static int gpio_keys_setup_key()

in keyboard/gpio_keys.c [502:679]

• 125 lines of code
• 26 McCabe index (conditional complexity)

static int gpio_keys_setup_key(struct platform_device *pdev,
				struct input_dev *input,
				struct gpio_keys_drvdata *ddata,
				const struct gpio_keys_button *button,
				int idx,
				struct fwnode_handle *child)
{
	const char *desc = button->desc ? button->desc : "gpio_keys";
	struct device *dev = &pdev->dev;
	struct gpio_button_data *bdata = &ddata->data[idx];
	irq_handler_t isr;
	unsigned long irqflags;
	int irq;
	int error;

	bdata->input = input;
	bdata->button = button;
	spin_lock_init(&bdata->lock);

	if (child) {
		bdata->gpiod = devm_fwnode_gpiod_get(dev, child,
						     NULL, GPIOD_IN, desc);
		if (IS_ERR(bdata->gpiod)) {
			error = PTR_ERR(bdata->gpiod);
			if (error == -ENOENT) {
				/*
				 * GPIO is optional, we may be dealing with
				 * purely interrupt-driven setup.
				 */
				bdata->gpiod = NULL;
			} else {
				if (error != -EPROBE_DEFER)
					dev_err(dev, "failed to get gpio: %d\n",
						error);
				return error;
			}
		}
	} else if (gpio_is_valid(button->gpio)) {
		/*
		 * Legacy GPIO number, so request the GPIO here and
		 * convert it to descriptor.
		 */
		unsigned flags = GPIOF_IN;

		if (button->active_low)
			flags |= GPIOF_ACTIVE_LOW;

		error = devm_gpio_request_one(dev, button->gpio, flags, desc);
		if (error < 0) {
			dev_err(dev, "Failed to request GPIO %d, error %d\n",
				button->gpio, error);
			return error;
		}

		bdata->gpiod = gpio_to_desc(button->gpio);
		if (!bdata->gpiod)
			return -EINVAL;
	}

	if (bdata->gpiod) {
		bool active_low = gpiod_is_active_low(bdata->gpiod);

		if (button->debounce_interval) {
			error = gpiod_set_debounce(bdata->gpiod,
					button->debounce_interval * 1000);
			/* use timer if gpiolib doesn't provide debounce */
			if (error < 0)
				bdata->software_debounce =
						button->debounce_interval;

			/*
			 * If reading the GPIO won't sleep, we can use a
			 * hrtimer instead of a standard timer for the software
			 * debounce, to reduce the latency as much as possible.
			 */
			bdata->debounce_use_hrtimer =
					!gpiod_cansleep(bdata->gpiod);
		}

		if (button->irq) {
			bdata->irq = button->irq;
		} else {
			irq = gpiod_to_irq(bdata->gpiod);
			if (irq < 0) {
				error = irq;
				dev_err(dev,
					"Unable to get irq number for GPIO %d, error %d\n",
					button->gpio, error);
				return error;
			}
			bdata->irq = irq;
		}

		INIT_DELAYED_WORK(&bdata->work, gpio_keys_gpio_work_func);

		hrtimer_init(&bdata->debounce_timer,
			     CLOCK_REALTIME, HRTIMER_MODE_REL);
		bdata->debounce_timer.function = gpio_keys_debounce_timer;

		isr = gpio_keys_gpio_isr;
		irqflags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING;

		switch (button->wakeup_event_action) {
		case EV_ACT_ASSERTED:
			bdata->wakeup_trigger_type = active_low ?
				IRQ_TYPE_EDGE_FALLING : IRQ_TYPE_EDGE_RISING;
			break;
		case EV_ACT_DEASSERTED:
			bdata->wakeup_trigger_type = active_low ?
				IRQ_TYPE_EDGE_RISING : IRQ_TYPE_EDGE_FALLING;
			break;
		case EV_ACT_ANY:
		default:
			/*
			 * For other cases, we are OK letting suspend/resume
			 * not reconfigure the trigger type.
			 */
			break;
		}
	} else {
		if (!button->irq) {
			dev_err(dev, "Found button without gpio or irq\n");
			return -EINVAL;
		}

		bdata->irq = button->irq;

		if (button->type && button->type != EV_KEY) {
			dev_err(dev, "Only EV_KEY allowed for IRQ buttons.\n");
			return -EINVAL;
		}

		bdata->release_delay = button->debounce_interval;
		hrtimer_init(&bdata->release_timer,
			     CLOCK_REALTIME, HRTIMER_MODE_REL_HARD);
		bdata->release_timer.function = gpio_keys_irq_timer;

		isr = gpio_keys_irq_isr;
		irqflags = 0;

		/*
		 * For IRQ buttons, there is no interrupt for release.
		 * So we don't need to reconfigure the trigger type for wakeup.
		 */
	}

	bdata->code = &ddata->keymap[idx];
	*bdata->code = button->code;
	input_set_capability(input, button->type ?: EV_KEY, *bdata->code);

	/*
	 * Install custom action to cancel release timer and
	 * workqueue item.
	 */
	error = devm_add_action(dev, gpio_keys_quiesce_key, bdata);
	if (error) {
		dev_err(dev, "failed to register quiesce action, error: %d\n",
			error);
		return error;
	}

	/*
	 * If platform has specified that the button can be disabled,
	 * we don't want it to share the interrupt line.
	 */
	if (!button->can_disable)
		irqflags |= IRQF_SHARED;

	error = devm_request_any_context_irq(dev, bdata->irq, isr, irqflags,
					     desc, bdata);
	if (error < 0) {
		dev_err(dev, "Unable to claim irq %d; error %d\n",
			bdata->irq, error);
		return error;
	}

	return 0;
}