We have discovered that some power lines were always on even if the devices
on that power line was not used.
This happens because we failed to probe a device on the i2c bus, and the
ACPI Power Resource were never turned off.
This patch tries to fix this issue.
To: Wolfram Sang <[email protected]>
To: Sakari Ailus <[email protected]>
To: Tomasz Figa <[email protected]>
To: "Rafael J. Wysocki" <[email protected]>
Cc: Hidenori Kobayashi <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Ricardo Ribalda <[email protected]>
---
Changes in v3:
- Introduce full_power variable to make more clear what we are doing.
- Link to v2: https://lore.kernel.org/r/[email protected]
Changes in v2:
- Cover also device remove
- Link to v1: https://lore.kernel.org/r/[email protected]
---
Ricardo Ribalda (1):
i2c: Restore initial power state when we are done.
drivers/i2c/i2c-core-base.c | 11 +++++++----
include/linux/i2c.h | 3 +++
2 files changed, 10 insertions(+), 4 deletions(-)
---
base-commit: f141df371335645ce29a87d9683a3f79fba7fd67
change-id: 20221109-i2c-waive-ae97fea1f1b5
Best regards,
--
Ricardo Ribalda <[email protected]>
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.
Fixes: b18c1ad685d9 ("i2c: Allow an ACPI driver to manage the device's power state during probe")
Signed-off-by: Ricardo Ribalda <[email protected]>
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index b4edf10e8fd0..75da19bcfb2b 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 full_power;
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));
+ full_power = !i2c_acpi_waive_d0_probe(dev);
+ status = dev_pm_domain_attach(&client->dev, full_power);
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->turn_off_on_remove = full_power;
+
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, full_power);
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->turn_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..6b2dacb0bae1 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.
+ * @turn_off_on_remove: Record if we have turned on the device before probing
+ * so we can restore the initial state after remove/probe error.
*
* 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 +357,7 @@ struct i2c_client {
i2c_slave_cb_t slave_cb; /* callback for slave mode */
#endif
void *devres_group_id; /* ID of probe devres group */
+ bool turn_off_on_remove; /* power state when done */
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
--
b4 0.11.0-dev-d93f8