i2c: Allow an ACPI driver to manage the device's power state during probe

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.

Add a field called "flags" into struct i2c_driver for driver flags, and a
flag I2C_DRV_ACPI_WAIVE_D0_PROBE to tell a driver supports probe in ACPI D
states other than 0.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Acked-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 546cc935e035a57dcb65c2896216a408f3a4a705..c025919cdaaeeba0e4f9a1ace6980a5f64a7f770 100644 (file)
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -526,6 +526,16 @@ struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 }
 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 
+bool i2c_acpi_waive_d0_probe(struct device *dev)
+{
+       struct i2c_driver *driver = to_i2c_driver(dev->driver);
+       struct acpi_device *adev = ACPI_COMPANION(dev);
+
+       return driver->flags & I2C_DRV_ACPI_WAIVE_D0_PROBE &&
+               adev && adev->power.state_for_enumeration >= adev->power.state;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_waive_d0_probe);
+
 #ifdef CONFIG_ACPI_I2C_OPREGION
 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
                u8 cmd, u8 *data, u8 data_len)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 54964fbe3f0336630d3b6a410f45fae11d483cff..f193f90585841eabdfc98e379604001d5890db01 100644 (file)
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -551,7 +551,8 @@ 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,
+                                     !i2c_acpi_waive_d0_probe(dev));
        if (status)
                goto err_clear_wakeup_irq;
 
@@ -590,7 +591,7 @@ static int i2c_device_probe(struct device *dev)
 err_release_driver_resources:
        devres_release_group(&client->dev, client->devres_group_id);
 err_detach_pm_domain:
-       dev_pm_domain_detach(&client->dev, true);
+       dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
 err_clear_wakeup_irq:
        dev_pm_clear_wake_irq(&client->dev);
        device_init_wakeup(&client->dev, false);
@@ -621,7 +622,7 @@ static void i2c_device_remove(struct device *dev)
 
        devres_release_group(&client->dev, client->devres_group_id);
 
-       dev_pm_domain_detach(&client->dev, true);
+       dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
        if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator)
                regulator_disable(adap->bus_regulator);
 

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 2ce3efbe9198acf0d952a1eb08367bb2c50880f1..16119ac1aa97ebdf6a2c59952eafca847bb6e324 100644 (file)
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -11,6 +11,7 @@
 #define _LINUX_I2C_H
 
 #include <linux/acpi.h>                /* for acpi_handle */
+#include <linux/bits.h>
 #include <linux/mod_devicetable.h>
 #include <linux/device.h>      /* for struct device */
 #include <linux/sched.h>       /* for completion */
@@ -222,6 +223,15 @@ enum i2c_alert_protocol {
        I2C_PROTOCOL_SMBUS_HOST_NOTIFY,
 };
 
+/**
+ * enum i2c_driver_flags - Flags for an I2C device driver
+ *
+ * @I2C_DRV_ACPI_WAIVE_D0_PROBE: Don't put the device in D0 state for probe
+ */
+enum i2c_driver_flags {
+       I2C_DRV_ACPI_WAIVE_D0_PROBE = BIT(0),
+};
+
 /**
  * struct i2c_driver - represent an I2C device driver
  * @class: What kind of i2c device we instantiate (for detect)
@@ -236,6 +246,7 @@ enum i2c_alert_protocol {
  * @detect: Callback for device detection
  * @address_list: The I2C addresses to probe (for detect)
  * @clients: List of detected clients we created (for i2c-core use only)
+ * @flags: A bitmask of flags defined in &enum i2c_driver_flags
  *
  * 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.
@@ -294,6 +305,8 @@ struct i2c_driver {
        int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
        const unsigned short *address_list;
        struct list_head clients;
+
+       u32 flags;
 };
 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 
@@ -1015,6 +1028,7 @@ u32 i2c_acpi_find_bus_speed(struct device *dev);
 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
                                       struct i2c_board_info *info);
 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle);
+bool i2c_acpi_waive_d0_probe(struct device *dev);
 #else
 static inline bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
                                             struct acpi_resource_i2c_serialbus **i2c)
@@ -1038,6 +1052,10 @@ static inline struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle ha
 {
        return NULL;
 }
+static inline bool i2c_acpi_waive_d0_probe(struct device *dev)
+{
+       return false;
+}
 #endif /* CONFIG_ACPI */
 
 #endif /* _LINUX_I2C_H */