// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cirrus Logic CLPS711X Keypad driver
 *
 * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
 */

#include <linux/input.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/sched.h>
#include <linux/input/matrix_keypad.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/clps711x.h>

#define CLPS711X_KEYPAD_COL_COUNT       8

struct clps711x_gpio_data {
        struct gpio_desc *desc;
        DECLARE_BITMAP(last_state, CLPS711X_KEYPAD_COL_COUNT);
};

struct clps711x_keypad_data {
        struct regmap                   *syscon;
        int                             row_count;
        unsigned int                    row_shift;
        struct clps711x_gpio_data       *gpio_data;
};

static void clps711x_keypad_poll(struct input_dev *input)
{
        const unsigned short *keycodes = input->keycode;
        struct clps711x_keypad_data *priv = input_get_drvdata(input);
        bool sync = false;
        int col, row;

        for (col = 0; col < CLPS711X_KEYPAD_COL_COUNT; col++) {
                /* Assert column */
                regmap_update_bits(priv->syscon, SYSCON_OFFSET,
                                   SYSCON1_KBDSCAN_MASK,
                                   SYSCON1_KBDSCAN(8 + col));

                /* Scan rows */
                for (row = 0; row < priv->row_count; row++) {
                        struct clps711x_gpio_data *data = &priv->gpio_data[row];
                        bool state, state1;

                        /* Read twice for protection against fluctuations */
                        do {
                                state = gpiod_get_value_cansleep(data->desc);
                                cond_resched();
                                state1 = gpiod_get_value_cansleep(data->desc);
                        } while (state != state1);

                        if (test_bit(col, data->last_state) != state) {
                                int code = MATRIX_SCAN_CODE(row, col,
                                                            priv->row_shift);

                                if (state) {
                                        set_bit(col, data->last_state);
                                        input_event(input,
                                                    EV_MSC, MSC_SCAN, code);
                                } else {
                                        clear_bit(col, data->last_state);
                                }

                                if (keycodes[code])
                                        input_report_key(input,
                                                         keycodes[code], state);
                                sync = true;
                        }
                }

                /* Set all columns to low */
                regmap_update_bits(priv->syscon, SYSCON_OFFSET,
                                   SYSCON1_KBDSCAN_MASK, SYSCON1_KBDSCAN(1));
        }

        if (sync)
                input_sync(input);
}

static int clps711x_keypad_probe(struct platform_device *pdev)
{
        struct clps711x_keypad_data *priv;
        struct device *dev = &pdev->dev;
        struct input_dev *input;
        u32 poll_interval;
        int i, err;

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
        if (IS_ERR(priv->syscon))
                return PTR_ERR(priv->syscon);

        priv->row_count = gpiod_count(dev, "row");
        if (priv->row_count < 1)
                return -EINVAL;

        priv->gpio_data = devm_kcalloc(dev,
                                priv->row_count, sizeof(*priv->gpio_data),
                                GFP_KERNEL);
        if (!priv->gpio_data)
                return -ENOMEM;

        priv->row_shift = get_count_order(CLPS711X_KEYPAD_COL_COUNT);

        for (i = 0; i < priv->row_count; i++) {
                struct clps711x_gpio_data *data = &priv->gpio_data[i];

                data->desc = devm_gpiod_get_index(dev, "row", i, GPIOD_IN);
                if (IS_ERR(data->desc))
                        return PTR_ERR(data->desc);
        }

        err = device_property_read_u32(dev, "poll-interval", &poll_interval);
        if (err)
                return err;

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

        input_set_drvdata(input, priv);

        input->name             = pdev->name;
        input->dev.parent       = dev;
        input->id.bustype       = BUS_HOST;
        input->id.vendor        = 0x0001;
        input->id.product       = 0x0001;
        input->id.version       = 0x0100;

        err = matrix_keypad_build_keymap(NULL, NULL, priv->row_count,
                                         CLPS711X_KEYPAD_COL_COUNT,
                                         NULL, input);
        if (err)
                return err;

        input_set_capability(input, EV_MSC, MSC_SCAN);
        if (device_property_read_bool(dev, "autorepeat"))
                __set_bit(EV_REP, input->evbit);

        /* Set all columns to low */
        regmap_update_bits(priv->syscon, SYSCON_OFFSET, SYSCON1_KBDSCAN_MASK,
                           SYSCON1_KBDSCAN(1));


        err = input_setup_polling(input, clps711x_keypad_poll);
        if (err)
                return err;

        input_set_poll_interval(input, poll_interval);

        err = input_register_device(input);
        if (err)
                return err;

        return 0;
}

static const struct of_device_id clps711x_keypad_of_match[] = {
        { .compatible = "cirrus,ep7209-keypad", },
        { }
};
MODULE_DEVICE_TABLE(of, clps711x_keypad_of_match);

static struct platform_driver clps711x_keypad_driver = {
        .driver = {
                .name           = "clps711x-keypad",
                .of_match_table = clps711x_keypad_of_match,
        },
        .probe  = clps711x_keypad_probe,
};
module_platform_driver(clps711x_keypad_driver);

MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("Cirrus Logic CLPS711X Keypad driver");
MODULE_LICENSE("GPL");