Re: [PATCH] pinctrl: intel: Clear interrupt status in unmask callback

[Kai-Heng Feng]

at 05:47, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:

> On Mon, Apr 22, 2019 at 12:45:39PM +0800, Kai-Heng Feng wrote:
> > Commit a939bb57cd47 ("pinctrl: intel: implement gpio_irq_enable") was
> > added because clearing interrupt status bit is required to avoid
> > unexpected behavior.
> >
> > Turns out the unmask callback also needs the fix, which can solve weird
> > IRQ triggering issues on I2C touchpad ELAN1200.
>
> > -static void intel_gpio_irq_enable(struct irq_data *d)
> > -{
> > -	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > -	struct intel_pinctrl *pctrl = gpiochip_get_data(gc);
> > -	const struct intel_community *community;
> > -	const struct intel_padgroup *padgrp;
> > -	int pin;
> > -
> > -	pin = intel_gpio_to_pin(pctrl, irqd_to_hwirq(d), &community, &padgrp);
> > -	if (pin >= 0) {
> > -		unsigned int gpp, gpp_offset, is_offset;
> > -		unsigned long flags;
> > -		u32 value;
> > -
> > -		gpp = padgrp->reg_num;
> > -		gpp_offset = padgroup_offset(padgrp, pin);
> > -		is_offset = community->is_offset + gpp * 4;
> > -
> > -		raw_spin_lock_irqsave(&pctrl->lock, flags);
> > -		/* Clear interrupt status first to avoid unexpected interrupt */
> > -		writel(BIT(gpp_offset), community->regs + is_offset);
> > -
> > -		value = readl(community->regs + community->ie_offset + gpp * 4);
> > -		value |= BIT(gpp_offset);
> > -		writel(value, community->regs + community->ie_offset + gpp * 4);
> > -		raw_spin_unlock_irqrestore(&pctrl->lock, flags);
> > -	}
> > -}
> > -
> >  static void intel_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
> >  {
> >  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > @@ -963,6 +934,11 @@ static void intel_gpio_irq_mask_unmask(struct  
> > irq_data *d, bool mask)
> >  		reg = community->regs + community->ie_offset + gpp * 4;
> >
> >  		raw_spin_lock_irqsave(&pctrl->lock, flags);
> > +
> > +		/* Clear interrupt status first to avoid unexpected interrupt */
>
> > +		if (!mask)
>
> Can we do this unconditionally?

Yes I think so.

> > +			writel(BIT(gpp_offset), community->regs +  
> > community->is_offset + gpp * 4);
>
> I would rather prefer to follow the below pattern, like
>
> reg = ...;
> writel(..., reg);
>
> or, to decrease calculus under spin lock, something like
>
> reg = ->regs + gpp * 4;
>
> writel(..., reg + is_offset);
>
> readl(reg + ie_offset);
>
> etc.

Ok, will do.

> > +
> >  		value = readl(reg);
> >  		if (mask)
> >  			value &= ~BIT(gpp_offset);
> > @@ -1106,7 +1082,6 @@ static irqreturn_t intel_gpio_irq(int irq, void  
> > *data)
> >
> >  static struct irq_chip intel_gpio_irqchip = {
> >  	.name = "intel-gpio",
>
> > -	.irq_enable = intel_gpio_irq_enable,
>
> Is it possible scenario when IRQ enable is called, but not masking  
> callbacks?
> For _AEI or GPE?

I am unfamiliar with both of them, what are the callbacks to be used for  
_AEI and GPE case?
Seems like both gpiolib and irqchip call irq_unmask() when irq_enable() is  
absent.

Kai-Heng

> > .irq_ack = intel_gpio_irq_ack,
> >  	.irq_mask = intel_gpio_irq_mask,
> >  	.irq_unmask = intel_gpio_irq_unmask,
>
> --
> With Best Regards,
> Andy Shevchenko