// SPDX-License-Identifier: GPL-2.0-only
/*
 * HID driver for ELO usb touchscreen 4000/4500
 *
 * Copyright (c) 2013 Jiri Slaby
 *
 * Data parsing taken from elousb driver by Vojtech Pavlik.
 */

#include <linux/hid.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/workqueue.h>

#include "hid-ids.h"

#define ELO_PERIODIC_READ_INTERVAL      HZ
#define ELO_SMARTSET_CMD_TIMEOUT        2000 /* msec */

/* Elo SmartSet commands */
#define ELO_FLUSH_SMARTSET_RESPONSES    0x02 /* Flush all pending smartset responses */
#define ELO_SEND_SMARTSET_COMMAND       0x05 /* Send a smartset command */
#define ELO_GET_SMARTSET_RESPONSE       0x06 /* Get a smartset response */
#define ELO_DIAG                        0x64 /* Diagnostics command */
#define ELO_SMARTSET_PACKET_SIZE        8

struct elo_priv {
        struct usb_device *usbdev;
        struct delayed_work work;
        unsigned char buffer[ELO_SMARTSET_PACKET_SIZE];
};

static struct workqueue_struct *wq;
static bool use_fw_quirk = true;
module_param(use_fw_quirk, bool, S_IRUGO);
MODULE_PARM_DESC(use_fw_quirk, "Do periodic pokes for broken M firmwares (default = true)");

static int elo_input_configured(struct hid_device *hdev,
                struct hid_input *hidinput)
{
        struct input_dev *input = hidinput->input;

        /*
         * ELO devices have one Button usage in GenDesk field, which makes
         * hid-input map it to BTN_LEFT; that confuses userspace, which then
         * considers the device to be a mouse/touchpad instead of touchscreen.
         */
        clear_bit(BTN_LEFT, input->keybit);
        set_bit(BTN_TOUCH, input->keybit);
        set_bit(ABS_PRESSURE, input->absbit);
        input_set_abs_params(input, ABS_PRESSURE, 0, 256, 0, 0);

        return 0;
}

static void elo_process_data(struct input_dev *input, const u8 *data, int size)
{
        int press;

        input_report_abs(input, ABS_X, (data[3] << 8) | data[2]);
        input_report_abs(input, ABS_Y, (data[5] << 8) | data[4]);

        press = 0;
        if (data[1] & 0x80)
                press = (data[7] << 8) | data[6];
        input_report_abs(input, ABS_PRESSURE, press);

        if (data[1] & 0x03) {
                input_report_key(input, BTN_TOUCH, 1);
                input_sync(input);
        }

        if (data[1] & 0x04)
                input_report_key(input, BTN_TOUCH, 0);

        input_sync(input);
}

static int elo_raw_event(struct hid_device *hdev, struct hid_report *report,
         u8 *data, int size)
{
        struct hid_input *hidinput;

        if (!(hdev->claimed & HID_CLAIMED_INPUT) || list_empty(&hdev->inputs))
                return 0;

        hidinput = list_first_entry(&hdev->inputs, struct hid_input, list);

        switch (report->id) {
        case 0:
                if (data[0] == 'T') {   /* Mandatory ELO packet marker */
                        elo_process_data(hidinput->input, data, size);
                        return 1;
                }
                break;
        default:        /* unknown report */
                /* Unknown report type; pass upstream */
                hid_info(hdev, "unknown report type %d\n", report->id);
                break;
        }

        return 0;
}

static int elo_smartset_send_get(struct usb_device *dev, u8 command,
                void *data)
{
        unsigned int pipe;
        u8 dir;

        if (command == ELO_SEND_SMARTSET_COMMAND) {
                pipe = usb_sndctrlpipe(dev, 0);
                dir = USB_DIR_OUT;
        } else if (command == ELO_GET_SMARTSET_RESPONSE) {
                pipe = usb_rcvctrlpipe(dev, 0);
                dir = USB_DIR_IN;
        } else
                return -EINVAL;

        return usb_control_msg(dev, pipe, command,
                        dir | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                        0, 0, data, ELO_SMARTSET_PACKET_SIZE,
                        ELO_SMARTSET_CMD_TIMEOUT);
}

static int elo_flush_smartset_responses(struct usb_device *dev)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                        ELO_FLUSH_SMARTSET_RESPONSES,
                        USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                        0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT);
}

static void elo_work(struct work_struct *work)
{
        struct elo_priv *priv = container_of(work, struct elo_priv, work.work);
        struct usb_device *dev = priv->usbdev;
        unsigned char *buffer = priv->buffer;
        int ret;

        ret = elo_flush_smartset_responses(dev);
        if (ret < 0) {
                dev_err(&dev->dev, "initial FLUSH_SMARTSET_RESPONSES failed, error %d\n",
                                ret);
                goto fail;
        }

        /* send Diagnostics command */
        *buffer = ELO_DIAG;
        ret = elo_smartset_send_get(dev, ELO_SEND_SMARTSET_COMMAND, buffer);
        if (ret < 0) {
                dev_err(&dev->dev, "send Diagnostics Command failed, error %d\n",
                                ret);
                goto fail;
        }

        /* get the result */
        ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE, buffer);
        if (ret < 0) {
                dev_err(&dev->dev, "get Diagnostics Command response failed, error %d\n",
                                ret);
                goto fail;
        }

        /* read the ack */
        if (*buffer != 'A') {
                ret = elo_smartset_send_get(dev, ELO_GET_SMARTSET_RESPONSE,
                                buffer);
                if (ret < 0) {
                        dev_err(&dev->dev, "get acknowledge response failed, error %d\n",
                                        ret);
                        goto fail;
                }
        }

fail:
        ret = elo_flush_smartset_responses(dev);
        if (ret < 0)
                dev_err(&dev->dev, "final FLUSH_SMARTSET_RESPONSES failed, error %d\n",
                                ret);
        queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
}

/*
 * Not all Elo devices need the periodic HID descriptor reads.
 * Only firmware version M needs this.
 */
static bool elo_broken_firmware(struct usb_device *dev)
{
        struct usb_device *hub = dev->parent;
        struct usb_device *child = NULL;
        u16 fw_lvl = le16_to_cpu(dev->descriptor.bcdDevice);
        u16 child_vid, child_pid;
        int i;
    
        if (!use_fw_quirk)
                return false;
        if (fw_lvl != 0x10d)
                return false;

        /* iterate sibling devices of the touch controller */
        usb_hub_for_each_child(hub, i, child) {
                child_vid = le16_to_cpu(child->descriptor.idVendor);
                child_pid = le16_to_cpu(child->descriptor.idProduct);

                /*
                 * If one of the devices below is present attached as a sibling of 
                 * the touch controller then  this is a newer IBM 4820 monitor that 
                 * does not need the IBM-requested workaround if fw level is
                 * 0x010d - aka 'M'.
                 * No other HW can have this combination.
                 */
                if (child_vid==0x04b3) {
                        switch (child_pid) {
                        case 0x4676: /* 4820 21x Video */
                        case 0x4677: /* 4820 51x Video */
                        case 0x4678: /* 4820 2Lx Video */
                        case 0x4679: /* 4820 5Lx Video */
                                return false;
                        }
                }
        }
        return true;
}

static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        struct elo_priv *priv;
        int ret;

        if (!hid_is_usb(hdev))
                return -EINVAL;

        priv = kzalloc_obj(*priv);
        if (!priv)
                return -ENOMEM;

        INIT_DELAYED_WORK(&priv->work, elo_work);
        priv->usbdev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));

        hid_set_drvdata(hdev, priv);

        ret = hid_parse(hdev);
        if (ret) {
                hid_err(hdev, "parse failed\n");
                goto err_free;
        }

        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
        if (ret) {
                hid_err(hdev, "hw start failed\n");
                goto err_free;
        }

        if (elo_broken_firmware(priv->usbdev)) {
                hid_info(hdev, "broken firmware found, installing workaround\n");
                queue_delayed_work(wq, &priv->work, ELO_PERIODIC_READ_INTERVAL);
        }

        return 0;
err_free:
        kfree(priv);
        return ret;
}

static void elo_remove(struct hid_device *hdev)
{
        struct elo_priv *priv = hid_get_drvdata(hdev);

        hid_hw_stop(hdev);
        cancel_delayed_work_sync(&priv->work);
        kfree(priv);
}

static const struct hid_device_id elo_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0009), },
        { HID_USB_DEVICE(USB_VENDOR_ID_ELO, 0x0030), },
        { }
};
MODULE_DEVICE_TABLE(hid, elo_devices);

static struct hid_driver elo_driver = {
        .name = "elo",
        .id_table = elo_devices,
        .probe = elo_probe,
        .remove = elo_remove,
        .raw_event = elo_raw_event,
        .input_configured = elo_input_configured,
};

static int __init elo_driver_init(void)
{
        int ret;

        wq = create_singlethread_workqueue("elousb");
        if (!wq)
                return -ENOMEM;

        ret = hid_register_driver(&elo_driver);
        if (ret)
                destroy_workqueue(wq);

        return ret;
}
module_init(elo_driver_init);

static void __exit elo_driver_exit(void)
{
        hid_unregister_driver(&elo_driver);
        destroy_workqueue(wq);
}
module_exit(elo_driver_exit);

MODULE_AUTHOR("Jiri Slaby <jslaby@suse.cz>");
MODULE_DESCRIPTION("HID driver for ELO usb touchscreen 4000/4500");
MODULE_LICENSE("GPL");