Re: [PATCH 3/4] extcon: usb-gpio: make debounce value configurable in devicetree

Roger Quadros
2015-03-31T09:30:23Z

On 31/03/15 10:46, Robert Baldyga wrote:
> This patch adds devicetree property for setting debounce value. It allows
> to set debounce time shorter or longer depending on the needs of given
> platform.
>
> Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
> ---
> drivers/extcon/extcon-usb-gpio.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/extcon/extcon-usb-gpio.c b/drivers/extcon/extcon-usb-gpio.c
> index 02ff40e..86e3ece 100644
> --- a/drivers/extcon/extcon-usb-gpio.c
> +++ b/drivers/extcon/extcon-usb-gpio.c
> @@ -130,6 +130,7 @@ static int usb_extcon_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct device_node *np = dev->of_node;
> struct usb_extcon_info *info;
> + u32 debounce;
> int ret;
>
> if (!np)
> @@ -140,6 +141,11 @@ static int usb_extcon_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> info->dev = dev;
> +
> + ret = of_property_read_u32(np, "debounce", &debounce);
> + if (ret < 0)
> + debounce = USB_GPIO_DEBOUNCE_MS;
> +

Should we sanity check debounce value provided by device tree?
e.g. if it is greater than USB_GPIO_DEBOUNCE_MAX then we error out.
MAX could be 100 or 250ms.

> info->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id");
> info->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus");
>
> @@ -161,16 +167,14 @@ static int usb_extcon_probe(struct platform_device *pdev)
> }
>
> if (info->id_gpiod)
> - ret = gpiod_set_debounce(info->id_gpiod,
> - USB_GPIO_DEBOUNCE_MS * 1000);
> + ret = gpiod_set_debounce(info->id_gpiod, debounce * 1000);
> if (!ret && info->vbus_gpiod) {
> - ret = gpiod_set_debounce(info->vbus_gpiod,
> - USB_GPIO_DEBOUNCE_MS * 1000);
> + ret = gpiod_set_debounce(info->vbus_gpiod, debounce * 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);
> + info->debounce_jiffies = msecs_to_jiffies(debounce);
>
> INIT_DELAYED_WORK(&info->wq_detcable, usb_extcon_detect_cable);
>
>

cheers,
-roger