linux-kernel - Re: [PATCH fixes 2/2] extcon: max77693: Fix always masked MUIC interrupts

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Date:	Fri, 10 Oct 2014 19:05:44 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Lee Jones <lee.jones@...aro.org>, linux-kernel@...r.kernel.org,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	stable@...r.kernel.org
Subject: Re: [PATCH fixes 2/2] extcon: max77693: Fix always masked MUIC
 interrupts

On 10/10/2014 06:03 PM, Krzysztof Kozlowski wrote:
> On pią, 2014-10-10 at 17:45 +0900, Chanwoo Choi wrote:
>> On 10/10/2014 05:22 PM, Krzysztof Kozlowski wrote:
>>> All interrupts coming from MUIC were ignored because interrupt source
>>> register was masked.
>>>
>>> The Maxim 77693 has a "interrupt source" - a separate register and interrupts
>>> which give information about PMIC block triggering the individual
>>> interrupt (charger, topsys, MUIC, flash LED).
>>>
>>> By default bootloader could initialize this register to "mask all"
>>> value. In such case (observed on Trats2 board) MUIC interrupts won't be
>>> generated regardless of their mask status. Regmap irq chip was unmasking
>>> individual MUIC interrupts but the source was masked
>>>
>>> Before introducing regmap irq chip this interrupt source was unmasked,
>>> read and acked. Reading and acking is not necessary but unmasking is. Do
>>> it in extcon driver.
>>>
>>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
>>> Cc: <stable@...r.kernel.org>
>>> Fixes: 342d669c1ee4 ("mfd: max77693: Handle IRQs using regmap")
>>> ---
>>>  drivers/extcon/extcon-max77693.c     | 16 ++++++++++++++++
>>>  include/linux/mfd/max77693-private.h |  5 +++++
>>>  2 files changed, 21 insertions(+)
>>>
>>> diff --git a/drivers/extcon/extcon-max77693.c b/drivers/extcon/extcon-max77693.c
>>> index 490e27475bac..d3adacf3187f 100644
>>> --- a/drivers/extcon/extcon-max77693.c
>>> +++ b/drivers/extcon/extcon-max77693.c
>>> @@ -1176,6 +1176,22 @@ static int max77693_muic_probe(struct platform_device *pdev)
>>>  		}
>>>  	}
>>>  
>>> +	if (i) {
>>> +		/*
>>> +		 * i>0, at least one MUIC interrupt requested so need to unmask
>>> +		 * MUIC interrupt in INTSRC register. Without that MUIC
>>> +		 * interrupts will not be reported.
>>> +		 */
>>> +		ret = regmap_update_bits(max77693->regmap,
>>> +				MAX77693_PMIC_REG_INTSRC_MASK, SRC_IRQ_MUIC,
>>> +				~SRC_IRQ_MUIC);
>>> +		if (ret < 0) {
>>> +			dev_err(&pdev->dev, "Could not unmask MUIC interrupt in INTSRC: %d\n",
>>> +					ret);
>>> +			return ret;
>>> +		}
>>> +	}
>>> +
>>
>> No,
>> The extcon-max77693 driver cannot enable IRQ_CHARGER/TOP/FLASH
>> because MAX77693_PMIC_REG_INTSRC_MASK register is common register of MAX77693.
>>
>> The IRQ_CHARGER/TOP/FLASH of MAX77693_PMIC_REG_INTSRC_MASK register should be enabled
>> in drivers/mfd/max77693.c.
> 
> The code above unmasks only SRC_IRQ_MUIC. Other bits are not touched.
> Why do you think that other IRQs will be enabled?

I think that MAX77693_PMIC_REG_INTSRC_MASK common register better to be controlled
in drivers/mfd/max77693.c. I prefer that MAX77693 extcon driver would read/write only MUIC registers.

Also, MAX77693 extcon driver have to be always unmasked.
If IRQ_MUIC is masked, MAX77693 extcon driver could not detect any external cables.

For example,
The max77836 enable MUIC_IRQ by un-masking MUIC_IRQ.
You can check it on drivers/mfd/max14577.c (line 251~258)

Best Regards,
Chanwoo Choi

> 
> Best regards,
> Krzysztof
> 
>>
>>>  	/* Initialize extcon device */
>>>  	info->edev = devm_extcon_dev_allocate(&pdev->dev,
>>>  					      max77693_extcon_cable);
>>> diff --git a/include/linux/mfd/max77693-private.h b/include/linux/mfd/max77693-private.h
>>> index e1b2b61285b9..4f1a80b66ecf 100644
>>> --- a/include/linux/mfd/max77693-private.h
>>> +++ b/include/linux/mfd/max77693-private.h
>>> @@ -438,6 +438,11 @@ enum max77693_irq_source {
>>>  	MAX77693_IRQ_GROUP_NR,
>>>  };
>>>  
>>> +#define SRC_IRQ_CHARGER			BIT(0)
>>> +#define SRC_IRQ_TOP			BIT(1)
>>> +#define SRC_IRQ_FLASH			BIT(2)
>>> +#define SRC_IRQ_MUIC			BIT(3)
>>> +
>>>  #define LED_IRQ_FLED2_OPEN		BIT(0)
>>>  #define LED_IRQ_FLED2_SHORT		BIT(1)
>>>  #define LED_IRQ_FLED1_OPEN		BIT(2)
>>>
> 
> 

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