linux-kernel - Re: [PATCH V2 3/6] i3c: mipi-i3c-hci: Add quirk to allow IBI while runtime suspended

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Message-ID: <aYNrxOHJg7rw-kpM@lizhi-Precision-Tower-5810>
Date: Wed, 4 Feb 2026 10:54:44 -0500
From: Frank Li <Frank.li@....com>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: alexandre.belloni@...tlin.com, rafael@...nel.org,
	linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCH V2 3/6] i3c: mipi-i3c-hci: Add quirk to allow IBI while
 runtime suspended

On Wed, Feb 04, 2026 at 01:15:08PM +0200, Adrian Hunter wrote:
> Some I3C controllers can be automatically runtime-resumed in order to
> handle in-band interrupts (IBIs), meaning that runtime suspend does not
> need to be blocked when IBIs are enabled.
>
> For example, a PCI-attached controller in a low-power state may generate
> a Power Management Event (PME) when the SDA line is pulled low to signal
> the START condition of an IBI. The PCI subsystem will then runtime-resume
> the device, allowing the IBI to be received without requiring the
> controller to remain active.
>
> Introduce a new quirk, HCI_QUIRK_RPM_IBI_ALLOWED, so that drivers can
> opt-in to this capability via driver data.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
Reviewed-by: Frank Li <Frank.Li@....com>
>
>
> Changes in V2:
>
> 	None
>
>
>  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
>