[patch v2 1/3] drivers: phy: Make NULL a valid phy reference

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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>
---
v2
No change.
---
 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 645c867c1257..56535253e50c 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -162,6 +162,9 @@ 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;
@@ -187,6 +190,9 @@ 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;
@@ -212,6 +218,9 @@ int phy_power_on(struct phy *phy)
 {
 	int ret;
 
+	if (!phy)
+		return 0;
+
 	ret = phy_pm_runtime_get_sync(phy);
 	if (ret < 0 && ret != -ENOTSUPP)
 		return ret;
@@ -240,6 +249,9 @@ int phy_power_off(struct phy *phy)
 {
 	int ret;
 
+	if (!phy)
+		return 0;
+
 	mutex_lock(&phy->mutex);
 	if (phy->power_count == 1 && phy->ops->power_off) {
 		ret =  phy->ops->power_off(phy);
@@ -308,6 +320,9 @@ err0:
  */
 void phy_put(struct phy *phy)
 {
+	if (!phy)
+		return;
+
 	if (IS_ERR(phy))
 		return;
 
@@ -328,6 +343,9 @@ 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

--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Filesystems]     [Linux SCSI]     [Linux RAID]     [Git]     [Kernel Newbies]     [Linux Newbie]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Samba]     [Device Mapper]

  Powered by Linux