From 353bdd7d1456ff601794d2e196ffcb097f131214 Mon Sep 17 00:00:00 2001 From: Markus Burri Date: Wed, 26 Feb 2025 16:28:43 +0100 Subject: [PATCH] Input: matrix_keypad - detect change during scan For a setup where the matrix keypad is connected over a slow interface (e.g. a gpio-expansion over i2c), the scan can take a longer time to read. Interrupts need to be disabled during scan. And therefore changes in this period are not detected. To improve this situation, scan the matrix again if the row state changed during interrupts disabled. The rescan is repeated until no change is detected anymore. Signed-off-by: Markus Burri Link: https://lore.kernel.org/r/20250226152843.43932-4-markus.burri@mt.com Signed-off-by: Dmitry Torokhov --- drivers/input/keyboard/matrix_keypad.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c index fdb3499660a3..e50a6fea9a60 100644 --- a/drivers/input/keyboard/matrix_keypad.c +++ b/drivers/input/keyboard/matrix_keypad.c @@ -125,6 +125,10 @@ static void matrix_keypad_scan(struct work_struct *work) const unsigned short *keycodes = input_dev->keycode; uint32_t new_state[MATRIX_MAX_COLS]; int row, col, code; + u32 init_row_state, new_row_state; + + /* read initial row state to detect changes between scan */ + init_row_state = read_row_state(keypad); /* de-activate all columns for scanning */ activate_all_cols(keypad, false); @@ -173,6 +177,18 @@ static void matrix_keypad_scan(struct work_struct *work) keypad->scan_pending = false; enable_row_irqs(keypad); } + + /* read new row state and detect if value has changed */ + new_row_state = read_row_state(keypad); + if (init_row_state != new_row_state) { + guard(spinlock_irq)(&keypad->lock); + if (unlikely(keypad->scan_pending || keypad->stopped)) + return; + disable_row_irqs(keypad); + keypad->scan_pending = true; + schedule_delayed_work(&keypad->work, + msecs_to_jiffies(keypad->debounce_ms)); + } } static irqreturn_t matrix_keypad_interrupt(int irq, void *id) -- 2.50.1