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

AngeloGioacchino Del Regno
2022-07-21T08:34:13Z

Il 20/07/22 16:48, Mattijs Korpershoek ha scritto:
> 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 <mkorpershoek@baylibre.com>
> 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...

>
> 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;

> + 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;
}

> 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?

Cheers,
Angelo