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authorSaravana Kannan <saravanak@google.com>2020-05-21 12:17:59 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-07-10 15:24:56 +0200
commit8fd456ec0cf03875908d6b67c1cd20cf0a7b4474 (patch)
tree553496d0bbead2370f0eb1510a92db046bc9df9e /drivers/base
parent287905e68dd29873bcb7986a8290cd1e4cfde600 (diff)
downloadlinux-8fd456ec0cf03875908d6b67c1cd20cf0a7b4474.tar.bz2
driver core: Add state_synced sysfs file for devices that support it
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>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/dd.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 2aef1e4ce60a..a0b9ff5220cf 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -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)