[PATCH 2/3] i3c: mipi-i3c-hci: Add optional System Suspend support

[David Nyström]

On Fri, 16 Jan 2026, Adrian Hunter wrote:

> Add system suspend callbacks.  Implement them by forcing runtime PM.
> Consequently bail out if Runtime PM is not allowed.
>
> On resume from System Suspend (suspend to RAM), rerun Dynamic Address
> Assignment to restore addresses for devices that may have lost power.
>
> On resume from System Hibernation (suspend to disk), use the new
> i3c_master_restore_daa() helper which additionally handles the case where
> devices are assigned different dynamic addresses after a hibernation boot.

Why do you make this distinction ?
RSTDAA+DAA during boot is motivated by that uboot might have assigned 
addresses.
Why would we need to behave differently in suspend and suspend-to-disk?
Its fair to assume that I3C devices might have been powered off in suspend 
too, right ?

> Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
> ---
> drivers/i3c/master/mipi-i3c-hci/core.c | 53 ++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> index 02c5a133e329..b972d8bc81e6 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> @@ -769,6 +769,53 @@ static int i3c_hci_runtime_resume(struct device *dev)
> 	return 0;
> }
>
> +static int i3c_hci_suspend(struct device *dev)
> +{
> +	struct i3c_hci *hci = dev_get_drvdata(dev);
> +
> +	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> +		return 0;
> +
> +	return pm_runtime_force_suspend(dev);
> +}
> +
> +static int i3c_hci_resume_common(struct device *dev, bool restore)
> +{
> +	struct i3c_hci *hci = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (!(hci->quirks & HCI_QUIRK_RPM_ALLOWED))
> +		return 0;
> +
> +	ret = pm_runtime_force_resume(dev);
> +	if (ret)
> +		return ret;
> +
> +	if (restore)
> +		ret = i3c_master_restore_daa(&hci->master);
> +	else
> +		ret = i3c_master_do_daa(&hci->master);
> +
> +	if (ret)
> +		dev_err(dev, "Dynamic Address Assignment failed on resume, error %d\n", ret);
> +
> +	/*
> +	 * I3C devices may have retained their dynamic address anyway. Do not
> +	 * fail the resume because of DAA error.
> +	 */
> +	return 0;
> +}
> +
> +static int i3c_hci_resume(struct device *dev)
> +{
> +	return i3c_hci_resume_common(dev, false);
> +}
> +
> +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)
> @@ -945,6 +992,12 @@ static const struct platform_device_id i3c_hci_driver_ids[] = {
> MODULE_DEVICE_TABLE(platform, i3c_hci_driver_ids);
>
> static const struct dev_pm_ops i3c_hci_pm_ops = {
> +	.suspend  = pm_sleep_ptr(i3c_hci_suspend),
> +	.resume   = pm_sleep_ptr(i3c_hci_resume),
> +	.freeze   = pm_sleep_ptr(i3c_hci_suspend),
> +	.thaw     = pm_sleep_ptr(i3c_hci_resume),
> +	.poweroff = pm_sleep_ptr(i3c_hci_suspend),
> +	.restore  = pm_sleep_ptr(i3c_hci_restore),
> 	RUNTIME_PM_OPS(i3c_hci_runtime_suspend, i3c_hci_runtime_resume, NULL)
> };
>
> -- 
> 2.51.0
>
>
> -- 
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