论gpio --- Linux kernel 实现欣赏

int pinctrl_bind_pins(struct device *dev)
{
	int ret;

	if (dev->of_node_reused)	 默认值为 False.
		return 0;

	dev->pins = devm_kzalloc(dev, sizeof(*(dev->pins)), GFP_KERNEL);
	if (!dev->pins)
		return -ENOMEM;

	dev->pins->p = devm_pinctrl_get(dev);
	if (IS_ERR(dev->pins->p)) {
		dev_dbg(dev, "no pinctrl handle\n");
		ret = PTR_ERR(dev->pins->p);
		goto cleanup_alloc;
	}

	dev->pins->default_state = pinctrl_lookup_state(dev->pins->p,
					PINCTRL_STATE_DEFAULT);
	if (IS_ERR(dev->pins->default_state)) {
		dev_dbg(dev, "no default pinctrl state\n");
		ret = 0;
		goto cleanup_get;
	}