src/hardware/uni-t-ut32x/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <string.h>
  22 #include <math.h>
  23 #include "protocol.h"
  24
  25 static float parse_temperature(unsigned char *buf)
  26 {
  27         float temp;
  28         int i;
  29         gboolean negative;
  30
  31         negative = FALSE;
  32         temp = 0.0;
  33         for (i = 0; i < 4; i++) {
  34                 if (buf[i] == 0x3a)
  35                         continue;
  36                 if (buf[i] == 0x3b) {
  37                         if (negative) {
  38                                 sr_dbg("Double negative sign!");
  39                                 return NAN;
  40                         } else {
  41                                 negative = TRUE;
  42                                 continue;
  43                         }
  44                 }
  45                 if (buf[i] < 0x30 || buf[i] > 0x39) {
  46                         sr_dbg("Invalid digit '%.2x'!", buf[i]);
  47                         return NAN;
  48                 }
  49                 temp *= 10;
  50                 temp += (buf[i] - 0x30);
  51         }
  52         temp /= 10;
  53         if (negative)
  54                 temp = -temp;
  55
  56         return temp;
  57 }
  58
  59 static void process_packet(struct sr_dev_inst *sdi)
  60 {
  61         struct dev_context *devc;
  62         struct sr_datafeed_packet packet;
  63         struct sr_datafeed_analog analog;
  64         struct sr_analog_encoding encoding;
  65         struct sr_analog_meaning meaning;
  66         struct sr_analog_spec spec;
  67         GString *spew;
  68         float temp;
  69         int i;
  70         gboolean is_valid;
  71
  72         devc = sdi->priv;
  73         sr_dbg("Received full 19-byte packet.");
  74         if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
  75                 spew = g_string_sized_new(60);
  76                 for (i = 0; i < devc->packet_len; i++)
  77                         g_string_append_printf(spew, "%.2x ", devc->packet[i]);
  78                 sr_spew("%s", spew->str);
  79                 g_string_free(spew, TRUE);
  80         }
  81
  82         is_valid = TRUE;
  83         if (devc->packet[1] == 0x3b && devc->packet[2] == 0x3b
  84                         && devc->packet[3] == 0x3b && devc->packet[4] == 0x3b)
  85                 /* No measurement: missing channel, empty storage location, ... */
  86                 is_valid = FALSE;
  87
  88         temp = parse_temperature(devc->packet + 1);
  89         if (isnan(temp))
  90                 is_valid = FALSE;
  91
  92         if (is_valid) {
  93                 sr_analog_init(&analog, &encoding, &meaning, &spec, 1);
  94                 analog.meaning->mq = SR_MQ_TEMPERATURE;
  95                 analog.meaning->mqflags = 0;
  96                 switch (devc->packet[5] - 0x30) {
  97                 case 1:
  98                         analog.meaning->unit = SR_UNIT_CELSIUS;
  99                         break;
 100                 case 2:
 101                         analog.meaning->unit = SR_UNIT_FAHRENHEIT;
 102                         break;
 103                 case 3:
 104                         analog.meaning->unit = SR_UNIT_KELVIN;
 105                         break;
 106                 default:
 107                         /* We can still pass on the measurement, whatever it is. */
 108                         sr_dbg("Unknown unit 0x%.2x.", devc->packet[5]);
 109                 }
 110                 switch (devc->packet[13] - 0x30) {
 111                 case 0:
 112                         /* Channel T1. */
 113                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 0));
 114                         break;
 115                 case 1:
 116                         /* Channel T2. */
 117                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 1));
 118                         break;
 119                 case 2:
 120                 case 3:
 121                         /* Channel T1-T2. */
 122                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 2));
 123                         analog.meaning->mqflags |= SR_MQFLAG_RELATIVE;
 124                         break;
 125                 default:
 126                         sr_err("Unknown channel 0x%.2x.", devc->packet[13]);
 127                         is_valid = FALSE;
 128                 }
 129                 if (is_valid) {
 130                         analog.num_samples = 1;
 131                         analog.data = &temp;
 132                         packet.type = SR_DF_ANALOG;
 133                         packet.payload = &analog;
 134                         sr_session_send(sdi, &packet);
 135                         g_slist_free(analog.meaning->channels);
 136                 }
 137         }
 138
 139         /*
 140          * We count packets even if the measurement was invalid. This way
 141          * a sample limit on "Memory" data source still works: Unused
 142          * memory slots come through as "----" measurements.
 143          */
 144         sr_sw_limits_update_samples_read(&devc->limits, 1);
 145         if (sr_sw_limits_check(&devc->limits))
 146                 sr_dev_acquisition_stop(sdi);
 147 }
 148
 149 SR_PRIV void LIBUSB_CALL uni_t_ut32x_receive_transfer(struct libusb_transfer *transfer)
 150 {
 151         struct dev_context *devc;
 152         struct sr_dev_inst *sdi;
 153         int hid_payload_len, ret;
 154
 155         sdi = transfer->user_data;
 156         devc = sdi->priv;
 157         if (transfer->actual_length == 8) {
 158                 /* CH9325 encodes length in low nibble of first byte, with
 159                  * bytes 1-7 being the (padded) payload. */
 160                 hid_payload_len = transfer->buffer[0] & 0x0f;
 161                 memcpy(devc->packet + devc->packet_len, transfer->buffer + 1,
 162                                 hid_payload_len);
 163                 devc->packet_len += hid_payload_len;
 164                 if (devc->packet_len >= 2
 165                                 && devc->packet[devc->packet_len - 2] == 0x0d
 166                                 && devc->packet[devc->packet_len - 1] == 0x0a) {
 167                         /* Got end of packet, but do we have a complete packet? */
 168                         if (devc->packet_len == 19)
 169                                 process_packet(sdi);
 170                         /* Either way, done with it. */
 171                         devc->packet_len = 0;
 172                 } else if (devc->packet_len > 19) {
 173                         /* Guard against garbage from the device overrunning
 174                          * our packet buffer. */
 175                         sr_dbg("Buffer overrun!");
 176                         devc->packet_len = 0;
 177                 }
 178         }
 179
 180         /* Get the next transfer (unless we're shutting down). */
 181         if (sdi->status != SR_ST_STOPPING) {
 182                 if ((ret = libusb_submit_transfer(devc->xfer)) != 0) {
 183                         sr_dbg("Failed to resubmit transfer: %s", libusb_error_name(ret));
 184                         sdi->status = SR_ST_STOPPING;
 185                         libusb_free_transfer(devc->xfer);
 186                 }
 187         } else
 188                 libusb_free_transfer(devc->xfer);
 189
 190 }
 191
 192 SR_PRIV int uni_t_ut32x_handle_events(int fd, int revents, void *cb_data)
 193 {
 194         struct drv_context *drvc;
 195         struct dev_context *devc;
 196         struct sr_dev_driver *di;
 197         struct sr_dev_inst *sdi;
 198         struct sr_usb_dev_inst *usb;
 199         struct timeval tv;
 200         int len, ret;
 201         unsigned char cmd[2];
 202
 203         (void)fd;
 204         (void)revents;
 205
 206         if (!(sdi = cb_data))
 207                 return TRUE;
 208
 209         di = sdi->driver;
 210         drvc = di->context;
 211
 212         if (!(devc = sdi->priv))
 213                 return TRUE;
 214
 215         memset(&tv, 0, sizeof(struct timeval));
 216         libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx, &tv,
 217                         NULL);
 218
 219         if (sdi->status == SR_ST_STOPPING) {
 220                 usb_source_remove(sdi->session, drvc->sr_ctx);
 221                 std_session_send_df_end(sdi);
 222
 223                 /* Tell the device to stop sending USB packets. */
 224                 usb = sdi->conn;
 225                 cmd[0] = 0x01;
 226                 cmd[1] = CMD_STOP;
 227                 ret = libusb_bulk_transfer(usb->devhdl, EP_OUT, cmd, 2, &len, 5);
 228                 if (ret != 0 || len != 2) {
 229                         /* Warning only, doesn't matter. */
 230                         sr_dbg("Failed to send stop command: %s", libusb_error_name(ret));
 231                 }
 232
 233                 sdi->status = SR_ST_ACTIVE;
 234                 return TRUE;
 235         }
 236
 237         return TRUE;
 238 }