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 16:57:32 +0800

> > +static int txgbe_gpio_direction_out(struct gpio_chip *chip, unsigned int offset,
> > +				    int val)
> > +{
> > +	struct wx *wx = gpiochip_get_data(chip);
> > +	u32 mask;
> > +
> > +	mask = BIT(offset) | BIT(offset - 1);
> > +	if (val)
> > +		wr32m(wx, WX_GPIO_DR, mask, mask);
> > +	else
> > +		wr32m(wx, WX_GPIO_DR, mask, 0);
> > +
> > +	wr32m(wx, WX_GPIO_DDR, BIT(offset), BIT(offset));
> 
> Can you explain, what prevents to have this flow to be interleaved by other API
> calls, like ->direction_in()? Didn't you missed proper locking schema?

It's true, I should add spinlock for writing GPIO registers.

> 
> > +	return 0;
> > +}
> 
> ...
> 
> > +	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);
> 
> This...
> 
> > +		break;
> > +	case IRQ_TYPE_LEVEL_HIGH:
> > +		level &= ~BIT(hwirq);
> 
> ...and this can be done outside of the switch-case. Then you simply set certain
> bits where it's needed.
> 
> > +		polarity |= BIT(hwirq);
> > +		break;
> > +	case IRQ_TYPE_LEVEL_LOW:
> > +		level &= ~BIT(hwirq);
> > +		polarity &= ~BIT(hwirq);
> > +		break;
> 
> default?

Do you mean that treat IRQ_TYPE_LEVEL_LOW as default case, clear level and
polarity firstly, then set the bits in other needed case?