| Message ID | 1377007416-13851-2-git-send-email-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Tuesday, August 20, 2013 05:03:35 PM Mika Westerberg wrote: > From: Aaron Lu <aaron.lu@intel.com> > > This patch adds runtime PM support for the I2C bus in a similar way that > has been done for PCI bus already. This means that the I2C bus core > prepares runtime PM for a client device just before a driver is about to be > bound to it. Devices that are not bound to any driver are not prepared for > runtime PM. > > In order to take advantage of this runtime PM support, the client device > driver needs drop the device runtime PM reference count by calling > pm_runtime_put() in its ->probe() callback and possibly implement rest of > the runtime PM callbacks. > > However, this does not yet make runtime PM happen for the device, it has to > be explicitly allowed from userspace per each I2C client device. The > reason for this is that things like HID over I2C might not work as smoothly > when runtime PM is active. So we leave it to the user to balance between > performance and power efficiency. > > User can allow runtime PM for the client device by running: > > # echo auto > /sys/bus/i2c/devices/<device>/power/control > > and it can be forbidden again by: > > # echo on > /sys/bus/i2c/devices/<device>/power/control > > Status of the device can be monitored by reading files under the device > power directory. > > If the driver doesn't support runtime PM (like most of the existing I2C > client drivers), the device in question is regarded as being runtime PM > active and powered on. > > The patch adds also runtime PM support for the adapter device because it is > needed to be able to runtime power manage the I2C controller device. The > adapter device is handled along with the I2C controller device (it uses > pm_runtime_no_callbacks()). > > Signed-off-by: Aaron Lu <aaron.lu@intel.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/i2c/i2c-core.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 47 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 3d44292..8fad5ac 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -254,11 +254,34 @@ static int i2c_device_probe(struct device *dev) > client->flags & I2C_CLIENT_WAKE); > dev_dbg(dev, "probe\n"); > > + /* Make sure the adapter is active */ > + pm_runtime_get_sync(&client->adapter->dev); > + > + /* > + * Enable runtime PM for the client device. If the client wants to > + * participate on runtime PM it should call pm_runtime_put() in its > + * probe() callback. > + * > + * User still needs to allow the PM runtime before it can actually > + * happen. > + */ > + pm_runtime_forbid(&client->dev); > + pm_runtime_get_noresume(&client->dev); > + pm_runtime_set_active(&client->dev); > + pm_runtime_enable(&client->dev); > + > status = driver->probe(client, i2c_match_id(driver->id_table, client)); > if (status) { > client->driver = NULL; > i2c_set_clientdata(client, NULL); > + > + pm_runtime_disable(&client->dev); > + pm_runtime_set_suspended(&client->dev); > + pm_runtime_put_noidle(&client->dev); > } > + > + pm_runtime_put(&client->adapter->dev); > + > return status; > } > > @@ -271,6 +294,8 @@ static int i2c_device_remove(struct device *dev) > if (!client || !dev->driver) > return 0; > > + pm_runtime_get_sync(&client->adapter->dev); > + > driver = to_i2c_driver(dev->driver); > if (driver->remove) { > dev_dbg(dev, "remove\n"); > @@ -283,6 +308,13 @@ static int i2c_device_remove(struct device *dev) > client->driver = NULL; > i2c_set_clientdata(client, NULL); > } > + > + /* Undo the runtime PM done in i2c_probe() */ > + pm_runtime_disable(&client->dev); > + pm_runtime_set_suspended(&client->dev); > + pm_runtime_put_noidle(&client->dev); > + > + pm_runtime_put(&client->adapter->dev); > return status; > } > > @@ -294,8 +326,11 @@ static void i2c_device_shutdown(struct device *dev) > if (!client || !dev->driver) > return; > driver = to_i2c_driver(dev->driver); > - if (driver->shutdown) > + if (driver->shutdown) { > + pm_runtime_get_sync(&client->adapter->dev); > driver->shutdown(client); > + pm_runtime_put(&client->adapter->dev); > + } > } > > #ifdef CONFIG_PM_SLEEP > @@ -1263,6 +1298,15 @@ exit_recovery: > bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); > mutex_unlock(&core_lock); > > + /* > + * Make sure the adapter runtime PM follows the parent device (the > + * host controller) so that we can suspend it once there aren't any > + * active clients anymore. > + */ > + pm_runtime_set_active(&adap->dev); > + pm_runtime_no_callbacks(&adap->dev); > + pm_runtime_enable(&adap->dev); > + > return 0; > > out_list: > @@ -1427,6 +1471,8 @@ void i2c_del_adapter(struct i2c_adapter *adap) > return; > } > > + pm_runtime_disable(&adap->dev); > + > /* Tell drivers about this removal */ > mutex_lock(&core_lock); > bus_for_each_drv(&i2c_bus_type, NULL, adap, >
On Tue, Aug 20, 2013 at 05:03:35PM +0300, Mika Westerberg wrote: > From: Aaron Lu <aaron.lu@intel.com> > > This patch adds runtime PM support for the I2C bus in a similar way that > has been done for PCI bus already. This means that the I2C bus core > prepares runtime PM for a client device just before a driver is about to be > bound to it. Devices that are not bound to any driver are not prepared for > runtime PM. > > In order to take advantage of this runtime PM support, the client device > driver needs drop the device runtime PM reference count by calling > pm_runtime_put() in its ->probe() callback and possibly implement rest of > the runtime PM callbacks. > > However, this does not yet make runtime PM happen for the device, it has to > be explicitly allowed from userspace per each I2C client device. The > reason for this is that things like HID over I2C might not work as smoothly > when runtime PM is active. So we leave it to the user to balance between > performance and power efficiency. > > User can allow runtime PM for the client device by running: > > # echo auto > /sys/bus/i2c/devices/<device>/power/control > > and it can be forbidden again by: > > # echo on > /sys/bus/i2c/devices/<device>/power/control > > Status of the device can be monitored by reading files under the device > power directory. > > If the driver doesn't support runtime PM (like most of the existing I2C > client drivers), the device in question is regarded as being runtime PM > active and powered on. > > The patch adds also runtime PM support for the adapter device because it is > needed to be able to runtime power manage the I2C controller device. The > adapter device is handled along with the I2C controller device (it uses > pm_runtime_no_callbacks()). > > Signed-off-by: Aaron Lu <aaron.lu@intel.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> CCing ALKML. Would appreciate comments/tags from the runtime-PM users of the ARM world. > --- > drivers/i2c/i2c-core.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 47 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 3d44292..8fad5ac 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -254,11 +254,34 @@ static int i2c_device_probe(struct device *dev) > client->flags & I2C_CLIENT_WAKE); > dev_dbg(dev, "probe\n"); > > + /* Make sure the adapter is active */ > + pm_runtime_get_sync(&client->adapter->dev); > + > + /* > + * Enable runtime PM for the client device. If the client wants to > + * participate on runtime PM it should call pm_runtime_put() in its > + * probe() callback. > + * > + * User still needs to allow the PM runtime before it can actually > + * happen. > + */ > + pm_runtime_forbid(&client->dev); > + pm_runtime_get_noresume(&client->dev); > + pm_runtime_set_active(&client->dev); > + pm_runtime_enable(&client->dev); > + > status = driver->probe(client, i2c_match_id(driver->id_table, client)); > if (status) { > client->driver = NULL; > i2c_set_clientdata(client, NULL); > + > + pm_runtime_disable(&client->dev); > + pm_runtime_set_suspended(&client->dev); > + pm_runtime_put_noidle(&client->dev); > } > + > + pm_runtime_put(&client->adapter->dev); > + > return status; > } > > @@ -271,6 +294,8 @@ static int i2c_device_remove(struct device *dev) > if (!client || !dev->driver) > return 0; > > + pm_runtime_get_sync(&client->adapter->dev); > + > driver = to_i2c_driver(dev->driver); > if (driver->remove) { > dev_dbg(dev, "remove\n"); > @@ -283,6 +308,13 @@ static int i2c_device_remove(struct device *dev) > client->driver = NULL; > i2c_set_clientdata(client, NULL); > } > + > + /* Undo the runtime PM done in i2c_probe() */ > + pm_runtime_disable(&client->dev); > + pm_runtime_set_suspended(&client->dev); > + pm_runtime_put_noidle(&client->dev); > + > + pm_runtime_put(&client->adapter->dev); > return status; > } > > @@ -294,8 +326,11 @@ static void i2c_device_shutdown(struct device *dev) > if (!client || !dev->driver) > return; > driver = to_i2c_driver(dev->driver); > - if (driver->shutdown) > + if (driver->shutdown) { > + pm_runtime_get_sync(&client->adapter->dev); > driver->shutdown(client); > + pm_runtime_put(&client->adapter->dev); > + } > } > > #ifdef CONFIG_PM_SLEEP > @@ -1263,6 +1298,15 @@ exit_recovery: > bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); > mutex_unlock(&core_lock); > > + /* > + * Make sure the adapter runtime PM follows the parent device (the > + * host controller) so that we can suspend it once there aren't any > + * active clients anymore. > + */ > + pm_runtime_set_active(&adap->dev); > + pm_runtime_no_callbacks(&adap->dev); > + pm_runtime_enable(&adap->dev); > + > return 0; > > out_list: > @@ -1427,6 +1471,8 @@ void i2c_del_adapter(struct i2c_adapter *adap) > return; > } > > + pm_runtime_disable(&adap->dev); > + > /* Tell drivers about this removal */ > mutex_lock(&core_lock); > bus_for_each_drv(&i2c_bus_type, NULL, adap, > -- > 1.8.4.rc2 >
On Wed, Aug 28, 2013 at 11:38:58AM +0200, Wolfram Sang wrote: > On Tue, Aug 20, 2013 at 05:03:35PM +0300, Mika Westerberg wrote: > > From: Aaron Lu <aaron.lu@intel.com> > > > > This patch adds runtime PM support for the I2C bus in a similar way that > > has been done for PCI bus already. This means that the I2C bus core > > prepares runtime PM for a client device just before a driver is about to be > > bound to it. Devices that are not bound to any driver are not prepared for > > runtime PM. > > > > In order to take advantage of this runtime PM support, the client device > > driver needs drop the device runtime PM reference count by calling > > pm_runtime_put() in its ->probe() callback and possibly implement rest of > > the runtime PM callbacks. > > > > However, this does not yet make runtime PM happen for the device, it has to > > be explicitly allowed from userspace per each I2C client device. The > > reason for this is that things like HID over I2C might not work as smoothly > > when runtime PM is active. So we leave it to the user to balance between > > performance and power efficiency. > > > > User can allow runtime PM for the client device by running: > > > > # echo auto > /sys/bus/i2c/devices/<device>/power/control > > > > and it can be forbidden again by: > > > > # echo on > /sys/bus/i2c/devices/<device>/power/control > > > > Status of the device can be monitored by reading files under the device > > power directory. > > > > If the driver doesn't support runtime PM (like most of the existing I2C > > client drivers), the device in question is regarded as being runtime PM > > active and powered on. > > > > The patch adds also runtime PM support for the adapter device because it is > > needed to be able to runtime power manage the I2C controller device. The > > adapter device is handled along with the I2C controller device (it uses > > pm_runtime_no_callbacks()). > > > > Signed-off-by: Aaron Lu <aaron.lu@intel.com> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > CCing ALKML. Would appreciate comments/tags from the runtime-PM users of > the ARM world. Any comments on this? I can resend the whole series with ALKML included if that helps. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 3d44292..8fad5ac 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -254,11 +254,34 @@ static int i2c_device_probe(struct device *dev) client->flags & I2C_CLIENT_WAKE); dev_dbg(dev, "probe\n"); + /* Make sure the adapter is active */ + pm_runtime_get_sync(&client->adapter->dev); + + /* + * Enable runtime PM for the client device. If the client wants to + * participate on runtime PM it should call pm_runtime_put() in its + * probe() callback. + * + * User still needs to allow the PM runtime before it can actually + * happen. + */ + pm_runtime_forbid(&client->dev); + pm_runtime_get_noresume(&client->dev); + pm_runtime_set_active(&client->dev); + pm_runtime_enable(&client->dev); + status = driver->probe(client, i2c_match_id(driver->id_table, client)); if (status) { client->driver = NULL; i2c_set_clientdata(client, NULL); + + pm_runtime_disable(&client->dev); + pm_runtime_set_suspended(&client->dev); + pm_runtime_put_noidle(&client->dev); } + + pm_runtime_put(&client->adapter->dev); + return status; } @@ -271,6 +294,8 @@ static int i2c_device_remove(struct device *dev) if (!client || !dev->driver) return 0; + pm_runtime_get_sync(&client->adapter->dev); + driver = to_i2c_driver(dev->driver); if (driver->remove) { dev_dbg(dev, "remove\n"); @@ -283,6 +308,13 @@ static int i2c_device_remove(struct device *dev) client->driver = NULL; i2c_set_clientdata(client, NULL); } + + /* Undo the runtime PM done in i2c_probe() */ + pm_runtime_disable(&client->dev); + pm_runtime_set_suspended(&client->dev); + pm_runtime_put_noidle(&client->dev); + + pm_runtime_put(&client->adapter->dev); return status; } @@ -294,8 +326,11 @@ static void i2c_device_shutdown(struct device *dev) if (!client || !dev->driver) return; driver = to_i2c_driver(dev->driver); - if (driver->shutdown) + if (driver->shutdown) { + pm_runtime_get_sync(&client->adapter->dev); driver->shutdown(client); + pm_runtime_put(&client->adapter->dev); + } } #ifdef CONFIG_PM_SLEEP @@ -1263,6 +1298,15 @@ exit_recovery: bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); mutex_unlock(&core_lock); + /* + * Make sure the adapter runtime PM follows the parent device (the + * host controller) so that we can suspend it once there aren't any + * active clients anymore. + */ + pm_runtime_set_active(&adap->dev); + pm_runtime_no_callbacks(&adap->dev); + pm_runtime_enable(&adap->dev); + return 0; out_list: @@ -1427,6 +1471,8 @@ void i2c_del_adapter(struct i2c_adapter *adap) return; } + pm_runtime_disable(&adap->dev); + /* Tell drivers about this removal */ mutex_lock(&core_lock); bus_for_each_drv(&i2c_bus_type, NULL, adap,