On Fri, Mar 22, 2019 at 11:14:14AM +0800, zhuchangc...@cvte.com wrote:
> static int intel_gpio_set_direction(struct pinctrl_dev *pctldev,
> struct pinctrl_gpio_range *range,
> unsigned pin, bool input)
> {
> struct intel_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> void __iomem *padcfg0;
> unsigned long flags;
> u32 value;
> spin_lock_irqsave(&pctrl->lock, flags);
> padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
> value = readl(padcfg0);
> if (input)
> value |= PADCFG0_GPIOTXDIS;
> else
> value &= ~PADCFG0_GPIOTXDIS;
> writel(value, padcfg0);
> spin_unlock_irqrestore(&pctrl->lock, flags);
> return 0;
> }
>
> From above,you can kown when you export a GPIO ,it will do request,
>
> and there will set TX and RX register at the time same time.
>
> when you try to set direction in and set value, TX register value can
> roll back
>
> the value,but RX register was not set, so who will set RX value back??
I think you are looking at some older code. There is now function
__intel_gpio_set_direction() that is supposed to set both buffers
depending on the direction. It was introduced with commit 17fab473693e
("pinctrl: intel: Set pin direction properly").
