// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2025 André Apitzsch <git@apitzsch.eu>
 */

#include <linux/input.h>
#include <linux/property.h>
#include "rmi_driver.h"

struct f1a_data {
        struct input_dev *input;

        u32 *keymap;
        unsigned int num_keys;
};

static int rmi_f1a_parse_device_properties(struct rmi_function *fn, struct f1a_data *f1a)
{
        static const char buttons_property[] = "linux,keycodes";
        struct device *dev = &fn->dev;
        u32 *buttonmap;
        int n_keys;
        int error;

        if (!device_property_present(dev, buttons_property))
                return 0;

        n_keys = device_property_count_u32(dev, buttons_property);
        if (n_keys <= 0) {
                error = n_keys < 0 ? n_keys : -EINVAL;
                dev_err(dev, "Invalid/malformed '%s' property: %d\n",
                        buttons_property, error);
                return error;
        }

        buttonmap = devm_kmalloc_array(dev, n_keys, sizeof(*buttonmap),
                                       GFP_KERNEL);
        if (!buttonmap)
                return -ENOMEM;

        error = device_property_read_u32_array(dev, buttons_property,
                                               buttonmap, n_keys);
        if (error) {
                dev_err(dev, "Failed to parse '%s' property: %d\n",
                        buttons_property, error);
                return error;
        }

        f1a->keymap = buttonmap;
        f1a->num_keys = n_keys;

        return 0;
}

static irqreturn_t rmi_f1a_attention(int irq, void *ctx)
{
        struct rmi_function *fn = ctx;
        struct f1a_data *f1a = dev_get_drvdata(&fn->dev);
        char button_bitmask;
        int key;
        int error;

        error = rmi_read_block(fn->rmi_dev, fn->fd.data_base_addr,
                               &button_bitmask, sizeof(button_bitmask));
        if (error) {
                dev_err(&fn->dev, "Failed to read object data. Code: %d.\n",
                        error);
                return IRQ_RETVAL(error);
        }

        for (key = 0; key < f1a->num_keys; key++)
                input_report_key(f1a->input, f1a->keymap[key],
                                 button_bitmask & BIT(key));

        return IRQ_HANDLED;
}

static int rmi_f1a_config(struct rmi_function *fn)
{
        struct f1a_data *f1a = dev_get_drvdata(&fn->dev);
        struct rmi_driver *drv = fn->rmi_dev->driver;

        if (f1a->num_keys)
                drv->set_irq_bits(fn->rmi_dev, fn->irq_mask);

        return 0;
}

static int rmi_f1a_initialize(struct rmi_function *fn, struct f1a_data *f1a)
{
        int error;
        int i;

        error = rmi_f1a_parse_device_properties(fn, f1a);
        if (error)
                return error;

        for (i = 0; i < f1a->num_keys; i++)
                input_set_capability(f1a->input, EV_KEY, f1a->keymap[i]);

        f1a->input->keycode = f1a->keymap;
        f1a->input->keycodemax = f1a->num_keys;
        f1a->input->keycodesize = sizeof(f1a->keymap[0]);

        return 0;
}

static int rmi_f1a_probe(struct rmi_function *fn)
{
        struct rmi_device *rmi_dev = fn->rmi_dev;
        struct rmi_driver_data *drv_data = dev_get_drvdata(&rmi_dev->dev);
        struct f1a_data *f1a;
        int error;

        if (!drv_data->input) {
                dev_info(&fn->dev, "F1A: no input device found, ignoring\n");
                return -ENXIO;
        }

        f1a = devm_kzalloc(&fn->dev, sizeof(*f1a), GFP_KERNEL);
        if (!f1a)
                return -ENOMEM;

        f1a->input = drv_data->input;

        error = rmi_f1a_initialize(fn, f1a);
        if (error)
                return error;

        dev_set_drvdata(&fn->dev, f1a);

        return 0;
}

struct rmi_function_handler rmi_f1a_handler = {
        .driver = {
                .name = "rmi4_f1a",
        },
        .func = 0x1a,
        .probe = rmi_f1a_probe,
        .config = rmi_f1a_config,
        .attention = rmi_f1a_attention,
};