Input: mt6779-keypad - support double keys matrix

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,keys-per-group
device tree property.

Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220720-mt8183-keypad-v2-5-6d42c357cb76@baylibre.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/keyboard/mt6779-keypad.c b/drivers/input/keyboard/mt6779-keypad.c
index 9decdfa..a05e70a 100644 (file)
--- 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)
@@ -103,12 +104,21 @@ static void mt6779_keypad_calc_row_col_single(unsigned int key,
        *col = key % 9;
 }
 
+static void mt6779_keypad_calc_row_col_double(unsigned int key,
+                                             unsigned int *row,
+                                             unsigned int *col)
+{
+       *row = key / 13;
+       *col = (key % 13) / 2;
+}
+
 static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
 {
        struct mt6779_keypad *keypad;
        void __iomem *base;
        int irq;
        u32 debounce;
+       u32 keys_per_group;
        bool wakeup;
        int error;
 
@@ -157,7 +167,22 @@ static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
-       keypad->calc_row_col = mt6779_keypad_calc_row_col_single;
+       if (device_property_read_u32(&pdev->dev, "mediatek,keys-per-group",
+                                    &keys_per_group))
+               keys_per_group = 1;
+
+       switch (keys_per_group) {
+       case 1:
+               keypad->calc_row_col = mt6779_keypad_calc_row_col_single;
+               break;
+       case 2:
+               keypad->calc_row_col = mt6779_keypad_calc_row_col_double;
+               break;
+       default:
+               dev_err(&pdev->dev,
+                       "Invalid keys-per-group: %d\n", keys_per_group);
+               return -EINVAL;
+       }
 
        wakeup = device_property_read_bool(&pdev->dev, "wakeup-source");
 
@@ -177,6 +202,11 @@ static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
        regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
                     (debounce * (1 << 5)) & MTK_KPD_DEBOUNCE_MASK);
 
+       if (keys_per_group == 2)
+               regmap_update_bits(keypad->regmap, MTK_KPD_SEL,
+                                  MTK_KPD_SEL_DOUBLE_KP_MODE,
+                                  MTK_KPD_SEL_DOUBLE_KP_MODE);
+
        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,