Re: [Patch v4 1/3] drivers: phy: Make NULL a valid phy reference

[Kishon Vijay Abraham I <kishon@ti.com>]

On Wednesday 05 February 2014 10:44 AM, Jason Cooper wrote:
> Kishon,
> 
> On Tue, Feb 04, 2014 at 06:33:11PM +0100, Andrew Lunn wrote:
>> 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@lunn.ch>
>> Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
>> ---
>> v2
>>  No change.
>> v4
>>  combine !phy and IS_ERR().
>>  Add Tested-by
>> ---
>>  Documentation/phy.txt  |  6 ++++++
>>  drivers/phy/phy-core.c | 17 ++++++++++++++++-
>>  2 files changed, 22 insertions(+), 1 deletion(-)
> 
> Looking over the overall diffstat (there isn't one, Andrew, please don't
> forget the coverletter in the future), this series is predominately
> changing the phy subsystem.  However, since it's fixing a boot failure
> in the arm-soc bootfarm, we'd like to get it into our tree without
> pulling in a bunch of unnecessary changes (eg by pulling in -rc2 or
> -rc3).
> 
> Could you create a topic branch with this series in it we could base off
> of?  Or, could you Ack it so we could take it through arm-soc?

I can just ACK it so you can take it through your tree.

Cheers
Kishon

> 
> thx,
> 
> Jason.
> 
>> 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..a9cdeee20d91 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);
>> @@ -308,7 +320,7 @@ err0:
>>   */
>>  void phy_put(struct phy *phy)
>>  {
>> -	if (IS_ERR(phy))
>> +	if (!phy || IS_ERR(phy))
>>  		return;
>>  
>>  	module_put(phy->ops->owner);
>> @@ -328,6 +340,9 @@ 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
>>