// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * TechnoTrend USB IR Receiver
 *
 * Copyright (C) 2012 Sean Young <sean@mess.org>
 */

#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/input.h>
#include <linux/slab.h>
#include <linux/leds.h>
#include <media/rc-core.h>

#define DRIVER_NAME     "ttusbir"
#define DRIVER_DESC     "TechnoTrend USB IR Receiver"
/*
 * The Windows driver uses 8 URBS, the original lirc drivers has a
 * configurable amount (2 default, 4 max). This device generates about 125
 * messages per second (!), whether IR is idle or not.
 */
#define NUM_URBS        4
#define US_PER_BYTE     62
#define US_PER_BIT      (US_PER_BYTE / 8)

struct ttusbir {
        struct rc_dev *rc;
        struct device *dev;
        struct usb_device *udev;

        struct urb *urb[NUM_URBS];

        struct led_classdev led;
        struct urb *bulk_urb;
        uint8_t bulk_buffer[5];
        int bulk_out_endp, iso_in_endp;
        bool led_on, is_led_on;
        atomic_t led_complete;

        char phys[64];
};

static enum led_brightness ttusbir_brightness_get(struct led_classdev *led_dev)
{
        struct ttusbir *tt = container_of(led_dev, struct ttusbir, led);

        return tt->led_on ? LED_FULL : LED_OFF;
}

static void ttusbir_set_led(struct ttusbir *tt)
{
        int ret;

        smp_mb();

        if (tt->led_on != tt->is_led_on && tt->udev &&
                                atomic_add_unless(&tt->led_complete, 1, 1)) {
                tt->bulk_buffer[4] = tt->is_led_on = tt->led_on;
                ret = usb_submit_urb(tt->bulk_urb, GFP_ATOMIC);
                if (ret) {
                        dev_warn(tt->dev, "failed to submit bulk urb: %d\n",
                                                                        ret);
                        atomic_dec(&tt->led_complete);
                }
        }
}

static void ttusbir_brightness_set(struct led_classdev *led_dev, enum
                                                led_brightness brightness)
{
        struct ttusbir *tt = container_of(led_dev, struct ttusbir, led);

        tt->led_on = brightness != LED_OFF;

        ttusbir_set_led(tt);
}

/*
 * The urb cannot be reused until the urb completes
 */
static void ttusbir_bulk_complete(struct urb *urb)
{
        struct ttusbir *tt = urb->context;

        atomic_dec(&tt->led_complete);

        switch (urb->status) {
        case 0:
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                return;
        case -EPIPE:
        default:
                dev_dbg(tt->dev, "Error: urb status = %d\n", urb->status);
                break;
        }

        ttusbir_set_led(tt);
}

/*
 * The data is one bit per sample, a set bit signifying silence and samples
 * being MSB first. Bit 0 can contain garbage so take it to be whatever
 * bit 1 is, so we don't have unexpected edges.
 */
static void ttusbir_process_ir_data(struct ttusbir *tt, uint8_t *buf)
{
        struct ir_raw_event rawir = {};
        unsigned i, v, b;
        bool event = false;

        for (i = 0; i < 128; i++) {
                v = buf[i] & 0xfe;
                switch (v) {
                case 0xfe:
                        rawir.pulse = false;
                        rawir.duration = US_PER_BYTE;
                        if (ir_raw_event_store_with_filter(tt->rc, &rawir))
                                event = true;
                        break;
                case 0:
                        rawir.pulse = true;
                        rawir.duration = US_PER_BYTE;
                        if (ir_raw_event_store_with_filter(tt->rc, &rawir))
                                event = true;
                        break;
                default:
                        /* one edge per byte */
                        if (v & 2) {
                                b = ffz(v | 1);
                                rawir.pulse = true;
                        } else {
                                b = ffs(v) - 1;
                                rawir.pulse = false;
                        }

                        rawir.duration = US_PER_BIT * (8 - b);
                        if (ir_raw_event_store_with_filter(tt->rc, &rawir))
                                event = true;

                        rawir.pulse = !rawir.pulse;
                        rawir.duration = US_PER_BIT * b;
                        if (ir_raw_event_store_with_filter(tt->rc, &rawir))
                                event = true;
                        break;
                }
        }

        /* don't wakeup when there's nothing to do */
        if (event)
                ir_raw_event_handle(tt->rc);
}

static void ttusbir_urb_complete(struct urb *urb)
{
        struct ttusbir *tt = urb->context;
        int rc;

        switch (urb->status) {
        case 0:
                ttusbir_process_ir_data(tt, urb->transfer_buffer);
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                return;
        case -EPIPE:
        default:
                dev_dbg(tt->dev, "Error: urb status = %d\n", urb->status);
                break;
        }

        rc = usb_submit_urb(urb, GFP_ATOMIC);
        if (rc && rc != -ENODEV)
                dev_warn(tt->dev, "failed to resubmit urb: %d\n", rc);
}

static int ttusbir_probe(struct usb_interface *intf,
                         const struct usb_device_id *id)
{
        struct ttusbir *tt;
        struct usb_interface_descriptor *idesc;
        struct usb_endpoint_descriptor *desc;
        struct rc_dev *rc;
        int i, j, ret;
        int altsetting = -1;

        tt = kzalloc_obj(*tt);
        rc = rc_allocate_device(RC_DRIVER_IR_RAW);
        if (!tt || !rc) {
                ret = -ENOMEM;
                goto out;
        }

        /* find the correct alt setting */
        for (i = 0; i < intf->num_altsetting && altsetting == -1; i++) {
                int max_packet, bulk_out_endp = -1, iso_in_endp = -1;

                idesc = &intf->altsetting[i].desc;

                for (j = 0; j < idesc->bNumEndpoints; j++) {
                        desc = &intf->altsetting[i].endpoint[j].desc;
                        max_packet = le16_to_cpu(desc->wMaxPacketSize);
                        if (usb_endpoint_dir_in(desc) &&
                                        usb_endpoint_xfer_isoc(desc) &&
                                        max_packet == 0x10)
                                iso_in_endp = j;
                        else if (usb_endpoint_dir_out(desc) &&
                                        usb_endpoint_xfer_bulk(desc) &&
                                        max_packet == 0x20)
                                bulk_out_endp = j;

                        if (bulk_out_endp != -1 && iso_in_endp != -1) {
                                tt->bulk_out_endp = bulk_out_endp;
                                tt->iso_in_endp = iso_in_endp;
                                altsetting = i;
                                break;
                        }
                }
        }

        if (altsetting == -1) {
                dev_err(&intf->dev, "cannot find expected altsetting\n");
                ret = -ENODEV;
                goto out;
        }

        tt->dev = &intf->dev;
        tt->udev = interface_to_usbdev(intf);
        tt->rc = rc;

        ret = usb_set_interface(tt->udev, 0, altsetting);
        if (ret)
                goto out;

        for (i = 0; i < NUM_URBS; i++) {
                struct urb *urb = usb_alloc_urb(8, GFP_KERNEL);
                void *buffer;

                if (!urb) {
                        ret = -ENOMEM;
                        goto out;
                }

                urb->dev = tt->udev;
                urb->context = tt;
                urb->pipe = usb_rcvisocpipe(tt->udev, tt->iso_in_endp);
                urb->interval = 1;
                buffer = usb_alloc_coherent(tt->udev, 128, GFP_KERNEL,
                                                &urb->transfer_dma);
                if (!buffer) {
                        usb_free_urb(urb);
                        ret = -ENOMEM;
                        goto out;
                }
                urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP | URB_ISO_ASAP;
                urb->transfer_buffer = buffer;
                urb->complete = ttusbir_urb_complete;
                urb->number_of_packets = 8;
                urb->transfer_buffer_length = 128;

                for (j = 0; j < 8; j++) {
                        urb->iso_frame_desc[j].offset = j * 16;
                        urb->iso_frame_desc[j].length = 16;
                }

                tt->urb[i] = urb;
        }

        tt->bulk_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!tt->bulk_urb) {
                ret = -ENOMEM;
                goto out;
        }

        tt->bulk_buffer[0] = 0xaa;
        tt->bulk_buffer[1] = 0x01;
        tt->bulk_buffer[2] = 0x05;
        tt->bulk_buffer[3] = 0x01;

        usb_fill_bulk_urb(tt->bulk_urb, tt->udev, usb_sndbulkpipe(tt->udev,
                tt->bulk_out_endp), tt->bulk_buffer, sizeof(tt->bulk_buffer),
                                                ttusbir_bulk_complete, tt);

        tt->led.name = "ttusbir:green:power";
        tt->led.default_trigger = "rc-feedback";
        tt->led.brightness_set = ttusbir_brightness_set;
        tt->led.brightness_get = ttusbir_brightness_get;
        tt->is_led_on = tt->led_on = true;
        atomic_set(&tt->led_complete, 0);
        ret = led_classdev_register(&intf->dev, &tt->led);
        if (ret)
                goto out;

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

        rc->device_name = DRIVER_DESC;
        rc->input_phys = tt->phys;
        usb_to_input_id(tt->udev, &rc->input_id);
        rc->dev.parent = &intf->dev;
        rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
        rc->priv = tt;
        rc->driver_name = DRIVER_NAME;
        rc->map_name = RC_MAP_TT_1500;
        rc->min_timeout = 1;
        rc->timeout = IR_DEFAULT_TIMEOUT;
        rc->max_timeout = 10 * IR_DEFAULT_TIMEOUT;

        /*
         * The precision is US_PER_BIT, but since every 8th bit can be
         * overwritten with garbage the accuracy is at best 2 * US_PER_BIT.
         */
        rc->rx_resolution = 2 * US_PER_BIT;

        ret = rc_register_device(rc);
        if (ret) {
                dev_err(&intf->dev, "failed to register rc device %d\n", ret);
                goto out2;
        }

        usb_set_intfdata(intf, tt);

        for (i = 0; i < NUM_URBS; i++) {
                ret = usb_submit_urb(tt->urb[i], GFP_KERNEL);
                if (ret) {
                        dev_err(tt->dev, "failed to submit urb %d\n", ret);
                        goto out3;
                }
        }

        return 0;
out3:
        rc_unregister_device(rc);
        rc = NULL;
out2:
        led_classdev_unregister(&tt->led);
out:
        if (tt) {
                for (i = 0; i < NUM_URBS && tt->urb[i]; i++) {
                        struct urb *urb = tt->urb[i];

                        usb_kill_urb(urb);
                        usb_free_coherent(tt->udev, 128, urb->transfer_buffer,
                                                        urb->transfer_dma);
                        usb_free_urb(urb);
                }
                usb_kill_urb(tt->bulk_urb);
                usb_free_urb(tt->bulk_urb);
                kfree(tt);
        }
        rc_free_device(rc);

        return ret;
}

static void ttusbir_disconnect(struct usb_interface *intf)
{
        struct ttusbir *tt = usb_get_intfdata(intf);
        struct usb_device *udev = tt->udev;
        int i;

        tt->udev = NULL;

        rc_unregister_device(tt->rc);
        led_classdev_unregister(&tt->led);
        for (i = 0; i < NUM_URBS; i++) {
                usb_kill_urb(tt->urb[i]);
                usb_free_coherent(udev, 128, tt->urb[i]->transfer_buffer,
                                                tt->urb[i]->transfer_dma);
                usb_free_urb(tt->urb[i]);
        }
        usb_kill_urb(tt->bulk_urb);
        usb_free_urb(tt->bulk_urb);
        usb_set_intfdata(intf, NULL);
        kfree(tt);
}

static int ttusbir_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct ttusbir *tt = usb_get_intfdata(intf);
        int i;

        for (i = 0; i < NUM_URBS; i++)
                usb_kill_urb(tt->urb[i]);

        led_classdev_suspend(&tt->led);
        usb_kill_urb(tt->bulk_urb);

        return 0;
}

static int ttusbir_resume(struct usb_interface *intf)
{
        struct ttusbir *tt = usb_get_intfdata(intf);
        int i, rc;

        tt->is_led_on = true;
        led_classdev_resume(&tt->led);

        for (i = 0; i < NUM_URBS; i++) {
                rc = usb_submit_urb(tt->urb[i], GFP_NOIO);
                if (rc) {
                        dev_warn(tt->dev, "failed to submit urb: %d\n", rc);
                        break;
                }
        }

        return rc;
}

static const struct usb_device_id ttusbir_table[] = {
        { USB_DEVICE(0x0b48, 0x2003) },
        { }
};

static struct usb_driver ttusbir_driver = {
        .name = DRIVER_NAME,
        .id_table = ttusbir_table,
        .probe = ttusbir_probe,
        .suspend = ttusbir_suspend,
        .resume = ttusbir_resume,
        .reset_resume = ttusbir_resume,
        .disconnect = ttusbir_disconnect,
};

module_usb_driver(ttusbir_driver);

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