[v4,1/6] i2c: Allow driver to manage the device's power state during probe
diff mbox series

Message ID 20200121134157.20396-2-sakari.ailus@linux.intel.com
State Changes Requested
Headers show
Series
  • Support running driver's probe for a device powered off
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Commit Message

Sakari Ailus Jan. 21, 2020, 1:41 p.m. UTC
Enable drivers to tell ACPI that there's no need to power on a device for
probe. Drivers should still perform this by themselves if there's a need
to. In some cases powering on the device during probe is undesirable, and
this change enables a driver to choose what fits best for it.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/i2c/i2c-core-base.c | 15 ++++++++++++---
 include/linux/i2c.h         |  3 +++
 2 files changed, 15 insertions(+), 3 deletions(-)

Comments

Bartosz Golaszewski Jan. 29, 2020, 1:54 p.m. UTC | #1
wt., 21 sty 2020 o 14:41 Sakari Ailus <sakari.ailus@linux.intel.com> napisaƂ(a):
>
> Enable drivers to tell ACPI that there's no need to power on a device for
> probe. Drivers should still perform this by themselves if there's a need
> to. In some cases powering on the device during probe is undesirable, and
> this change enables a driver to choose what fits best for it.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/i2c/i2c-core-base.c | 15 ++++++++++++---
>  include/linux/i2c.h         |  3 +++
>  2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 9f8dcd3f83850..7bf1699c9044d 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -303,6 +303,14 @@ static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
>         return irq > 0 ? irq : -ENXIO;
>  }
>
> +static bool probe_low_power(struct device *dev)
> +{
> +       struct i2c_driver *driver = to_i2c_driver(dev->driver);
> +
> +       return driver->probe_low_power &&
> +               device_property_present(dev, "probe-low-power");
> +}
> +
>  static int i2c_device_probe(struct device *dev)
>  {
>         struct i2c_client       *client = i2c_verify_client(dev);
> @@ -375,7 +383,8 @@ static int i2c_device_probe(struct device *dev)
>         if (status < 0)
>                 goto err_clear_wakeup_irq;
>
> -       status = dev_pm_domain_attach(&client->dev, true);
> +       status = dev_pm_domain_attach(&client->dev,
> +                                     !probe_low_power(&client->dev));
>         if (status)
>                 goto err_clear_wakeup_irq;
>
> @@ -397,7 +406,7 @@ static int i2c_device_probe(struct device *dev)
>         return 0;
>
>  err_detach_pm_domain:
> -       dev_pm_domain_detach(&client->dev, true);
> +       dev_pm_domain_detach(&client->dev, !probe_low_power(&client->dev));
>  err_clear_wakeup_irq:
>         dev_pm_clear_wake_irq(&client->dev);
>         device_init_wakeup(&client->dev, false);
> @@ -419,7 +428,7 @@ static int i2c_device_remove(struct device *dev)
>                 status = driver->remove(client);
>         }
>
> -       dev_pm_domain_detach(&client->dev, true);
> +       dev_pm_domain_detach(&client->dev, !probe_low_power(&client->dev));
>
>         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 582ef05ec07ed..6d0d6af393c56 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -229,6 +229,8 @@ enum i2c_alert_protocol {
>   * @address_list: The I2C addresses to probe (for detect)
>   * @clients: List of detected clients we created (for i2c-core use only)
>   * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
> + * @probe_low_power: Let the driver manage the device's power state
> + *                  during probe and remove.
>   *
>   * The driver.owner field should be set to the module owner of this driver.
>   * The driver.name field should be set to the name of this driver.
> @@ -289,6 +291,7 @@ struct i2c_driver {
>         struct list_head clients;
>
>         bool disable_i2c_core_irq_mapping;
> +       bool probe_low_power;

I don't see any users of disable_i2c_core_irq_mapping in current
mainline. Maybe instead of adding another 1-byte boolean for every
such property, let's just use the fact that this struct will have at
least an alignment of 32-bits anyway and merge the two into an int
field called 'flags' so that we can extend it in the future if needed?

The name 'probe_low_power' is misleading to me too. It makes me think
it's the default state for some reason. It should be something like
'allow_low_power_probe'.

Bartosz

>  };
>  #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
>
> --
> 2.20.1
>

Patch
diff mbox series

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 9f8dcd3f83850..7bf1699c9044d 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -303,6 +303,14 @@  static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 	return irq > 0 ? irq : -ENXIO;
 }
 
+static bool probe_low_power(struct device *dev)
+{
+	struct i2c_driver *driver = to_i2c_driver(dev->driver);
+
+	return driver->probe_low_power &&
+		device_property_present(dev, "probe-low-power");
+}
+
 static int i2c_device_probe(struct device *dev)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
@@ -375,7 +383,8 @@  static int i2c_device_probe(struct device *dev)
 	if (status < 0)
 		goto err_clear_wakeup_irq;
 
-	status = dev_pm_domain_attach(&client->dev, true);
+	status = dev_pm_domain_attach(&client->dev,
+				      !probe_low_power(&client->dev));
 	if (status)
 		goto err_clear_wakeup_irq;
 
@@ -397,7 +406,7 @@  static int i2c_device_probe(struct device *dev)
 	return 0;
 
 err_detach_pm_domain:
-	dev_pm_domain_detach(&client->dev, true);
+	dev_pm_domain_detach(&client->dev, !probe_low_power(&client->dev));
 err_clear_wakeup_irq:
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -419,7 +428,7 @@  static int i2c_device_remove(struct device *dev)
 		status = driver->remove(client);
 	}
 
-	dev_pm_domain_detach(&client->dev, true);
+	dev_pm_domain_detach(&client->dev, !probe_low_power(&client->dev));
 
 	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 582ef05ec07ed..6d0d6af393c56 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -229,6 +229,8 @@  enum i2c_alert_protocol {
  * @address_list: The I2C addresses to probe (for detect)
  * @clients: List of detected clients we created (for i2c-core use only)
  * @disable_i2c_core_irq_mapping: Tell the i2c-core to not do irq-mapping
+ * @probe_low_power: Let the driver manage the device's power state
+ *		     during probe and remove.
  *
  * The driver.owner field should be set to the module owner of this driver.
  * The driver.name field should be set to the name of this driver.
@@ -289,6 +291,7 @@  struct i2c_driver {
 	struct list_head clients;
 
 	bool disable_i2c_core_irq_mapping;
+	bool probe_low_power;
 };
 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)