Drivers can us of_platform_populate() to create
platform devices for children of the device
main node (this can particularly happen in case
of MFD devices). Unfortunately, there was no
standard way of removing such sub-devices when
the main one is being removed.
This patch adds of_platform_depopulate() as
a complementary operation for the _populate()
one. It removes all platform and amba devices
that have been created from the Device Tree,
but leaves all other ones untouched (returning
-EBUSY in such case).
Signed-off-by: Pawel Moll <pawel.moll@xxxxxxx>
---
Changes since v1:
- using bool rather than int to signal remaining children
- recursing using of_platform_depopulate() itself
drivers/of/platform.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_platform.h | 5 +++++
2 files changed, 55 insertions(+)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 236f47e..3b51e04 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -495,4 +495,54 @@ int of_platform_populate(struct device_node *root,
return rc;
}
EXPORT_SYMBOL_GPL(of_platform_populate);
+
+static int of_platform_device_destroy(struct device *dev, void *data)
+{
+ bool *children_left = data;
+
+ /* Do not touch devices not populated from the device tree */
+ if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED)) {
+ *children_left = true;
+ return 0;
+ }
+
+ /* Recurse, but don't touch this device if it has any children left */
+ if (of_platform_depopulate(dev) != 0) {
+ *children_left = true;
+ return 0;
+ }
+
+ if (dev->bus == &platform_bus_type)
+ platform_device_unregister(to_platform_device(dev));
+ else if (dev->bus == &amba_bustype)
+ amba_device_unregister(to_amba_device(dev));
+ else
+ *children_left = true;
+
+ return 0;
+}
+
+/**
+ * of_platform_depopulate() - Remove devices populated from device tree
+ * @parent: device which childred will be removed
+ *
+ * Complementary to of_platform_populate(), this function removes children
+ * of the given device (and, recurrently, their children) that have been
+ * created from their respective device tree nodes (and only those,
+ * leaving others - eg. manually created - unharmed).
+ *
+ * Returns 0 when all children devices have been removed or
+ * -EBUSY when some children remained.
+ */
+int of_platform_depopulate(struct device *parent)
+{
+ bool children_left = false;
+
+ device_for_each_child(parent, &children_left,
+ of_platform_device_destroy);
+
+ return children_left ? -EBUSY : 0;
+}
+EXPORT_SYMBOL_GPL(of_platform_depopulate);
+
#endif /* CONFIG_OF_ADDRESS */
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 05cb4a9..b1010ee 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -72,6 +72,7 @@ extern int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent);
+extern int of_platform_depopulate(struct device *parent);
#else
static inline int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
@@ -80,6 +81,10 @@ static inline int of_platform_populate(struct device_node *root,
{
return -ENODEV;
}
+static inline int of_platform_depopulate(struct device *parent)
+{
+ return -ENODEV;
+}
#endif
#endif /* _LINUX_OF_PLATFORM_H */
--
1.9.1
--
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