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

Markus Burri
2025-01-10T05:50:50Z

Matrix_keypad with 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.

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

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