Subject: RE: [PATCH net-next v7 6/9] net: txgbe: Support GPIO to SFP socket

From: Jiawen Wu <[email-masked]>
Date: Fri, 12 May 2023 14:35:38 +0800

On Thursday, May 11, 2023 8:39 PM, Andrew Lunn wrote:
> > +static int txgbe_gpio_set_type(struct irq_data *d, unsigned int type)
> > +{
> > +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +	irq_hw_number_t hwirq = irqd_to_hwirq(d);
> > +	struct wx *wx = gpiochip_get_data(gc);
> > +	u32 level, polarity;
> > +
> > +	level = rd32(wx, WX_GPIO_INTTYPE_LEVEL);
> > +	polarity = rd32(wx, WX_GPIO_POLARITY);
> > +
> > +	switch (type) {
> > +	case IRQ_TYPE_EDGE_BOTH:
> > +		level |= BIT(hwirq);
> > +		break;
> > +	case IRQ_TYPE_EDGE_RISING:
> > +		level |= BIT(hwirq);
> > +		polarity |= BIT(hwirq);
> > +		break;
> > +	case IRQ_TYPE_EDGE_FALLING:
> > +		level |= BIT(hwirq);
> > +		polarity &= ~BIT(hwirq);
> > +		break;
> > +	case IRQ_TYPE_LEVEL_HIGH:
> > +		level &= ~BIT(hwirq);
> > +		polarity |= BIT(hwirq);
> > +		break;
> > +	case IRQ_TYPE_LEVEL_LOW:
> > +		level &= ~BIT(hwirq);
> > +		polarity &= ~BIT(hwirq);
> > +		break;
> > +	}
> 
> You have two configuration bits, level and polarity, yet handle 5 different types?
> 
> > +	wr32m(wx, WX_GPIO_INTEN, BIT(hwirq), BIT(hwirq));
> > +	wr32(wx, WX_GPIO_INTTYPE_LEVEL, level);
> > +	if (type != IRQ_TYPE_EDGE_BOTH)
> > +		wr32(wx, WX_GPIO_POLARITY, polarity);
> 
> If we are interested in both edges, then polarity is meaningless. So i can
> understand not writing it. But how does the hardware know polarity should not
> be used?

I will add toggle trigger to set polarity in both edges, to solve the hysteretic
interrupts problem that has been bothering me.