[PATCH 6/6] USB / PM: Allow USB devices to remain runtime-suspended when sleeping

[Tomeu Vizoso]

Have dev_pm_ops.prepare return 1 for USB devices, interfaces, endpoints
and ports so that USB devices can remain runtime-suspended when the
system goes to a sleep state.

Also enable runtime PM for endpoints, which is another requirement for
the above to work.

Signed-off-by: Tomeu Vizoso <tomeu.viz...@collabora.com>
---
 drivers/usb/core/endpoint.c | 17 +++++++++++++++++
 drivers/usb/core/message.c  | 16 ++++++++++++++++
 drivers/usb/core/port.c     |  6 ++++++
 drivers/usb/core/usb.c      |  2 +-
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/endpoint.c b/drivers/usb/core/endpoint.c
index 39a2402..7c82bb7 100644
--- a/drivers/usb/core/endpoint.c
+++ b/drivers/usb/core/endpoint.c
@@ -160,6 +160,19 @@ static const struct attribute_group *ep_dev_groups[] = {
        NULL
 };
 
+#ifdef CONFIG_PM
+
+static int usb_ep_device_prepare(struct device *dev)
+{
+       return 1;
+}
+
+static const struct dev_pm_ops usb_ep_device_pm_ops = {
+       .prepare =      usb_ep_device_prepare,
+};
+
+#endif /* CONFIG_PM */
+
 static void ep_device_release(struct device *dev)
 {
        struct ep_device *ep_dev = to_ep_device(dev);
@@ -170,6 +183,9 @@ static void ep_device_release(struct device *dev)
 struct device_type usb_ep_device_type = {
        .name =         "usb_endpoint",
        .release = ep_device_release,
+#ifdef CONFIG_PM
+       .pm =           &usb_ep_device_pm_ops,
+#endif
 };
 
 int usb_create_ep_devs(struct device *parent,
@@ -197,6 +213,7 @@ int usb_create_ep_devs(struct device *parent,
                goto error_register;
 
        device_enable_async_suspend(&ep_dev->dev);
+       pm_runtime_enable(&ep_dev->dev);
        endpoint->ep_dev = ep_dev;
        return retval;
 
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index f368d20..9041aee 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1589,10 +1589,26 @@ static int usb_if_uevent(struct device *dev, struct 
kobj_uevent_env *env)
        return 0;
 }
 
+#ifdef CONFIG_PM
+
+static int usb_if_prepare(struct device *dev)
+{
+       return 1;
+}
+
+static const struct dev_pm_ops usb_if_pm_ops = {
+       .prepare =      usb_if_prepare,
+};
+
+#endif /* CONFIG_PM */
+
 struct device_type usb_if_device_type = {
        .name =         "usb_interface",
        .release =      usb_release_interface,
        .uevent =       usb_if_uevent,
+#ifdef CONFIG_PM
+       .pm =           &usb_if_pm_ops,
+#endif
 };
 
 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 2106183..f49707d 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -168,12 +168,18 @@ static int usb_port_runtime_suspend(struct device *dev)
 
        return retval;
 }
+
+static int usb_port_prepare(struct device *dev)
+{
+       return 1;
+}
 #endif
 
 static const struct dev_pm_ops usb_port_pm_ops = {
 #ifdef CONFIG_PM
        .runtime_suspend =      usb_port_runtime_suspend,
        .runtime_resume =       usb_port_runtime_resume,
+       .prepare =              usb_port_prepare,
 #endif
 };
 
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index b1fb9ae..1498faa 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -300,7 +300,7 @@ static int usb_dev_uevent(struct device *dev, struct 
kobj_uevent_env *env)
 
 static int usb_dev_prepare(struct device *dev)
 {
-       return 0;               /* Implement eventually? */
+       return 1;               /* Implement eventually? */
 }
 
 static void usb_dev_complete(struct device *dev)
-- 
2.3.4

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