root/drivers/input/keyboard/mt6779-keypad.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022 MediaTek Inc.
 * Author Fengping Yu <fengping.yu@mediatek.com>
 */
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define MTK_KPD_NAME            "mt6779-keypad"
#define MTK_KPD_MEM             0x0004
#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_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)
#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 */

struct mt6779_keypad {
        struct regmap *regmap;
        struct input_dev *input_dev;
        struct clk *clk;
        u32 n_rows;
        u32 n_cols;
        void (*calc_row_col)(unsigned int key,
                             unsigned int *row, unsigned int *col);
        DECLARE_BITMAP(keymap_state, MTK_KPD_NUM_BITS);
};

static const struct regmap_config mt6779_keypad_regmap_cfg = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = sizeof(u32),
        .max_register = 36,
};

static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
{
        struct mt6779_keypad *keypad = dev_id;
        const unsigned short *keycode = keypad->input_dev->keycode;
        DECLARE_BITMAP(new_state, MTK_KPD_NUM_BITS);
        DECLARE_BITMAP(change, MTK_KPD_NUM_BITS);
        unsigned int bit_nr, key;
        unsigned int row, col;
        unsigned int scancode;
        unsigned int row_shift = get_count_order(keypad->n_cols);
        bool pressed;

        regmap_bulk_read(keypad->regmap, MTK_KPD_MEM,
                         new_state, MTK_KPD_NUM_MEMS);

        bitmap_xor(change, new_state, keypad->keymap_state, MTK_KPD_NUM_BITS);

        for_each_set_bit(bit_nr, change, MTK_KPD_NUM_BITS) {
                /*
                 * Registers are 32bits, but only bits [15:0] are used to
                 * indicate key status.
                 */
                if (bit_nr % 32 >= 16)
                        continue;

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

                scancode = MATRIX_SCAN_CODE(row, col, row_shift);
                /* 1: not pressed, 0: pressed */
                pressed = !test_bit(bit_nr, new_state);
                dev_dbg(&keypad->input_dev->dev, "%s",
                        pressed ? "pressed" : "released");

                input_event(keypad->input_dev, EV_MSC, MSC_SCAN, scancode);
                input_report_key(keypad->input_dev, keycode[scancode], pressed);
                input_sync(keypad->input_dev);

                dev_dbg(&keypad->input_dev->dev,
                        "report Linux keycode = %d\n", keycode[scancode]);
        }

        bitmap_copy(keypad->keymap_state, new_state, MTK_KPD_NUM_BITS);

        return IRQ_HANDLED;
}

static void mt6779_keypad_calc_row_col_single(unsigned int key,
                                              unsigned int *row,
                                              unsigned int *col)
{
        *row = key / 9;
        *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;

        keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
        if (!keypad)
                return -ENOMEM;

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        keypad->regmap = devm_regmap_init_mmio(&pdev->dev, base,
                                               &mt6779_keypad_regmap_cfg);
        if (IS_ERR(keypad->regmap)) {
                dev_err(&pdev->dev,
                        "regmap init failed:%pe\n", keypad->regmap);
                return PTR_ERR(keypad->regmap);
        }

        bitmap_fill(keypad->keymap_state, MTK_KPD_NUM_BITS);

        keypad->input_dev = devm_input_allocate_device(&pdev->dev);
        if (!keypad->input_dev) {
                dev_err(&pdev->dev, "Failed to allocate input dev\n");
                return -ENOMEM;
        }

        keypad->input_dev->name = MTK_KPD_NAME;
        keypad->input_dev->id.bustype = BUS_HOST;

        error = matrix_keypad_parse_properties(&pdev->dev, &keypad->n_rows,
                                               &keypad->n_cols);
        if (error) {
                dev_err(&pdev->dev, "Failed to parse keypad params\n");
                return error;
        }

        if (device_property_read_u32(&pdev->dev, "debounce-delay-ms",
                                     &debounce))
                debounce = 16;

        if (debounce > MTK_KPD_DEBOUNCE_MAX_MS) {
                dev_err(&pdev->dev,
                        "Debounce time exceeds the maximum allowed time %dms\n",
                        MTK_KPD_DEBOUNCE_MAX_MS);
                return -EINVAL;
        }

        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");

        dev_dbg(&pdev->dev, "n_row=%d n_col=%d debounce=%d\n",
                keypad->n_rows, keypad->n_cols, debounce);

        error = matrix_keypad_build_keymap(NULL, NULL,
                                           keypad->n_rows, keypad->n_cols,
                                           NULL, keypad->input_dev);
        if (error) {
                dev_err(&pdev->dev, "Failed to build keymap\n");
                return error;
        }

        input_set_capability(keypad->input_dev, EV_MSC, MSC_SCAN);

        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,
                           MTK_KPD_SEL_COLMASK(keypad->n_cols));

        keypad->clk = devm_clk_get_enabled(&pdev->dev, "kpd");
        if (IS_ERR(keypad->clk))
                return PTR_ERR(keypad->clk);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        error = devm_request_threaded_irq(&pdev->dev, irq,
                                          NULL, mt6779_keypad_irq_handler,
                                          IRQF_ONESHOT, MTK_KPD_NAME, keypad);
        if (error) {
                dev_err(&pdev->dev, "Failed to request IRQ#%d: %d\n",
                        irq, error);
                return error;
        }

        error = input_register_device(keypad->input_dev);
        if (error) {
                dev_err(&pdev->dev, "Failed to register device\n");
                return error;
        }

        error = device_init_wakeup(&pdev->dev, wakeup);
        if (error)
                dev_warn(&pdev->dev, "device_init_wakeup() failed: %d\n",
                         error);

        return 0;
}

static const struct of_device_id mt6779_keypad_of_match[] = {
        { .compatible = "mediatek,mt6779-keypad" },
        { .compatible = "mediatek,mt6873-keypad" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mt6779_keypad_of_match);

static struct platform_driver mt6779_keypad_pdrv = {
        .probe = mt6779_keypad_pdrv_probe,
        .driver = {
                   .name = MTK_KPD_NAME,
                   .of_match_table = mt6779_keypad_of_match,
        },
};
module_platform_driver(mt6779_keypad_pdrv);

MODULE_AUTHOR("Mediatek Corporation");
MODULE_DESCRIPTION("MTK Keypad (KPD) Driver");
MODULE_LICENSE("GPL");