/*
 * IgorPlug-USB IR Receiver
 *
 * Copyright (C) 2014 Sean Young <sean@mess.org>
 *
 * Supports the standard homebrew IgorPlugUSB receiver with Igor's firmware.
 * See http://www.cesko.host.sk/IgorPlugUSB/IgorPlug-USB%20(AVR)_eng.htm
 *
 * Based on the lirc_igorplugusb.c driver:
 *      Copyright (C) 2004 Jan M. Hochstein
 *      <hochstein@algo.informatik.tu-darmstadt.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/input.h>
#include <media/rc-core.h>

#define DRIVER_DESC             "IgorPlug-USB IR Receiver"
#define DRIVER_NAME             "igorplugusb"

#define HEADERLEN               3
#define BUFLEN                  36
#define MAX_PACKET              (HEADERLEN + BUFLEN)

#define SET_INFRABUFFER_EMPTY   1
#define GET_INFRACODE           2


struct igorplugusb {
        struct rc_dev *rc;
        struct device *dev;

        struct urb *urb;
        struct usb_ctrlrequest request;

        struct timer_list timer;

        uint8_t buf_in[MAX_PACKET];

        char phys[64];
};

static void igorplugusb_cmd(struct igorplugusb *ir, int cmd);

static void igorplugusb_irdata(struct igorplugusb *ir, unsigned len)
{
        DEFINE_IR_RAW_EVENT(rawir);
        unsigned i, start, overflow;

        dev_dbg(ir->dev, "irdata: %*ph (len=%u)", len, ir->buf_in, len);

        /*
         * If more than 36 pulses and spaces follow each other, the igorplugusb
         * overwrites its buffer from the beginning. The overflow value is the
         * last offset which was not overwritten. Everything from this offset
         * onwards occurred before everything until this offset.
         */
        overflow = ir->buf_in[2];
        i = start = overflow + HEADERLEN;

        if (start >= len) {
                dev_err(ir->dev, "receive overflow invalid: %u", overflow);
        } else {
                if (overflow > 0)
                        dev_warn(ir->dev, "receive overflow, at least %u lost",
                                                                overflow);

                do {
                        rawir.duration = ir->buf_in[i] * 85333;
                        rawir.pulse = i & 1;

                        ir_raw_event_store_with_filter(ir->rc, &rawir);

                        if (++i == len)
                                i = HEADERLEN;
                } while (i != start);

                /* add a trailing space */
                rawir.duration = ir->rc->timeout;
                rawir.pulse = false;
                ir_raw_event_store_with_filter(ir->rc, &rawir);

                ir_raw_event_handle(ir->rc);
        }

        igorplugusb_cmd(ir, SET_INFRABUFFER_EMPTY);
}

static void igorplugusb_callback(struct urb *urb)
{
        struct usb_ctrlrequest *req;
        struct igorplugusb *ir = urb->context;

        req = (struct usb_ctrlrequest *)urb->setup_packet;

        switch (urb->status) {
        case 0:
                if (req->bRequest == GET_INFRACODE &&
                                        urb->actual_length > HEADERLEN)
                        igorplugusb_irdata(ir, urb->actual_length);
                else /* request IR */
                        mod_timer(&ir->timer, jiffies + msecs_to_jiffies(50));
                break;
        case -EPROTO:
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                usb_unlink_urb(urb);
                return;
        default:
                dev_warn(ir->dev, "Error: urb status = %d\n", urb->status);
                igorplugusb_cmd(ir, SET_INFRABUFFER_EMPTY);
                break;
        }
}

static void igorplugusb_cmd(struct igorplugusb *ir, int cmd)
{
        int ret;

        ir->request.bRequest = cmd;
        ir->urb->transfer_flags = 0;
        ret = usb_submit_urb(ir->urb, GFP_ATOMIC);
        if (ret)
                dev_err(ir->dev, "submit urb failed: %d", ret);
}

static void igorplugusb_timer(unsigned long data)
{
        struct igorplugusb *ir = (struct igorplugusb *)data;

        igorplugusb_cmd(ir, GET_INFRACODE);
}

static int igorplugusb_probe(struct usb_interface *intf,
                                        const struct usb_device_id *id)
{
        struct usb_device *udev;
        struct usb_host_interface *idesc;
        struct usb_endpoint_descriptor *ep;
        struct igorplugusb *ir;
        struct rc_dev *rc;
        int ret;

        udev = interface_to_usbdev(intf);
        idesc = intf->cur_altsetting;

        if (idesc->desc.bNumEndpoints != 1) {
                dev_err(&intf->dev, "incorrect number of endpoints");
                return -ENODEV;
        }

        ep = &idesc->endpoint[0].desc;
        if (!usb_endpoint_dir_in(ep) || !usb_endpoint_xfer_control(ep)) {
                dev_err(&intf->dev, "endpoint incorrect");
                return -ENODEV;
        }

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

        ir->dev = &intf->dev;

        setup_timer(&ir->timer, igorplugusb_timer, (unsigned long)ir);

        ir->request.bRequest = GET_INFRACODE;
        ir->request.bRequestType = USB_TYPE_VENDOR | USB_DIR_IN;
        ir->request.wLength = cpu_to_le16(sizeof(ir->buf_in));

        ir->urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!ir->urb)
                return -ENOMEM;

        usb_fill_control_urb(ir->urb, udev,
                usb_rcvctrlpipe(udev, 0), (uint8_t *)&ir->request,
                ir->buf_in, sizeof(ir->buf_in), igorplugusb_callback, ir);

        usb_make_path(udev, ir->phys, sizeof(ir->phys));

        rc = rc_allocate_device();
        rc->input_name = DRIVER_DESC;
        rc->input_phys = ir->phys;
        usb_to_input_id(udev, &rc->input_id);
        rc->dev.parent = &intf->dev;
        rc->driver_type = RC_DRIVER_IR_RAW;
        /*
         * This device can only store 36 pulses + spaces, which is not enough
         * for the NEC protocol and many others.
         */
        rc->allowed_protocols = RC_BIT_ALL & ~(RC_BIT_NEC | RC_BIT_RC6_6A_20 |
                        RC_BIT_RC6_6A_24 | RC_BIT_RC6_6A_32 | RC_BIT_RC6_MCE |
                        RC_BIT_SONY20 | RC_BIT_MCE_KBD | RC_BIT_SANYO);

        rc->priv = ir;
        rc->driver_name = DRIVER_NAME;
        rc->map_name = RC_MAP_HAUPPAUGE;
        rc->timeout = MS_TO_NS(100);
        rc->rx_resolution = 85333;

        ir->rc = rc;
        ret = rc_register_device(rc);
        if (ret) {
                dev_err(&intf->dev, "failed to register rc device: %d", ret);
                rc_free_device(rc);
                usb_free_urb(ir->urb);
                return ret;
        }

        usb_set_intfdata(intf, ir);

        igorplugusb_cmd(ir, SET_INFRABUFFER_EMPTY);

        return 0;
}

static void igorplugusb_disconnect(struct usb_interface *intf)
{
        struct igorplugusb *ir = usb_get_intfdata(intf);

        rc_unregister_device(ir->rc);
        del_timer_sync(&ir->timer);
        usb_set_intfdata(intf, NULL);
        usb_kill_urb(ir->urb);
        usb_free_urb(ir->urb);
}

static struct usb_device_id igorplugusb_table[] = {
        /* Igor Plug USB (Atmel's Manufact. ID) */
        { USB_DEVICE(0x03eb, 0x0002) },
        /* Fit PC2 Infrared Adapter */
        { USB_DEVICE(0x03eb, 0x21fe) },
        /* Terminating entry */
        { }
};

static struct usb_driver igorplugusb_driver = {
        .name = DRIVER_NAME,
        .probe = igorplugusb_probe,
        .disconnect = igorplugusb_disconnect,
        .id_table = igorplugusb_table
};

module_usb_driver(igorplugusb_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Sean Young <sean@mess.org>");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(usb, igorplugusb_table);