From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: linux-i2c <linux-i2c@vger.kernel.org>,
Wolfram Sang <wsa@the-dreams.de>,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-acpi@vger.kernel.org, Bingbu Cao <bingbu.cao@intel.com>,
linux-media <linux-media@vger.kernel.org>,
Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>,
Hyungwoo Yang <hyungwoo.yang@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
LKML <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
rajmohan.mani@intel.com, Tomasz Figa <tfiga@chromium.org>
Subject: Re: [PATCH v4 1/6] i2c: Allow driver to manage the device's power state during probe
Date: Wed, 29 Jan 2020 14:54:20 +0100 [thread overview]
Message-ID: <CAMpxmJX8gF3TujMMeEgERAFM4YbpgnNjOmuV+U7uWCndqsyGeA@mail.gmail.com> (raw)
In-Reply-To: <20200121134157.20396-2-sakari.ailus@linux.intel.com>
wt., 21 sty 2020 o 14:41 Sakari Ailus <sakari.ailus@linux.intel.com> 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@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
>
next prev parent reply other threads:[~2020-01-29 13:54 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 13:41 [PATCH v4 0/6] Support running driver's probe for a device powered off Sakari Ailus
2020-01-21 13:41 ` [PATCH v4 1/6] i2c: Allow driver to manage the device's power state during probe Sakari Ailus
2020-01-29 13:54 ` Bartosz Golaszewski [this message]
2020-03-23 21:36 ` Sakari Ailus
2020-01-21 13:41 ` [PATCH v4 2/6] ACPI: Add a convenience function to tell a device is in low power state Sakari Ailus
2020-01-21 16:07 ` Rafael J. Wysocki
2020-01-21 13:41 ` [PATCH v4 3/6] ov5670: Support probe whilst the device is in a " Sakari Ailus
2020-01-21 13:41 ` [PATCH v4 4/6] media: i2c: imx319: Support probe while the device is off Sakari Ailus
2020-01-21 13:41 ` [PATCH v4 5/6] at24: Support probing while off Sakari Ailus
2020-01-29 13:36 ` Bartosz Golaszewski
2020-03-11 8:55 ` Sakari Ailus
2020-03-12 13:10 ` Bartosz Golaszewski
2020-03-23 21:31 ` Sakari Ailus
2020-03-25 13:48 ` Bartosz Golaszewski
2020-08-10 8:25 ` Sakari Ailus
2020-08-10 18:12 ` Bartosz Golaszewski
2020-08-11 8:00 ` Sakari Ailus
2020-08-12 18:07 ` Bartosz Golaszewski
2020-08-12 19:25 ` Wolfram Sang
2020-08-12 19:33 ` Bartosz Golaszewski
2020-01-21 13:41 ` [PATCH v4 6/6] Documentation: ACPI: Document probe-low-power _DSD property Sakari Ailus
2020-01-21 16:09 ` Rafael J. Wysocki
2020-01-21 16:18 ` Sakari Ailus
2020-01-21 16:56 ` Rafael J. Wysocki
2020-01-21 16:58 ` Sakari Ailus
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