Re: [PATCH v20 2/6] phy: core: Add phy_get_by_of_node()
From: Neil Armstrong
Date: Tue Sep 22 2026 - 08:24:45 EST
On 9/18/26 17:35, johannes.goede@xxxxxxxxxxxxxxxx wrote:
Hi Neil,
On 18-Sep-26 16:10, Neil Armstrong wrote:
On 9/18/26 15:56, Bryan O'Donoghue wrote:
Add new function phy_get_by_of_node() allowing lookup of a phy by
device_node. Separates existing logic in _of_phy_get() into an internal
helper method _of_phy_get_with_args() to allow for reuse in new method.
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
drivers/phy/phy-core.c | 83 ++++++++++++++++++++++++++++++++++++++-----------
include/linux/phy/phy.h | 6 ++++
2 files changed, 71 insertions(+), 18 deletions(-)
diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 89addd732bff3..42c27a2b45159 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -606,6 +606,38 @@ int phy_validate(struct phy *phy, enum phy_mode mode, int submode,
}
EXPORT_SYMBOL_GPL(phy_validate);
+/**
+ * _of_phy_get_with_args() - lookup and obtain a reference to a phy by of_phandle_args
+ * @args: of_phandle_args to the phy
+ *
+ * Returns: the phy from the provider's of_xlate, -ENODEV if disabled,
+ * -EPROBE_DEFER if the provider is not yet registered.
+ */
+static struct phy *_of_phy_get_with_args(struct of_phandle_args *args)
+{
+ struct phy *phy;
+ struct phy_provider *phy_provider;
+
+ lockdep_assert_held(&phy_provider_mutex);
+
+ phy_provider = of_phy_provider_lookup(args->np);
+ if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner))
+ return ERR_PTR(-EPROBE_DEFER);
+
+ if (!of_device_is_available(args->np)) {
+ dev_warn(phy_provider->dev, "Requested PHY is disabled\n");
+ phy = ERR_PTR(-ENODEV);
+ goto out_put_module;
+ }
+
+ phy = phy_provider->of_xlate(phy_provider->dev, args);
+
+out_put_module:
+ module_put(phy_provider->owner);
+
+ return phy;
+}
+
/**
* _of_phy_get() - lookup and obtain a reference to a phy by phandle
* @np: device_node for which to get the phy
@@ -620,8 +652,7 @@ EXPORT_SYMBOL_GPL(phy_validate);
static struct phy *_of_phy_get(struct device_node *np, int index)
{
int ret;
- struct phy_provider *phy_provider;
- struct phy *phy = NULL;
+ struct phy *phy;
struct of_phandle_args args;
lockdep_assert_held(&phy_provider_mutex);
@@ -637,22 +668,7 @@ static struct phy *_of_phy_get(struct device_node *np, int index)
goto out_put_node;
}
- phy_provider = of_phy_provider_lookup(args.np);
- if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner)) {
- phy = ERR_PTR(-EPROBE_DEFER);
- goto out_put_node;
- }
-
- if (!of_device_is_available(args.np)) {
- dev_warn(phy_provider->dev, "Requested PHY is disabled\n");
- phy = ERR_PTR(-ENODEV);
- goto out_put_module;
- }
-
- phy = phy_provider->of_xlate(phy_provider->dev, &args);
-
-out_put_module:
- module_put(phy_provider->owner);
+ phy = _of_phy_get_with_args(&args);
out_put_node:
of_node_put(args.np);
@@ -1001,6 +1017,37 @@ struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
}
EXPORT_SYMBOL_GPL(devm_of_phy_get_by_index);
+/**
+ * phy_get_by_of_node() - lookup and obtain a reference to a phy by device_node
+ * @np: node containing the phy
+ *
+ * Returns: the phy associated with the device node or ERR_PTR.
+ */
+struct phy *phy_get_by_of_node(struct device_node *np)
+{
+ struct of_phandle_args args = { .np = np, .args_count = 0 };
+ struct phy *phy;
+
+ mutex_lock(&phy_provider_mutex);
I don't really understand the usage of lockdep_assert_held(), but why
does _of_phy_get() uses lockdep_assert_held() and here you use mutex_lock()
like before patch 1 ?
Hi, not Bryan but I can answer this question.
lockdep_assert_held() check that the mutex is lock and triggers
a WARN() when not held.
So lockdep_assert_held() is used in functions which expect to
be called with the mutex already locked, like the new
_of_phy_get_with_args() helper which is added here.
This new helper factors out bits of _of_phy_get(), which itself
already has lockdep_assert_held(), but since this new helper
also is directly called from the new phy_get_by_of_node() it
is good for it to also check the mutex is locked itself.
And since the new phy_get_by_of_node() calls this new helper
it must lock the mutex.
Note that _of_phy_get() is already always called with the mutex
locked from of_phy_get(), phy_get(), or devm_of_phy_get_by_index().
Ok thanks for the detailed explanation, I missed that !
Neil
Regards,
Hans
Neil
+
+ phy = _of_phy_get_with_args(&args);
+ if (IS_ERR(phy))
+ goto out_unlock;
+
+ if (!try_module_get(phy->ops->owner)) {
+ phy = ERR_PTR(-EPROBE_DEFER);
+ goto out_unlock;
+ }
+
+ get_device(&phy->dev);
+
+out_unlock:
+ mutex_unlock(&phy_provider_mutex);
+
+ return phy;
+}
+EXPORT_SYMBOL_GPL(phy_get_by_of_node);
+
/**
* phy_create() - create a new phy
* @dev: device that is creating the new phy
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index ea47975e288ae..71c2e16397130 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -284,6 +284,7 @@ struct phy *devm_of_phy_optional_get(struct device *dev, struct device_node *np,
const char *con_id);
struct phy *devm_of_phy_get_by_index(struct device *dev, struct device_node *np,
int index);
+struct phy *phy_get_by_of_node(struct device_node *np);
void of_phy_put(struct phy *phy);
void phy_put(struct device *dev, struct phy *phy);
void devm_phy_put(struct device *dev, struct phy *phy);
@@ -493,6 +494,11 @@ static inline struct phy *devm_of_phy_get_by_index(struct device *dev,
return ERR_PTR(-ENOSYS);
}
+static inline struct phy *phy_get_by_of_node(struct device_node *np)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
static inline void of_phy_put(struct phy *phy)
{
}