Re: [PATCH v5 6/7] Input: matrix_keypad - add settle time after enable all columns

Manuel Traut
2025-02-19T16:48:08Z

On Fri, Jan 10, 2025 at 06:49:05AM +0100, Markus Burri wrote:
> Matrix_keypad with high capacity need a longer settle time after enable

matrix keypads with a high capacity need a longer settle time after enable

> all columns and re-enabling interrupts.

> This to give time stable the system and not generate interrupts.
It avoids spurios interrupts by giving the system time to stable.

> Add a new optional device-tree property to configure the time before
> enabling interrupts after disable all columns.
> The default is no delay.

The delay for re-enabling the interrupts can be configured by a
device-tree property. The default is no delay.

> Signed-off-by: Markus Burri <markus.burri@mt.com>

Reviewed-by: Manuel Traut <manuel.traut@mt.com>

> ---
> drivers/input/keyboard/matrix_keypad.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
> index 90148d3..fdb3499 100644
> --- a/drivers/input/keyboard/matrix_keypad.c
> +++ b/drivers/input/keyboard/matrix_keypad.c
> @@ -26,6 +26,7 @@ struct matrix_keypad {
> unsigned int row_shift;
>
> unsigned int col_scan_delay_us;
> + unsigned int all_cols_on_delay_us;
> /* key debounce interval in milli-second */
> unsigned int debounce_ms;
> bool drive_inactive_cols;
> @@ -77,6 +78,9 @@ static void activate_all_cols(struct matrix_keypad *keypad, bool on)
>
> for (col = 0; col < keypad->num_col_gpios; col++)
> __activate_col(keypad, col, on);
> +
> + if (on && keypad->all_cols_on_delay_us)
> + fsleep(keypad->all_cols_on_delay_us);
> }
>
> static bool row_asserted(struct matrix_keypad *keypad, int row)
> @@ -400,6 +404,8 @@ static int matrix_keypad_probe(struct platform_device *pdev)
> &keypad->debounce_ms);
> device_property_read_u32(&pdev->dev, "col-scan-delay-us",
> &keypad->col_scan_delay_us);
> + device_property_read_u32(&pdev->dev, "all-cols-on-delay-us",
> + &keypad->all_cols_on_delay_us);
>
> err = matrix_keypad_init_gpio(pdev, keypad);
> if (err)
> --
> 2.39.5
>