[PATCH v3 2/2] Input: mt6779-keypad - implement row/column selection

From: Mattijs Korpershoek
Date: Fri Jun 17 2022 - 04:19:23 EST


The MediaTek keypad has a total of 6 input rows and 6 input columns.
By default, rows/columns 0-2 are enabled.

This is controlled by the KP_SEL register:
- bits[9:4] control row selection
- bits[15:10] control column selection

Each bit enables the corresponding row/column number (e.g KP_SEL[4]
enables ROW0)

Depending on how the keypad is wired, this may result in wrong readings
of the keypad state.

Program the KP_SEL register to limit the key detection to n_rows,
n_cols we retrieve from the device tree.

Signed-off-by: Mattijs Korpershoek <mkorpershoek@xxxxxxxxxxxx>
---
drivers/input/keyboard/mt6779-keypad.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
index bd86cb95bde3..bf447bf598fb 100644
--- a/drivers/input/keyboard/mt6779-keypad.c
+++ b/drivers/input/keyboard/mt6779-keypad.c
@@ -17,6 +17,11 @@
#define MTK_KPD_DEBOUNCE 0x0018
#define MTK_KPD_DEBOUNCE_MASK GENMASK(13, 0)
#define MTK_KPD_DEBOUNCE_MAX_MS 256
+#define MTK_KPD_SEL 0x0020
+#define MTK_KPD_SEL_COL GENMASK(15, 10)
+#define MTK_KPD_SEL_ROW GENMASK(9, 4)
+#define MTK_KPD_SEL_COLMASK(c) GENMASK((c) + 9, 10)
+#define MTK_KPD_SEL_ROWMASK(r) GENMASK((r) + 3, 4)
#define MTK_KPD_NUM_MEMS 5
#define MTK_KPD_NUM_BITS 136 /* 4*32+8 MEM5 only use 8 BITS */

@@ -161,6 +166,11 @@ static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
(debounce * (1 << 5)) & MTK_KPD_DEBOUNCE_MASK);

+ regmap_update_bits(keypad->regmap, MTK_KPD_SEL, MTK_KPD_SEL_ROW,
+ MTK_KPD_SEL_ROWMASK(keypad->n_rows));
+ regmap_update_bits(keypad->regmap, MTK_KPD_SEL, MTK_KPD_SEL_COL,
+ MTK_KPD_SEL_COLMASK(keypad->n_cols));
+
keypad->clk = devm_clk_get(&pdev->dev, "kpd");
if (IS_ERR(keypad->clk))
return PTR_ERR(keypad->clk);
--
2.34.1