diff mbox series

[v5,1/1] i2c: Restore initial power state when we are done.

Message ID 20221109-i2c-waive-v5-1-2839667f8f6a@chromium.org
State New
Headers
Series i2c: Restore power status of device if probe fail or device is removed |

Commit Message

Ricardo Ribalda Nov. 10, 2022, 4:20 p.m. UTC 
  A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
power off a device that it has not powered on previously.

For devices operating in "full_power" mode, the first call to
`i2c_acpi_waive_d0_probe` will return 0, which means that the device
will be turned on with `dev_pm_domain_attach`.

If probe fails or the device is removed the second call to
`i2c_acpi_waive_d0_probe` will return 1, which means that the device
will not be turned off. This is, it will be left in a different power
state. Lets fix it.

Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

Comments

Hidenori Kobayashi Nov. 11, 2022, 12:20 a.m. UTC | #1 
Hi Ricardo,

On Thu, Nov 10, 2022 at 05:20:39PM +0100, Ricardo Ribalda wrote:
> A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> power off a device that it has not powered on previously.
> 
> For devices operating in "full_power" mode, the first call to
> `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> will be turned on with `dev_pm_domain_attach`.
> 
> If probe fails or the device is removed the second call to
> `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> will not be turned off. This is, it will be left in a different power
> state. Lets fix it.
> 
> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: stable@vger.kernel.org
> Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

It's much easier to read now. Thanks!

Reviewed-by: Hidenori Kobayashi <hidenorik@chromium.org>

> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index b4edf10e8fd0..6f4974c76404 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -467,6 +467,7 @@ static int i2c_device_probe(struct device *dev)
>  {
>  	struct i2c_client	*client = i2c_verify_client(dev);
>  	struct i2c_driver	*driver;
> +	bool do_power_on;
>  	int status;
>  
>  	if (!client)
> @@ -545,8 +546,8 @@ static int i2c_device_probe(struct device *dev)
>  	if (status < 0)
>  		goto err_clear_wakeup_irq;
>  
> -	status = dev_pm_domain_attach(&client->dev,
> -				      !i2c_acpi_waive_d0_probe(dev));
> +	do_power_on = !i2c_acpi_waive_d0_probe(dev);
> +	status = dev_pm_domain_attach(&client->dev, do_power_on);
>  	if (status)
>  		goto err_clear_wakeup_irq;
>  
> @@ -580,12 +581,14 @@ static int i2c_device_probe(struct device *dev)
>  	if (status)
>  		goto err_release_driver_resources;
>  
> +	client->power_off_on_remove = do_power_on;
> +
>  	return 0;
>  
>  err_release_driver_resources:
>  	devres_release_group(&client->dev, client->devres_group_id);
>  err_detach_pm_domain:
> -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> +	dev_pm_domain_detach(&client->dev, do_power_on);
>  err_clear_wakeup_irq:
>  	dev_pm_clear_wake_irq(&client->dev);
>  	device_init_wakeup(&client->dev, false);
> @@ -610,7 +613,7 @@ static void i2c_device_remove(struct device *dev)
>  
>  	devres_release_group(&client->dev, client->devres_group_id);
>  
> -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> +	dev_pm_domain_detach(&client->dev, client->power_off_on_remove);
>  
>  	dev_pm_clear_wake_irq(&client->dev);
>  	device_init_wakeup(&client->dev, false);
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index f7c49bbdb8a1..eba83bc5459e 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -326,6 +326,8 @@ struct i2c_driver {
>   *	calls it to pass on slave events to the slave driver.
>   * @devres_group_id: id of the devres group that will be created for resources
>   *	acquired when probing this device.
> + * @power_off_on_remove: Record if we have turned on the device before probing
> + *	so we can turn off the device at removal.
>   *
>   * An i2c_client identifies a single device (i.e. chip) connected to an
>   * i2c bus. The behaviour exposed to Linux is defined by the driver
> @@ -355,6 +357,8 @@ struct i2c_client {
>  	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
>  #endif
>  	void *devres_group_id;		/* ID of probe devres group	*/
> +	bool power_off_on_remove;	/* if device needs to be turned	*/
> +					/* off by framework at removal	*/
>  };
>  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
>  
> 
> -- 
> b4 0.11.0-dev-d93f8
>
Sergey Senozhatsky Nov. 11, 2022, 12:31 a.m. UTC | #2 
On (22/11/10 17:20), Ricardo Ribalda wrote:
> A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> power off a device that it has not powered on previously.
> 
> For devices operating in "full_power" mode, the first call to
> `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> will be turned on with `dev_pm_domain_attach`.
> 
> If probe fails or the device is removed the second call to
> `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> will not be turned off. This is, it will be left in a different power
> state. Lets fix it.
> 
> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: stable@vger.kernel.org
> Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Wolfram Sang Nov. 12, 2022, 8:24 p.m. UTC | #3 
On Thu, Nov 10, 2022 at 05:20:39PM +0100, Ricardo Ribalda wrote:
> A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> power off a device that it has not powered on previously.
> 
> For devices operating in "full_power" mode, the first call to
> `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> will be turned on with `dev_pm_domain_attach`.
> 
> If probe fails or the device is removed the second call to
> `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> will not be turned off. This is, it will be left in a different power
> state. Lets fix it.
> 
> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: stable@vger.kernel.org
> Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

Adding I2C ACPI maintainer to CC. Mika, could you please help
reviewing?

> 
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index b4edf10e8fd0..6f4974c76404 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -467,6 +467,7 @@ static int i2c_device_probe(struct device *dev)
>  {
>  	struct i2c_client	*client = i2c_verify_client(dev);
>  	struct i2c_driver	*driver;
> +	bool do_power_on;
>  	int status;
>  
>  	if (!client)
> @@ -545,8 +546,8 @@ static int i2c_device_probe(struct device *dev)
>  	if (status < 0)
>  		goto err_clear_wakeup_irq;
>  
> -	status = dev_pm_domain_attach(&client->dev,
> -				      !i2c_acpi_waive_d0_probe(dev));
> +	do_power_on = !i2c_acpi_waive_d0_probe(dev);
> +	status = dev_pm_domain_attach(&client->dev, do_power_on);
>  	if (status)
>  		goto err_clear_wakeup_irq;
>  
> @@ -580,12 +581,14 @@ static int i2c_device_probe(struct device *dev)
>  	if (status)
>  		goto err_release_driver_resources;
>  
> +	client->power_off_on_remove = do_power_on;
> +
>  	return 0;
>  
>  err_release_driver_resources:
>  	devres_release_group(&client->dev, client->devres_group_id);
>  err_detach_pm_domain:
> -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> +	dev_pm_domain_detach(&client->dev, do_power_on);
>  err_clear_wakeup_irq:
>  	dev_pm_clear_wake_irq(&client->dev);
>  	device_init_wakeup(&client->dev, false);
> @@ -610,7 +613,7 @@ static void i2c_device_remove(struct device *dev)
>  
>  	devres_release_group(&client->dev, client->devres_group_id);
>  
> -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> +	dev_pm_domain_detach(&client->dev, client->power_off_on_remove);
>  
>  	dev_pm_clear_wake_irq(&client->dev);
>  	device_init_wakeup(&client->dev, false);
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index f7c49bbdb8a1..eba83bc5459e 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -326,6 +326,8 @@ struct i2c_driver {
>   *	calls it to pass on slave events to the slave driver.
>   * @devres_group_id: id of the devres group that will be created for resources
>   *	acquired when probing this device.
> + * @power_off_on_remove: Record if we have turned on the device before probing
> + *	so we can turn off the device at removal.
>   *
>   * An i2c_client identifies a single device (i.e. chip) connected to an
>   * i2c bus. The behaviour exposed to Linux is defined by the driver
> @@ -355,6 +357,8 @@ struct i2c_client {
>  	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
>  #endif
>  	void *devres_group_id;		/* ID of probe devres group	*/
> +	bool power_off_on_remove;	/* if device needs to be turned	*/
> +					/* off by framework at removal	*/
>  };
>  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
>  
> 
> -- 
> b4 0.11.0-dev-d93f8
Mika Westerberg Nov. 14, 2022, 10:33 a.m. UTC | #4 
Hi,

On Sat, Nov 12, 2022 at 09:24:14PM +0100, Wolfram Sang wrote:
> On Thu, Nov 10, 2022 at 05:20:39PM +0100, Ricardo Ribalda wrote:
> > A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> > power off a device that it has not powered on previously.
> > 
> > For devices operating in "full_power" mode, the first call to
> > `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> > will be turned on with `dev_pm_domain_attach`.
> > 
> > If probe fails or the device is removed the second call to
> > `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> > will not be turned off. This is, it will be left in a different power
> > state. Lets fix it.
> > 
> > Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Cc: stable@vger.kernel.org
> > Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> 
> Adding I2C ACPI maintainer to CC. Mika, could you please help
> reviewing?

Sure.

> > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> > index b4edf10e8fd0..6f4974c76404 100644
> > --- a/drivers/i2c/i2c-core-base.c
> > +++ b/drivers/i2c/i2c-core-base.c
> > @@ -467,6 +467,7 @@ static int i2c_device_probe(struct device *dev)
> >  {
> >  	struct i2c_client	*client = i2c_verify_client(dev);
> >  	struct i2c_driver	*driver;
> > +	bool do_power_on;
> >  	int status;
> >  
> >  	if (!client)
> > @@ -545,8 +546,8 @@ static int i2c_device_probe(struct device *dev)
> >  	if (status < 0)
> >  		goto err_clear_wakeup_irq;
> >  
> > -	status = dev_pm_domain_attach(&client->dev,
> > -				      !i2c_acpi_waive_d0_probe(dev));
> > +	do_power_on = !i2c_acpi_waive_d0_probe(dev);
> > +	status = dev_pm_domain_attach(&client->dev, do_power_on);

I think this is fine as the driver says it is OK to see the device in
whatever power state (I assume this is what the
i2c_acpi_waive_d0_probe() is supposed to be doing but there is no
kernel-doc, though).

> >  	if (status)
> >  		goto err_clear_wakeup_irq;
> >  
> > @@ -580,12 +581,14 @@ static int i2c_device_probe(struct device *dev)
> >  	if (status)
> >  		goto err_release_driver_resources;
> >  
> > +	client->power_off_on_remove = do_power_on;
> > +
> >  	return 0;
> >  
> >  err_release_driver_resources:
> >  	devres_release_group(&client->dev, client->devres_group_id);
> >  err_detach_pm_domain:
> > -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > +	dev_pm_domain_detach(&client->dev, do_power_on);
> >  err_clear_wakeup_irq:
> >  	dev_pm_clear_wake_irq(&client->dev);
> >  	device_init_wakeup(&client->dev, false);
> > @@ -610,7 +613,7 @@ static void i2c_device_remove(struct device *dev)
> >  
> >  	devres_release_group(&client->dev, client->devres_group_id);
> >  
> > -	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > +	dev_pm_domain_detach(&client->dev, client->power_off_on_remove);

However, on the remove path I think we should not call
i2c_acpi_waive_d0_probe() at all as that has nothing to do with remove
(it is for whether the driver accepts any power state on probe AFAICT)
so this should stil be "true" here. Unless I'm missing something.

> >  
> >  	dev_pm_clear_wake_irq(&client->dev);
> >  	device_init_wakeup(&client->dev, false);
> > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> > index f7c49bbdb8a1..eba83bc5459e 100644
> > --- a/include/linux/i2c.h
> > +++ b/include/linux/i2c.h
> > @@ -326,6 +326,8 @@ struct i2c_driver {
> >   *	calls it to pass on slave events to the slave driver.
> >   * @devres_group_id: id of the devres group that will be created for resources
> >   *	acquired when probing this device.
> > + * @power_off_on_remove: Record if we have turned on the device before probing
> > + *	so we can turn off the device at removal.
> >   *
> >   * An i2c_client identifies a single device (i.e. chip) connected to an
> >   * i2c bus. The behaviour exposed to Linux is defined by the driver
> > @@ -355,6 +357,8 @@ struct i2c_client {
> >  	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
> >  #endif
> >  	void *devres_group_id;		/* ID of probe devres group	*/
> > +	bool power_off_on_remove;	/* if device needs to be turned	*/
> > +					/* off by framework at removal	*/
> >  };
> >  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
> >  
> > 
> > -- 
> > b4 0.11.0-dev-d93f8
Ricardo Ribalda Nov. 14, 2022, 10:51 a.m. UTC | #5 
Hi Mika

Thanks for your review!

On Mon, 14 Nov 2022 at 11:33, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
>
> Hi,
>
> On Sat, Nov 12, 2022 at 09:24:14PM +0100, Wolfram Sang wrote:
> > On Thu, Nov 10, 2022 at 05:20:39PM +0100, Ricardo Ribalda wrote:
> > > A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> > > power off a device that it has not powered on previously.
> > >
> > > For devices operating in "full_power" mode, the first call to
> > > `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> > > will be turned on with `dev_pm_domain_attach`.
> > >
> > > If probe fails or the device is removed the second call to
> > > `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> > > will not be turned off. This is, it will be left in a different power
> > > state. Lets fix it.
> > >
> > > Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > Cc: stable@vger.kernel.org
> > > Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> >
> > Adding I2C ACPI maintainer to CC. Mika, could you please help
> > reviewing?
>
> Sure.
>
> > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> > > index b4edf10e8fd0..6f4974c76404 100644
> > > --- a/drivers/i2c/i2c-core-base.c
> > > +++ b/drivers/i2c/i2c-core-base.c
> > > @@ -467,6 +467,7 @@ static int i2c_device_probe(struct device *dev)
> > >  {
> > >     struct i2c_client       *client = i2c_verify_client(dev);
> > >     struct i2c_driver       *driver;
> > > +   bool do_power_on;
> > >     int status;
> > >
> > >     if (!client)
> > > @@ -545,8 +546,8 @@ static int i2c_device_probe(struct device *dev)
> > >     if (status < 0)
> > >             goto err_clear_wakeup_irq;
> > >
> > > -   status = dev_pm_domain_attach(&client->dev,
> > > -                                 !i2c_acpi_waive_d0_probe(dev));
> > > +   do_power_on = !i2c_acpi_waive_d0_probe(dev);
> > > +   status = dev_pm_domain_attach(&client->dev, do_power_on);
>
> I think this is fine as the driver says it is OK to see the device in
> whatever power state (I assume this is what the
> i2c_acpi_waive_d0_probe() is supposed to be doing but there is no
> kernel-doc, though).
>
> > >     if (status)
> > >             goto err_clear_wakeup_irq;
> > >
> > > @@ -580,12 +581,14 @@ static int i2c_device_probe(struct device *dev)
> > >     if (status)
> > >             goto err_release_driver_resources;
> > >
> > > +   client->power_off_on_remove = do_power_on;
> > > +
> > >     return 0;
> > >
> > >  err_release_driver_resources:
> > >     devres_release_group(&client->dev, client->devres_group_id);
> > >  err_detach_pm_domain:
> > > -   dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > > +   dev_pm_domain_detach(&client->dev, do_power_on);
> > >  err_clear_wakeup_irq:
> > >     dev_pm_clear_wake_irq(&client->dev);
> > >     device_init_wakeup(&client->dev, false);
> > > @@ -610,7 +613,7 @@ static void i2c_device_remove(struct device *dev)
> > >
> > >     devres_release_group(&client->dev, client->devres_group_id);
> > >
> > > -   dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > > +   dev_pm_domain_detach(&client->dev, client->power_off_on_remove);
>
> However, on the remove path I think we should not call
> i2c_acpi_waive_d0_probe() at all as that has nothing to do with remove
> (it is for whether the driver accepts any power state on probe AFAICT)
> so this should stil be "true" here. Unless I'm missing something.

I guess the problem is that we would be undoing something (power-off),
that we did not do.


Sakari, can you think of a use-case where this can break something? If
not I can send a v6.

Regards!

>
> > >
> > >     dev_pm_clear_wake_irq(&client->dev);
> > >     device_init_wakeup(&client->dev, false);
> > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> > > index f7c49bbdb8a1..eba83bc5459e 100644
> > > --- a/include/linux/i2c.h
> > > +++ b/include/linux/i2c.h
> > > @@ -326,6 +326,8 @@ struct i2c_driver {
> > >   * calls it to pass on slave events to the slave driver.
> > >   * @devres_group_id: id of the devres group that will be created for resources
> > >   * acquired when probing this device.
> > > + * @power_off_on_remove: Record if we have turned on the device before probing
> > > + * so we can turn off the device at removal.
> > >   *
> > >   * An i2c_client identifies a single device (i.e. chip) connected to an
> > >   * i2c bus. The behaviour exposed to Linux is defined by the driver
> > > @@ -355,6 +357,8 @@ struct i2c_client {
> > >     i2c_slave_cb_t slave_cb;        /* callback for slave mode      */
> > >  #endif
> > >     void *devres_group_id;          /* ID of probe devres group     */
> > > +   bool power_off_on_remove;       /* if device needs to be turned */
> > > +                                   /* off by framework at removal  */
> > >  };
> > >  #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
> > >
> > >
> > > --
> > > b4 0.11.0-dev-d93f8
>
>
Sakari Ailus Nov. 14, 2022, 11:10 a.m. UTC | #6 
Hi Ricardo, Mika,

On Mon, Nov 14, 2022 at 11:51:24AM +0100, Ricardo Ribalda wrote:
> Hi Mika
> 
> Thanks for your review!
> 
> On Mon, 14 Nov 2022 at 11:33, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
> > Hi,
> >
> > On Sat, Nov 12, 2022 at 09:24:14PM +0100, Wolfram Sang wrote:
> > > On Thu, Nov 10, 2022 at 05:20:39PM +0100, Ricardo Ribalda wrote:
> > > > A driver that supports I2C_DRV_ACPI_WAIVE_D0_PROBE is not expected to
> > > > power off a device that it has not powered on previously.
> > > >
> > > > For devices operating in "full_power" mode, the first call to
> > > > `i2c_acpi_waive_d0_probe` will return 0, which means that the device
> > > > will be turned on with `dev_pm_domain_attach`.
> > > >
> > > > If probe fails or the device is removed the second call to
> > > > `i2c_acpi_waive_d0_probe` will return 1, which means that the device
> > > > will not be turned off. This is, it will be left in a different power
> > > > state. Lets fix it.
> > > >
> > > > Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > Cc: stable@vger.kernel.org
> > > > Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
> > > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > >
> > > Adding I2C ACPI maintainer to CC. Mika, could you please help
> > > reviewing?
> >
> > Sure.
> >
> > > > diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> > > > index b4edf10e8fd0..6f4974c76404 100644
> > > > --- a/drivers/i2c/i2c-core-base.c
> > > > +++ b/drivers/i2c/i2c-core-base.c
> > > > @@ -467,6 +467,7 @@ static int i2c_device_probe(struct device *dev)
> > > >  {
> > > >     struct i2c_client       *client = i2c_verify_client(dev);
> > > >     struct i2c_driver       *driver;
> > > > +   bool do_power_on;
> > > >     int status;
> > > >
> > > >     if (!client)
> > > > @@ -545,8 +546,8 @@ static int i2c_device_probe(struct device *dev)
> > > >     if (status < 0)
> > > >             goto err_clear_wakeup_irq;
> > > >
> > > > -   status = dev_pm_domain_attach(&client->dev,
> > > > -                                 !i2c_acpi_waive_d0_probe(dev));
> > > > +   do_power_on = !i2c_acpi_waive_d0_probe(dev);
> > > > +   status = dev_pm_domain_attach(&client->dev, do_power_on);
> >
> > I think this is fine as the driver says it is OK to see the device in
> > whatever power state (I assume this is what the
> > i2c_acpi_waive_d0_probe() is supposed to be doing but there is no
> > kernel-doc, though).
> >
> > > >     if (status)
> > > >             goto err_clear_wakeup_irq;
> > > >
> > > > @@ -580,12 +581,14 @@ static int i2c_device_probe(struct device *dev)
> > > >     if (status)
> > > >             goto err_release_driver_resources;
> > > >
> > > > +   client->power_off_on_remove = do_power_on;
> > > > +
> > > >     return 0;
> > > >
> > > >  err_release_driver_resources:
> > > >     devres_release_group(&client->dev, client->devres_group_id);
> > > >  err_detach_pm_domain:
> > > > -   dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > > > +   dev_pm_domain_detach(&client->dev, do_power_on);
> > > >  err_clear_wakeup_irq:
> > > >     dev_pm_clear_wake_irq(&client->dev);
> > > >     device_init_wakeup(&client->dev, false);
> > > > @@ -610,7 +613,7 @@ static void i2c_device_remove(struct device *dev)
> > > >
> > > >     devres_release_group(&client->dev, client->devres_group_id);
> > > >
> > > > -   dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
> > > > +   dev_pm_domain_detach(&client->dev, client->power_off_on_remove);
> >
> > However, on the remove path I think we should not call
> > i2c_acpi_waive_d0_probe() at all as that has nothing to do with remove
> > (it is for whether the driver accepts any power state on probe AFAICT)
> > so this should stil be "true" here. Unless I'm missing something.
> 
> I guess the problem is that we would be undoing something (power-off),
> that we did not do.
> 
> 
> Sakari, can you think of a use-case where this can break something? If
> not I can send a v6.

I don't think there's any harm from powering the device off here. The
driver should have done it but there could be bugs...

The genpd equivalent doesn't even use the argument but powers off the
domain in any case.
diff mbox series

Patch

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index b4edf10e8fd0..6f4974c76404 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -467,6 +467,7 @@  static int i2c_device_probe(struct device *dev)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
 	struct i2c_driver	*driver;
+	bool do_power_on;
 	int status;
 
 	if (!client)
@@ -545,8 +546,8 @@  static int i2c_device_probe(struct device *dev)
 	if (status < 0)
 		goto err_clear_wakeup_irq;
 
-	status = dev_pm_domain_attach(&client->dev,
-				      !i2c_acpi_waive_d0_probe(dev));
+	do_power_on = !i2c_acpi_waive_d0_probe(dev);
+	status = dev_pm_domain_attach(&client->dev, do_power_on);
 	if (status)
 		goto err_clear_wakeup_irq;
 
@@ -580,12 +581,14 @@  static int i2c_device_probe(struct device *dev)
 	if (status)
 		goto err_release_driver_resources;
 
+	client->power_off_on_remove = do_power_on;
+
 	return 0;
 
 err_release_driver_resources:
 	devres_release_group(&client->dev, client->devres_group_id);
 err_detach_pm_domain:
-	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
+	dev_pm_domain_detach(&client->dev, do_power_on);
 err_clear_wakeup_irq:
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -610,7 +613,7 @@  static void i2c_device_remove(struct device *dev)
 
 	devres_release_group(&client->dev, client->devres_group_id);
 
-	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
+	dev_pm_domain_detach(&client->dev, client->power_off_on_remove);
 
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index f7c49bbdb8a1..eba83bc5459e 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -326,6 +326,8 @@  struct i2c_driver {
  *	calls it to pass on slave events to the slave driver.
  * @devres_group_id: id of the devres group that will be created for resources
  *	acquired when probing this device.
+ * @power_off_on_remove: Record if we have turned on the device before probing
+ *	so we can turn off the device at removal.
  *
  * An i2c_client identifies a single device (i.e. chip) connected to an
  * i2c bus. The behaviour exposed to Linux is defined by the driver
@@ -355,6 +357,8 @@  struct i2c_client {
 	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
 #endif
 	void *devres_group_id;		/* ID of probe devres group	*/
+	bool power_off_on_remove;	/* if device needs to be turned	*/
+					/* off by framework at removal	*/
 };
 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)