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Subject[PATCH v2 1/5] of/device: Add of_device_link_add function
Date
Use 'suspend-dependencies' property from device node to ensure that
the listed devices will suspended after it and resumed before it.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
---
CC: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
version 2:
- only keep of_device_links_add() and use
DL_FLAG_PM_RUNTIME and DL_FLAG_AUTOREMOVE_CONSUMER flags to follow Rafael
advices
- reword function description
- try to use a more explicit property name

drivers/of/device.c | 37 +++++++++++++++++++++++++++++++++++++
include/linux/of_device.h | 7 +++++++
2 files changed, 44 insertions(+)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 3717f2a20d0d..44ec84eee310 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -336,3 +336,40 @@ int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
return 0;
}
EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
+
+/**
+ * of_device_links_add - Create links between a consumer device
+ * and it listed dependencies from device tree data
+ *
+ * @consumer: consumer device
+ *
+ * Ensure that consumer's dependencies will be suspended after it
+ * and resumed before it.
+ *
+ * Returns 0 on success, < 0 on failure.
+ */
+int of_device_links_add(struct device *consumer)
+{
+ struct device_node *np;
+ struct platform_device *pdev;
+ int i = 0;
+
+ np = of_parse_phandle(consumer->of_node, "suspend-dependencies", i++);
+ while (np) {
+ pdev = of_find_device_by_node(np);
+ of_node_put(np);
+ if (!pdev)
+ return -EINVAL;
+
+ device_link_add(consumer, &pdev->dev,
+ DL_FLAG_PM_RUNTIME |
+ DL_FLAG_AUTOREMOVE_CONSUMER);
+ platform_device_put(pdev);
+
+ np = of_parse_phandle(consumer->of_node, "suspend-dependencies",
+ i++);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_device_links_add);
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index 8d31e39dd564..83f24c386d51 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -41,6 +41,8 @@ extern int of_device_request_module(struct device *dev);
extern void of_device_uevent(struct device *dev, struct kobj_uevent_env *env);
extern int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env);

+extern int of_device_links_add(struct device *consumer);
+
static inline void of_device_node_put(struct device *dev)
{
of_node_put(dev->of_node);
@@ -91,6 +93,11 @@ static inline int of_device_uevent_modalias(struct device *dev,
return -ENODEV;
}

+static int of_device_links_add(struct device *consumer)
+{
+ return 0;
+}
+
static inline void of_device_node_put(struct device *dev) { }

static inline const struct of_device_id *__of_match_device(
--
2.15.0
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