wt., 21 sty 2020 o 14:41 Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> napisał(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@xxxxxxxxxxxxxxx>
> ---
> 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
>
