Re: [PATCH 1/1] extcon: gpio: queue work only if debounce is NZ

Guenter Roeck
2016-03-08T15:00:39Z

On Tue, Mar 08, 2016 at 05:15:53PM +0530, Venkat Reddy Talla wrote:
> Use queue_delayed_work only when debounce time is
> required to read gpio state properly, read the gpio
> state and set the extcon cable state in IRQ handler
> context if gpio settling time is not needed.
>
> Signed-off-by: Venkat Reddy Talla <vreddytalla@nvidia.com>
> ---
> drivers/extcon/extcon-gpio.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
> index 279ff8f..1beb086 100644
> --- a/drivers/extcon/extcon-gpio.c
> +++ b/drivers/extcon/extcon-gpio.c
> @@ -56,8 +56,12 @@ static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
> {
> struct gpio_extcon_data *data = dev_id;
>
> - queue_delayed_work(system_power_efficient_wq, &data->work,
> + if (data->debounce_jiffies)
> + queue_delayed_work(system_power_efficient_wq, &data->work,
> data->debounce_jiffies);
> + else
> + gpio_extcon_work(&data->work.work);
> +

The interrupt is requested with devm_request_any_context_irq(), meaning
the handler may run in hard interrupt context. gpio_extcon_work() calls
gpiod_get_value_cansleep(), which may not be a good idea in hard interrupt
context.

Guenter

> return IRQ_HANDLED;
> }
>
> --
> 2.1.4
>
>