hardware support recieve IBI when runtime suspend?
>>
>> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
>> the clock is started and the IBI is received.
> 
> It align my assumption, why need complex solution.
> 
> SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
> queue.
> 
> IBI work will try do transfer, which will call runtime resume(), then
> transfer data.
> 
> What's issue?

The PME indicates I3C START (SDA line pulled low).  The controller is
in a low power state unable to operate the bus.  At this point it is not
known what I3C device has pulled down the SDA line, or even if it is an
IBI since it is indistinguishable from hot-join at this point.

The PCI PME IRQ is not the device's IRQ.  It is handled by acpi_irq()
which ultimately informs the PCI subsystem to wake the PCI device.
The PCI subsystem performs pm_request_resume(), refer pci_acpi_wake_dev().

When the controller is resumed, it enables the I3C bus and the IBI is
finally delivered normally.

However, none of that is related to this patch.

This patch is because the PCI device has 2 I3C bus instances and only 1 PME
wakeup.  The PME becomes active when the PCI device is put to a low
power state.  Both I3C bus instances must be runtime suspended then.
Similarly, upon resume the PME is no longer active, so both I3C bus instances
must make their buses operational - we don't know which may have received
an IBI.  And there may be further IBIs which can't be received unless the
associated bus is operational.  The PCI device is no longer in a low power
state, so there will be no PME in that case.

> 
> Frank
> 
>>
>>>
>>> Frank
>>>
>>>> every bus instance must remain able to receive IBIs up
>>>> until that point.  This requires deferring the individual controllers’
>>>> runtime suspend callbacks (which disable bus activity) until the parent
>>>> decides it is safe for all instances to suspend together.
>>>>
>>>> To support this usage model:
>>>>
>>>>   * Export the controller's runtime PM suspend/resume callbacks so that
>>>>     the parent can invoke them directly.
>>>>
>>>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
>>>>     parent device as the controller’s runtime PM device (rpm_dev).  When
>>>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
>>>>     instance’s system-suspend callbacks from using
>>>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
>>>>     PM is managed entirely by the parent.
>>>>
>>>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
>>>>     by parent-managed PM implementations.
>>>>
>>>> The new quirk allows platforms with multi-bus parent-managed PM
>>>> infrastructure to correctly coordinate runtime PM across all I3C HCI
>>>> instances.
>>>>
>>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>>>> ---
>>>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
>>>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
>>>>  2 files changed, 22 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
>>>> index ec4dbe64c35e..cb974b0f9e17 100644
>>>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
>>>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
>>>>  	return 0;
>>>>  }
>>>>
>>>> -static int i3c_hci_runtime_suspend(struct device *dev)
>>>> +int i3c_hci_runtime_suspend(struct device *dev)
>>>>  {
>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>  	int ret;
>>>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
>>>>
>>>>  	return 0;
>>>>  }
>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
>>>>
>>>> -static int i3c_hci_runtime_resume(struct device *dev)
>>>> +int i3c_hci_runtime_resume(struct device *dev)
>>>>  {
>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>  	int ret;
>>>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
>>>>
>>>>  	return 0;
>>>>  }
>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
>>>>
>>>>  static int i3c_hci_suspend(struct device *dev)
>>>>  {
>>>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>  	int ret;
>>>>
>>>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>>>> -		return 0;
>>>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
>>>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>>>> +			return 0;
>>>>
>>>> -	ret = pm_runtime_force_resume(dev);
>>>> -	if (ret)
>>>> -		return ret;
>>>> +		ret = pm_runtime_force_resume(dev);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +	}
>>>>
>>>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
>>>>  	if (ret)
>>>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
>>>>  	return i3c_hci_resume_common(dev, true);
>>>>  }
>>>>
>>>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>>>> -
>>>>  static void i3c_hci_rpm_enable(struct device *dev)
>>>>  {
>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
>>>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
>>>>  		hci->master.rpm_ibi_allowed = true;
>>>>
>>>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
>>>> +		hci->master.rpm_dev = pdev->dev.parent;
>>>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
>>>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
>>>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
>>>>  #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 */
>>>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
>>>>
>>>>  /* global functions */
>>>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
>>>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
>>>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
>>>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
>>>>
>>>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>>>> +
>>>> +int i3c_hci_runtime_suspend(struct device *dev);
>>>> +int i3c_hci_runtime_resume(struct device *dev);
>>>> +
>>>>  #endif
>>>> --
>>>> 2.51.0
>>>>
>>

Re: [PATCH 3/7] i3c: master: Mark last_busy on IBI when runtime PM is allowed

[Adrian Hunter]

On 29/01/2026 22:55, Frank Li wrote:
> On Thu, Jan 29, 2026 at 10:42:32PM +0200, Adrian Hunter wrote:
>> On 29/01/2026 21:56, Frank Li wrote:
>>> On Thu, Jan 29, 2026 at 08:18:37PM +0200, Adrian Hunter wrote:
>>>> When an IBI can be received after the controller is
>>>> pm_runtime_put_autosuspend()'ed, the interrupt may occur just before the
>>>> device is auto‑suspended.  In such cases, the runtime PM core may not see
>>>> any recent activity and may suspend the device earlier than intended.
>>>>
>>>> Mark the controller as last busy whenever an IBI is queued (when
>>>> rpm_ibi_allowed is set) so that the auto-suspend delay correctly reflects
>>>> recent bus activity and avoids premature suspension.
>>>
>>> look like this can't resolve problem. pm_runtime_mark_last_busy() just
>>> change dev->power.last_busy. If suspend before it, nothing happen.
>>
>> It should be effective.
>>
>> rpm_suspend() recalculates the autosuspend expiry time based on
>> last_busy (see pm_runtime_autosuspend_expiration()) and restarts
>> the timer is it is in the future.
>>
>>>
>>> irq use thread irq, in irq thread call pm_runtime_resume() if needs.
>>>
>>> And this function call by irq handle, just put to work queue, what's impact
>>> if do nothing here?
>>
>> Just premature runtime suspension inconsistent with autosuspend_delay.
> 
> 
>    CPU 0            CPU 1
> 1. rpm_suspend()    2. pm_runtime_mark_last_busy(master->rpm_dev)
> 
> if 2 happen before 1, it can extend suspend. 2 happen after 1, it should
> do nothing.

2 happening after 1 is a separate issue.  It will never happen
in the wakeup case because the wakeup does a runtime resume:

	pm_runtime_put_autosuspend()
	IBI -> pm_runtime_mark_last_busy()
	another IBI -> pm_runtime_mark_last_busy() and so on
	<autosuspend_delay finally elapses>
	rpm_suspend() -> device suspended, PME activated
	IBI START -> PME -> pm_request_resume()
	IBI is delivered after controller runtime resumes

> 
> Frank
>>
>>>
>>> Frank
>>>
>>>>
>>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>>>> ---
>>>>  drivers/i3c/master.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
>>>> index bcc493dc9d04..dcc07ebc50a2 100644
>>>> --- a/drivers/i3c/master.c
>>>> +++ b/drivers/i3c/master.c
>>>> @@ -2721,9 +2721,14 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master)
>>>>   */
>>>>  void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot)
>>>>  {
>>>> +	struct i3c_master_controller *master = i3c_dev_get_master(dev);
>>>> +
>>>>  	if (!dev->ibi || !slot)
>>>>  		return;
>>>>
>>>> +	if (master->rpm_ibi_allowed)
>>>> +		pm_runtime_mark_last_busy(master->rpm_dev);
>>>> +
>>>>  	atomic_inc(&dev->ibi->pending_ibis);
>>>>  	queue_work(dev->ibi->wq, &slot->work);
>>>>  }
>>>> --
>>>> 2.51.0
>>>>
>>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Fri, Jan 30, 2026 at 09:00:33AM +0200, Adrian Hunter wrote:
> On 29/01/2026 23:00, Frank Li wrote:
> > On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
> >> On 29/01/2026 22:00, Frank Li wrote:
> >>> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
> >>>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
> >>>> where a single parent device hosts multiple I3C controller instances.  In
> >>>> such designs, the parent - not the individual child instances - may need to
> >>>> coordinate runtime PM so that all controllers enter low-power states
> >>>> together, and all runtime suspend callbacks are invoked in a controlled
> >>>> and synchronized manner.
> >>>>
> >>>> For example, if the parent enables IBI-wakeup when transitioning into a
> >>>> low-power state,
> >>>
> >>> Does your hardware support recieve IBI when runtime suspend?
> >>
> >> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
> >> the clock is started and the IBI is received.
> >
> > It align my assumption, why need complex solution.
> >
> > SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
> > queue.
> >
> > IBI work will try do transfer, which will call runtime resume(), then
> > transfer data.
> >
> > What's issue?
>
> The PME indicates I3C START (SDA line pulled low).  The controller is
> in a low power state unable to operate the bus.  At this point it is not
> known what I3C device has pulled down the SDA line, or even if it is an
> IBI since it is indistinguishable from hot-join at this point.
>
> The PCI PME IRQ is not the device's IRQ.  It is handled by acpi_irq()
> which ultimately informs the PCI subsystem to wake the PCI device.
> The PCI subsystem performs pm_request_resume(), refer pci_acpi_wake_dev().
>
> When the controller is resumed, it enables the I3C bus and the IBI is
> finally delivered normally.
>
> However, none of that is related to this patch.
>
> This patch is because the PCI device has 2 I3C bus instances and only 1 PME
> wakeup.  The PME becomes active when the PCI device is put to a low
> power state.

One instance 1 suspend, instance 2 running, PME is inactive, what's happen
if instance 1 request IBI?

IBI will be missed?

> Both I3C bus instances must be runtime suspended then.
> Similarly, upon resume the PME is no longer active, so both I3C bus instances
> must make their buses operational - we don't know which may have received
> an IBI.

Does PME active auto by hardware or need software config?

Frank
> And there may be further IBIs which can't be received unless the
> associated bus is operational.  The PCI device is no longer in a low power
> state, so there will be no PME in that case.
>
> >
> > Frank
> >
> >>
> >>>
> >>> Frank
> >>>
> >>>> every bus instance must remain able to receive IBIs up
> >>>> until that point.  This requires deferring the individual controllers’
> >>>> runtime suspend callbacks (which disable bus activity) until the parent
> >>>> decides it is safe for all instances to suspend together.
> >>>>
> >>>> To support this usage model:
> >>>>
> >>>>   * Export the controller's runtime PM suspend/resume callbacks so that
> >>>>     the parent can invoke them directly.
> >>>>
> >>>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
> >>>>     parent device as the controller’s runtime PM device (rpm_dev).  When
> >>>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
> >>>>     instance’s system-suspend callbacks from using
> >>>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
> >>>>     PM is managed entirely by the parent.
> >>>>
> >>>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
> >>>>     by parent-managed PM implementations.
> >>>>
> >>>> The new quirk allows platforms with multi-bus parent-managed PM
> >>>> infrastructure to correctly coordinate runtime PM across all I3C HCI
> >>>> instances.
> >>>>
> >>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >>>> ---
> >>>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
> >>>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
> >>>>  2 files changed, 22 insertions(+), 9 deletions(-)
> >>>>
> >>>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>> index ec4dbe64c35e..cb974b0f9e17 100644
> >>>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
> >>>>  	return 0;
> >>>>  }
> >>>>
> >>>> -static int i3c_hci_runtime_suspend(struct device *dev)
> >>>> +int i3c_hci_runtime_suspend(struct device *dev)
> >>>>  {
> >>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>  	int ret;
> >>>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
> >>>>
> >>>>  	return 0;
> >>>>  }
> >>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
> >>>>
> >>>> -static int i3c_hci_runtime_resume(struct device *dev)
> >>>> +int i3c_hci_runtime_resume(struct device *dev)
> >>>>  {
> >>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>  	int ret;
> >>>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
> >>>>
> >>>>  	return 0;
> >>>>  }
> >>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
> >>>>
> >>>>  static int i3c_hci_suspend(struct device *dev)
> >>>>  {
> >>>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
> >>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>  	int ret;
> >>>>
> >>>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>> -		return 0;
> >>>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
> >>>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>> +			return 0;
> >>>>
> >>>> -	ret = pm_runtime_force_resume(dev);
> >>>> -	if (ret)
> >>>> -		return ret;
> >>>> +		ret = pm_runtime_force_resume(dev);
> >>>> +		if (ret)
> >>>> +			return ret;
> >>>> +	}
> >>>>
> >>>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
> >>>>  	if (ret)
> >>>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
> >>>>  	return i3c_hci_resume_common(dev, true);
> >>>>  }
> >>>>
> >>>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>> -
> >>>>  static void i3c_hci_rpm_enable(struct device *dev)
> >>>>  {
> >>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
> >>>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
> >>>>  		hci->master.rpm_ibi_allowed = true;
> >>>>
> >>>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
> >>>> +		hci->master.rpm_dev = pdev->dev.parent;
> >>>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
> >>>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
> >>>>  #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 */
> >>>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
> >>>>
> >>>>  /* global functions */
> >>>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
> >>>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
> >>>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
> >>>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
> >>>>
> >>>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>> +
> >>>> +int i3c_hci_runtime_suspend(struct device *dev);
> >>>> +int i3c_hci_runtime_resume(struct device *dev);
> >>>> +
> >>>>  #endif
> >>>> --
> >>>> 2.51.0
> >>>>
> >>
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

On 30/01/2026 17:04, Frank Li wrote:
> On Fri, Jan 30, 2026 at 09:00:33AM +0200, Adrian Hunter wrote:
>> On 29/01/2026 23:00, Frank Li wrote:
>>> On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
>>>> On 29/01/2026 22:00, Frank Li wrote:
>>>>> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
>>>>>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
>>>>>> where a single parent device hosts multiple I3C controller instances.  In
>>>>>> such designs, the parent - not the individual child instances - may need to
>>>>>> coordinate runtime PM so that all controllers enter low-power states
>>>>>> together, and all runtime suspend callbacks are invoked in a controlled
>>>>>> and synchronized manner.
>>>>>>
>>>>>> For example, if the parent enables IBI-wakeup when transitioning into a
>>>>>> low-power state,
>>>>>
>>>>> Does your hardware support recieve IBI when runtime suspend?
>>>>
>>>> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
>>>> the clock is started and the IBI is received.
>>>
>>> It align my assumption, why need complex solution.
>>>
>>> SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
>>> queue.
>>>
>>> IBI work will try do transfer, which will call runtime resume(), then
>>> transfer data.
>>>
>>> What's issue?
>>
>> The PME indicates I3C START (SDA line pulled low).  The controller is
>> in a low power state unable to operate the bus.  At this point it is not
>> known what I3C device has pulled down the SDA line, or even if it is an
>> IBI since it is indistinguishable from hot-join at this point.
>>
>> The PCI PME IRQ is not the device's IRQ.  It is handled by acpi_irq()
>> which ultimately informs the PCI subsystem to wake the PCI device.
>> The PCI subsystem performs pm_request_resume(), refer pci_acpi_wake_dev().
>>
>> When the controller is resumed, it enables the I3C bus and the IBI is
>> finally delivered normally.
>>
>> However, none of that is related to this patch.
>>
>> This patch is because the PCI device has 2 I3C bus instances and only 1 PME
>> wakeup.  The PME becomes active when the PCI device is put to a low
>> power state.
> 
> One instance 1 suspend, instance 2 running, PME is inactive, what's happen
> if instance 1 request IBI?

Nothing will happen.  Instance 1 I3C bus is not operational and there can
be no PME when the PCI device is not in a low power state (D3hot)

> 
> IBI will be missed?

Possibly not if instance 1 is eventually resumed and the I3C device
requesting the IBI has not yet given up.

> 
>> Both I3C bus instances must be runtime suspended then.
>> Similarly, upon resume the PME is no longer active, so both I3C bus instances
>> must make their buses operational - we don't know which may have received
>> an IBI.
> 
> Does PME active auto by hardware or need software config?

PCI devices (hardware) advertise their PME capability in terms of
which states are capable of PMEs.  Currently the Intel LPSS I3C
device lists only D3hot.

The PCI subsystem (software) automatically enables the PME before
runtime suspend if the target power state allows it.

> 
> Frank
>> And there may be further IBIs which can't be received unless the
>> associated bus is operational.  The PCI device is no longer in a low power
>> state, so there will be no PME in that case.
>>
>>>
>>> Frank
>>>
>>>>
>>>>>
>>>>> Frank
>>>>>
>>>>>> every bus instance must remain able to receive IBIs up
>>>>>> until that point.  This requires deferring the individual controllers’
>>>>>> runtime suspend callbacks (which disable bus activity) until the parent
>>>>>> decides it is safe for all instances to suspend together.
>>>>>>
>>>>>> To support this usage model:
>>>>>>
>>>>>>   * Export the controller's runtime PM suspend/resume callbacks so that
>>>>>>     the parent can invoke them directly.
>>>>>>
>>>>>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
>>>>>>     parent device as the controller’s runtime PM device (rpm_dev).  When
>>>>>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
>>>>>>     instance’s system-suspend callbacks from using
>>>>>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
>>>>>>     PM is managed entirely by the parent.
>>>>>>
>>>>>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
>>>>>>     by parent-managed PM implementations.
>>>>>>
>>>>>> The new quirk allows platforms with multi-bus parent-managed PM
>>>>>> infrastructure to correctly coordinate runtime PM across all I3C HCI
>>>>>> instances.
>>>>>>
>>>>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
>>>>>> ---
>>>>>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
>>>>>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
>>>>>>  2 files changed, 22 insertions(+), 9 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
>>>>>> index ec4dbe64c35e..cb974b0f9e17 100644
>>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
>>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
>>>>>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
>>>>>>  	return 0;
>>>>>>  }
>>>>>>
>>>>>> -static int i3c_hci_runtime_suspend(struct device *dev)
>>>>>> +int i3c_hci_runtime_suspend(struct device *dev)
>>>>>>  {
>>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>>>  	int ret;
>>>>>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
>>>>>>
>>>>>>  	return 0;
>>>>>>  }
>>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
>>>>>>
>>>>>> -static int i3c_hci_runtime_resume(struct device *dev)
>>>>>> +int i3c_hci_runtime_resume(struct device *dev)
>>>>>>  {
>>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>>>  	int ret;
>>>>>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
>>>>>>
>>>>>>  	return 0;
>>>>>>  }
>>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
>>>>>>
>>>>>>  static int i3c_hci_suspend(struct device *dev)
>>>>>>  {
>>>>>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
>>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>>>  	int ret;
>>>>>>
>>>>>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>>>>>> -		return 0;
>>>>>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
>>>>>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
>>>>>> +			return 0;
>>>>>>
>>>>>> -	ret = pm_runtime_force_resume(dev);
>>>>>> -	if (ret)
>>>>>> -		return ret;
>>>>>> +		ret = pm_runtime_force_resume(dev);
>>>>>> +		if (ret)
>>>>>> +			return ret;
>>>>>> +	}
>>>>>>
>>>>>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
>>>>>>  	if (ret)
>>>>>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
>>>>>>  	return i3c_hci_resume_common(dev, true);
>>>>>>  }
>>>>>>
>>>>>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>>>>>> -
>>>>>>  static void i3c_hci_rpm_enable(struct device *dev)
>>>>>>  {
>>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
>>>>>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
>>>>>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
>>>>>>  		hci->master.rpm_ibi_allowed = true;
>>>>>>
>>>>>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
>>>>>> +		hci->master.rpm_dev = pdev->dev.parent;
>>>>>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
>>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
>>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
>>>>>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
>>>>>>  #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 */
>>>>>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
>>>>>>
>>>>>>  /* global functions */
>>>>>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
>>>>>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
>>>>>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
>>>>>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
>>>>>>
>>>>>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>>>>>> +
>>>>>> +int i3c_hci_runtime_suspend(struct device *dev);
>>>>>> +int i3c_hci_runtime_resume(struct device *dev);
>>>>>> +
>>>>>>  #endif
>>>>>> --
>>>>>> 2.51.0
>>>>>>
>>>>
>>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Fri, Jan 30, 2026 at 06:34:37PM +0200, Adrian Hunter wrote:
> On 30/01/2026 17:04, Frank Li wrote:
> > On Fri, Jan 30, 2026 at 09:00:33AM +0200, Adrian Hunter wrote:
> >> On 29/01/2026 23:00, Frank Li wrote:
> >>> On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
> >>>> On 29/01/2026 22:00, Frank Li wrote:
> >>>>> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
> >>>>>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
> >>>>>> where a single parent device hosts multiple I3C controller instances.  In
> >>>>>> such designs, the parent - not the individual child instances - may need to
> >>>>>> coordinate runtime PM so that all controllers enter low-power states
> >>>>>> together, and all runtime suspend callbacks are invoked in a controlled
> >>>>>> and synchronized manner.
> >>>>>>
> >>>>>> For example, if the parent enables IBI-wakeup when transitioning into a
> >>>>>> low-power state,
> >>>>>
> >>>>> Does your hardware support recieve IBI when runtime suspend?
> >>>>
> >>>> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
> >>>> the clock is started and the IBI is received.
> >>>
> >>> It align my assumption, why need complex solution.
> >>>
> >>> SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
> >>> queue.
> >>>
> >>> IBI work will try do transfer, which will call runtime resume(), then
> >>> transfer data.
> >>>
> >>> What's issue?
> >>
> >> The PME indicates I3C START (SDA line pulled low).  The controller is
> >> in a low power state unable to operate the bus.  At this point it is not
> >> known what I3C device has pulled down the SDA line, or even if it is an
> >> IBI since it is indistinguishable from hot-join at this point.
> >>
> >> The PCI PME IRQ is not the device's IRQ.  It is handled by acpi_irq()
> >> which ultimately informs the PCI subsystem to wake the PCI device.
> >> The PCI subsystem performs pm_request_resume(), refer pci_acpi_wake_dev().
> >>
> >> When the controller is resumed, it enables the I3C bus and the IBI is
> >> finally delivered normally.
> >>
> >> However, none of that is related to this patch.
> >>
> >> This patch is because the PCI device has 2 I3C bus instances and only 1 PME
> >> wakeup.  The PME becomes active when the PCI device is put to a low
> >> power state.
> >
> > One instance 1 suspend, instance 2 running, PME is inactive, what's happen
> > if instance 1 request IBI?
>
> Nothing will happen.  Instance 1 I3C bus is not operational and there can
> be no PME when the PCI device is not in a low power state (D3hot)
>
> >
> > IBI will be missed?
>
> Possibly not if instance 1 is eventually resumed and the I3C device
> requesting the IBI has not yet given up.
>
> >
> >> Both I3C bus instances must be runtime suspended then.
> >> Similarly, upon resume the PME is no longer active, so both I3C bus instances
> >> must make their buses operational - we don't know which may have received
> >> an IBI.
> >
> > Does PME active auto by hardware or need software config?
>
> PCI devices (hardware) advertise their PME capability in terms of
> which states are capable of PMEs.  Currently the Intel LPSS I3C
> device lists only D3hot.
>
> The PCI subsystem (software) automatically enables the PME before
> runtime suspend if the target power state allows it.

Okay, I think I understand your situation, let me check patch again.

Frank
>
> >
> > Frank
> >> And there may be further IBIs which can't be received unless the
> >> associated bus is operational.  The PCI device is no longer in a low power
> >> state, so there will be no PME in that case.
> >>
> >>>
> >>> Frank
> >>>
> >>>>
> >>>>>
> >>>>> Frank
> >>>>>
> >>>>>> every bus instance must remain able to receive IBIs up
> >>>>>> until that point.  This requires deferring the individual controllers’
> >>>>>> runtime suspend callbacks (which disable bus activity) until the parent
> >>>>>> decides it is safe for all instances to suspend together.
> >>>>>>
> >>>>>> To support this usage model:
> >>>>>>
> >>>>>>   * Export the controller's runtime PM suspend/resume callbacks so that
> >>>>>>     the parent can invoke them directly.
> >>>>>>
> >>>>>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
> >>>>>>     parent device as the controller’s runtime PM device (rpm_dev).  When
> >>>>>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
> >>>>>>     instance’s system-suspend callbacks from using
> >>>>>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
> >>>>>>     PM is managed entirely by the parent.
> >>>>>>
> >>>>>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
> >>>>>>     by parent-managed PM implementations.
> >>>>>>
> >>>>>> The new quirk allows platforms with multi-bus parent-managed PM
> >>>>>> infrastructure to correctly coordinate runtime PM across all I3C HCI
> >>>>>> instances.
> >>>>>>
> >>>>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >>>>>> ---
> >>>>>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
> >>>>>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
> >>>>>>  2 files changed, 22 insertions(+), 9 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> index ec4dbe64c35e..cb974b0f9e17 100644
> >>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>>
> >>>>>> -static int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>> +int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>>
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
> >>>>>>
> >>>>>> -static int i3c_hci_runtime_resume(struct device *dev)
> >>>>>> +int i3c_hci_runtime_resume(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
> >>>>>>
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
> >>>>>>
> >>>>>>  static int i3c_hci_suspend(struct device *dev)
> >>>>>>  {
> >>>>>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>>
> >>>>>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>>>> -		return 0;
> >>>>>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
> >>>>>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>>>> +			return 0;
> >>>>>>
> >>>>>> -	ret = pm_runtime_force_resume(dev);
> >>>>>> -	if (ret)
> >>>>>> -		return ret;
> >>>>>> +		ret = pm_runtime_force_resume(dev);
> >>>>>> +		if (ret)
> >>>>>> +			return ret;
> >>>>>> +	}
> >>>>>>
> >>>>>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
> >>>>>>  	if (ret)
> >>>>>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
> >>>>>>  	return i3c_hci_resume_common(dev, true);
> >>>>>>  }
> >>>>>>
> >>>>>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>>>> -
> >>>>>>  static void i3c_hci_rpm_enable(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
> >>>>>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
> >>>>>>  		hci->master.rpm_ibi_allowed = true;
> >>>>>>
> >>>>>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
> >>>>>> +		hci->master.rpm_dev = pdev->dev.parent;
> >>>>>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
> >>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>>>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
> >>>>>>  #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 */
> >>>>>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
> >>>>>>
> >>>>>>  /* global functions */
> >>>>>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
> >>>>>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
> >>>>>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
> >>>>>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
> >>>>>>
> >>>>>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>>>> +
> >>>>>> +int i3c_hci_runtime_suspend(struct device *dev);
> >>>>>> +int i3c_hci_runtime_resume(struct device *dev);
> >>>>>> +
> >>>>>>  #endif
> >>>>>> --
> >>>>>> 2.51.0
> >>>>>>
> >>>>
> >>
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Fri, Jan 30, 2026 at 06:34:37PM +0200, Adrian Hunter wrote:
> On 30/01/2026 17:04, Frank Li wrote:
> > On Fri, Jan 30, 2026 at 09:00:33AM +0200, Adrian Hunter wrote:
> >> On 29/01/2026 23:00, Frank Li wrote:
> >>> On Thu, Jan 29, 2026 at 10:28:14PM +0200, Adrian Hunter wrote:
> >>>> On 29/01/2026 22:00, Frank Li wrote:
> >>>>> On Thu, Jan 29, 2026 at 08:18:39PM +0200, Adrian Hunter wrote:
> >>>>>> Some platforms implement the MIPI I3C HCI Multi-Bus Instance capability,
> >>>>>> where a single parent device hosts multiple I3C controller instances.  In
> >>>>>> such designs, the parent - not the individual child instances - may need to
> >>>>>> coordinate runtime PM so that all controllers enter low-power states
> >>>>>> together, and all runtime suspend callbacks are invoked in a controlled
> >>>>>> and synchronized manner.
> >>>>>>
> >>>>>> For example, if the parent enables IBI-wakeup when transitioning into a
> >>>>>> low-power state,
> >>>>>
> >>>>> Does your hardware support recieve IBI when runtime suspend?
> >>>>
> >>>> When runtime suspended (in D3), the hardware first triggers 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.  When the bus is enabled,
> >>>> the clock is started and the IBI is received.
> >>>
> >>> It align my assumption, why need complex solution.
> >>>
> >>> SDA->PME->IRQ should handle by hardware, so irq handle queue IBI to working
> >>> queue.
> >>>
> >>> IBI work will try do transfer, which will call runtime resume(), then
> >>> transfer data.
> >>>
> >>> What's issue?
> >>
> >> The PME indicates I3C START (SDA line pulled low).  The controller is
> >> in a low power state unable to operate the bus.  At this point it is not
> >> known what I3C device has pulled down the SDA line, or even if it is an
> >> IBI since it is indistinguishable from hot-join at this point.
> >>
> >> The PCI PME IRQ is not the device's IRQ.  It is handled by acpi_irq()
> >> which ultimately informs the PCI subsystem to wake the PCI device.
> >> The PCI subsystem performs pm_request_resume(), refer pci_acpi_wake_dev().
> >>
> >> When the controller is resumed, it enables the I3C bus and the IBI is
> >> finally delivered normally.
> >>
> >> However, none of that is related to this patch.
> >>
> >> This patch is because the PCI device has 2 I3C bus instances and only 1 PME
> >> wakeup.  The PME becomes active when the PCI device is put to a low
> >> power state.
> >
> > One instance 1 suspend, instance 2 running, PME is inactive, what's happen
> > if instance 1 request IBI?
>
> Nothing will happen.  Instance 1 I3C bus is not operational and there can
> be no PME when the PCI device is not in a low power state (D3hot)
>
> >
> > IBI will be missed?
>
> Possibly not if instance 1 is eventually resumed and the I3C device
> requesting the IBI has not yet given up.
>
> >
> >> Both I3C bus instances must be runtime suspended then.
> >> Similarly, upon resume the PME is no longer active, so both I3C bus instances
> >> must make their buses operational - we don't know which may have received
> >> an IBI.
> >
> > Does PME active auto by hardware or need software config?
>
> PCI devices (hardware) advertise their PME capability in terms of
> which states are capable of PMEs.  Currently the Intel LPSS I3C
> device lists only D3hot.
>
> The PCI subsystem (software) automatically enables the PME before
> runtime suspend if the target power state allows it.

Does your device Hierarchy look like

           PCI device
               |
       -----------------
      HCI1            HCI2
       |               |
     I3C M1          I3C M2


You want HCI1 and HCI2 suspened only when both HCI1 and HCI2 can enter RM
time suspend status?

Device Link can link two devices, but not sure if it can handle cyclic
case, HCI1 and HCI2 depend each other.

Or you create common power domain for HCI1 and HCI2, in power domain to
handle suspend.

It'd better ask run time pm owner to provide better suggestion.

Frank

>
> >
> > Frank
> >> And there may be further IBIs which can't be received unless the
> >> associated bus is operational.  The PCI device is no longer in a low power
> >> state, so there will be no PME in that case.
> >>
> >>>
> >>> Frank
> >>>
> >>>>
> >>>>>
> >>>>> Frank
> >>>>>
> >>>>>> every bus instance must remain able to receive IBIs up
> >>>>>> until that point.  This requires deferring the individual controllers’
> >>>>>> runtime suspend callbacks (which disable bus activity) until the parent
> >>>>>> decides it is safe for all instances to suspend together.
> >>>>>>
> >>>>>> To support this usage model:
> >>>>>>
> >>>>>>   * Export the controller's runtime PM suspend/resume callbacks so that
> >>>>>>     the parent can invoke them directly.
> >>>>>>
> >>>>>>   * Add a new quirk, HCI_QUIRK_RPM_PARENT_MANAGED, which designates the
> >>>>>>     parent device as the controller’s runtime PM device (rpm_dev).  When
> >>>>>>     used without HCI_QUIRK_RPM_ALLOWED, this also prevents the child
> >>>>>>     instance’s system-suspend callbacks from using
> >>>>>>     pm_runtime_force_suspend()/pm_runtime_force_resume(), since runtime
> >>>>>>     PM is managed entirely by the parent.
> >>>>>>
> >>>>>>   * Move DEFAULT_AUTOSUSPEND_DELAY_MS into the header so it can be shared
> >>>>>>     by parent-managed PM implementations.
> >>>>>>
> >>>>>> The new quirk allows platforms with multi-bus parent-managed PM
> >>>>>> infrastructure to correctly coordinate runtime PM across all I3C HCI
> >>>>>> instances.
> >>>>>>
> >>>>>> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> >>>>>> ---
> >>>>>>  drivers/i3c/master/mipi-i3c-hci/core.c | 25 ++++++++++++++++---------
> >>>>>>  drivers/i3c/master/mipi-i3c-hci/hci.h  |  6 ++++++
> >>>>>>  2 files changed, 22 insertions(+), 9 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> index ec4dbe64c35e..cb974b0f9e17 100644
> >>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> >>>>>> @@ -733,7 +733,7 @@ static int i3c_hci_reset_and_init(struct i3c_hci *hci)
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>>
> >>>>>> -static int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>> +int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>> @@ -746,8 +746,9 @@ static int i3c_hci_runtime_suspend(struct device *dev)
> >>>>>>
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_suspend);
> >>>>>>
> >>>>>> -static int i3c_hci_runtime_resume(struct device *dev)
> >>>>>> +int i3c_hci_runtime_resume(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>> @@ -768,6 +769,7 @@ static int i3c_hci_runtime_resume(struct device *dev)
> >>>>>>
> >>>>>>  	return 0;
> >>>>>>  }
> >>>>>> +EXPORT_SYMBOL_GPL(i3c_hci_runtime_resume);
> >>>>>>
> >>>>>>  static int i3c_hci_suspend(struct device *dev)
> >>>>>>  {
> >>>>>> @@ -784,12 +786,14 @@ static int i3c_hci_resume_common(struct device *dev, bool rstdaa)
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>>  	int ret;
> >>>>>>
> >>>>>> -	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>>>> -		return 0;
> >>>>>> +	if (!(hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED)) {
> >>>>>> +		if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> >>>>>> +			return 0;
> >>>>>>
> >>>>>> -	ret = pm_runtime_force_resume(dev);
> >>>>>> -	if (ret)
> >>>>>> -		return ret;
> >>>>>> +		ret = pm_runtime_force_resume(dev);
> >>>>>> +		if (ret)
> >>>>>> +			return ret;
> >>>>>> +	}
> >>>>>>
> >>>>>>  	ret = i3c_master_do_daa_ext(&hci->master, rstdaa);
> >>>>>>  	if (ret)
> >>>>>> @@ -812,8 +816,6 @@ static int i3c_hci_restore(struct device *dev)
> >>>>>>  	return i3c_hci_resume_common(dev, true);
> >>>>>>  }
> >>>>>>
> >>>>>> -#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>>>> -
> >>>>>>  static void i3c_hci_rpm_enable(struct device *dev)
> >>>>>>  {
> >>>>>>  	struct i3c_hci *hci = dev_get_drvdata(dev);
> >>>>>> @@ -962,6 +964,11 @@ static int i3c_hci_probe(struct platform_device *pdev)
> >>>>>>  	if (hci->quirks & HCI_QUIRK_RPM_IBI_ALLOWED)
> >>>>>>  		hci->master.rpm_ibi_allowed = true;
> >>>>>>
> >>>>>> +	if (hci->quirks & HCI_QUIRK_RPM_PARENT_MANAGED) {
> >>>>>> +		hci->master.rpm_dev = pdev->dev.parent;
> >>>>>> +		hci->master.rpm_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 819328a85b84..d0e7ad58ac15 100644
> >>>>>> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>>>> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> >>>>>> @@ -147,6 +147,7 @@ struct i3c_hci_dev_data {
> >>>>>>  #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 */
> >>>>>> +#define HCI_QUIRK_RPM_PARENT_MANAGED	BIT(7)  /* Runtime PM managed by parent device */
> >>>>>>
> >>>>>>  /* global functions */
> >>>>>>  void mipi_i3c_hci_resume(struct i3c_hci *hci);
> >>>>>> @@ -156,4 +157,9 @@ void amd_set_od_pp_timing(struct i3c_hci *hci);
> >>>>>>  void amd_set_resp_buf_thld(struct i3c_hci *hci);
> >>>>>>  void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
> >>>>>>
> >>>>>> +#define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
> >>>>>> +
> >>>>>> +int i3c_hci_runtime_suspend(struct device *dev);
> >>>>>> +int i3c_hci_runtime_resume(struct device *dev);
> >>>>>> +
> >>>>>>  #endif
> >>>>>> --
> >>>>>> 2.51.0
> >>>>>>
> >>>>
> >>
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

+ Rafael

Rafael, this is not at all urgent, but when you have time
please have a look at this patch set.  There is also some
more explanation below.  Is it acceptable?  Is there a
better way?

On 02/02/2026 18:25, Frank Li wrote:
> 
> Does your device Hierarchy look like
> 
>            PCI device
>                |
>        -----------------
>       HCI1            HCI2
>        |               |
>      I3C M1          I3C M2

Yes and no.  There is only 1 real device : the PCI device.
It implements the MIPI I3C HCI standard which allows multiple
I3C bus controllers in one device (in our case 2 controllers).

The PCI driver mipi-i3c-hci-pci creates 2 platform devices,
one for each controller.  The platform driver is mipi-i3c-hci:

 Driver                        Device                     Bus

 mipi-i3c-hci-pci            0000:00:11.1                 PCI
                            /            \
 mipi-i3c-hci      intel-lpss-i3c.0  intel-lpss-i3c.1     Platform

LPSS I3C also supports wake-up from in-band interrupt (IBI) via
PCI PME.  The PME only works when the PCI device is in a low power
state (D3hot in our case).  Also the PME is effectively shared by
the 2 controllers i.e. an IBI signal (the controller's SDA line
pulled low) for either controller will cause the PME.

That means there are only 2 valid configurations:

	1: Both controllers enabled to receive IBIs
		PCI device	D0
		Controller 1	Enabled
		Controller 2	Enabled

	2: Both controllers disabled to enable PME wakeup
		PCI device	D3hot
		Controller 1	Disabled
		Controller 2	Disabled

However, represented as platform devices, the 2 controllers
runtime suspend and resume independently from each other.
Whereas they effectively need to runtime suspend (or resume)
at the same time.

The proposed solution is for the PCI driver mipi-i3c-hci-pci
to take over managing runtime PM for both controllers, calling
into mipi-i3c-hci when it is safe to do so, to save/restore state
and disable/enable the controllers one after the other.

Current situation (I3C next branch):

	PCI device	Runtime PM enabled, dependent on child devices
			PCI subsystem controls PCI device power state

	Controller 1	Runtime PM enabled plus auto-suspend
			I3C subsystem runtime PM gets/puts the Platform device
			Runtime suspend: disable and save state
			Runtime resume: restore state and enable

	Controller 2	Runtime PM enabled plus auto-suspend
			I3C subsystem runtime PM gets/puts the Platform device
			Runtime suspend: disable and save state
			Runtime resume: restore state and enable

Proposed (this patch set):

	PCI device	Runtime PM enabled plus auto-suspend
			I3C subsystem runtime PM gets/puts the PCI device
			For each controller:
				Call into mipi-i3c-hci (when it is safe)
					Runtime suspend: disable and save state
					Runtime resume: restore state and enable

	Controller 1	Runtime PM disabled

	Controller 2	Runtime PM disabled

> 
> 
> You want HCI1 and HCI2 suspened only when both HCI1 and HCI2 can enter RM
> time suspend status?
> 
> Device Link can link two devices, but not sure if it can handle cyclic
> case, HCI1 and HCI2 depend each other.
> 
> Or you create common power domain for HCI1 and HCI2, in power domain to
> handle suspend.
> 
> It'd better ask run time pm owner to provide better suggestion.

Ok

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Frank Li]

On Tue, Feb 03, 2026 at 02:54:44PM +0200, Adrian Hunter wrote:
> + Rafael
>
> Rafael, this is not at all urgent, but when you have time
> please have a look at this patch set.  There is also some
> more explanation below.  Is it acceptable?  Is there a
> better way?
>
> On 02/02/2026 18:25, Frank Li wrote:
> >
> > Does your device Hierarchy look like
> >
> >            PCI device
> >                |
> >        -----------------
> >       HCI1            HCI2
> >        |               |
> >      I3C M1          I3C M2
>
> Yes and no.  There is only 1 real device : the PCI device.
> It implements the MIPI I3C HCI standard which allows multiple
> I3C bus controllers in one device (in our case 2 controllers).
>
> The PCI driver mipi-i3c-hci-pci creates 2 platform devices,
> one for each controller.  The platform driver is mipi-i3c-hci:
>
>  Driver                        Device                     Bus
>
>  mipi-i3c-hci-pci            0000:00:11.1                 PCI
>                             /            \
>  mipi-i3c-hci      intel-lpss-i3c.0  intel-lpss-i3c.1     Platform
>
> LPSS I3C also supports wake-up from in-band interrupt (IBI) via
> PCI PME.  The PME only works when the PCI device is in a low power
> state (D3hot in our case).  Also the PME is effectively shared by
> the 2 controllers i.e. an IBI signal (the controller's SDA line
> pulled low) for either controller will cause the PME.
>
> That means there are only 2 valid configurations:
>
> 	1: Both controllers enabled to receive IBIs
> 		PCI device	D0
> 		Controller 1	Enabled
> 		Controller 2	Enabled
>
> 	2: Both controllers disabled to enable PME wakeup
> 		PCI device	D3hot
> 		Controller 1	Disabled
> 		Controller 2	Disabled
>
> However, represented as platform devices, the 2 controllers
> runtime suspend and resume independently from each other.
> Whereas they effectively need to runtime suspend (or resume)
> at the same time.
>
> The proposed solution is for the PCI driver mipi-i3c-hci-pci
> to take over managing runtime PM for both controllers, calling
> into mipi-i3c-hci when it is safe to do so, to save/restore state
> and disable/enable the controllers one after the other.
>
> Current situation (I3C next branch):
>
> 	PCI device	Runtime PM enabled, dependent on child devices
> 			PCI subsystem controls PCI device power state
>
> 	Controller 1	Runtime PM enabled plus auto-suspend
> 			I3C subsystem runtime PM gets/puts the Platform device
> 			Runtime suspend: disable and save state
> 			Runtime resume: restore state and enable
>
> 	Controller 2	Runtime PM enabled plus auto-suspend
> 			I3C subsystem runtime PM gets/puts the Platform device
> 			Runtime suspend: disable and save state
> 			Runtime resume: restore state and enable
>
> Proposed (this patch set):
>
> 	PCI device	Runtime PM enabled plus auto-suspend
> 			I3C subsystem runtime PM gets/puts the PCI device
> 			For each controller:
> 				Call into mipi-i3c-hci (when it is safe)
> 					Runtime suspend: disable and save state
> 					Runtime resume: restore state and enable
>
> 	Controller 1	Runtime PM disabled
>
> 	Controller 2	Runtime PM disabled

Controller 1/2 is child device of PCI device.

So first patch "i3c: master: Allow controller drivers to select runtime PM device"
is not necessary.

You can enable controller 1 and 2 Runtime PM with dummy operation.

When controller 1 run time suspend, parent PCI device will reduce ref counter
when controller 2 run time suspend, parent PCI device will reduce ref counter

Only runtime pm reference counter of PCI device is 0, PCI device's run time
suspend will be called, you can do actual disable and save work.

Frank

>
> >
> >
> > You want HCI1 and HCI2 suspened only when both HCI1 and HCI2 can enter RM
> > time suspend status?
> >
> > Device Link can link two devices, but not sure if it can handle cyclic
> > case, HCI1 and HCI2 depend each other.
> >
> > Or you create common power domain for HCI1 and HCI2, in power domain to
> > handle suspend.
> >
> > It'd better ask run time pm owner to provide better suggestion.
>
> Ok
>

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Wysocki, Rafael J]

On 2/3/2026 4:59 PM, Frank Li wrote:
> On Tue, Feb 03, 2026 at 02:54:44PM +0200, Adrian Hunter wrote:
>> + Rafael
>>
>> Rafael, this is not at all urgent, but when you have time
>> please have a look at this patch set.  There is also some
>> more explanation below.  Is it acceptable?  Is there a
>> better way?
>>
>> On 02/02/2026 18:25, Frank Li wrote:
>>> Does your device Hierarchy look like
>>>
>>>             PCI device
>>>                 |
>>>         -----------------
>>>        HCI1            HCI2
>>>         |               |
>>>       I3C M1          I3C M2
>> Yes and no.  There is only 1 real device : the PCI device.
>> It implements the MIPI I3C HCI standard which allows multiple
>> I3C bus controllers in one device (in our case 2 controllers).
>>
>> The PCI driver mipi-i3c-hci-pci creates 2 platform devices,
>> one for each controller.  The platform driver is mipi-i3c-hci:
>>
>>   Driver                        Device                     Bus
>>
>>   mipi-i3c-hci-pci            0000:00:11.1                 PCI
>>                              /            \
>>   mipi-i3c-hci      intel-lpss-i3c.0  intel-lpss-i3c.1     Platform
>>
>> LPSS I3C also supports wake-up from in-band interrupt (IBI) via
>> PCI PME.  The PME only works when the PCI device is in a low power
>> state (D3hot in our case).  Also the PME is effectively shared by
>> the 2 controllers i.e. an IBI signal (the controller's SDA line
>> pulled low) for either controller will cause the PME.
>>
>> That means there are only 2 valid configurations:
>>
>> 	1: Both controllers enabled to receive IBIs
>> 		PCI device	D0
>> 		Controller 1	Enabled
>> 		Controller 2	Enabled
>>
>> 	2: Both controllers disabled to enable PME wakeup
>> 		PCI device	D3hot
>> 		Controller 1	Disabled
>> 		Controller 2	Disabled
>>
>> However, represented as platform devices, the 2 controllers
>> runtime suspend and resume independently from each other.
>> Whereas they effectively need to runtime suspend (or resume)
>> at the same time.
>>
>> The proposed solution is for the PCI driver mipi-i3c-hci-pci
>> to take over managing runtime PM for both controllers, calling
>> into mipi-i3c-hci when it is safe to do so, to save/restore state
>> and disable/enable the controllers one after the other.
>>
>> Current situation (I3C next branch):
>>
>> 	PCI device	Runtime PM enabled, dependent on child devices
>> 			PCI subsystem controls PCI device power state
>>
>> 	Controller 1	Runtime PM enabled plus auto-suspend
>> 			I3C subsystem runtime PM gets/puts the Platform device
>> 			Runtime suspend: disable and save state
>> 			Runtime resume: restore state and enable
>>
>> 	Controller 2	Runtime PM enabled plus auto-suspend
>> 			I3C subsystem runtime PM gets/puts the Platform device
>> 			Runtime suspend: disable and save state
>> 			Runtime resume: restore state and enable
>>
>> Proposed (this patch set):
>>
>> 	PCI device	Runtime PM enabled plus auto-suspend
>> 			I3C subsystem runtime PM gets/puts the PCI device
>> 			For each controller:
>> 				Call into mipi-i3c-hci (when it is safe)
>> 					Runtime suspend: disable and save state
>> 					Runtime resume: restore state and enable
>>
>> 	Controller 1	Runtime PM disabled
>>
>> 	Controller 2	Runtime PM disabled
> Controller 1/2 is child device of PCI device.
>
> So first patch "i3c: master: Allow controller drivers to select runtime PM device"
> is not necessary.
>
> You can enable controller 1 and 2 Runtime PM with dummy operation.
>
> When controller 1 run time suspend, parent PCI device will reduce ref counter
> when controller 2 run time suspend, parent PCI device will reduce ref counter
>
> Only runtime pm reference counter of PCI device is 0, PCI device's run time
> suspend will be called, you can do actual disable and save work.

This sounds to me like it should work.

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Adrian Hunter]

On 03/02/2026 18:22, Wysocki, Rafael J wrote:
> 
> On 2/3/2026 4:59 PM, Frank Li wrote:
>> On Tue, Feb 03, 2026 at 02:54:44PM +0200, Adrian Hunter wrote:
>>> + Rafael
>>>
>>> Rafael, this is not at all urgent, but when you have time
>>> please have a look at this patch set.  There is also some
>>> more explanation below.  Is it acceptable?  Is there a
>>> better way?
>>>
>>> On 02/02/2026 18:25, Frank Li wrote:
>>>> Does your device Hierarchy look like
>>>>
>>>>             PCI device
>>>>                 |
>>>>         -----------------
>>>>        HCI1            HCI2
>>>>         |               |
>>>>       I3C M1          I3C M2
>>> Yes and no.  There is only 1 real device : the PCI device.
>>> It implements the MIPI I3C HCI standard which allows multiple
>>> I3C bus controllers in one device (in our case 2 controllers).
>>>
>>> The PCI driver mipi-i3c-hci-pci creates 2 platform devices,
>>> one for each controller.  The platform driver is mipi-i3c-hci:
>>>
>>>   Driver                        Device                     Bus
>>>
>>>   mipi-i3c-hci-pci            0000:00:11.1                 PCI
>>>                              /            \
>>>   mipi-i3c-hci      intel-lpss-i3c.0  intel-lpss-i3c.1     Platform
>>>
>>> LPSS I3C also supports wake-up from in-band interrupt (IBI) via
>>> PCI PME.  The PME only works when the PCI device is in a low power
>>> state (D3hot in our case).  Also the PME is effectively shared by
>>> the 2 controllers i.e. an IBI signal (the controller's SDA line
>>> pulled low) for either controller will cause the PME.
>>>
>>> That means there are only 2 valid configurations:
>>>
>>>     1: Both controllers enabled to receive IBIs
>>>         PCI device    D0
>>>         Controller 1    Enabled
>>>         Controller 2    Enabled
>>>
>>>     2: Both controllers disabled to enable PME wakeup
>>>         PCI device    D3hot
>>>         Controller 1    Disabled
>>>         Controller 2    Disabled
>>>
>>> However, represented as platform devices, the 2 controllers
>>> runtime suspend and resume independently from each other.
>>> Whereas they effectively need to runtime suspend (or resume)
>>> at the same time.
>>>
>>> The proposed solution is for the PCI driver mipi-i3c-hci-pci
>>> to take over managing runtime PM for both controllers, calling
>>> into mipi-i3c-hci when it is safe to do so, to save/restore state
>>> and disable/enable the controllers one after the other.
>>>
>>> Current situation (I3C next branch):
>>>
>>>     PCI device    Runtime PM enabled, dependent on child devices
>>>             PCI subsystem controls PCI device power state
>>>
>>>     Controller 1    Runtime PM enabled plus auto-suspend
>>>             I3C subsystem runtime PM gets/puts the Platform device
>>>             Runtime suspend: disable and save state
>>>             Runtime resume: restore state and enable
>>>
>>>     Controller 2    Runtime PM enabled plus auto-suspend
>>>             I3C subsystem runtime PM gets/puts the Platform device
>>>             Runtime suspend: disable and save state
>>>             Runtime resume: restore state and enable
>>>
>>> Proposed (this patch set):
>>>
>>>     PCI device    Runtime PM enabled plus auto-suspend
>>>             I3C subsystem runtime PM gets/puts the PCI device
>>>             For each controller:
>>>                 Call into mipi-i3c-hci (when it is safe)
>>>                     Runtime suspend: disable and save state
>>>                     Runtime resume: restore state and enable
>>>
>>>     Controller 1    Runtime PM disabled
>>>
>>>     Controller 2    Runtime PM disabled
>> Controller 1/2 is child device of PCI device.
>>
>> So first patch "i3c: master: Allow controller drivers to select runtime PM device"
>> is not necessary.
>>
>> You can enable controller 1 and 2 Runtime PM with dummy operation.
>>
>> When controller 1 run time suspend, parent PCI device will reduce ref counter
>> when controller 2 run time suspend, parent PCI device will reduce ref counter
>>
>> Only runtime pm reference counter of PCI device is 0, PCI device's run time
>> suspend will be called, you can do actual disable and save work.
> 
> This sounds to me like it should work.
So, like this, then?

	PCI device	Runtime PM enabled
			For each controller:
				Call into mipi-i3c-hci (when it is safe)
					Runtime suspend: disable and save state
					Runtime resume: restore state and enable

	Controller 1	Runtime PM enabled plus auto-suspend
			I3C subsystem runtime PM gets/puts the Platform device
			Runtime suspend: does nothing
			Runtime resume: does nothing

	Controller 2	Runtime PM enabled plus auto-suspend
			I3C subsystem runtime PM gets/puts the Platform device
			Runtime suspend: does nothing
			Runtime resume: does nothing

Re: [PATCH 5/7] i3c: mipi-i3c-hci: Allow parent to manage runtime PM

[Rafael J. Wysocki]

On Tue, Feb 3, 2026 at 5:57 PM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> On 03/02/2026 18:22, Wysocki, Rafael J wrote:
> >
> > On 2/3/2026 4:59 PM, Frank Li wrote:
> >> On Tue, Feb 03, 2026 at 02:54:44PM +0200, Adrian Hunter wrote:
> >>> + Rafael
> >>>
> >>> Rafael, this is not at all urgent, but when you have time
> >>> please have a look at this patch set.  There is also some
> >>> more explanation below.  Is it acceptable?  Is there a
> >>> better way?
> >>>
> >>> On 02/02/2026 18:25, Frank Li wrote:
> >>>> Does your device Hierarchy look like
> >>>>
> >>>>             PCI device
> >>>>                 |
> >>>>         -----------------
> >>>>        HCI1            HCI2
> >>>>         |               |
> >>>>       I3C M1          I3C M2
> >>> Yes and no.  There is only 1 real device : the PCI device.
> >>> It implements the MIPI I3C HCI standard which allows multiple
> >>> I3C bus controllers in one device (in our case 2 controllers).
> >>>
> >>> The PCI driver mipi-i3c-hci-pci creates 2 platform devices,
> >>> one for each controller.  The platform driver is mipi-i3c-hci:
> >>>
> >>>   Driver                        Device                     Bus
> >>>
> >>>   mipi-i3c-hci-pci            0000:00:11.1                 PCI
> >>>                              /            \
> >>>   mipi-i3c-hci      intel-lpss-i3c.0  intel-lpss-i3c.1     Platform
> >>>
> >>> LPSS I3C also supports wake-up from in-band interrupt (IBI) via
> >>> PCI PME.  The PME only works when the PCI device is in a low power
> >>> state (D3hot in our case).  Also the PME is effectively shared by
> >>> the 2 controllers i.e. an IBI signal (the controller's SDA line
> >>> pulled low) for either controller will cause the PME.
> >>>
> >>> That means there are only 2 valid configurations:
> >>>
> >>>     1: Both controllers enabled to receive IBIs
> >>>         PCI device    D0
> >>>         Controller 1    Enabled
> >>>         Controller 2    Enabled
> >>>
> >>>     2: Both controllers disabled to enable PME wakeup
> >>>         PCI device    D3hot
> >>>         Controller 1    Disabled
> >>>         Controller 2    Disabled
> >>>
> >>> However, represented as platform devices, the 2 controllers
> >>> runtime suspend and resume independently from each other.
> >>> Whereas they effectively need to runtime suspend (or resume)
> >>> at the same time.
> >>>
> >>> The proposed solution is for the PCI driver mipi-i3c-hci-pci
> >>> to take over managing runtime PM for both controllers, calling
> >>> into mipi-i3c-hci when it is safe to do so, to save/restore state
> >>> and disable/enable the controllers one after the other.
> >>>
> >>> Current situation (I3C next branch):
> >>>
> >>>     PCI device    Runtime PM enabled, dependent on child devices
> >>>             PCI subsystem controls PCI device power state
> >>>
> >>>     Controller 1    Runtime PM enabled plus auto-suspend
> >>>             I3C subsystem runtime PM gets/puts the Platform device
> >>>             Runtime suspend: disable and save state
> >>>             Runtime resume: restore state and enable
> >>>
> >>>     Controller 2    Runtime PM enabled plus auto-suspend
> >>>             I3C subsystem runtime PM gets/puts the Platform device
> >>>             Runtime suspend: disable and save state
> >>>             Runtime resume: restore state and enable
> >>>
> >>> Proposed (this patch set):
> >>>
> >>>     PCI device    Runtime PM enabled plus auto-suspend
> >>>             I3C subsystem runtime PM gets/puts the PCI device
> >>>             For each controller:
> >>>                 Call into mipi-i3c-hci (when it is safe)
> >>>                     Runtime suspend: disable and save state
> >>>                     Runtime resume: restore state and enable
> >>>
> >>>     Controller 1    Runtime PM disabled
> >>>
> >>>     Controller 2    Runtime PM disabled
> >> Controller 1/2 is child device of PCI device.
> >>
> >> So first patch "i3c: master: Allow controller drivers to select runtime PM device"
> >> is not necessary.
> >>
> >> You can enable controller 1 and 2 Runtime PM with dummy operation.
> >>
> >> When controller 1 run time suspend, parent PCI device will reduce ref counter
> >> when controller 2 run time suspend, parent PCI device will reduce ref counter
> >>
> >> Only runtime pm reference counter of PCI device is 0, PCI device's run time
> >> suspend will be called, you can do actual disable and save work.
> >
> > This sounds to me like it should work.
> So, like this, then?
>
>         PCI device      Runtime PM enabled
>                         For each controller:
>                                 Call into mipi-i3c-hci (when it is safe)
>                                         Runtime suspend: disable and save state
>                                         Runtime resume: restore state and enable
>
>         Controller 1    Runtime PM enabled plus auto-suspend
>                         I3C subsystem runtime PM gets/puts the Platform device
>                         Runtime suspend: does nothing
>                         Runtime resume: does nothing
>
>         Controller 2    Runtime PM enabled plus auto-suspend
>                         I3C subsystem runtime PM gets/puts the Platform device
>                         Runtime suspend: does nothing
>                         Runtime resume: does nothing

I would think so.