linux-kernel - [PATCH 5/6] Input: matrix_keypad - add settle time after enable all columns

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Message-Id: <20241031063004.69956-6-markus.burri@mt.com>
Date: Thu, 31 Oct 2024 07:30:03 +0100
From: Markus Burri <markus.burri@...com>
To: linux-kernel@...r.kernel.org
Cc: Markus Burri <markus.burri@...com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	linux-input@...r.kernel.org,
	devicetree@...r.kernel.org,
	Manuel Traut <manuel.traut@...com>,
	HeDong Zhao <hedong.zhao@...com>
Subject: [PATCH 5/6] Input: matrix_keypad - add settle time after enable all columns

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@...com>
Reviewed-by: Manuel Traut <manuel.traut@...com>
Tested-by: HeDong Zhao <hedong.zhao@...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 c091f90..f0d3004 100644
--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -27,6 +27,7 @@ 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;
@@ -78,6 +79,9 @@ 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)
@@ -402,6 +406,8 @@ 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