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From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: linux-acpi@vger.kernel.org
Cc: rajmohan.mani@intel.com, linux-media@vger.kernel.org
Subject: [PATCH 1/5] ACPI: Enable driver and firmware hints to control power at probe time
Date: Fri, 10 May 2019 13:09:26 +0300
Message-ID: <20190510100930.14641-2-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20190510100930.14641-1-sakari.ailus@linux.intel.com>

Allow drivers and firmware tell ACPI that there's no need to power on a
device for probe. This requires both a hint from the firmware as well as
an indication from a driver to leave the device off.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/acpi/device_pm.c | 9 +++++++--
 include/linux/device.h   | 6 ++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index b859d75eaf9f6..ca2409a30d26d 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -1225,7 +1225,9 @@ static void acpi_dev_pm_detach(struct device *dev, bool power_off)
 	if (adev && dev->pm_domain == &acpi_general_pm_domain) {
 		dev_pm_domain_set(dev, NULL);
 		acpi_remove_pm_notifier(adev);
-		if (power_off) {
+		if (power_off &&
+		    !(dev->driver->probe_powered_off &&
+		      device_property_present(dev, "avoid-power-probe"))) {
 			/*
 			 * If the device's PM QoS resume latency limit or flags
 			 * have been exposed to user space, they have to be
@@ -1273,7 +1275,10 @@ int acpi_dev_pm_attach(struct device *dev, bool power_on)
 
 	acpi_add_pm_notifier(adev, dev, acpi_pm_notify_work_func);
 	dev_pm_domain_set(dev, &acpi_general_pm_domain);
-	if (power_on) {
+
+	if (power_on &&
+	    !(dev->driver->probe_powered_off &&
+	      device_property_present(dev, "avoid-power-probe"))) {
 		acpi_dev_pm_full_power(adev);
 		acpi_device_wakeup_disable(adev);
 	}
diff --git a/include/linux/device.h b/include/linux/device.h
index e85264fb66161..2a459fd5b954a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -245,6 +245,11 @@ enum probe_type {
  * @owner:	The module owner.
  * @mod_name:	Used for built-in modules.
  * @suppress_bind_attrs: Disables bind/unbind via sysfs.
+ * @probe_powered_off: The driver supports its probe function being called while
+ *		       the device is powered off, independently of the expected
+ *		       behaviour on combination of a given bus and firmware
+ *		       interface etc. The driver is responsible for powering the
+ *		       device on using runtime PM in such case.
  * @probe_type:	Type of the probe (synchronous or asynchronous) to use.
  * @of_match_table: The open firmware table.
  * @acpi_match_table: The ACPI match table.
@@ -282,6 +287,7 @@ struct device_driver {
 	const char		*mod_name;	/* used for built-in modules */
 
 	bool suppress_bind_attrs;	/* disables bind/unbind via sysfs */
+	bool probe_powered_off;
 	enum probe_type probe_type;
 
 	const struct of_device_id	*of_match_table;
-- 
2.11.0


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-10 10:09 [PATCH 0/5] Support running driver's probe for a device powered off Sakari Ailus
2019-05-10 10:09 ` Sakari Ailus [this message]
2019-05-31  9:17   ` [PATCH 1/5] ACPI: Enable driver and firmware hints to control power at probe time Rafael J. Wysocki
2019-06-05 12:07     ` Sakari Ailus
2019-05-10 10:09 ` [PATCH 2/5] ACPI: Add a convenience function to tell a device is suspended in probe Sakari Ailus
2019-05-10 10:09 ` [PATCH 3/5] ov5670: Support probe whilst the device is off Sakari Ailus
2019-06-05  7:07   ` Tomasz Figa
2019-06-05 10:15     ` Sakari Ailus
2019-06-07  7:54       ` Tomasz Figa
2019-08-26  8:38         ` Sakari Ailus
2019-08-26  9:21           ` Tomasz Figa
2019-05-10 10:09 ` [PATCH 4/5] media: i2c: imx319: Support probe while " Sakari Ailus
2019-05-10 10:09 ` [PATCH 5/5] at24: Support probing while off Sakari Ailus

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