dcttech-usbrelay: accept conn=sn=<serno> user specs in probe

[libsigrok.git] / src / hardware / dcttech-usbrelay / api.c

diff --git a/src/hardware/dcttech-usbrelay/api.c b/src/hardware/dcttech-usbrelay/api.c
index a24025ec84376878d17c778bb4808f4fd622547a..137277d0176b014758883bba82d988cd1c58a985 100644 (file)
--- a/src/hardware/dcttech-usbrelay/api.c
+++ b/src/hardware/dcttech-usbrelay/api.c
@@ -45,7 +45,7 @@ static const uint32_t devopts_cg[] = {
 static struct sr_dev_driver dcttech_usbrelay_driver_info;
 
 static struct sr_dev_inst *probe_device_common(const char *path,
-       uint16_t vid, uint16_t pid,
+       uint16_t vid, uint16_t pid, const char *want_serno,
        const wchar_t *vendor, const wchar_t *product)
 {
        char nonws[16], *s, *endp;
@@ -128,6 +128,12 @@ static struct sr_dev_inst *probe_device_common(const char *path,
        sr_info("HID report data: serial number %s, relay state 0x%02x.",
                serno, curr_state);
 
+       /* Optionally filter by serial number. */
+       if (want_serno && *want_serno && strcmp(serno, want_serno) != 0) {
+               sr_dbg("Serial number does not match user spec. Skipping.");
+               return NULL;
+       }
+
        /* Create a device instance. */
        sdi = g_malloc0(sizeof(*sdi));
        sdi->vendor = g_strdup_printf("%ls", vendor);
@@ -158,9 +164,10 @@ static struct sr_dev_inst *probe_device_common(const char *path,
        return sdi;
 }
 
-static struct sr_dev_inst *probe_device_enum(struct hid_device_info *dev)
+static struct sr_dev_inst *probe_device_enum(struct hid_device_info *dev,
+       const char *want_serno)
 {
-       return probe_device_common(dev->path, 0, 0,
+       return probe_device_common(dev->path, 0, 0, want_serno,
                dev->manufacturer_string, dev->product_string);
 }
 
@@ -231,7 +238,7 @@ static struct sr_dev_inst *probe_device_conn(const char *path)
        if (!ok)
                return NULL;
 
-       return probe_device_common(path, vid, pid, vendor, product);
+       return probe_device_common(path, vid, pid, NULL, vendor, product);
 }
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
@@ -239,6 +246,7 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
        const char *conn;
        GSList *devices;
        struct drv_context *drvc;
+       char want_serno[SERNO_LENGTH + 1];
        struct hid_device_info *devs, *curdev;
        wchar_t *ws;
        char nonws[32];
@@ -257,14 +265,25 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
        /*
         * The firmware is V-USB based. The USB VID:PID identification
         * is shared across several projects. Need to inspect the vendor
-        * and product _strings_ to actually identify the device. The
-        * USB serial number need not be present nor reliable. The HID
-        * report content will carry the board's serial number.
+        * and product _strings_ to actually identify the device.
+        *
+        * The USB serial number need not be present nor reliable. The
+        * HID report content will carry the board's serial number.
+        * When users specify "sn=..." connection strings, then run a
+        * regular USB enumation, and filter the result set by serial
+        * numbers which only become available with HID reports.
         *
-        * When conn= was specified, then have HIDAPI open _this_ device
-        * and skip the enumeration. Which allows users to specify paths
-        * that need not match the enumeration's details.
+        * When other connection strings were specified, then have
+        * HIDAPI open _this_ device and skip the enumeration. Which
+        * allows users to specify paths that need not match the
+        * enumeration's details.
         */
+       memset(want_serno, 0, sizeof(want_serno));
+       if (conn && g_str_has_prefix(conn, "sn=")) {
+               conn += strlen("sn=");
+               snprintf(want_serno, sizeof(want_serno), "%s", conn);
+               conn = NULL;
+       }
        if (conn) {
                sr_info("Checking HID path %s.", conn);
                sdi = probe_device_conn(conn);
@@ -303,11 +322,9 @@ static GSList *scan(struct sr_dev_driver *di, GSList *options)
 
                /* Identify device by communicating to it. */
                sr_info("Checking HID path %s.", curdev->path);
-               sdi = probe_device_enum(curdev);
-               if (!sdi) {
-                       sr_warn("Failed to communicate to %s.", curdev->path);
+               sdi = probe_device_enum(curdev, want_serno);
+               if (!sdi)
                        continue;
-               }
                devices = g_slist_append(devices, sdi);
        }
        hid_free_enumeration(devs);