linux-kernel - [PATCH] Input: matrix_keypad - force switch rows to input mode

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Message-Id: <20221102165747.1528988-1-lis8215@gmail.com>
Date:   Wed,  2 Nov 2022 19:57:47 +0300
From:   Siarhei Volkau <lis8215@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Paul Cercueil <paul@...pouillou.net>,
        Siarhei Volkau <lis8215@...il.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Input: matrix_keypad - force switch rows to input mode

Some Pin/GPIO controllers can't get current GPIO status when interrupt
mode is set. Specifically Ingenic's JZ4755 always returns status at the
moment of interrupt.

The patch tries to fix that by forcibly setting pin mode to GPIO input
prior to reading actual row status. enable_row_irqs seems to set
interrupt mode back as it should be.

Signed-off-by: Siarhei Volkau <lis8215@...il.com>
---
 drivers/input/keyboard/matrix_keypad.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
index 7dd3f3eda..b4c0325bb 100644
--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -127,6 +127,9 @@ static void matrix_keypad_scan(struct work_struct *work)
 
 	memset(new_state, 0, sizeof(new_state));
 
+	for (row = 0; row < pdata->num_row_gpios; row++)
+		gpio_direction_input(pdata->row_gpios[row]);
+
 	/* assert each column and read the row status out */
 	for (col = 0; col < pdata->num_col_gpios; col++) {
 
-- 
2.36.1