linux-kernel - Re: [PATCH v3 2/4] mfd: max8997: handle IRQs using regmap

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Date:	Tue, 18 Mar 2014 18:52:37 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Robert Baldyga <r.baldyga@...sung.com>
Cc:	sameo@...ux.intel.com, lee.jones@...aro.org,
	myungjoo.ham@...sung.com, dmitry.torokhov@...il.com,
	cooloney@...il.com, rpurdie@...ys.net, dbaryshkov@...il.com,
	dwmw2@...radead.org, lgirdwood@...il.com, broonie@...nel.org,
	a.zummo@...ertech.it, paul.gortmaker@...driver.com,
	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
	linux-leds@...r.kernel.org, rtc-linux@...glegroups.com,
	m.szyprowski@...sung.com, k.kozlowski@...sung.com
Subject: Re: [PATCH v3 2/4] mfd: max8997: handle IRQs using regmap

On 03/14/2014 05:33 PM, Robert Baldyga wrote:
> On 03/13/2014 11:45 AM, Chanwoo Choi wrote:
>> Hi Robert,
>>
>> On 03/13/2014 06:38 PM, Robert Baldyga wrote:
>>> This patch modifies mfd driver to use regmap for handling interrupts.
>>> It allows to simplify irq handling process. This modifications needed
>>> to make small changes in function drivers, which use interrupts.
>>>
>>> Signed-off-by: Robert Baldyga <r.baldyga@...sung.com>
> 
> (...)
> 
>>> @@ -468,8 +560,11 @@ static int max8997_suspend(struct device *dev)
>>>  	struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
>>>  	struct max8997_dev *max8997 = i2c_get_clientdata(i2c);
>>>  
>>> -	if (device_may_wakeup(dev))
>>> -		irq_set_irq_wake(max8997->irq, 1);
>>> +	if (device_may_wakeup(dev)) {
>>> +		enable_irq_wake(max8997->irq);
>>> +		disable_irq(max8997->irq);
>>
>> irq_set_irq_wake() is same as enable_irq_wake().
> 
> It's more intuitive name and makes code reading easier.
> 
>> Why is it necessary for disable_irq(max8997->irq)?
> 
> It's because we don't want to get interrupts before i2c controller will
> be ready. So we disable irq in drivers suspend, and enable in resume.
> 
> If some iqr will come before enable_irq() call, it will be noticed, and
> IRQ_PENDING flag will be set. In this case irq will be handled
> immediately after enable_irq() call.
> 
> In previous version there was call of max8997_irq_resume() in resume
> function, which caused forced interrupt handling, which has similar effect.
> 

OK,

For extcon part,
Acked-by: Chanwoo Choi <cw00.choi@...sung.com>

Thanks,
Chanwoo Choi

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