[PATCH v2 1/7] Input: matrix_keypad - use fsleep for variable delay duration

Markus Burri posted 7 patches 2 weeks, 4 days ago
[PATCH v2 1/7] Input: matrix_keypad - use fsleep for variable delay duration
Posted by Markus Burri 2 weeks, 4 days ago
The delay is retrieved from a device-tree property, so the duration is
variable. fsleep guesses the best delay function based on duration.

Link: https://www.kernel.org/doc/html/latest/timers/timers-howto.html

Signed-off-by: Markus Burri <markus.burri@mt.com>
---
 drivers/input/keyboard/matrix_keypad.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
index 3c38bae..9eb6808 100644
--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -69,7 +69,7 @@ static void activate_col(struct matrix_keypad *keypad, int col, bool on)
 	__activate_col(keypad, col, on);
 
 	if (on && keypad->col_scan_delay_us)
-		udelay(keypad->col_scan_delay_us);
+		fsleep(keypad->col_scan_delay_us);
 }
 
 static void activate_all_cols(struct matrix_keypad *keypad, bool on)
-- 
2.39.5
Re: [PATCH v2 1/7] Input: matrix_keypad - use fsleep for variable delay duration
Posted by Dmitry Torokhov 2 weeks, 4 days ago
On Tue, Nov 05, 2024 at 02:03:16PM +0100, Markus Burri wrote:
> The delay is retrieved from a device-tree property, so the duration is
> variable. fsleep guesses the best delay function based on duration.

activate_col() may be called in atomic context, and if fsleep() turns
into usleep_range() or msleep() we are going to have a bad time.

We should either stop using request_any_context_irq() or figure out if
interrupt handler can sleep or not and adjust behavior properly.

> 
> Link: https://www.kernel.org/doc/html/latest/timers/timers-howto.html
> 
> Signed-off-by: Markus Burri <markus.burri@mt.com>
> ---
>  drivers/input/keyboard/matrix_keypad.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
> index 3c38bae..9eb6808 100644
> --- a/drivers/input/keyboard/matrix_keypad.c
> +++ b/drivers/input/keyboard/matrix_keypad.c
> @@ -69,7 +69,7 @@ static void activate_col(struct matrix_keypad *keypad, int col, bool on)
>  	__activate_col(keypad, col, on);
>  
>  	if (on && keypad->col_scan_delay_us)
> -		udelay(keypad->col_scan_delay_us);
> +		fsleep(keypad->col_scan_delay_us);
>  }
>  
>  static void activate_all_cols(struct matrix_keypad *keypad, bool on)
> -- 
> 2.39.5
> 

Thanks.

-- 
Dmitry