Add support for time synchronization

The Suunto d9/vyper2 protocol supports a command to synchronize the
clock.

Author: jefdriesen

src/suunto_common2.c

@@ -397,3 +397,32 @@ suunto_common2_device_foreach (dc_device_t *abstract, dc_dive_callback_t callbac
 
 	return status;
 }
+
+dc_status_t
+suunto_common2_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime)
+{
+	dc_status_t status = DC_STATUS_SUCCESS;
+
+	unsigned char answer[5] = {0};
+	unsigned char command[11] = {0x10, 0x00, 0x07,
+			(datetime->year >> 8) & 0xFF,
+			(datetime->year     ) & 0xFF,
+			datetime->month,
+			datetime->day,
+			datetime->hour,
+			datetime->minute,
+			datetime->second,
+			0};  // CRC
+	command[10] = checksum_xor_uint8 (command, 10, 0x00);
+
+	status = suunto_common2_transfer (abstract, command, sizeof (command), answer, sizeof (answer), 1);
+	if (status != DC_STATUS_SUCCESS)
+		return status;
+
+	if (answer[3] != 1) {
+		ERROR (abstract->context, "Unexpected response code (%u).", answer[3]);
+		return DC_STATUS_PROTOCOL;
+	}
+
+	return status;
+}

src/suunto_common2.h

@@ -73,6 +73,9 @@ suunto_common2_device_dump (dc_device_t *device, dc_buffer_t *buffer);
 dc_status_t
 suunto_common2_device_foreach (dc_device_t *device, dc_dive_callback_t callback, void *userdata);
 
+dc_status_t
+suunto_common2_device_timesync (dc_device_t *abstract, const dc_datetime_t *datetime);
+
 dc_status_t
 suunto_common2_device_reset_maxdepth (dc_device_t *device);
 

src/suunto_d9.c

@@ -56,7 +56,7 @@ static const suunto_common2_device_vtable_t suunto_d9_device_vtable = {
 		suunto_common2_device_write, /* write */
 		suunto_common2_device_dump, /* dump */
 		suunto_common2_device_foreach, /* foreach */
-		NULL, /* timesync */
+		suunto_common2_device_timesync, /* timesync */
 		NULL /* close */
 	},
 	suunto_d9_device_packet

src/suunto_vyper2.c

@@ -51,7 +51,7 @@ static const suunto_common2_device_vtable_t suunto_vyper2_device_vtable = {
 		suunto_common2_device_write, /* write */
 		suunto_common2_device_dump, /* dump */
 		suunto_common2_device_foreach, /* foreach */
-		NULL, /* timesync */
+		suunto_common2_device_timesync, /* timesync */
 		suunto_vyper2_device_close /* close */
 	},
 	suunto_vyper2_device_packet