add channel count and device listing functions

eismultiplexer.c

@@ -34,6 +34,22 @@
 #include <time.h>
 #include <stdio.h>
 
+uint16_t* eismultiplexer_list_available_devices(size_t* count)
+{
+	struct usbshm shm = {};
+	*count = 0;
+	unsigned char** serials;
+	int ret = usbshm_find(&shm, 0xfe17, 0x07dc, &serials, count);
+	usbshm_close(&shm);
+	if(ret < 0 || *count == 0)
+		return NULL;
+	uint16_t* numeric_serials = malloc(sizeof(*numeric_serials)*(*count));
+	for(size_t i = 0; i < *count; ++i) {
+		numeric_serials[i] = atoi((char*)serials[i]);
+	}
+	return numeric_serials;
+}
+
 int eismultiplexer_connect(struct eismultiplexer* muliplexer, uint16_t serial)
 {
 	int ret;
@@ -85,6 +101,14 @@ channel_t eismultiplexer_get_connected(struct eismultiplexer* muliplexer)
 	return buffer[0];
 }
 
+int eismultiplexer_get_channel_count(struct eismultiplexer* muliplexer, uint16_t *count)
+{
+	uint8_t buffer[2] = {};
+	int ret = usbshm_read_control_transfer(muliplexer->priv, 7, 0, 0, buffer, 1);
+	*count = buffer[0];
+	return ret;
+}
+
 int eismultiplexer_set_led(struct eismultiplexer* muliplexer, bool on)
 {
 	int ret;

eismultiplexer.h

@@ -50,6 +50,7 @@ typedef enum {
 	CHANNEL_E = (1 << 4),
 	CHANNEL_F = (1 << 5),
 	CHANNEL_G = (1 << 6),
+	CHANNEL_H = (1 << 7),
 	CHANNEL_NONE = 0,
 } channel_t;
 
@@ -57,6 +58,13 @@ struct eismultiplexer {
 	struct usbshm* priv;
 };
 
+/**
+ * @brief Lists the available eismultiplexer devices
+ * @param count The number of available eismultiplexer devices
+ * @return An newly allocated array of length count with the serial numbers of the available devices to be freed by the user with free()
+ */
+uint16_t* eismultiplexer_list_available_devices(size_t* count);
+
 /**
  * @brief Attempts to connect to a EISmultiplexer device and initializes a eismultiplexer struct
  * @param multiplexer pointer to a eismultiplexer struct to initialize
@@ -105,6 +113,14 @@ channel_t eismultiplexer_get_connected(struct eismultiplexer* muliplexer);
  */
 int eismultiplexer_set_led(struct eismultiplexer* muliplexer, bool on);
 
+/**
+ * @brief Gets the number of channels on the device
+ * @param multiplexer pointer to an eismultiplexer struct
+ * @param count a pointer where the nummber of channels will be stored.
+ * @return 0 on success and < 0 on failure
+ */
+int eismultiplexer_get_channel_count(struct eismultiplexer* muliplexer, uint16_t *count);
+
 /**
  * @brief Disconnects from the eismultiplexer
  */

main.c

@@ -80,6 +80,8 @@ void print_commands(void)
 	puts("get\t\t\t | get the state of all channels");
 	puts("read [ADDRESS] [LENGTH]\t | read from the device eeprom at address");
 	puts("write [ADDRESS] [LENGTH] | write to the device eeprom at address");
+	puts("list | list the serial nummbers of the connected devices");
+	puts("channels | get the channel of the device");
 }
 
 static int process_commands(char** commands, size_t command_count, struct eismultiplexer* multiplexer, char* name)
@@ -159,6 +161,32 @@ static int process_commands(char** commands, size_t command_count, struct eismul
 			printf("Channel %c: %s\n", (char)('A'+i), connected ? "on" : "off");
 		}
 	}
+	else if(strcmp(commands[0], "channels") == 0)
+	{
+		uint16_t channels;
+		if(eismultiplexer_get_channel_count(multiplexer, &channels) < 0)
+		{
+			printf("could not get the number of channels\n");
+			return 3;
+		}
+		printf("The connected device has %u channels\n", channels);
+	}
+	else if(strcmp(commands[0], "list") == 0)
+	{
+		size_t count;
+		uint16_t* serials = eismultiplexer_list_available_devices(&count);
+		if(count == 0)
+		{
+			printf("No devices connected\n");
+			return 3;
+		}
+
+		printf("Connected devices:\n");
+		for(size_t i = 0; i < count; ++i)
+			printf("%04u\n", serials[i]);
+
+		free(serials);
+	}
 	else
 	{
 		if(command_count != 2)

usbshm.c

@@ -94,6 +94,57 @@ bool usbshm_is_open(struct usbshm* instance)
 	return instance->handle != NULL;
 }
 
+__attribute__ ((visibility ("hidden")))
+int usbshm_find(struct usbshm* instance, int vendorID, int productID, unsigned char*** serials, size_t* count)
+{
+	int ret = usbshm_init(instance);
+	if(ret < 0)
+		return ret;
+
+	pthread_mutex_lock(instance->mutex);
+
+	libusb_device** list;
+	libusb_device_handle* handle;
+	int lusbcount = libusb_get_device_list(context, &list);
+	int errorCode = 0;
+
+	*count = 0;
+	*serials = malloc(sizeof(*serials)*lusbcount);
+
+	if(lusbcount > 0)
+	{
+		struct libusb_device_descriptor desc = {0};
+		for(int i = 0; i < lusbcount; ++i)
+		{
+			libusb_get_device_descriptor(list[i], &desc);
+			if(desc.idVendor == vendorID && desc.idProduct == productID)
+			{
+				errorCode = libusb_open(list[i], &handle) < 0 ? USBSHM_ERROR_ERR : 0;
+				if(errorCode != USBSHM_ERROR_ERR && handle)
+				{
+					(*serials)[*count] = calloc(16, 1);
+					libusb_get_string_descriptor_ascii(handle, desc.iSerialNumber, (*serials)[*count], 16);
+					++(*count);
+				}
+				else
+				{
+					handle = NULL;
+				}
+			}
+		}
+	}
+	else
+	{
+		printf("Can not list devices\n");
+		pthread_mutex_unlock(instance->mutex);
+		return USBSHM_ERROR_ERR;
+	}
+
+	pthread_mutex_unlock(instance->mutex);
+
+	return 0;
+}
+
 __attribute__ ((visibility ("hidden")))
 int usbshm_open(struct usbshm* instance, int vendorID, int productID, const unsigned char* serial)
 {

usbshm.h

@@ -48,6 +48,8 @@ struct usbshm {
 	pthread_mutex_t* mutex;
 };
 
+int usbshm_find(struct usbshm* instance, int vendorID, int productID, unsigned char*** serials, size_t* count);
+
 int usbshm_open(struct usbshm* instance, int vendorID, int productID, const unsigned char* serial);
 
 void usbshm_close(struct usbshm* instance);