// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012-2020 Synaptics Incorporated
 */

#include <linux/kernel.h>
#include <linux/rmi.h>
#include <linux/input.h>
#include <linux/slab.h>
#include "rmi_driver.h"

#define RMI_F3A_MAX_GPIO_COUNT          128
#define RMI_F3A_MAX_REG_SIZE            DIV_ROUND_UP(RMI_F3A_MAX_GPIO_COUNT, 8)

/* Defs for Query 0 */
#define RMI_F3A_GPIO_COUNT              0x7F

#define RMI_F3A_DATA_REGS_MAX_SIZE      RMI_F3A_MAX_REG_SIZE

#define TRACKSTICK_RANGE_START          3
#define TRACKSTICK_RANGE_END            6

struct f3a_data {
        /* Query Data */
        u8 gpio_count;

        u8 register_count;

        u8 data_regs[RMI_F3A_DATA_REGS_MAX_SIZE];
        u16 *gpio_key_map;

        struct input_dev *input;

        struct rmi_function *f03;
        bool trackstick_buttons;
};

static void rmi_f3a_report_button(struct rmi_function *fn,
                                  struct f3a_data *f3a, unsigned int button)
{
        u16 key_code = f3a->gpio_key_map[button];
        bool key_down = !(f3a->data_regs[0] & BIT(button));

        if (f3a->trackstick_buttons &&
                button >= TRACKSTICK_RANGE_START &&
                button <= TRACKSTICK_RANGE_END) {
                rmi_f03_overwrite_button(f3a->f03, key_code, key_down);
        } else {
                rmi_dbg(RMI_DEBUG_FN, &fn->dev,
                        "%s: call input report key (0x%04x) value (0x%02x)",
                        __func__, key_code, key_down);
                input_report_key(f3a->input, key_code, key_down);
        }
}

static irqreturn_t rmi_f3a_attention(int irq, void *ctx)
{
        struct rmi_function *fn = ctx;
        struct f3a_data *f3a = dev_get_drvdata(&fn->dev);
        struct rmi_driver_data *drvdata = dev_get_drvdata(&fn->rmi_dev->dev);
        int error;
        int i;

        if (drvdata->attn_data.data) {
                if (drvdata->attn_data.size < f3a->register_count) {
                        dev_warn(&fn->dev,
                                 "F3A interrupted, but data is missing\n");
                        return IRQ_HANDLED;
                }
                memcpy(f3a->data_regs, drvdata->attn_data.data,
                        f3a->register_count);
                drvdata->attn_data.data += f3a->register_count;
                drvdata->attn_data.size -= f3a->register_count;
        } else {
                error = rmi_read_block(fn->rmi_dev, fn->fd.data_base_addr,
                                        f3a->data_regs, f3a->register_count);
                if (error) {
                        dev_err(&fn->dev,
                                "%s: Failed to read F3a data registers: %d\n",
                                __func__, error);
                        return IRQ_RETVAL(error);
                }
        }

        for (i = 0; i < f3a->gpio_count; i++)
                if (f3a->gpio_key_map[i] != KEY_RESERVED)
                        rmi_f3a_report_button(fn, f3a, i);
        if (f3a->trackstick_buttons)
                rmi_f03_commit_buttons(f3a->f03);

        return IRQ_HANDLED;
}

static int rmi_f3a_config(struct rmi_function *fn)
{
        struct f3a_data *f3a = dev_get_drvdata(&fn->dev);
        struct rmi_driver *drv = fn->rmi_dev->driver;
        const struct rmi_device_platform_data *pdata =
                        rmi_get_platform_data(fn->rmi_dev);

        if (!f3a)
                return 0;

        if (pdata->gpio_data.trackstick_buttons) {
                /* Try [re-]establish link to F03. */
                f3a->f03 = rmi_find_function(fn->rmi_dev, 0x03);
                f3a->trackstick_buttons = f3a->f03 != NULL;
        }

        drv->set_irq_bits(fn->rmi_dev, fn->irq_mask);

        return 0;
}

static bool rmi_f3a_is_valid_button(int button, struct f3a_data *f3a,
                                        u8 *query1_regs, u8 *ctrl1_regs)
{
        /* gpio exist && direction input */
        return (query1_regs[0] & BIT(button)) && !(ctrl1_regs[0] & BIT(button));
}

static int rmi_f3a_map_gpios(struct rmi_function *fn, struct f3a_data *f3a,
                                u8 *query1_regs, u8 *ctrl1_regs)
{
        const struct rmi_device_platform_data *pdata =
                        rmi_get_platform_data(fn->rmi_dev);
        struct input_dev *input = f3a->input;
        unsigned int button = BTN_LEFT;
        unsigned int trackstick_button = BTN_LEFT;
        bool button_mapped = false;
        int i;
        int button_count = min_t(u8, f3a->gpio_count, TRACKSTICK_RANGE_END);

        f3a->gpio_key_map = devm_kcalloc(&fn->dev,
                                                button_count,
                                                sizeof(f3a->gpio_key_map[0]),
                                                GFP_KERNEL);
        if (!f3a->gpio_key_map) {
                dev_err(&fn->dev, "Failed to allocate gpio map memory.\n");
                return -ENOMEM;
        }

        for (i = 0; i < button_count; i++) {
                if (!rmi_f3a_is_valid_button(i, f3a, query1_regs, ctrl1_regs))
                        continue;

                if (pdata->gpio_data.trackstick_buttons &&
                        i >= TRACKSTICK_RANGE_START &&
                        i < TRACKSTICK_RANGE_END) {
                        f3a->gpio_key_map[i] = trackstick_button++;
                } else if (!pdata->gpio_data.buttonpad || !button_mapped) {
                        f3a->gpio_key_map[i] = button;
                        input_set_capability(input, EV_KEY, button++);
                        button_mapped = true;
                }
        }
        input->keycode = f3a->gpio_key_map;
        input->keycodesize = sizeof(f3a->gpio_key_map[0]);
        input->keycodemax = f3a->gpio_count;

        if (pdata->gpio_data.buttonpad || (button - BTN_LEFT == 1))
                __set_bit(INPUT_PROP_BUTTONPAD, input->propbit);

        return 0;
}

static int rmi_f3a_initialize(struct rmi_function *fn, struct f3a_data *f3a)
{
        u8 query1[RMI_F3A_MAX_REG_SIZE];
        u8 ctrl1[RMI_F3A_MAX_REG_SIZE];
        u8 buf;
        int error;

        error = rmi_read(fn->rmi_dev, fn->fd.query_base_addr, &buf);
        if (error < 0) {
                dev_err(&fn->dev, "Failed to read general info register: %d\n",
                        error);
                return -ENODEV;
        }

        f3a->gpio_count = buf & RMI_F3A_GPIO_COUNT;
        f3a->register_count = DIV_ROUND_UP(f3a->gpio_count, 8);

        /* Query1 -> gpio exist */
        error = rmi_read_block(fn->rmi_dev, fn->fd.query_base_addr + 1,
                                query1, f3a->register_count);
        if (error) {
                dev_err(&fn->dev, "Failed to read query1 register\n");
                return error;
        }

        /* Ctrl1 -> gpio direction */
        error = rmi_read_block(fn->rmi_dev, fn->fd.control_base_addr + 1,
                                ctrl1, f3a->register_count);
        if (error) {
                dev_err(&fn->dev, "Failed to read control1 register\n");
                return error;
        }

        error = rmi_f3a_map_gpios(fn, f3a, query1, ctrl1);
        if (error)
                return error;

        return 0;
}

static int rmi_f3a_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 f3a_data *f3a;
        int error;

        if (!drv_data->input) {
                dev_info(&fn->dev, "F3A: no input device found, ignoring\n");
                return -ENXIO;
        }

        f3a = devm_kzalloc(&fn->dev, sizeof(*f3a), GFP_KERNEL);
        if (!f3a)
                return -ENOMEM;

        f3a->input = drv_data->input;

        error = rmi_f3a_initialize(fn, f3a);
        if (error)
                return error;

        dev_set_drvdata(&fn->dev, f3a);
        return 0;
}

struct rmi_function_handler rmi_f3a_handler = {
        .driver = {
                .name = "rmi4_f3a",
        },
        .func = 0x3a,
        .probe = rmi_f3a_probe,
        .config = rmi_f3a_config,
        .attention = rmi_f3a_attention,
};