On Wed, Oct 19, 2016 at 04:41:07PM -0700, Dmitry Torokhov wrote:
> It does not matter if given GPIO may sleep or not when reading state,
> polling is always done in a non-atomic context, so we should always
> be able to simply use gpiod_get_value_cansleep().
>
> Also let's note in the logs when we fail to read gpio state.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> ---
> drivers/input/keyboard/gpio_keys_polled.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
> index daef8ea..3c79158 100644
> --- a/drivers/input/keyboard/gpio_keys_polled.c
> +++ b/drivers/input/keyboard/gpio_keys_polled.c
> @@ -34,7 +34,6 @@ struct gpio_keys_button_data {
> int last_state;
> int count;
> int threshold;
> - int can_sleep;
> };
>
> struct gpio_keys_polled_dev {
> @@ -76,16 +75,17 @@ static void gpio_keys_polled_check_state(struct input_polled_dev *dev,
> {
> int state;
>
> - if (bdata->can_sleep)
> - state = !!gpiod_get_value_cansleep(bdata->gpiod);
> - else
> - state = !!gpiod_get_value(bdata->gpiod);
> -
> - gpio_keys_button_event(dev, button, state);
> + state = gpiod_get_value_cansleep(bdata->gpiod);
> + if (unlikely(state < 0)) {
Is this unlikely() really bringing any performance benefits here?
Otherwise this patch looks good to me (sans the below line which you
mentioned in your followup email).
> + dev_err(input->dev.parent,
> + "failed to get gpio state: %d\n", state);
> + } else {
> + gpio_keys_button_event(dev, button, state);
>
> - if (state != bdata->last_state) {
> - bdata->count = 0;
> - bdata->last_state = state;
> + if (state != bdata->last_state) {
> + bdata->count = 0;
> + bdata->last_state = state;
> + }
> }
> }
>
> @@ -341,7 +341,6 @@ static int gpio_keys_polled_probe(struct platform_device *pdev)
> }
> }
>
> - bdata->can_sleep = gpiod_cansleep(bdata->gpiod);
> bdata->last_state = -1;
> bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
> pdata->poll_interval);
> --
> 2.8.0.rc3.226.g39d4020
>
>
> --
> Dmitry
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