linux-kernel - Re: [PATCH] extcon: max77843: Clear IRQ bits state before request IRQ

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Date:	Fri, 05 Jun 2015 04:54:13 +0000 (GMT)
From:	MyungJoo Ham <myungjoo.ham@...sung.com>
To:	김재원 <jaewon02.kim@...sung.com>,
	최찬우 <cw00.choi@...sung.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>
Subject: Re: [PATCH] extcon: max77843: Clear IRQ bits state before request IRQ

>   
>  IRQ signal before driver probe is needless because driver sends
> current state after platform booting done.
> So, this patch clears MUIC IRQ bits before request IRQ.
> 
> Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
> ---
>  drivers/extcon/extcon-max77843.c |    9 +++++++++
>  1 file changed, 9 insertions(+)

Q1. Is this because the pending bits are USELESS?
or because the pendeing bits incurs INCORRECT behaviors?

Q2. Does clearing (by reading) INT1 do everything you need?
What about INT2 and INT3?

Q3. I presume that "driver sends current state after..." is
coming from the invokation of "queue_delayed_work()" at the end 
of the probe function. It appears that you are only serving
the pending status of "cable detection" with it while INT1
seems to have more functionalities. Does that delayed work
do everything that are pending, really?


Cheers,
MyungJoo

> 
> diff --git a/drivers/extcon/extcon-max77843.c b/drivers/extcon/extcon-max77843.c
> index d78a64d..11e09d1 100644
> --- a/drivers/extcon/extcon-max77843.c
> +++ b/drivers/extcon/extcon-max77843.c
> @@ -781,6 +781,15 @@ static int max77843_muic_probe(struct platform_device *pdev)
>  	/* Support virtual irq domain for max77843 MUIC device */
>  	INIT_WORK(&info->irq_work, max77843_muic_irq_work);
>  
> +	/* Clear IRQ bits before request IRQs */
> +	ret = regmap_bulk_read(max77843->regmap_muic,
> +			MAX77843_MUIC_REG_INT1, info->status,
> +			MAX77843_MUIC_IRQ_NUM);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to Clear IRQ bits\n");
> +		goto err_muic_irq;
> +	}
> +
>  	for (i = 0; i < ARRAY_SIZE(max77843_muic_irqs); i++) {
>  		struct max77843_muic_irq *muic_irq = &max77843_muic_irqs[i];
>  		unsigned int virq = 0;
> -- 
> 1.7.9.5
>