[PATCH 15/17] i3c: master: Introduce optional Runtime PM support
Frank Li
Frank.li at nxp.com
Fri Dec 19 12:11:36 PST 2025
On Fri, Dec 19, 2025 at 12:08:22PM -0500, Frank Li wrote:
> On Fri, Dec 19, 2025 at 04:45:32PM +0200, Adrian Hunter wrote:
> > Master drivers currently manage Runtime PM individually, but all require
> > runtime resume for bus operations. This can be centralized in common code.
> >
> > Add optional Runtime PM support to ensure the parent device is runtime
> > resumed before bus operations and auto-suspended afterward.
> >
> > Notably, do not call ->bus_cleanup() if runtime resume fails. Master
> > drivers that opt-in to core runtime PM support must take that into account.
> >
> > Also provide an option to allow IBIs and hot-joins while runtime suspended.
> >
> > Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
> > ---
> > drivers/i3c/device.c | 46 +++++++++++++++++--
> > drivers/i3c/internals.h | 4 ++
> > drivers/i3c/master.c | 93 +++++++++++++++++++++++++++++++++++---
> > include/linux/i3c/master.h | 4 ++
> > 4 files changed, 138 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
> > index 8a156f5ad692..101eaa77de68 100644
> > --- a/drivers/i3c/device.c
> > +++ b/drivers/i3c/device.c
> > @@ -46,10 +46,16 @@ int i3c_device_do_xfers(struct i3c_device *dev, struct i3c_xfer *xfers,
> > return -EINVAL;
> > }
> >
> > + ret = i3c_bus_rpm_get(dev->bus);
>
> Is it i3c_bus_rpm_get(dev)? dev->bus is parent of dev. in case i3c
> periphal need enable clock or other run time pm enable call back?
After second think, it should be fine use dev->bus here.
Frank
>
> > + if (ret)
> > + return ret;
> > +
> > i3c_bus_normaluse_lock(dev->bus);
> > ret = i3c_dev_do_xfers_locked(dev->desc, xfers, nxfers, mode);
> > i3c_bus_normaluse_unlock(dev->bus);
> >
> > + i3c_bus_rpm_put(dev->bus);
> > +
> > return ret;
> > }
> ...
> >
> > +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;
>
> I think rpm_allowed is not necessary. If don't allow rpm, i3c bus driver
> should disable runtime_pm.
>
> I remember pm_runtime_resume_and_get() do nothing if runtime_pm disabled
> (need double check).
>
> Frank
>
> > +
> > + if (ret < 0) {
> > + dev_err(master->dev.parent, "runtime resume failed, error %d\n", ret);
> > + return ret;
> > + }
> > + return 0;
> > +}
> > +
> > +static void i3c_master_rpm_put(struct i3c_master_controller *master)
> > +{
> > + if (master->rpm_allowed)
> > + pm_runtime_put_autosuspend(master->dev.parent);
> > +}
> > +
> > +int i3c_bus_rpm_get(struct i3c_bus *bus)
> > +{
> > + return i3c_master_rpm_get(i3c_bus_to_i3c_master(bus));
> > +}
> > +
> > +void i3c_bus_rpm_put(struct i3c_bus *bus)
> > +{
> > + i3c_master_rpm_put(i3c_bus_to_i3c_master(bus));
> > +}
> > +
> > +bool i3c_bus_rpm_ibi_allowed(struct i3c_bus *bus)
> > +{
> > + return i3c_bus_to_i3c_master(bus)->rpm_ibi_allowed;
> > +}
> > +
> > static const struct device_type i3c_device_type;
> >
> > static struct i3c_bus *dev_to_i3cbus(struct device *dev)
> > @@ -611,6 +643,12 @@ static int i3c_set_hotjoin(struct i3c_master_controller *master, bool enable)
> > if (!master->ops->enable_hotjoin || !master->ops->disable_hotjoin)
> > return -EINVAL;
> >
> > + if (enable || master->rpm_ibi_allowed) {
> > + ret = i3c_master_rpm_get(master);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > i3c_bus_normaluse_lock(&master->bus);
> >
> > if (enable)
> > @@ -623,6 +661,9 @@ static int i3c_set_hotjoin(struct i3c_master_controller *master, bool enable)
> >
> > i3c_bus_normaluse_unlock(&master->bus);
> >
> > + if ((enable && ret) || (!enable && !ret) || master->rpm_ibi_allowed)
> > + i3c_master_rpm_put(master);
> > +
> > return ret;
> > }
> >
> > @@ -1712,18 +1753,23 @@ int i3c_master_do_daa(struct i3c_master_controller *master)
> > {
> > int ret;
> >
> > + ret = i3c_master_rpm_get(master);
> > + if (ret)
> > + return ret;
> > +
> > i3c_bus_maintenance_lock(&master->bus);
> > ret = master->ops->do_daa(master);
> > i3c_bus_maintenance_unlock(&master->bus);
> >
> > if (ret)
> > - return ret;
> > + goto out;
> >
> > i3c_bus_normaluse_lock(&master->bus);
> > i3c_master_register_new_i3c_devs(master);
> > i3c_bus_normaluse_unlock(&master->bus);
> > -
> > - return 0;
> > +out:
> > + i3c_master_rpm_put(master);
> > + return ret;
> > }
> > EXPORT_SYMBOL_GPL(i3c_master_do_daa);
> >
> > @@ -2065,8 +2111,17 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
> >
> > static void i3c_master_bus_cleanup(struct i3c_master_controller *master)
> > {
> > - if (master->ops->bus_cleanup)
> > - master->ops->bus_cleanup(master);
> > + if (master->ops->bus_cleanup) {
> > + int ret = i3c_master_rpm_get(master);
> > +
> > + if (ret) {
> > + dev_err(&master->dev,
> > + "runtime resume error: master bus_cleanup() not done\n");
> > + } else {
> > + master->ops->bus_cleanup(master);
> > + i3c_master_rpm_put(master);
> > + }
> > + }
> >
> > i3c_master_detach_free_devs(master);
> > }
> > @@ -2421,6 +2476,10 @@ static int i3c_master_i2c_adapter_xfer(struct i2c_adapter *adap,
> > return -EOPNOTSUPP;
> > }
> >
> > + ret = i3c_master_rpm_get(master);
> > + if (ret)
> > + return ret;
> > +
> > i3c_bus_normaluse_lock(&master->bus);
> > dev = i3c_master_find_i2c_dev_by_addr(master, addr);
> > if (!dev)
> > @@ -2429,6 +2488,8 @@ static int i3c_master_i2c_adapter_xfer(struct i2c_adapter *adap,
> > ret = master->ops->i2c_xfers(dev, xfers, nxfers);
> > i3c_bus_normaluse_unlock(&master->bus);
> >
> > + i3c_master_rpm_put(master);
> > +
> > return ret ? ret : nxfers;
> > }
> >
> > @@ -2531,6 +2592,10 @@ static int i3c_i2c_notifier_call(struct notifier_block *nb, unsigned long action
> >
> > master = i2c_adapter_to_i3c_master(adap);
> >
> > + ret = i3c_master_rpm_get(master);
> > + if (ret)
> > + return ret;
> > +
> > i3c_bus_maintenance_lock(&master->bus);
> > switch (action) {
> > case BUS_NOTIFY_ADD_DEVICE:
> > @@ -2544,6 +2609,8 @@ static int i3c_i2c_notifier_call(struct notifier_block *nb, unsigned long action
> > }
> > i3c_bus_maintenance_unlock(&master->bus);
> >
> > + i3c_master_rpm_put(master);
> > +
> > return ret;
> > }
> >
> > @@ -2881,6 +2948,10 @@ int i3c_master_register(struct i3c_master_controller *master,
> > INIT_LIST_HEAD(&master->boardinfo.i2c);
> > INIT_LIST_HEAD(&master->boardinfo.i3c);
> >
> > + ret = i3c_master_rpm_get(master);
> > + if (ret)
> > + return ret;
> > +
> > device_initialize(&master->dev);
> > dev_set_name(&master->dev, "i3c-%d", i3cbus->id);
> >
> > @@ -2960,6 +3031,8 @@ int i3c_master_register(struct i3c_master_controller *master,
> > i3c_master_register_new_i3c_devs(master);
> > i3c_bus_normaluse_unlock(&master->bus);
> >
> > + i3c_master_rpm_put(master);
> > +
> > return 0;
> >
> > err_del_dev:
> > @@ -2969,6 +3042,7 @@ int i3c_master_register(struct i3c_master_controller *master,
> > i3c_master_bus_cleanup(master);
> >
> > err_put_dev:
> > + i3c_master_rpm_put(master);
> > put_device(&master->dev);
> >
> > return ret;
> > @@ -3114,8 +3188,15 @@ void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev)
> > return;
> >
> > if (dev->ibi->enabled) {
> > + int ret;
> > +
> > dev_err(&master->dev, "Freeing IBI that is still enabled\n");
> > - if (i3c_dev_disable_ibi_locked(dev))
> > + ret = i3c_master_rpm_get(master);
> > + if (!ret) {
> > + ret = i3c_dev_disable_ibi_locked(dev);
> > + i3c_master_rpm_put(master);
> > + }
> > + if (ret)
> > dev_err(&master->dev, "Failed to disable IBI before freeing\n");
> > }
> >
> > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > index 6225ad28f210..c1ec597f655c 100644
> > --- a/include/linux/i3c/master.h
> > +++ b/include/linux/i3c/master.h
> > @@ -504,6 +504,8 @@ struct i3c_master_controller_ops {
> > * @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
> > + * @rpm_allowed: true if Runtime PM allowed
> > + * @rpm_ibi_allowed: true if IBI and Hot-Join allowed while runtime suspended
> > * @boardinfo.i3c: list of I3C boardinfo objects
> > * @boardinfo.i2c: list of I2C boardinfo objects
> > * @boardinfo: board-level information attached to devices connected on the bus
> > @@ -527,6 +529,8 @@ struct i3c_master_controller {
> > unsigned int secondary : 1;
> > unsigned int init_done : 1;
> > unsigned int hotjoin: 1;
> > + unsigned int rpm_allowed: 1;
> > + unsigned int rpm_ibi_allowed: 1;
> > struct {
> > struct list_head i3c;
> > struct list_head i2c;
> > --
> > 2.51.0
> >
> >
> > --
> > linux-i3c mailing list
> > linux-i3c at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-i3c
>
> --
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