The common clock framework considers NULL a valid clock
reference. This makes handling optional clocks simple, in that if the
optional clock is not available, a NULL reference can be used in the
place of a real clock, simplifying the clock consumer.
Extend this concept to the phy consumer API. A NULL can be passed to
the release calls, the phy_init() and phy_exit() calls, and
phy_power_on() and phy_power_off() and a NOP is performed.
Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
---
Documentation/phy.txt | 6 ++++++
drivers/phy/phy-core.c | 18 ++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/Documentation/phy.txt b/Documentation/phy.txt
index 0103e4b15b0e..2e24b993e95f 100644
--- a/Documentation/phy.txt
+++ b/Documentation/phy.txt
@@ -84,6 +84,12 @@ The only difference between the two APIs is that devm_phy_get associates the
device with the PHY using devres on successful PHY get. On driver detach,
release function is invoked on the the devres data and devres data is freed.
+It should be noted that NULL is a valid phy reference. All phy
+consumer calls on the NULL phy become NOPs. That is the release calls,
+the phy_init() and phy_exit() calls, and phy_power_on() and
+phy_power_off() calls are all NOP when applied to a NULL phy. The NULL
+phy is useful in devices for handling optional phy devices.
+
5. Releasing a reference to the PHY
When the controller no longer needs the PHY, it has to release the reference
diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 03cf8fb81554..74d34b5cc75c 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -150,6 +150,9 @@ int phy_init(struct phy *phy)
{
int ret;
+ if (!phy)
+ return 0;
+
ret = phy_pm_runtime_get_sync(phy);
if (ret < 0 && ret != -ENOTSUPP)
return ret;
@@ -174,6 +177,9 @@ int phy_exit(struct phy *phy)
{
int ret;
+ if (!phy)
+ return 0;
+
ret = phy_pm_runtime_get_sync(phy);
if (ret < 0 && ret != -ENOTSUPP)
return ret;
@@ -198,6 +204,9 @@ int phy_power_on(struct phy *phy)
{
int ret = -ENOTSUPP;
+ if (!phy)
+ return 0;
+
ret = phy_pm_runtime_get_sync(phy);
if (ret < 0 && ret != -ENOTSUPP)
return ret;
@@ -222,6 +231,9 @@ int phy_power_off(struct phy *phy)
{
int ret = -ENOTSUPP;
+ if (!phy)
+ return 0;
+
mutex_lock(&phy->mutex);
if (--phy->power_count == 0 && phy->ops->power_off) {
ret = phy->ops->power_off(phy);
@@ -290,6 +302,9 @@ err0:
*/
void phy_put(struct phy *phy)
{
+ if (!phy)
+ return;
+
if (IS_ERR(phy))
return;
@@ -310,6 +325,9 @@ void devm_phy_put(struct device *dev, struct phy *phy)
{
int r;
+ if (!phy)
+ return;
+
r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
}
--
1.8.5.2
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