drivers/media/rc/imon_raw.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Copyright (C) 2018 Sean Young <sean@mess.org>
   4
   5 #include <linux/module.h>
   6 #include <linux/usb.h>
   7 #include <linux/usb/input.h>
   8 #include <media/rc-core.h>
   9
  10 /* Each bit is 250us */
  11 #define BIT_DURATION 250
  12
  13 struct imon {
  14         struct device *dev;
  15         struct urb *ir_urb;
  16         struct rc_dev *rcdev;
  17         __be64 ir_buf;
  18         char phys[64];
  19 };
  20
  21 /*
  22  * The first 5 bytes of data represent IR pulse or space. Each bit, starting
  23  * from highest bit in the first byte, represents 250µs of data. It is 1
  24  * for space and 0 for pulse.
  25  *
  26  * The station sends 10 packets, and the 7th byte will be number 1 to 10, so
  27  * when we receive 10 we assume all the data has arrived.
  28  */
  29 static void imon_ir_data(struct imon *imon)
  30 {
  31         struct ir_raw_event rawir = {};
  32         u64 data = be64_to_cpu(imon->ir_buf);
  33         u8 packet_no = data & 0xff;
  34         int offset = 40;
  35         int bit;
  36
  37         if (packet_no == 0xff)
  38                 return;
  39
  40         dev_dbg(imon->dev, "data: %*ph", 8, &imon->ir_buf);
  41
  42         /*
  43          * Only the first 5 bytes contain IR data. Right shift so we move
  44          * the IR bits to the lower 40 bits.
  45          */
  46         data >>= 24;
  47
  48         do {
  49                 /*
  50                  * Find highest set bit which is less or equal to offset
  51                  *
  52                  * offset is the bit above (base 0) where we start looking.
  53                  *
  54                  * data & (BIT_ULL(offset) - 1) masks off any unwanted bits,
  55                  * so we have just bits less than offset.
  56                  *
  57                  * fls will tell us the highest bit set plus 1 (or 0 if no
  58                  * bits are set).
  59                  */
  60                 rawir.pulse = !rawir.pulse;
  61                 bit = fls64(data & (BIT_ULL(offset) - 1));
  62                 if (bit < offset) {
  63                         dev_dbg(imon->dev, "%s: %d bits",
  64                                 rawir.pulse ? "pulse" : "space", offset - bit);
  65                         rawir.duration = (offset - bit) * BIT_DURATION;
  66                         ir_raw_event_store_with_filter(imon->rcdev, &rawir);
  67
  68                         offset = bit;
  69                 }
  70
  71                 data = ~data;
  72         } while (offset > 0);
  73
  74         if (packet_no == 0x0a && !imon->rcdev->idle) {
  75                 ir_raw_event_set_idle(imon->rcdev, true);
  76                 ir_raw_event_handle(imon->rcdev);
  77         }
  78 }
  79
  80 static void imon_ir_rx(struct urb *urb)
  81 {
  82         struct imon *imon = urb->context;
  83         int ret;
  84
  85         switch (urb->status) {
  86         case 0:
  87                 imon_ir_data(imon);
  88                 break;
  89         case -ECONNRESET:
  90         case -ENOENT:
  91         case -ESHUTDOWN:
  92                 usb_unlink_urb(urb);
  93                 return;
  94         case -EPIPE:
  95         default:
  96                 dev_dbg(imon->dev, "error: urb status = %d", urb->status);
  97                 break;
  98         }
  99
 100         ret = usb_submit_urb(urb, GFP_ATOMIC);
 101         if (ret && ret != -ENODEV)
 102                 dev_warn(imon->dev, "failed to resubmit urb: %d", ret);
 103 }
 104
 105 static int imon_probe(struct usb_interface *intf,
 106                       const struct usb_device_id *id)
 107 {
 108         struct usb_endpoint_descriptor *ir_ep = NULL;
 109         struct usb_host_interface *idesc;
 110         struct usb_device *udev;
 111         struct rc_dev *rcdev;
 112         struct imon *imon;
 113         int i, ret;
 114
 115         udev = interface_to_usbdev(intf);
 116         idesc = intf->cur_altsetting;
 117
 118         for (i = 0; i < idesc->desc.bNumEndpoints; i++) {
 119                 struct usb_endpoint_descriptor *ep = &idesc->endpoint[i].desc;
 120
 121                 if (usb_endpoint_is_int_in(ep)) {
 122                         ir_ep = ep;
 123                         break;
 124                 }
 125         }
 126
 127         if (!ir_ep) {
 128                 dev_err(&intf->dev, "IR endpoint missing");
 129                 return -ENODEV;
 130         }
 131
 132         imon = devm_kmalloc(&intf->dev, sizeof(*imon), GFP_KERNEL);
 133         if (!imon)
 134                 return -ENOMEM;
 135
 136         imon->ir_urb = usb_alloc_urb(0, GFP_KERNEL);
 137         if (!imon->ir_urb)
 138                 return -ENOMEM;
 139
 140         imon->dev = &intf->dev;
 141         usb_fill_int_urb(imon->ir_urb, udev,
 142                          usb_rcvintpipe(udev, ir_ep->bEndpointAddress),
 143                          &imon->ir_buf, sizeof(imon->ir_buf),
 144                          imon_ir_rx, imon, ir_ep->bInterval);
 145
 146         rcdev = devm_rc_allocate_device(&intf->dev, RC_DRIVER_IR_RAW);
 147         if (!rcdev) {
 148                 ret = -ENOMEM;
 149                 goto free_urb;
 150         }
 151
 152         usb_make_path(udev, imon->phys, sizeof(imon->phys));
 153
 154         rcdev->device_name = "iMON Station";
 155         rcdev->driver_name = KBUILD_MODNAME;
 156         rcdev->input_phys = imon->phys;
 157         usb_to_input_id(udev, &rcdev->input_id);
 158         rcdev->dev.parent = &intf->dev;
 159         rcdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
 160         rcdev->map_name = RC_MAP_IMON_RSC;
 161         rcdev->rx_resolution = BIT_DURATION;
 162         rcdev->priv = imon;
 163
 164         ret = devm_rc_register_device(&intf->dev, rcdev);
 165         if (ret)
 166                 goto free_urb;
 167
 168         imon->rcdev = rcdev;
 169
 170         ret = usb_submit_urb(imon->ir_urb, GFP_KERNEL);
 171         if (ret)
 172                 goto free_urb;
 173
 174         usb_set_intfdata(intf, imon);
 175
 176         return 0;
 177
 178 free_urb:
 179         usb_free_urb(imon->ir_urb);
 180         return ret;
 181 }
 182
 183 static void imon_disconnect(struct usb_interface *intf)
 184 {
 185         struct imon *imon = usb_get_intfdata(intf);
 186
 187         usb_kill_urb(imon->ir_urb);
 188         usb_free_urb(imon->ir_urb);
 189 }
 190
 191 static const struct usb_device_id imon_table[] = {
 192         /* SoundGraph iMON (IR only) -- sg_imon.inf */
 193         { USB_DEVICE(0x04e8, 0xff30) },
 194         {}
 195 };
 196
 197 static struct usb_driver imon_driver = {
 198         .name = KBUILD_MODNAME,
 199         .probe = imon_probe,
 200         .disconnect = imon_disconnect,
 201         .id_table = imon_table
 202 };
 203
 204 module_usb_driver(imon_driver);
 205
 206 MODULE_DESCRIPTION("Early raw iMON IR devices");
 207 MODULE_AUTHOR("Sean Young <sean@mess.org>");
 208 MODULE_LICENSE("GPL");
 209 MODULE_DEVICE_TABLE(usb, imon_table);