X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=hardware%2Ftekpower-dmm%2Fapi.c;h=bd6cb9402137957bd31edecca545970e3629bd74;hb=6bef68a7e1abd472753e16e2188aadd36650c163;hp=2e4491661d0829f8fac0a96cb81c75d4942faf3a;hpb=6f22a8ef2ccf7091324b41b553632695507215a7;p=libsigrok.git

diff --git a/hardware/tekpower-dmm/api.c b/hardware/tekpower-dmm/api.c
index 2e449166..bd6cb940 100644
--- a/hardware/tekpower-dmm/api.c
+++ b/hardware/tekpower-dmm/api.c
@@ -28,6 +28,8 @@
 #include "libsigrok-internal.h"
 #include "protocol.h"
 
+#define SERIALCOMM "2400/8n1"
+
 static const int hwopts[] = {
 	SR_HWOPT_CONN,
 	SR_HWOPT_SERIALCOMM,
@@ -89,98 +91,164 @@ static int hw_init(void)
 	return SR_OK;
 }
 
+typedef gboolean (*packet_valid_t)(const uint8_t *buf);
+
+/**
+ * Try to find a valid packet in a serial data stream.
+ *
+ * @param serial Previously initialized serial port structure.
+ * @param buf Buffer containing the bytes to write.
+ * @param count Size of the buffer.
+ * @param packet_size Size, in bytes, of a valid packet.
+ * @param is_valid Callback that assesses whether the packet is valid or not.
+ * @param timeout_ms The timeout after which, if no packet is detected, to
+ *                   abort scanning.
+ * @param baudrate The baudrate of the serial port. This parameter is not
+ *                 critical, but it helps fine tune the serial port polling
+ *                 delay.
+ *
+ * @return SR_OK if a valid packet is found within the given timeout,
+ *         SR_ERR upon failure.
+ */
+static int serial_stream_detect(struct sr_serial_dev_inst *serial,
+				uint8_t *buf, size_t *buflen,
+				size_t packet_size, packet_valid_t is_valid,
+				uint64_t timeout_ms, int baudrate)
+{
+	uint64_t start, time, byte_delay_us;
+	size_t ibuf, i, maxlen;
+	int len;
+
+	maxlen = *buflen;
+
+	sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
+	       "ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
+
+	if (maxlen < (packet_size / 2) ) {
+		sr_err("Buffer size must be at least twice the packet size.");
+		return SR_ERR;
+	}
+
+	timeout_ms *= 1000;
+
+	/* Assume 8n1 transmission. That is 10 bits for every byte. */
+	byte_delay_us = 10 * (1000000 / baudrate);
+	start = g_get_monotonic_time();
+
+	i = ibuf = len = 0;
+	while (ibuf < maxlen) {
+		len = serial_read(serial, &buf[ibuf], 1);
+		if (len > 0) {
+			ibuf += len;
+		} else if (len == 0) {
+			sr_spew("Error: Only read 0 bytes.");
+		} else {
+			/* Error reading byte, but continuing anyway. */
+		}
+		if ((ibuf - i) >= packet_size) {
+			/* We have at least a packet's worth of data. */
+			if (is_valid(&buf[i])) {
+				time = g_get_monotonic_time() - start;
+				time /= 1000;
+				sr_spew("Found valid %d-byte packet after "
+					"%" PRIu64 "ms.", (ibuf - i), time);
+				*buflen = ibuf;
+				return SR_OK;
+			} else {
+				sr_spew("Got %d bytes, but not a valid "
+					"packet.", (ibuf - i));
+			}
+			/* Not a valid packet. Continue searching. */
+			i++;
+		}
+		if (g_get_monotonic_time() - start > timeout_ms) {
+			/* Timeout */
+			sr_dbg("Detection timed out after %dms.", timeout_ms);
+			break;
+		}
+		g_usleep(byte_delay_us);
+	}
+
+	*buflen = ibuf;
+
+	sr_err("Didn't find a valid packet (read %d bytes).", *buflen);
+
+	return SR_ERR;
+}
+
 static GSList *lcd14_scan(const char *conn, const char *serialcomm)
 {
 	struct sr_dev_inst *sdi;
 	struct drv_context *drvc;
 	struct dev_context *devc;
 	struct sr_probe *probe;
-	struct lcd14_packet *packet;
+	struct sr_serial_dev_inst *serial;
 	GSList *devices;
-	int i, len, fd, retry, good_packets = 0, dropped, ret;
-	char buf[128], *b;
+	int dropped, ret;
+	size_t len;
+	uint8_t buf[128];
 
-	if ((fd = serial_open(conn, O_RDONLY | O_NONBLOCK)) == -1) {
-		sr_err("Unable to open %s: %s.", conn, strerror(errno));
+	if (!(serial = sr_serial_dev_inst_new(conn, serialcomm)))
 		return NULL;
-	}
-	if ((ret = serial_set_paramstr(fd, serialcomm)) != SR_OK) {
-		sr_err("Unable to set serial parameters: %d", ret);
+
+	if (serial_open(serial, O_RDONLY | O_NONBLOCK) != SR_OK)
 		return NULL;
-	}
 
 	sr_info("Probing port %s readonly.", conn);
 
 	drvc = di->priv;
-	b = buf;
-	retry = 0;
 	devices = NULL;
-	serial_flush(fd);
+	serial_flush(serial);
 
 	/*
 	 * There's no way to get an ID from the multimeter. It just sends data
 	 * periodically, so the best we can do is check if the packets match
 	 * the expected format.
 	 */
-	while (!devices && retry < 3) {
-		retry++;
-
-		/* Let's get a bit of data and see if we can find a packet. */
-		len = sizeof(buf);
-		serial_readline(fd, &b, &len, 500);
-		if ((len == 0) || (len < LCD14_PACKET_SIZE)) {
-			/* Not enough data received, is the DMM connected? */
-			continue;
-		}
 
-		/* Let's treat our buffer like a stream, and find any
-		 * valid packets */
-		for (i = 0; i < len - LCD14_PACKET_SIZE + 1;) {
-			packet = (void *)(&buf[i]);
-			if (!lcd14_is_packet_valid(packet, NULL)) {
-				i++;
-				continue;
-			}
-			good_packets++;
-			i += LCD14_PACKET_SIZE;
-		}
+	/* Let's get a bit of data and see if we can find a packet. */
+	len = sizeof(buf);
 
-		/*
-		 * If we dropped more than two packets worth of data,
-		 * something is wrong.
-		 */
-		dropped = len - (good_packets * LCD14_PACKET_SIZE);
-		if (dropped > 2 * LCD14_PACKET_SIZE)
-			continue;
-
-		/* Let's see if we have anything good. */
-		if (good_packets == 0)
-			continue;
+	ret = serial_stream_detect(serial, buf, &len, FS9721_PACKET_SIZE,
+				   sr_fs9721_packet_valid, 1000, 2400);
+	if (ret != SR_OK)
+		goto scan_cleanup;
 
-		sr_info("Found device on port %s.", conn);
+	/*
+	 * If we dropped more than two packets worth of data, something is
+	 * wrong. We shouldn't quit however, since the dropped bytes might be
+	 * just zeroes at the beginning of the stream. Those can occur as a
+	 * combination of the nonstandard cable that ships with this device and
+	 * the serial port or USB to serial adapter.
+	 */
+	dropped = len - FS9721_PACKET_SIZE;
+	if (dropped > 2 * FS9721_PACKET_SIZE)
+		sr_warn("Had to drop too much data.");
 
-		if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "TekPower",
-					    "TP4000ZC", "")))
-			return NULL;
-		if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
-			sr_err("Device context malloc failed.");
-			return NULL;
-		}
+	sr_info("Found device on port %s.", conn);
 
-		devc->serial = sr_serial_dev_inst_new(conn, -1);
-		devc->serialcomm = g_strdup(serialcomm);
+	if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, "TekPower",
+				    "TP4000ZC", "")))
+		goto scan_cleanup;
 
-		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;
+	if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
+		sr_err("Device context malloc failed.");
+		goto scan_cleanup;
 	}
 
-	serial_close(fd);
+	devc->serial = serial;
+
+	sdi->priv = devc;
+	sdi->driver = di;
+	if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
+		goto scan_cleanup;
+	sdi->probes = g_slist_append(sdi->probes, probe);
+	drvc->instances = g_slist_append(drvc->instances, sdi);
+	devices = g_slist_append(devices, sdi);
+
+scan_cleanup:
+	serial_close(serial);
+
 	return devices;
 }
 
@@ -209,8 +277,8 @@ static GSList *hw_scan(GSList *options)
 		/* Use the provided comm specs. */
 		devices = lcd14_scan(conn, serialcomm);
 	} else {
-		/* Try the default 2400/8n1. */
-		devices = lcd14_scan(conn, "2400/8n1");
+		/* Try the default. */
+		devices = lcd14_scan(conn, SERIALCOMM);
 	}
 
 	return devices;
@@ -227,7 +295,6 @@ static GSList *hw_dev_list(void)
 
 static int hw_dev_open(struct sr_dev_inst *sdi)
 {
-	int ret;
 	struct dev_context *devc;
 
 	if (!(devc = sdi->priv)) {
@@ -235,17 +302,9 @@ static int hw_dev_open(struct sr_dev_inst *sdi)
 		return SR_ERR_BUG;
 	}
 
-	devc->serial->fd = serial_open(devc->serial->port, O_RDONLY);
-	if (devc->serial->fd == -1) {
-		sr_err("Couldn't open serial port '%s'.", devc->serial->port);
+	if (serial_open(devc->serial, O_RDONLY) != SR_OK)
 		return SR_ERR;
-	}
 
-	ret = serial_set_paramstr(devc->serial->fd, devc->serialcomm);
-	if (ret != SR_OK) {
-		sr_err("Unable to set serial parameters: %d.", ret);
-		return SR_ERR;
-	}
 	sdi->status = SR_ST_ACTIVE;
 
 	return SR_OK;
@@ -261,8 +320,7 @@ static int hw_dev_close(struct sr_dev_inst *sdi)
 	}
 
 	if (devc->serial && devc->serial->fd != -1) {
-		serial_close(devc->serial->fd);
-		devc->serial->fd = -1;
+		serial_close(devc->serial);
 		sdi->status = SR_ST_INACTIVE;
 	}
 
@@ -375,8 +433,7 @@ static int hw_dev_acquisition_start(const struct sr_dev_inst *sdi,
 	return SR_OK;
 }
 
-static int hw_dev_acquisition_stop(const struct sr_dev_inst *sdi,
-				   void *cb_data)
+static int hw_dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
 {
 	struct sr_datafeed_packet packet;
 	struct dev_context *devc;