Re: [PATCH v1 4/6] Input: mt6779-keypad - support double keys matrix

On Thu, Jul 21, 2022 at 10:34, AngeloGioacchino Del Regno [off-list ref] wrote:

Il 20/07/22 16:48, Mattijs Korpershoek ha scritto:

quoted

MediaTek keypad has 2 modes of detecting key events:
- single key: each (row, column) can detect one key
- double key: each (row, column) is a group of 2 keys

Double key support exists to minimize cost, since it reduces the number
of pins required for physical keys.

Double key is configured by setting BIT(0) of the KP_SEL register.

Enable double key matrix support based on the mediatek,double-keys
device tree property.

Signed-off-by: Mattijs Korpershoek <redacted>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
index bf447bf598fb..9a5dbd415dac 100644
--- a/drivers/input/keyboard/mt6779-keypad.c
+++ b/drivers/input/keyboard/mt6779-keypad.c

@@ -18,6 +18,7 @@
  #define MTK_KPD_DEBOUNCE_MASK	GENMASK(13, 0)
  #define MTK_KPD_DEBOUNCE_MAX_MS	256
  #define MTK_KPD_SEL		0x0020
+#define MTK_KPD_SEL_DOUBLE_KP_MODE	BIT(0)
  #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)

@@ -31,6 +32,7 @@ struct mt6779_keypad {
  	struct clk *clk;
  	u32 n_rows;
  	u32 n_cols;
+	bool double_keys;
  	DECLARE_BITMAP(keymap_state, MTK_KPD_NUM_BITS);
  };
  

@@ -67,8 +69,13 @@ static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
  			continue;
  
  		key = bit_nr / 32 * 16 + bit_nr % 32;
-		row = key / 9;
-		col = key % 9;
+		if (keypad->double_keys) {
+			row = key / 13;
+			col = (key % 13) / 2;
+		} else {
+			row = key / 9;
+			col = key % 9;
+		}

I don't fully like this if branch permanently evaluating true or false, as no
runtime can actually change this result...

In practice, it's fine, but I was wondering if anyone would disagree with the
following proposal...

struct mt6779_keypad {
	.......
	void (*calc_row_col)(unsigned int *row, unsigned int *col);
};

In mt6779_keypad_irq_handler:

	key = bit_nr / 32 * 16 + bit_nr % 32;
	keypad->calc_row_col(&row, &col);

and below...

quoted

  
  		scancode = MATRIX_SCAN_CODE(row, col, row_shift);
  		/* 1: not pressed, 0: pressed */

@@ -150,6 +157,8 @@ static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
  
  	wakeup = device_property_read_bool(&pdev->dev, "wakeup-source");
  
+	keypad->double_keys = device_property_read_bool(&pdev->dev, "mediatek,double-keys");
+
  	dev_dbg(&pdev->dev, "n_row=%d n_col=%d debounce=%d\n",
  		keypad->n_rows, keypad->n_cols, debounce);
  

@@ -166,6 +175,10 @@ static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
  	regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
  		     (debounce * (1 << 5)) & MTK_KPD_DEBOUNCE_MASK);
  
+	if (keypad->double_keys)

		keypad->calc_row_col = mt6779_keypad_calc_row_col_double_kp;

quoted

+		regmap_update_bits(keypad->regmap, MTK_KPD_SEL,
+				   MTK_KPD_SEL_DOUBLE_KP_MODE, MTK_KPD_SEL_DOUBLE_KP_MODE);
+

	} else {
		keypad->calc_row_col = mt6779_keypad_calc_row_col_single_kp;
	}

quoted

  	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,

what do you think?

Hi Angelo,

Thank you for your detailed suggestion. I like it and since I have to
resend a v2 anyways, I will consider implementing it.
On the other hand, I'm a little reluctant because it means that I'll
have to remove Matthias's reviewed-by :(

Cheers,
Angelo