[PATCH 0/2] Input: mt6779-keypad - fix hw code logic and row/col selection

[PATCH 0/2] Input: mt6779-keypad - fix hw code logic and row/col selection

[Mattijs Korpershoek]

This serie is the first follow-up on the mt6779-keypad in
order to enable it on the MediaTek mt8183-pumpkin board.

To fully enable it on mt8183-pumpkin, we still need:
* double key support
* dts changes

To ease up reviewing, I preferred sending this first.

The first patch fixes a logic bug based on the (non-public) datasheet
I have.
The second patch configures the keypad correctly in order to not
report bogus values.

Thank you,
Mattijs

Mattijs Korpershoek (2):
  Input: mt6779-keypad - fix hardware code mapping
  Input: mt6779-keypad - implement row/column selection

 drivers/input/keyboard/mt6779-keypad.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)


base-commit: b243018eafeb69bf074ef013c54504632fd161ec
-- 
2.32.0

[PATCH 1/2] Input: mt6779-keypad - fix hardware code mapping

[Mattijs Korpershoek]

In mt6779_keypad_irq_handler(), we
1. Read a hardware code from KPD_MEM1 -> KPD_MEM5
2. Use that hardware code to compute columns/rows for the standard
   keyboard matrix.

According to the (non-public) datasheet, the
map between the hardware code and the cols/rows is:

        |(0)  |(1)  |(2)
    ----*-----*-----*-----
        |     |     |
        |(9)  |(10) |(11)
    ----*-----*-----*-----
        |     |     |
        |(18) |(19) |(20)
    ----*-----*-----*-----
        |     |     |

This brings us to another formula:
-> row = code / 9;
-> col = code % 3;

Implement this mapping in bitnr_to_col_row() to fetch the
correct input event from keypad->input_dev->keycode and report that
back to userspace.

Fixes: f28af984e771 ("Input: mt6779-keypad - add MediaTek keypad driver")
Co-developed-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
---
 drivers/input/keyboard/mt6779-keypad.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
index 2e7c9187c10f..23360de20da5 100644
--- a/drivers/input/keyboard/mt6779-keypad.c
+++ b/drivers/input/keyboard/mt6779-keypad.c
@@ -36,6 +36,19 @@ static const struct regmap_config mt6779_keypad_regmap_cfg = {
 	.max_register = 36,
 };
 
+/*
+ * | hardware key code | col0 | col1 | col2|
+ * | ----------------- | -----| ---- | --- |
+ * | row0              | 0    | 1    | 2   |
+ * | row1              | 9    | 10   | 11  |
+ * | row2              | 18   | 19   | 20  |
+ */
+static void bitnr_to_col_row(int bit_nr, int *col, int *row)
+{
+	*row = bit_nr / 9;
+	*col = bit_nr % 3;
+}
+
 static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
 {
 	struct mt6779_keypad *keypad = dev_id;
@@ -61,8 +74,7 @@ static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
 		if (bit_nr % 32 >= 16)
 			continue;
 
-		row = bit_nr / 32;
-		col = bit_nr % 32;
+		bitnr_to_col_row(bit_nr, &col, &row);
 		scancode = MATRIX_SCAN_CODE(row, col, row_shift);
 		/* 1: not pressed, 0: pressed */
 		pressed = !test_bit(bit_nr, new_state);
-- 
2.32.0

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

[Mattijs Korpershoek]

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@baylibre.com>
---
 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 23360de20da5..653dfc619696 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)	(MTK_KPD_SEL_COL >> (6 - (c)))
+#define MTK_KPD_SEL_ROWMASK(r)	(MTK_KPD_SEL_ROW >> (6 - (r)))
 #define MTK_KPD_NUM_MEMS	5
 #define MTK_KPD_NUM_BITS	136	/* 4*32+8 MEM5 only use 8 BITS */
 
@@ -171,6 +176,11 @@ 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);
-- 
2.32.0