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driver core: Add state_synced sysfs file for devices that support it

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This can be used to check if a device supports sync_state() callbacks
and therefore keeps resources left on by the bootloader enabled till all
its consumers have probed.

This can also be used to check if sync_state() has been called for a
device or whether it is still trying to keep resources enabled because
they were left enabled by the bootloader and all its consumers haven't
probed yet.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200521191800.136035-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Saravana Kannan
2020-05-21 12:17:59 -07:00
committed by Greg Kroah-Hartman
parent 287905e68d
commit 8fd456ec0c
2 changed files with 46 additions and 0 deletions
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22
drivers/base/dd.c
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@@ -462,6 +462,18 @@ static void driver_deferred_probe_add_trigger(struct device *dev,
driver_deferred_probe_trigger();
}
static ssize_t state_synced_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
bool val;
device_lock(dev);
val = dev->state_synced;
device_unlock(dev);
return sprintf(buf, "%u\n", val);
}
static DEVICE_ATTR_RO(state_synced);
static int really_probe(struct device *dev, struct device_driver *drv)
{
int ret = -EPROBE_DEFER;
@@ -535,9 +547,16 @@ re_probe:
goto dev_groups_failed;
}
if (dev_has_sync_state(dev) &&
device_create_file(dev, &dev_attr_state_synced)) {
dev_err(dev, "state_synced sysfs add failed\n");
goto dev_sysfs_state_synced_failed;
}
if (test_remove) {
test_remove = false;
device_remove_file(dev, &dev_attr_state_synced);
device_remove_groups(dev, drv->dev_groups);
if (dev->bus->remove)
@@ -567,6 +586,8 @@ re_probe:
drv->bus->name, __func__, dev_name(dev), drv->name);
goto done;
dev_sysfs_state_synced_failed:
device_remove_groups(dev, drv->dev_groups);
dev_groups_failed:
if (dev->bus->remove)
dev->bus->remove(dev);
@@ -1104,6 +1125,7 @@ static void __device_release_driver(struct device *dev, struct device *parent)
pm_runtime_put_sync(dev);
device_remove_file(dev, &dev_attr_state_synced);
device_remove_groups(dev, drv->dev_groups);
if (dev->bus && dev->bus->remove)