sr: add new driver API call: scan()

This changes the semantics of the init() call as well. That now only
initializes the driver -- an administrative affair, no hardware gets
touched during this call. It returns a standard SR_OK or SR_ERR* code.

The scan() call does a discovery run for devices it knows, and returns
the number found. It can be called at any time.

hardware/asix-sigma/asix-sigma.c

@@ -406,6 +406,14 @@ static int bin2bitbang(const char *filename,
 }
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	struct context *ctx;
@@ -1437,6 +1445,7 @@ SR_PRIV struct sr_dev_driver asix_sigma_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/chronovu-la8/api.c

@@ -40,6 +40,14 @@ static const uint16_t usb_pids[] = {
 static int hw_dev_acquisition_stop(int dev_index, void *cb_data);
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	int ret;
 	struct sr_dev_inst *sdi;
@@ -542,6 +550,7 @@ SR_PRIV struct sr_dev_driver chronovu_la8_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/demo/demo.c

@@ -141,6 +141,14 @@ static int thread_running;
 static int hw_dev_acquisition_stop(int dev_index, void *cb_data);
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 
@@ -510,6 +518,7 @@ SR_PRIV struct sr_dev_driver demo_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/fx2lafw/fx2lafw.c

@@ -383,22 +383,27 @@ static struct context *fx2lafw_dev_new(void)
  */
 
 static int hw_init(void)
+{
+
+	if (libusb_init(&usb_context) != 0) {
+		sr_warn("fx2lafw: Failed to initialize libusb.");
+		return SR_ERR;
+	}
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	struct libusb_device_descriptor des;
 	const struct fx2lafw_profile *prof;
 	struct context *ctx;
 	libusb_device **devlist;
-	int ret;
+	int devcnt, ret, i, j;
-	int devcnt = 0;
-	int i, j;
-
-	if (libusb_init(&usb_context) != 0) {
-		sr_warn("fx2lafw: Failed to initialize libusb.");
-		return 0;
-	}
 
 	/* Find all fx2lafw compatible devices and upload firmware to them. */
+	devcnt = 0;
 	libusb_get_device_list(usb_context, &devlist);
 	for (i = 0; devlist[i]; i++) {
 
@@ -1009,6 +1014,7 @@ SR_PRIV struct sr_dev_driver fx2lafw_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/genericdmm/api.c

@@ -58,15 +58,22 @@ SR_PRIV libusb_context *genericdmm_usb_context = NULL;
 
 static int hw_init(void)
 {
-	struct sr_dev_inst *sdi;
-	struct context *ctx;
-	int devcnt = 0;
 
 	if (libusb_init(&genericdmm_usb_context) != 0) {
 		sr_err("genericdmm: Failed to initialize USB.");
-		return 0;
+		return SR_ERR;
 	}
 
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
+{
+	struct sr_dev_inst *sdi;
+	struct context *ctx;
+	int devcnt = 0;
+
 	if (!(ctx = g_try_malloc0(sizeof(struct context)))) {
 		sr_err("genericdmm: ctx malloc failed.");
 		return 0;
@@ -610,6 +617,7 @@ SR_PRIV struct sr_dev_driver genericdmm_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/hantek-dso/api.c

@@ -201,25 +201,31 @@ static int configure_probes(struct context *ctx, const GSList *probes)
 }
 
 static int hw_init(void)
+{
+
+	if (libusb_init(&usb_context) != 0) {
+		sr_err("hantek-dso: Failed to initialize USB.");
+		return SR_ERR;
+	}
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	struct libusb_device_descriptor des;
 	const struct dso_profile *prof;
 	struct context *ctx;
 	libusb_device **devlist;
-	int err, devcnt, i, j;
+	int devcnt, ret, i, j;
-
-	if (libusb_init(&usb_context) != 0) {
-		sr_err("hantek-dso: Failed to initialize USB.");
-		return 0;
-	}
 
 	/* Find all Hantek DSO devices and upload firmware to all of them. */
 	devcnt = 0;
 	libusb_get_device_list(usb_context, &devlist);
 	for (i = 0; devlist[i]; i++) {
-		if ((err = libusb_get_device_descriptor(devlist[i], &des))) {
+		if ((ret = libusb_get_device_descriptor(devlist[i], &des))) {
-			sr_err("hantek-dso: failed to get device descriptor: %d", err);
+			sr_err("hantek-dso: failed to get device descriptor: %d", ret);
 			continue;
 		}
 
@@ -856,6 +862,7 @@ SR_PRIV struct sr_dev_driver hantek_dso_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/link-mso19/link-mso19.c

@@ -402,6 +402,14 @@ static int mso_parse_serial(const char *iSerial, const char *iProduct,
 }
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	int devcnt = 0;
@@ -840,6 +848,7 @@ SR_PRIV struct sr_dev_driver link_mso19_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/openbench-logic-sniffer/ols.c

@@ -349,6 +349,14 @@ static struct sr_dev_inst *get_metadata(int fd)
 }
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	struct context *ctx;
@@ -1047,6 +1055,7 @@ SR_PRIV struct sr_dev_driver ols_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

hardware/zeroplus-logic-cube/zeroplus.c

@@ -328,6 +328,14 @@ static int configure_probes(struct sr_dev_inst *sdi, const GSList *probes)
  */
 
 static int hw_init(void)
+{
+
+	/* Nothing to do. */
+
+	return SR_OK;
+}
+
+static int hw_scan(void)
 {
 	struct sr_dev_inst *sdi;
 	struct libusb_device_descriptor des;
@@ -737,6 +745,7 @@ SR_PRIV struct sr_dev_driver zeroplus_logic_cube_driver_info = {
 	.api_version = 1,
 	.init = hw_init,
 	.cleanup = hw_cleanup,
+	.scan = hw_scan,
 	.dev_open = hw_dev_open,
 	.dev_close = hw_dev_close,
 	.dev_info_get = hw_dev_info_get,

libsigrok.h

@@ -472,6 +472,7 @@ struct sr_dev_driver {
 	int api_version;
 	int (*init) (void);
 	int (*cleanup) (void);
+	int (*scan) (void);
 
 	/* Device-specific */
 	int (*dev_open) (int dev_index);

session_driver.c

@@ -151,7 +151,7 @@ static int hw_cleanup(void);
 static int hw_init(void)
 {
 
-	return 0;
+	return SR_OK;
 }
 
 /**