// SPDX-License-Identifier: GPL-2.0-only
/*
 * max7359_keypad.c - MAX7359 Key Switch Controller Driver
 *
 * Copyright (C) 2009 Samsung Electronics
 * Kim Kyuwon <q1.kim@samsung.com>
 *
 * Based on pxa27x_keypad.c
 *
 * Datasheet: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5456
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>

#define MAX7359_MAX_KEY_ROWS    8
#define MAX7359_MAX_KEY_COLS    8
#define MAX7359_MAX_KEY_NUM     (MAX7359_MAX_KEY_ROWS * MAX7359_MAX_KEY_COLS)
#define MAX7359_ROW_SHIFT       3

/*
 * MAX7359 registers
 */
#define MAX7359_REG_KEYFIFO     0x00
#define MAX7359_REG_CONFIG      0x01
#define MAX7359_REG_DEBOUNCE    0x02
#define MAX7359_REG_INTERRUPT   0x03
#define MAX7359_REG_PORTS       0x04
#define MAX7359_REG_KEYREP      0x05
#define MAX7359_REG_SLEEP       0x06

/*
 * Configuration register bits
 */
#define MAX7359_CFG_SLEEP       (1 << 7)
#define MAX7359_CFG_INTERRUPT   (1 << 5)
#define MAX7359_CFG_KEY_RELEASE (1 << 3)
#define MAX7359_CFG_WAKEUP      (1 << 1)
#define MAX7359_CFG_TIMEOUT     (1 << 0)

/*
 * Autosleep register values (ms)
 */
#define MAX7359_AUTOSLEEP_8192  0x01
#define MAX7359_AUTOSLEEP_4096  0x02
#define MAX7359_AUTOSLEEP_2048  0x03
#define MAX7359_AUTOSLEEP_1024  0x04
#define MAX7359_AUTOSLEEP_512   0x05
#define MAX7359_AUTOSLEEP_256   0x06

struct max7359_keypad {
        /* matrix key code map */
        unsigned short keycodes[MAX7359_MAX_KEY_NUM];

        struct input_dev *input_dev;
        struct i2c_client *client;
};

static int max7359_write_reg(struct i2c_client *client, u8 reg, u8 val)
{
        int ret = i2c_smbus_write_byte_data(client, reg, val);

        if (ret < 0)
                dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
                        __func__, reg, val, ret);
        return ret;
}

static int max7359_read_reg(struct i2c_client *client, int reg)
{
        int ret = i2c_smbus_read_byte_data(client, reg);

        if (ret < 0)
                dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
                        __func__, reg, ret);
        return ret;
}

/* runs in an IRQ thread -- can (and will!) sleep */
static irqreturn_t max7359_interrupt(int irq, void *dev_id)
{
        struct max7359_keypad *keypad = dev_id;
        struct input_dev *input_dev = keypad->input_dev;
        int val, row, col, release, code;

        val = max7359_read_reg(keypad->client, MAX7359_REG_KEYFIFO);
        row = val & 0x7;
        col = (val >> 3) & 0x7;
        release = val & 0x40;

        code = MATRIX_SCAN_CODE(row, col, MAX7359_ROW_SHIFT);

        dev_dbg(&keypad->client->dev,
                "key[%d:%d] %s\n", row, col, release ? "release" : "press");

        input_event(input_dev, EV_MSC, MSC_SCAN, code);
        input_report_key(input_dev, keypad->keycodes[code], !release);
        input_sync(input_dev);

        return IRQ_HANDLED;
}

/*
 * Let MAX7359 fall into a deep sleep:
 * If no keys are pressed, enter sleep mode for 8192 ms. And if any
 * key is pressed, the MAX7359 returns to normal operating mode.
 */
static inline void max7359_fall_deepsleep(struct i2c_client *client)
{
        max7359_write_reg(client, MAX7359_REG_SLEEP, MAX7359_AUTOSLEEP_8192);
}

/*
 * Let MAX7359 take a catnap:
 * Autosleep just for 256 ms.
 */
static inline void max7359_take_catnap(struct i2c_client *client)
{
        max7359_write_reg(client, MAX7359_REG_SLEEP, MAX7359_AUTOSLEEP_256);
}

static int max7359_open(struct input_dev *dev)
{
        struct max7359_keypad *keypad = input_get_drvdata(dev);

        max7359_take_catnap(keypad->client);

        return 0;
}

static void max7359_close(struct input_dev *dev)
{
        struct max7359_keypad *keypad = input_get_drvdata(dev);

        max7359_fall_deepsleep(keypad->client);
}

static void max7359_initialize(struct i2c_client *client)
{
        max7359_write_reg(client, MAX7359_REG_CONFIG,
                MAX7359_CFG_KEY_RELEASE | /* Key release enable */
                MAX7359_CFG_WAKEUP); /* Key press wakeup enable */

        /* Full key-scan functionality */
        max7359_write_reg(client, MAX7359_REG_DEBOUNCE, 0x1F);

        /* nINT asserts every debounce cycles */
        max7359_write_reg(client, MAX7359_REG_INTERRUPT, 0x01);

        max7359_fall_deepsleep(client);
}

static int max7359_probe(struct i2c_client *client)
{
        const struct matrix_keymap_data *keymap_data =
                        dev_get_platdata(&client->dev);
        struct max7359_keypad *keypad;
        struct input_dev *input_dev;
        int ret;
        int error;

        if (!client->irq) {
                dev_err(&client->dev, "The irq number should not be zero\n");
                return -EINVAL;
        }

        /* Detect MAX7359: The initial Keys FIFO value is '0x3F' */
        ret = max7359_read_reg(client, MAX7359_REG_KEYFIFO);
        if (ret < 0) {
                dev_err(&client->dev, "failed to detect device\n");
                return -ENODEV;
        }

        dev_dbg(&client->dev, "keys FIFO is 0x%02x\n", ret);

        keypad = devm_kzalloc(&client->dev, sizeof(struct max7359_keypad),
                              GFP_KERNEL);
        if (!keypad) {
                dev_err(&client->dev, "failed to allocate memory\n");
                return -ENOMEM;
        }

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

        keypad->client = client;
        keypad->input_dev = input_dev;

        input_dev->name = client->name;
        input_dev->id.bustype = BUS_I2C;
        input_dev->open = max7359_open;
        input_dev->close = max7359_close;
        input_dev->dev.parent = &client->dev;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
        input_dev->keycodesize = sizeof(keypad->keycodes[0]);
        input_dev->keycodemax = ARRAY_SIZE(keypad->keycodes);
        input_dev->keycode = keypad->keycodes;

        input_set_capability(input_dev, EV_MSC, MSC_SCAN);
        input_set_drvdata(input_dev, keypad);

        error = matrix_keypad_build_keymap(keymap_data, NULL,
                                           MAX7359_MAX_KEY_ROWS,
                                           MAX7359_MAX_KEY_COLS,
                                           keypad->keycodes,
                                           input_dev);
        if (error) {
                dev_err(&client->dev, "failed to build keymap\n");
                return error;
        }

        error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
                                          max7359_interrupt,
                                          IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                          client->name, keypad);
        if (error) {
                dev_err(&client->dev, "failed to register interrupt\n");
                return error;
        }

        /* Register the input device */
        error = input_register_device(input_dev);
        if (error) {
                dev_err(&client->dev, "failed to register input device\n");
                return error;
        }

        /* Initialize MAX7359 */
        max7359_initialize(client);

        device_init_wakeup(&client->dev, 1);

        return 0;
}

static int max7359_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        max7359_fall_deepsleep(client);

        if (device_may_wakeup(&client->dev))
                enable_irq_wake(client->irq);

        return 0;
}

static int max7359_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        if (device_may_wakeup(&client->dev))
                disable_irq_wake(client->irq);

        /* Restore the default setting */
        max7359_take_catnap(client);

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(max7359_pm, max7359_suspend, max7359_resume);

static const struct i2c_device_id max7359_ids[] = {
        { .name = "max7359" },
        { }
};
MODULE_DEVICE_TABLE(i2c, max7359_ids);

static struct i2c_driver max7359_i2c_driver = {
        .driver = {
                .name = "max7359",
                .pm   = pm_sleep_ptr(&max7359_pm),
        },
        .probe          = max7359_probe,
        .id_table       = max7359_ids,
};

module_i2c_driver(max7359_i2c_driver);

MODULE_AUTHOR("Kim Kyuwon <q1.kim@samsung.com>");
MODULE_DESCRIPTION("MAX7359 Key Switch Controller Driver");
MODULE_LICENSE("GPL v2");