Re: [PATCH v3 2/4] extcon: usb-gpio: add support for VBUS detection

[Roger Quadros <rogerq@ti.com>]

On 02/04/15 16:13, Robert Baldyga wrote:
> This patch adds VBUS pin detection support to extcon-usb-gpio driver.
> It allows to use this driver with boards which have both VBUS and ID
> pins, or only one of them.
> 
> Following table of states presents relationship between this signals
> and detected cable type:
> 
>  State              |    ID   |   VBUS
> ----------------------------------------
>  [1] USB            |    H    |    H
>  [2] none           |    H    |    L
>  [3] USB & USB-HOST |    L    |    H
>  [4] USB-HOST       |    L    |    L
> 
> In case we have only one of these signals:
> - VBUS only - we want to distinguish between [1] and [2], so ID is always 1.
> - ID only - we want to distinguish between [1] and [4], so VBUS = ID.
> 
> Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>

Acked-by: Roger Quadros <rogerq@ti.com>

cheers,
-roger

> ---
>  drivers/extcon/extcon-usb-gpio.c | 169 +++++++++++++++++++++++++++------------
>  1 file changed, 119 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
> index f6aa99d..baf7add 100644
> --- a/drivers/extcon/extcon-usb-gpio.c
> +++ b/drivers/extcon/extcon-usb-gpio.c
> @@ -32,7 +32,9 @@ struct usb_extcon_info {
>  	struct extcon_dev *edev;
>  
>  	struct gpio_desc *id_gpiod;
> +	struct gpio_desc *vbus_gpiod;
>  	int id_irq;
> +	int vbus_irq;
>  
>  	unsigned long debounce_jiffies;
>  	struct delayed_work wq_detcable;
> @@ -52,40 +54,51 @@ static const char *usb_extcon_cable[] = {
>  	NULL,
>  };
>  
> +/*
> + * "USB" = VBUS and "USB-HOST" = !ID, so we have:
> + *
> + *  State              |    ID   |   VBUS
> + * ----------------------------------------
> + *  [1] USB            |    H    |    H
> + *  [2] none           |    H    |    L
> + *  [3] USB & USB-HOST |    L    |    H
> + *  [4] USB-HOST       |    L    |    L
> + *
> + * In case we have only one of these signals:
> + * - VBUS only - we want to distinguish between [1] and [2], so ID is always 1.
> + * - ID only - we want to distinguish between [1] and [4], so VBUS = ID.
> + */
> +
>  static void usb_extcon_detect_cable(struct work_struct *work)
>  {
>  	int id;
> +	int vbus;
>  	struct usb_extcon_info *info = container_of(to_delayed_work(work),
>  						    struct usb_extcon_info,
>  						    wq_detcable);
>  
> -	/* check ID and update cable state */
> -	id = gpiod_get_value_cansleep(info->id_gpiod);
> -	if (id) {
> -		/*
> -		 * ID = 1 means USB HOST cable detached.
> -		 * As we don't have event for USB peripheral cable attached,
> -		 * we simulate USB peripheral attach here.
> -		 */
> +	/* check ID and VBUS and update cable state */
> +
> +	id = info->id_gpiod ?
> +		gpiod_get_value_cansleep(info->id_gpiod) : 1;
> +
> +	vbus = info->vbus_gpiod ?
> +		gpiod_get_value_cansleep(info->vbus_gpiod) : id;
> +
> +	/* at first we clean states which are no longer active */
> +	if (id)
>  		extcon_set_cable_state(info->edev,
> -				       usb_extcon_cable[EXTCON_CABLE_USB_HOST],
> -				       false);
> +			usb_extcon_cable[EXTCON_CABLE_USB_HOST], false);
> +	if (!vbus)
>  		extcon_set_cable_state(info->edev,
> -				       usb_extcon_cable[EXTCON_CABLE_USB],
> -				       true);
> -	} else {
> -		/*
> -		 * ID = 0 means USB HOST cable attached.
> -		 * As we don't have event for USB peripheral cable detached,
> -		 * we simulate USB peripheral detach here.
> -		 */
> +			usb_extcon_cable[EXTCON_CABLE_USB], false);
> +
> +	if (!id)
>  		extcon_set_cable_state(info->edev,
> -				       usb_extcon_cable[EXTCON_CABLE_USB],
> -				       false);
> +				usb_extcon_cable[EXTCON_CABLE_USB_HOST], true);
> +	if (vbus)
>  		extcon_set_cable_state(info->edev,
> -				       usb_extcon_cable[EXTCON_CABLE_USB_HOST],
> -				       true);
> -	}
> +			usb_extcon_cable[EXTCON_CABLE_USB], true);
>  }
>  
>  static irqreturn_t usb_irq_handler(int irq, void *dev_id)
> @@ -113,10 +126,12 @@ static int usb_extcon_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	info->dev = dev;
> -	info->id_gpiod = devm_gpiod_get(&pdev->dev, "id");
> -	if (IS_ERR(info->id_gpiod)) {
> -		dev_err(dev, "failed to get ID GPIO\n");
> -		return PTR_ERR(info->id_gpiod);
> +	info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id");
> +	info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus");
> +
> +	if (!info->id_gpiod && !info->vbus_gpiod) {
> +		dev_err(dev, "failed to get gpios\n");
> +		return -ENODEV;
>  	}
>  
>  	info->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
> @@ -131,27 +146,51 @@ static int usb_extcon_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = gpiod_set_debounce(info->id_gpiod,
> -				 USB_GPIO_DEBOUNCE_MS * 1000);
> +	if (info->id_gpiod)
> +		ret = gpiod_set_debounce(info->id_gpiod,
> +			USB_GPIO_DEBOUNCE_MS * 1000);
> +	if (!ret && info->vbus_gpiod) {
> +		ret = gpiod_set_debounce(info->vbus_gpiod,
> +			USB_GPIO_DEBOUNCE_MS * 1000);
> +		if (ret < 0 && info->id_gpiod)
> +			gpiod_set_debounce(info->vbus_gpiod, 0);
> +	}
>  	if (ret < 0)
>  		info->debounce_jiffies = msecs_to_jiffies(USB_GPIO_DEBOUNCE_MS);
>  
>  	INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
>  
> -	info->id_irq = gpiod_to_irq(info->id_gpiod);
> -	if (info->id_irq < 0) {
> -		dev_err(dev, "failed to get ID IRQ\n");
> -		return info->id_irq;
> +	if (info->id_gpiod) {
> +		info->id_irq = gpiod_to_irq(info->id_gpiod);
> +		if (info->id_irq < 0) {
> +			dev_err(dev, "failed to get ID IRQ\n");
> +			return info->id_irq;
> +		}
> +		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
> +				usb_irq_handler,
> +				IRQF_TRIGGER_RISING |
> +				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +				pdev->name, info);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to request handler for ID IRQ\n");
> +			return ret;
> +		}
>  	}
> -
> -	ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
> -					usb_irq_handler,
> -					IRQF_TRIGGER_RISING |
> -					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> -					pdev->name, info);
> -	if (ret < 0) {
> -		dev_err(dev, "failed to request handler for ID IRQ\n");
> -		return ret;
> +	if (info->vbus_gpiod) {
> +		info->vbus_irq = gpiod_to_irq(info->vbus_gpiod);
> +		if (info->vbus_irq < 0) {
> +			dev_err(dev, "failed to get VBUS IRQ\n");
> +			return info->vbus_irq;
> +		}
> +		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
> +				usb_irq_handler,
> +				IRQF_TRIGGER_RISING |
> +				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +				pdev->name, info);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to request handler for VBUS IRQ\n");
> +			return ret;
> +		}
>  	}
>  
>  	platform_set_drvdata(pdev, info);
> @@ -179,9 +218,16 @@ static int usb_extcon_suspend(struct device *dev)
>  	int ret = 0;
>  
>  	if (device_may_wakeup(dev)) {
> -		ret = enable_irq_wake(info->id_irq);
> -		if (ret)
> -			return ret;
> +		if (info->id_gpiod) {
> +			ret = enable_irq_wake(info->id_irq);
> +			if (ret)
> +				return ret;
> +		}
> +		if (info->vbus_gpiod) {
> +			ret = enable_irq_wake(info->vbus_irq);
> +			if (ret)
> +				goto err;
> +		}
>  	}
>  
>  	/*
> @@ -189,9 +235,17 @@ static int usb_extcon_suspend(struct device *dev)
>  	 * as GPIOs used behind I2C subsystem might not be
>  	 * accessible until resume completes. So disable IRQ.
>  	 */
> -	disable_irq(info->id_irq);
> +	if (info->id_gpiod)
> +		disable_irq(info->id_irq);
> +	if (info->vbus_gpiod)
> +		disable_irq(info->vbus_irq);
>  
>  	return ret;
> +
> +err:
> +	if (info->id_gpiod)
> +		disable_irq_wake(info->id_irq);
> +	return ret;
>  }
>  
>  static int usb_extcon_resume(struct device *dev)
> @@ -200,13 +254,28 @@ static int usb_extcon_resume(struct device *dev)
>  	int ret = 0;
>  
>  	if (device_may_wakeup(dev)) {
> -		ret = disable_irq_wake(info->id_irq);
> -		if (ret)
> -			return ret;
> +		if (info->id_gpiod) {
> +			ret = disable_irq_wake(info->id_irq);
> +			if (ret)
> +				return ret;
> +		}
> +		if (info->vbus_gpiod) {
> +			ret = disable_irq_wake(info->vbus_irq);
> +			if (ret)
> +				goto err;
> +		}
>  	}
>  
> -	enable_irq(info->id_irq);
> +	if (info->id_gpiod)
> +		enable_irq(info->id_irq);
> +	if (info->vbus_gpiod)
> +		enable_irq(info->vbus_irq);
> +
> +	return ret;
>  
> +err:
> +	if (info->id_gpiod)
> +		enable_irq_wake(info->id_irq);
>  	return ret;
>  }
>  #endif
>