fluke-dmm: fix discovery

diff --git a/hardware/fluke-dmm/api.c b/hardware/fluke-dmm/api.c
index cec9f3ef7cd5f0aa5d6b44a42655de7a04229b4c..bba2f1291a1e271519cf548906c01a98536dc0be 100644 (file)
--- a/hardware/fluke-dmm/api.c
+++ b/hardware/fluke-dmm/api.c
@@ -91,29 +91,22 @@ static int serial_readline(int fd, char **buf, int *buflen, uint64_t timeout_ms)
                len = maxlen - *buflen - 1;
                if (len < 1)
                        break;
-               len = serial_read(fd, *buf + *buflen, len);
+               len = serial_read(fd, *buf + *buflen, 1);
                if (len > 0) {
                        *buflen += len;
                        *(*buf + *buflen) = '\0';
-                       if (*buflen > 0 && *(*buf + *buflen - 1) == '\r')
-                               /* End of line */
+                       if (*buflen > 0 && *(*buf + *buflen - 1) == '\n') {
+                               /* Strip LF and terminate. */
+                               *(*buf + --*buflen) = '\0';
                                break;
+                       }
                }
                if (g_get_monotonic_time() - start > timeout_ms)
                        /* Timeout */
                        break;
                g_usleep(2000);
        }
-
-       /* Strip CRLF */
-       while (*buflen) {
-               if (*(*buf + *buflen - 1) == '\r' || *(*buf + *buflen - 1) == '\n')
-                       *(*buf + --*buflen) = '\0';
-               else
-                       break;
-       }
-       if (*buflen)
-               sr_dbg("fluke-dmm: received '%s'", *buf);
+       sr_dbg("fluke-dmm: received %d: '%s'", *buflen, *buf);
 
        return SR_OK;
 }
@@ -126,9 +119,9 @@ static GSList *hw_scan(GSList *options)
        struct sr_hwopt *opt;
        struct sr_probe *probe;
        GSList *l, *devices;
-       int len, fd, i;
+       int retry, len, fd, i, s;
        const char *conn, *serialcomm;
-       char *buf, **tokens;
+       char buf[128], *b, **tokens;
 
        drvc = di->priv;
        drvc->instances = NULL;
@@ -166,51 +159,64 @@ static GSList *hw_scan(GSList *options)
                return NULL;
        }
 
-       serial_flush(fd);
-       if (serial_write(fd, "ID\r", 3) == -1) {
-               sr_err("fluke-dmm: unable to send identification string: %s",
-                               strerror(errno));
-               return NULL;
-       }
-
-       len = 128;
-       buf = g_try_malloc(len);
-       serial_readline(fd, &buf, &len, 150);
-       if (!len)
-               return NULL;
+       b = buf;
+       retry = 0;
+       /* We'll try the discovery sequence three times in case the device
+        * is not in an idle state when we send ID. */
+       while (!devices && retry < 3) {
+               retry++;
+               serial_flush(fd);
+               if (serial_write(fd, "ID\r", 3) == -1) {
+                       sr_err("fluke-dmm: unable to send ID string: %s",
+                                       strerror(errno));
+                       continue;
+               }
 
-       if (len < 2 || buf[0] != '0' || buf[1] != '\r') {
-               sr_err("fluke-dmm: invalid response to identification string");
-               return NULL;
-       }
+               /* Response is first a CMD_ACK byte (ASCII '0' for OK,
+                * or '1' to signify an error. */
+               len = 128;
+               serial_readline(fd, &b, &len, 150);
+               if (len != 1)
+                       continue;
+               if (buf[0] != '0') {
+                       sr_dbg("fluke-dmm: got ID response %.2x", buf[0]);
+                       continue;
+               }
 
-       tokens = g_strsplit(buf + 2, ",", 3);
-       if (!strncmp("FLUKE", tokens[0], 5)
-                       && tokens[1] && tokens[2]) {
-               for (i = 0; supported_flukedmm[i].model; i++) {
-                       if (strcmp(supported_flukedmm[i].modelname, tokens[0]))
-                               continue;
-                       if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "Fluke",
-                                       tokens[0] + 6, tokens[1])))
-                               return NULL;
-                       if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
-                               sr_dbg("fluke-dmm: failed to malloc devc");
-                               return NULL;
+               /* If CMD_ACK was OK, ID string follows. */
+               len = 128;
+               serial_readline(fd, &b, &len, 150);
+               if (len < 10)
+                       continue;
+               tokens = g_strsplit(buf, ",", 3);
+               if (!strncmp("FLUKE", tokens[0], 5)
+                               && tokens[1] && tokens[2]) {
+                       for (i = 0; supported_flukedmm[i].model; i++) {
+                               if (strcmp(supported_flukedmm[i].modelname, tokens[0] + 6))
+                                       continue;
+                               /* Skip leading spaces in version number. */
+                               for (s = 0; tokens[1][s] == ' '; s++);
+                               if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "Fluke",
+                                               tokens[0] + 6, tokens[1] + s)))
+                                       return NULL;
+                               if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
+                                       sr_dbg("fluke-dmm: failed to malloc devc");
+                                       return NULL;
+                               }
+                               devc->profile = &supported_flukedmm[i];
+                               devc->serial = sr_serial_dev_inst_new(conn, -1);
+                               sdi->priv = devc;
+                               sdi->driver = di;
+                               if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
+                                       return NULL;
+                               sdi->probes = g_slist_append(sdi->probes, probe);
+                               drvc->instances = g_slist_append(drvc->instances, sdi);
+                               devices = g_slist_append(devices, sdi);
+                               break;
                        }
-                       devc->profile = &supported_flukedmm[i];
-                       devc->serial = sr_serial_dev_inst_new(conn, -1);
-                       sdi->priv = devc;
-                       sdi->driver = di;
-                       if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
-                               return NULL;
-                       sdi->probes = g_slist_append(sdi->probes, probe);
-                       drvc->instances = g_slist_append(drvc->instances, sdi);
-                       devices = g_slist_append(devices, sdi);
-                       break;
                }
+               g_strfreev(tokens);
        }
-       g_strfreev(tokens);
-       g_free(buf);
 
        serial_close(fd);