// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson SA 2010
 *
 * Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/input/matrix_keypad.h>
#include <linux/mfd/stmpe.h>

/* These are at the same addresses in all STMPE variants */
#define STMPE_KPC_COL                   0x60
#define STMPE_KPC_ROW_MSB               0x61
#define STMPE_KPC_ROW_LSB               0x62
#define STMPE_KPC_CTRL_MSB              0x63
#define STMPE_KPC_CTRL_LSB              0x64
#define STMPE_KPC_COMBI_KEY_0           0x65
#define STMPE_KPC_COMBI_KEY_1           0x66
#define STMPE_KPC_COMBI_KEY_2           0x67
#define STMPE_KPC_DATA_BYTE0            0x68
#define STMPE_KPC_DATA_BYTE1            0x69
#define STMPE_KPC_DATA_BYTE2            0x6a
#define STMPE_KPC_DATA_BYTE3            0x6b
#define STMPE_KPC_DATA_BYTE4            0x6c

#define STMPE_KPC_CTRL_LSB_SCAN         (0x1 << 0)
#define STMPE_KPC_CTRL_LSB_DEBOUNCE     (0x7f << 1)
#define STMPE_KPC_CTRL_MSB_SCAN_COUNT   (0xf << 4)

#define STMPE_KPC_ROW_MSB_ROWS          0xff

#define STMPE_KPC_DATA_UP               (0x1 << 7)
#define STMPE_KPC_DATA_ROW              (0xf << 3)
#define STMPE_KPC_DATA_COL              (0x7 << 0)
#define STMPE_KPC_DATA_NOKEY_MASK       0x78

#define STMPE_KEYPAD_MAX_DEBOUNCE       127
#define STMPE_KEYPAD_MAX_SCAN_COUNT     15

#define STMPE_KEYPAD_MAX_ROWS           8
#define STMPE_KEYPAD_MAX_COLS           8
#define STMPE_KEYPAD_ROW_SHIFT          3
#define STMPE_KEYPAD_KEYMAP_MAX_SIZE \
        (STMPE_KEYPAD_MAX_ROWS * STMPE_KEYPAD_MAX_COLS)


#define STMPE1601_NUM_DATA      5
#define STMPE2401_NUM_DATA      3
#define STMPE2403_NUM_DATA      5

/* Make sure it covers all cases above */
#define MAX_NUM_DATA            5

/**
 * struct stmpe_keypad_variant - model-specific attributes
 * @auto_increment: whether the KPC_DATA_BYTE register address
 *                  auto-increments on multiple read
 * @set_pullup: whether the pins need to have their pull-ups set
 * @num_data: number of data bytes
 * @num_normal_data: number of normal keys' data bytes
 * @max_cols: maximum number of columns supported
 * @max_rows: maximum number of rows supported
 * @col_gpios: bitmask of gpios which can be used for columns
 * @row_gpios: bitmask of gpios which can be used for rows
 */
struct stmpe_keypad_variant {
        bool            auto_increment;
        bool            set_pullup;
        int             num_data;
        int             num_normal_data;
        int             max_cols;
        int             max_rows;
        unsigned int    col_gpios;
        unsigned int    row_gpios;
};

static const struct stmpe_keypad_variant stmpe_keypad_variants[] = {
        [STMPE1601] = {
                .auto_increment         = true,
                .num_data               = STMPE1601_NUM_DATA,
                .num_normal_data        = 3,
                .max_cols               = 8,
                .max_rows               = 8,
                .col_gpios              = 0x000ff,      /* GPIO 0 - 7 */
                .row_gpios              = 0x0ff00,      /* GPIO 8 - 15 */
        },
        [STMPE2401] = {
                .auto_increment         = false,
                .set_pullup             = true,
                .num_data               = STMPE2401_NUM_DATA,
                .num_normal_data        = 2,
                .max_cols               = 8,
                .max_rows               = 12,
                .col_gpios              = 0x0000ff,     /* GPIO 0 - 7*/
                .row_gpios              = 0x1f7f00,     /* GPIO 8-14, 16-20 */
        },
        [STMPE2403] = {
                .auto_increment         = true,
                .set_pullup             = true,
                .num_data               = STMPE2403_NUM_DATA,
                .num_normal_data        = 3,
                .max_cols               = 8,
                .max_rows               = 12,
                .col_gpios              = 0x0000ff,     /* GPIO 0 - 7*/
                .row_gpios              = 0x1fef00,     /* GPIO 8-14, 16-20 */
        },
};

/**
 * struct stmpe_keypad - STMPE keypad state container
 * @stmpe: pointer to parent STMPE device
 * @input: spawned input device
 * @variant: STMPE variant
 * @debounce_ms: debounce interval, in ms.  Maximum is
 *               %STMPE_KEYPAD_MAX_DEBOUNCE.
 * @scan_count: number of key scanning cycles to confirm key data.
 *              Maximum is %STMPE_KEYPAD_MAX_SCAN_COUNT.
 * @no_autorepeat: disable key autorepeat
 * @rows: bitmask for the rows
 * @cols: bitmask for the columns
 * @keymap: the keymap
 */
struct stmpe_keypad {
        struct stmpe *stmpe;
        struct input_dev *input;
        const struct stmpe_keypad_variant *variant;
        unsigned int debounce_ms;
        unsigned int scan_count;
        bool no_autorepeat;
        unsigned int rows;
        unsigned int cols;
        unsigned short keymap[STMPE_KEYPAD_KEYMAP_MAX_SIZE];
};

static int stmpe_keypad_read_data(struct stmpe_keypad *keypad, u8 *data)
{
        const struct stmpe_keypad_variant *variant = keypad->variant;
        struct stmpe *stmpe = keypad->stmpe;
        int ret;
        int i;

        if (variant->auto_increment)
                return stmpe_block_read(stmpe, STMPE_KPC_DATA_BYTE0,
                                        variant->num_data, data);

        for (i = 0; i < variant->num_data; i++) {
                ret = stmpe_reg_read(stmpe, STMPE_KPC_DATA_BYTE0 + i);
                if (ret < 0)
                        return ret;

                data[i] = ret;
        }

        return 0;
}

static irqreturn_t stmpe_keypad_irq(int irq, void *dev)
{
        struct stmpe_keypad *keypad = dev;
        struct input_dev *input = keypad->input;
        const struct stmpe_keypad_variant *variant = keypad->variant;
        u8 fifo[MAX_NUM_DATA];
        int ret;
        int i;

        ret = stmpe_keypad_read_data(keypad, fifo);
        if (ret < 0)
                return IRQ_NONE;

        for (i = 0; i < variant->num_normal_data; i++) {
                u8 data = fifo[i];
                int row = (data & STMPE_KPC_DATA_ROW) >> 3;
                int col = data & STMPE_KPC_DATA_COL;
                int code = MATRIX_SCAN_CODE(row, col, STMPE_KEYPAD_ROW_SHIFT);
                bool up = data & STMPE_KPC_DATA_UP;

                if ((data & STMPE_KPC_DATA_NOKEY_MASK)
                        == STMPE_KPC_DATA_NOKEY_MASK)
                        continue;

                input_event(input, EV_MSC, MSC_SCAN, code);
                input_report_key(input, keypad->keymap[code], !up);
                input_sync(input);
        }

        return IRQ_HANDLED;
}

static int stmpe_keypad_altfunc_init(struct stmpe_keypad *keypad)
{
        const struct stmpe_keypad_variant *variant = keypad->variant;
        unsigned int col_gpios = variant->col_gpios;
        unsigned int row_gpios = variant->row_gpios;
        struct stmpe *stmpe = keypad->stmpe;
        u8 pureg = stmpe->regs[STMPE_IDX_GPPUR_LSB];
        unsigned int pins = 0;
        unsigned int pu_pins = 0;
        int ret;
        int i;

        /*
         * Figure out which pins need to be set to the keypad alternate
         * function.
         *
         * {cols,rows}_gpios are bitmasks of which pins on the chip can be used
         * for the keypad.
         *
         * keypad->{cols,rows} are a bitmask of which pins (of the ones useable
         * for the keypad) are used on the board.
         */

        for (i = 0; i < variant->max_cols; i++) {
                int num = __ffs(col_gpios);

                if (keypad->cols & (1 << i)) {
                        pins |= 1 << num;
                        pu_pins |= 1 << num;
                }

                col_gpios &= ~(1 << num);
        }

        for (i = 0; i < variant->max_rows; i++) {
                int num = __ffs(row_gpios);

                if (keypad->rows & (1 << i))
                        pins |= 1 << num;

                row_gpios &= ~(1 << num);
        }

        ret = stmpe_set_altfunc(stmpe, pins, STMPE_BLOCK_KEYPAD);
        if (ret)
                return ret;

        /*
         * On STMPE24xx, set pin bias to pull-up on all keypad input
         * pins (columns), this incidentally happen to be maximum 8 pins
         * and placed at GPIO0-7 so only the LSB of the pull up register
         * ever needs to be written.
         */
        if (variant->set_pullup) {
                u8 val;

                ret = stmpe_reg_read(stmpe, pureg);
                if (ret)
                        return ret;

                /* Do not touch unused pins, may be used for GPIO */
                val = ret & ~pu_pins;
                val |= pu_pins;

                ret = stmpe_reg_write(stmpe, pureg, val);
        }

        return 0;
}

static int stmpe_keypad_chip_init(struct stmpe_keypad *keypad)
{
        const struct stmpe_keypad_variant *variant = keypad->variant;
        struct stmpe *stmpe = keypad->stmpe;
        int ret;

        if (keypad->debounce_ms > STMPE_KEYPAD_MAX_DEBOUNCE)
                return -EINVAL;

        if (keypad->scan_count > STMPE_KEYPAD_MAX_SCAN_COUNT)
                return -EINVAL;

        ret = stmpe_enable(stmpe, STMPE_BLOCK_KEYPAD);
        if (ret < 0)
                return ret;

        ret = stmpe_keypad_altfunc_init(keypad);
        if (ret < 0)
                return ret;

        ret = stmpe_reg_write(stmpe, STMPE_KPC_COL, keypad->cols);
        if (ret < 0)
                return ret;

        ret = stmpe_reg_write(stmpe, STMPE_KPC_ROW_LSB, keypad->rows);
        if (ret < 0)
                return ret;

        if (variant->max_rows > 8) {
                ret = stmpe_set_bits(stmpe, STMPE_KPC_ROW_MSB,
                                     STMPE_KPC_ROW_MSB_ROWS,
                                     keypad->rows >> 8);
                if (ret < 0)
                        return ret;
        }

        ret = stmpe_set_bits(stmpe, STMPE_KPC_CTRL_MSB,
                             STMPE_KPC_CTRL_MSB_SCAN_COUNT,
                             keypad->scan_count << 4);
        if (ret < 0)
                return ret;

        return stmpe_set_bits(stmpe, STMPE_KPC_CTRL_LSB,
                              STMPE_KPC_CTRL_LSB_SCAN |
                              STMPE_KPC_CTRL_LSB_DEBOUNCE,
                              STMPE_KPC_CTRL_LSB_SCAN |
                              (keypad->debounce_ms << 1));
}

static void stmpe_keypad_fill_used_pins(struct stmpe_keypad *keypad,
                                        u32 used_rows, u32 used_cols)
{
        int row, col;

        for (row = 0; row < used_rows; row++) {
                for (col = 0; col < used_cols; col++) {
                        int code = MATRIX_SCAN_CODE(row, col,
                                                    STMPE_KEYPAD_ROW_SHIFT);
                        if (keypad->keymap[code] != KEY_RESERVED) {
                                keypad->rows |= 1 << row;
                                keypad->cols |= 1 << col;
                        }
                }
        }
}

static int stmpe_keypad_probe(struct platform_device *pdev)
{
        struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
        struct device_node *np = pdev->dev.of_node;
        struct stmpe_keypad *keypad;
        struct input_dev *input;
        u32 rows;
        u32 cols;
        int error;
        int irq;

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

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

        keypad->stmpe = stmpe;
        keypad->variant = &stmpe_keypad_variants[stmpe->partnum];

        of_property_read_u32(np, "debounce-interval", &keypad->debounce_ms);
        of_property_read_u32(np, "st,scan-count", &keypad->scan_count);
        keypad->no_autorepeat = of_property_read_bool(np, "st,no-autorepeat");

        input = devm_input_allocate_device(&pdev->dev);
        if (!input)
                return -ENOMEM;

        input->name = "STMPE keypad";
        input->id.bustype = BUS_I2C;
        input->dev.parent = &pdev->dev;

        error = matrix_keypad_parse_properties(&pdev->dev, &rows, &cols);
        if (error)
                return error;

        error = matrix_keypad_build_keymap(NULL, NULL, rows, cols,
                                           keypad->keymap, input);
        if (error)
                return error;

        input_set_capability(input, EV_MSC, MSC_SCAN);
        if (!keypad->no_autorepeat)
                __set_bit(EV_REP, input->evbit);

        stmpe_keypad_fill_used_pins(keypad, rows, cols);

        keypad->input = input;

        error = stmpe_keypad_chip_init(keypad);
        if (error < 0)
                return error;

        error = devm_request_threaded_irq(&pdev->dev, irq,
                                          NULL, stmpe_keypad_irq,
                                          IRQF_ONESHOT, "stmpe-keypad", keypad);
        if (error) {
                dev_err(&pdev->dev, "unable to get irq: %d\n", error);
                return error;
        }

        error = input_register_device(input);
        if (error) {
                dev_err(&pdev->dev,
                        "unable to register input device: %d\n", error);
                return error;
        }

        platform_set_drvdata(pdev, keypad);

        return 0;
}

static void stmpe_keypad_remove(struct platform_device *pdev)
{
        struct stmpe_keypad *keypad = platform_get_drvdata(pdev);

        stmpe_disable(keypad->stmpe, STMPE_BLOCK_KEYPAD);
}

static struct platform_driver stmpe_keypad_driver = {
        .driver.name    = "stmpe-keypad",
        .probe          = stmpe_keypad_probe,
        .remove         = stmpe_keypad_remove,
};
module_platform_driver(stmpe_keypad_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("STMPExxxx keypad driver");
MODULE_AUTHOR("Rabin Vincent <rabin.vincent@stericsson.com>");