Re: [PATCH v5 1/7] Input: matrix_keypad - use fsleep for variable delay duration

Dmitry Torokhov
2025-02-25T06:40:59Z

On Wed, Feb 19, 2025 at 05:34:49PM +0100, Manuel Traut wrote:
> On Fri, Jan 10, 2025 at 06:49:00AM +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.
> >
> > see Documentation/timers/delay_sleep_functions.rst
> >
> > Signed-off-by: Markus Burri <markus.burri@mt.com>
>
> Reviewed-by: Manuel Traut <manuel.traut@mt.com>

As I mentioned in other review activate_col() may be called in atomic
context where we can not sleep:

"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."

Unfortunately this was completely ignored.

>
> > ---
> > 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 2a3b3bf..5571d2e 100644
> > --- a/drivers/input/keyboard/matrix_keypad.c
> > +++ b/drivers/input/keyboard/matrix_keypad.c
> > @@ -68,7 +68,7 @@ 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