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 #define SEP     "\r\n"
  26 #define BLANK   ':'
  27 #define NEG     ';'
  28
  29 /*
  30  * Get a temperature value from a four-character buffer. The value is
  31  * encoded in ASCII and the unit is deci-degrees (tenths of degrees).
  32  */
  33 static float parse_temperature(unsigned char *buf)
  34 {
  35         float temp;
  36         int i;
  37         gboolean negative;
  38
  39         negative = FALSE;
  40         temp = 0.0;
  41         for (i = 0; i < 4; i++) {
  42                 if (buf[i] == BLANK)
  43                         continue;
  44                 if (buf[i] == NEG) {
  45                         if (negative) {
  46                                 sr_dbg("Double negative sign!");
  47                                 return NAN;
  48                         }
  49                         negative = TRUE;
  50                         continue;
  51                 }
  52                 if (buf[i] < '0' || buf[i] > '9') {
  53                         sr_dbg("Invalid digit '%.2x'!", buf[i]);
  54                         return NAN;
  55                 }
  56                 temp *= 10;
  57                 temp += buf[i] - '0';
  58         }
  59         temp /= 10;
  60         if (negative)
  61                 temp = -temp;
  62
  63         return temp;
  64 }
  65
  66 static void process_packet(struct sr_dev_inst *sdi, uint8_t *pkt, size_t len)
  67 {
  68         struct dev_context *devc;
  69         struct sr_datafeed_packet packet;
  70         struct sr_datafeed_analog analog;
  71         struct sr_analog_encoding encoding;
  72         struct sr_analog_meaning meaning;
  73         struct sr_analog_spec spec;
  74         GString *spew;
  75         float temp;
  76         gboolean is_valid;
  77
  78         if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
  79                 spew = sr_hexdump_new(pkt, len);
  80                 sr_spew("Got a packet, len %zu, bytes%s", len, spew->str);
  81                 sr_hexdump_free(spew);
  82         }
  83         if (len != PACKET_SIZE)
  84                 return;
  85         if (pkt[17] != SEP[0] || pkt[18] != SEP[1])
  86                 return;
  87         if (pkt[8] != '0' || pkt[16] != '1')
  88                 return;
  89         sr_dbg("Processing 19-byte packet.");
  90
  91         is_valid = TRUE;
  92         if (pkt[1] == NEG && pkt[2] == NEG && pkt[3] == NEG && pkt[4] == NEG)
  93                 /* No measurement: missing channel, empty storage location, ... */
  94                 is_valid = FALSE;
  95
  96         temp = parse_temperature(&pkt[1]);
  97         if (isnan(temp))
  98                 is_valid = FALSE;
  99
 100         if (is_valid) {
 101                 memset(&packet, 0, sizeof(packet));
 102                 sr_analog_init(&analog, &encoding, &meaning, &spec, 1);
 103                 analog.meaning->mq = SR_MQ_TEMPERATURE;
 104                 analog.meaning->mqflags = 0;
 105                 switch (pkt[5] - '0') {
 106                 case 1:
 107                         analog.meaning->unit = SR_UNIT_CELSIUS;
 108                         break;
 109                 case 2:
 110                         analog.meaning->unit = SR_UNIT_FAHRENHEIT;
 111                         break;
 112                 case 3:
 113                         analog.meaning->unit = SR_UNIT_KELVIN;
 114                         break;
 115                 default:
 116                         /* We can still pass on the measurement, whatever it is. */
 117                         sr_dbg("Unknown unit 0x%.2x.", pkt[5]);
 118                 }
 119                 switch (pkt[13] - '0') {
 120                 case 0:
 121                         /* Channel T1. */
 122                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 0));
 123                         break;
 124                 case 1:
 125                         /* Channel T2. */
 126                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 1));
 127                         break;
 128                 case 2:
 129                 case 3:
 130                         /* Channel T1-T2. */
 131                         analog.meaning->channels = g_slist_append(NULL, g_slist_nth_data(sdi->channels, 2));
 132                         analog.meaning->mqflags |= SR_MQFLAG_RELATIVE;
 133                         break;
 134                 default:
 135                         sr_err("Unknown channel 0x%.2x.", pkt[13]);
 136                         is_valid = FALSE;
 137                 }
 138                 if (is_valid) {
 139                         analog.num_samples = 1;
 140                         analog.data = &temp;
 141                         packet.type = SR_DF_ANALOG;
 142                         packet.payload = &analog;
 143                         sr_session_send(sdi, &packet);
 144                         g_slist_free(analog.meaning->channels);
 145                 }
 146         }
 147
 148         /*
 149          * We count packets even if the measurement was invalid. This way
 150          * a sample limit on "Memory" data source still works: Unused
 151          * memory slots come through as "----" measurements.
 152          */
 153         devc = sdi->priv;
 154         sr_sw_limits_update_samples_read(&devc->limits, 1);
 155         if (sr_sw_limits_check(&devc->limits))
 156                 sr_dev_acquisition_stop(sdi);
 157 }
 158
 159 SR_PRIV void LIBUSB_CALL uni_t_ut32x_receive_transfer(struct libusb_transfer *transfer)
 160 {
 161         struct dev_context *devc;
 162         struct sr_dev_inst *sdi;
 163         int hid_payload_len, ret;
 164
 165         sdi = transfer->user_data;
 166         devc = sdi->priv;
 167         if (transfer->actual_length == 8) {
 168                 /* CH9325 encodes length in low nibble of first byte, with
 169                  * bytes 1-7 being the (padded) payload. */
 170                 hid_payload_len = transfer->buffer[0] & 0x0f;
 171                 memcpy(devc->packet + devc->packet_len, transfer->buffer + 1,
 172                                 hid_payload_len);
 173                 devc->packet_len += hid_payload_len;
 174                 if (devc->packet_len >= 2
 175                                 && devc->packet[devc->packet_len - 2] == SEP[0]
 176                                 && devc->packet[devc->packet_len - 1] == SEP[1]) {
 177                         /* Got end of packet. */
 178                         process_packet(sdi, devc->packet, devc->packet_len);
 179                         devc->packet_len = 0;
 180                 } else if (devc->packet_len > PACKET_SIZE) {
 181                         /* Guard against garbage from the device overrunning
 182                          * our packet buffer. */
 183                         sr_dbg("Buffer overrun!");
 184                         process_packet(sdi, devc->packet, devc->packet_len);
 185                         devc->packet_len = 0;
 186                 }
 187         }
 188
 189         /* Get the next transfer (unless we're shutting down). */
 190         if (sdi->status != SR_ST_STOPPING) {
 191                 if ((ret = libusb_submit_transfer(devc->xfer)) != 0) {
 192                         sr_dbg("Failed to resubmit transfer: %s", libusb_error_name(ret));
 193                         sdi->status = SR_ST_STOPPING;
 194                         libusb_free_transfer(devc->xfer);
 195                 }
 196         } else
 197                 libusb_free_transfer(devc->xfer);
 198
 199 }
 200
 201 SR_PRIV int uni_t_ut32x_handle_events(int fd, int revents, void *cb_data)
 202 {
 203         struct drv_context *drvc;
 204         struct dev_context *devc;
 205         struct sr_dev_driver *di;
 206         struct sr_dev_inst *sdi;
 207         struct sr_usb_dev_inst *usb;
 208         struct timeval tv;
 209         int len, ret;
 210         unsigned char cmd[2];
 211
 212         (void)fd;
 213         (void)revents;
 214
 215         if (!(sdi = cb_data))
 216                 return TRUE;
 217
 218         di = sdi->driver;
 219         drvc = di->context;
 220
 221         if (!(devc = sdi->priv))
 222                 return TRUE;
 223
 224         memset(&tv, 0, sizeof(struct timeval));
 225         libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx, &tv,
 226                         NULL);
 227
 228         if (sdi->status == SR_ST_STOPPING) {
 229                 usb_source_remove(sdi->session, drvc->sr_ctx);
 230                 std_session_send_df_end(sdi);
 231
 232                 /* Tell the device to stop sending USB packets. */
 233                 usb = sdi->conn;
 234                 cmd[0] = 0x01;
 235                 cmd[1] = CMD_STOP;
 236                 ret = libusb_bulk_transfer(usb->devhdl, EP_OUT, cmd, 2, &len, 5);
 237                 if (ret != 0 || len != 2) {
 238                         /* Warning only, doesn't matter. */
 239                         sr_dbg("Failed to send stop command: %s", libusb_error_name(ret));
 240                 }
 241
 242                 sdi->status = SR_ST_ACTIVE;
 243                 return TRUE;
 244         }
 245
 246         return TRUE;
 247 }