Date:	Tue, 5 Aug 2014 11:37:00 +0530
From:	Kishon Vijay Abraham I <kishon@...com>
To:	<ygardi@...eaurora.org>
CC:	<linux-arm-msm@...r.kernel>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	<noag@...eaurora.org>, <subhashj@...eaurora.org>
Subject: Re: [PATCH v1] phy: extend APIs of the generic phy framework

Hi,

On Tuesday 05 August 2014 12:03 AM, ygardi@...eaurora.org wrote:
>> Hi,
>>
>> On Thursday 31 July 2014 06:07 PM, Yaniv Gardi wrote:
>>> This change adds a few more APIs to the phy_ops structure:
>>> advertise_quirks - API for setting the phy quirks
>>
>> What are these phy quirks? An explanation on what you are are planning to
>> do
>> with these quirks might help.
> 
> A phy HW might have a specific behavior that should be exposed to the phy
> SW structure by calling this callback. This is the reason behind this
> callback. does it make more sense now ?

I'm more interested in the _specific_ behaviour you are talking about. Such
callbacks can be abused easily.
> 
> 
>>> suspend - API for the implementation of phy suspend sequence
>>> resume - API for the implementation of phy resume sequence
>>
>> Why not use the existing pm_runtime's suspend/resume callbacks?
>>
> Like we observed in our case, often there are need to be extra operations
> in the suspend/resume sequence. those specific operations include turning
> off/on specific clocks, disabling/enabling regulators etc. the specific
> implementation must give enough flexibility to add whatever needed to be
> done in suspend/resume sequences.

All these can be done in suspend and resume callbacks of pm_runtime.

Thanks
Kishon
> 
> 
> 
> 
>>>
>>> Change-Id: I44dd77f2603d20acb02ccb0cc0d20ade884f97c2
>> Remove this..
>>
>>> Signed-off-by: Yaniv Gardi <ygardi@...eaurora.org>
>>> ---
>>>  Documentation/phy.txt   |  6 ++---
>>>  drivers/phy/phy-core.c  | 58
>>> +++++++++++++++++++++++++++++++++++++++++++++++++
>>>  include/linux/phy/phy.h | 33 ++++++++++++++++++++++++++++
>>>  3 files changed, 94 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/phy.txt b/Documentation/phy.txt
>>> index c6594af..f0dc28e 100644
>>> --- a/Documentation/phy.txt
>>> +++ b/Documentation/phy.txt
>>> @@ -63,9 +63,9 @@ struct phy *devm_phy_create(struct device *dev, struct
>>> device_node *node,
>>>  The PHY drivers can use one of the above 2 APIs to create the PHY by
>>> passing
>>>  the device pointer, phy ops and init_data.
>>>  phy_ops is a set of function pointers for performing PHY operations
>>> such as
>>> -init, exit, power_on and power_off. *init_data* is mandatory to get a
>>> reference
>>> -to the PHY in the case of non-dt boot. See section *Board File
>>> Initialization*
>>> -on how init_data should be used.
>>> +init, exit, power_on and power_off, , suspend, resume and
>>> advertise_quirks.
>>> +*init_data* is mandatory to get a reference to the PHY in the case of
>>> non-dt
>>> +boot. See section *Board File Initialization* on how init_data should
>>> be used.
>>>
>>>  Inorder to dereference the private data (in phy_ops), the phy provider
>>> driver
>>>  can use phy_set_drvdata() after creating the PHY and use
>>> phy_get_drvdata() in
>>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>>> index ff5eec5..77abaab 100644
>>> --- a/drivers/phy/phy-core.c
>>> +++ b/drivers/phy/phy-core.c
>>> @@ -293,6 +293,64 @@ int phy_power_off(struct phy *phy)
>>>  }
>>>  EXPORT_SYMBOL_GPL(phy_power_off);
>>>
>>> +int phy_suspend(struct phy *phy)
>>> +{
>>> +	int ret = 0;
>>> +
>>> +	if (!phy->ops->suspend)
>>> +		return -ENOTSUPP;
>>> +
>>> +	mutex_lock(&phy->mutex);
>>> +
>>> +	if (--phy->resume_count == 0) {
>>> +		ret =  phy->ops->suspend(phy);
>>> +		if (ret) {
>>> +			dev_err(&phy->dev, "phy suspend failed --> %d\n", ret);
>>> +			/* reverting the resume_count since suspend failed */
>>> +			phy->resume_count++;
>>> +			goto out;
>>> +		}
>>> +	}
>>> +out:
>>> +	mutex_unlock(&phy->mutex);
>>> +	return ret;
>>> +}
>>> +EXPORT_SYMBOL(phy_suspend);
>>> +
>>> +int phy_resume(struct phy *phy)
>>> +{
>>> +	int ret = 0;
>>> +
>>> +	if (!phy->ops->resume)
>>> +		return -ENOTSUPP;
>>> +
>>> +	mutex_lock(&phy->mutex);
>>> +
>>> +	if (phy->resume_count++ == 0) {
>>> +		ret =  phy->ops->resume(phy);
>>> +		if (ret) {
>>> +			dev_err(&phy->dev, "phy resume failed --> %d\n", ret);
>>> +			/* reverting the resume_count since resume failed */
>>> +			phy->resume_count--;
>>> +			goto out;
>>> +		}
>>> +	}
>>> +out:
>>> +	mutex_unlock(&phy->mutex);
>>> +	return ret;
>>> +}
>>> +EXPORT_SYMBOL(phy_resume);
>>> +
>>> +void phy_advertise_quirks(struct phy *phy)
>>> +{
>>> +	if (phy->ops->advertise_quirks) {
>>> +		mutex_lock(&phy->mutex);
>>> +		phy->ops->advertise_quirks(phy);
>>> +		mutex_unlock(&phy->mutex);
>>> +	}
>>> +}
>>> +EXPORT_SYMBOL(phy_advertise_quirks);
>>> +
>>>  /**
>>>   * _of_phy_get() - lookup and obtain a reference to a phy by phandle
>>>   * @np: device_node for which to get the phy
>>> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
>>> index 8cb6f81..5b96d65 100644
>>> --- a/include/linux/phy/phy.h
>>> +++ b/include/linux/phy/phy.h
>>> @@ -28,6 +28,14 @@ struct phy;
>>>   * @exit: operation to be performed while exiting
>>>   * @power_on: powering on the phy
>>>   * @power_off: powering off the phy
>>> + * @advertise_quirks: setting specific phy quirks. this api is for an
>>> +		      internal use of the device driver, and its
>>> +		      purpose is to exteriorize the driver's phy quirks
>>> +		      according to phy version (or other parameters),
>>> +		      so further behaviour of the driver's phy is based
>>> +		      on those quirks.
>>
>> Can you be more specific on what you do with this? This looks more like a
>> candidate for flags than callback to me?
>>
>> Thanks
>> Kishon
>>
> 
> 
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