[8/8] PM / doc: Update device documentation for devices in IRQ safe PM domains

Message ID 1475699519-109623-9-git-send-email-lina.iyer@linaro.org
State New
Headers show

Commit Message

Lina Iyer Oct. 5, 2016, 8:31 p.m.
Update documentation to reflect the changes made to support IRQ safe PM
domains.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>

---
 Documentation/power/devices.txt | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

-- 
2.7.4

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diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 8ba6625..a622136 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -607,7 +607,17 @@  individually.  Instead, a set of devices sharing a power resource can be put
 into a low-power state together at the same time by turning off the shared
 power resource.  Of course, they also need to be put into the full-power state
 together, by turning the shared power resource on.  A set of devices with this
-property is often referred to as a power domain.
+property is often referred to as a power domain. A power domain may also be
+nested inside another power domain.
+
+Devices, by default, operate in process context. If a device can operate in
+IRQ safe context that has to be explicitly indicated by setting the irq_safe
+boolean inside struct generic_pm_domain to be true. Power domains by default,
+operate in process context but could have devices that are IRQ safe. Such
+power domains cannot be powered on/off during runtime PM. On the other hand,
+IRQ safe PM domains that have IRQ safe devices may be powered off when all
+the devices are in idle. An IRQ safe domain may only be attached as a
+subdomain to another IRQ safe domain.
 
 Support for power domains is provided through the pm_domain field of struct
 device.  This field is a pointer to an object of type struct dev_pm_domain,