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

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Date:	Fri, 10 Oct 2014 12:10:50 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Chanwoo Choi <cw00.choi@...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 pią, 2014-10-10 at 19:05 +0900, Chanwoo Choi wrote:
> 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)

Sure, I get it. I'll do it the same as in max14577 driver.

Thanks for feedback!
Krzysztof

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