X-Git-Url: https://git.ao2.it/libam7xxx.git/blobdiff_plain/3339bee3f62dbfa3586cc4db5201f7fc704ab037..5cdf0524c38f60d2559e7e00db22383b8bb880a2:/src/am7xxx.c

diff --git a/src/am7xxx.c b/src/am7xxx.c
index d81d1a8..84d7e9c 100644
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -1,10 +1,10 @@
 /* am7xxx - communication with AM7xxx based USB Pico Projectors and DPFs
  *
- * Copyright (C) 2011  Antonio Ospite <ospite@studenti.unina.it>
+ * Copyright (C) 2012-2014  Antonio Ospite <ao2@ao2.it>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
+ * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
@@ -17,181 +17,1395 @@
  */
 
 #include <stdio.h>
-#include <endian.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
 #include <errno.h>
+#include <libusb.h>
+#include <math.h>
 
 #include "am7xxx.h"
+#include "serialize.h"
+#include "tools.h"
 
-#define AM7XXX_VENDOR_ID  0x1de1
-#define AM7XXX_PRODUCT_ID 0xc101
-
-#if 1
-static uint8_t reference_image_header[] = {
-	0x02, 0x00, 0x00, 0x00,
-	0x00,
-	0x10,
-	0x3e,
-	0x10,
-	0x01, 0x00, 0x00, 0x00,
-	0x20, 0x03, 0x00, 0x00,
-	0xe0, 0x01, 0x00, 0x00,
-	0x53, 0xE8, 0x00, 0x00
-};
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+/* If we're not using GNU C, elide __attribute__
+ * taken from: http://unixwiz.net/techtips/gnu-c-attributes.html)
+ */
+#ifndef __GNUC__
+#  define  __attribute__(x)  /* NOTHING */
 #endif
 
-static void dump_image_header(struct am7xxx_image_header *i)
+/* Control shared library symbols visibility */
+#if defined _WIN32 || defined __CYGWIN__
+	#define AM7XXX_PUBLIC __declspec(dllexport)
+	#define AM7XXX_LOCAL
+#else
+	#if __GNUC__ >= 4
+		#define AM7XXX_PUBLIC __attribute__ ((visibility ("default")))
+		#define AM7XXX_LOCAL  __attribute__ ((visibility ("hidden")))
+	#else
+		#define AM7XXX_PUBLIC
+		#define AM7XXX_LOCAL
+	#endif
+#endif
+
+static void log_message(am7xxx_context *ctx,
+			int level,
+			const char *function_name,
+			int line,
+			const char *fmt,
+			...) __attribute__ ((format (printf, 5, 6)));
+
+#define fatal(...)        log_message(NULL, AM7XXX_LOG_FATAL,   __func__, __LINE__, __VA_ARGS__)
+#define error(ctx, ...)   log_message(ctx,  AM7XXX_LOG_ERROR,   __func__, __LINE__, __VA_ARGS__)
+#define warning(ctx, ...) log_message(ctx,  AM7XXX_LOG_WARNING, __func__, 0,        __VA_ARGS__)
+#define info(ctx, ...)    log_message(ctx,  AM7XXX_LOG_INFO,    __func__, 0,        __VA_ARGS__)
+#define debug(ctx, ...)   log_message(ctx,  AM7XXX_LOG_DEBUG,   __func__, 0,        __VA_ARGS__)
+#define trace(ctx, ...)   log_message(ctx,  AM7XXX_LOG_TRACE,   NULL,     0,        __VA_ARGS__)
+
+struct am7xxx_ops {
+	int (*set_power_mode)(am7xxx_device *dev, am7xxx_power_mode power);
+	int (*set_zoom_mode)(am7xxx_device *dev, am7xxx_zoom_mode zoom);
+};
+
+struct am7xxx_usb_device_descriptor {
+	const char *name;
+	uint16_t vendor_id;
+	uint16_t product_id;
+	uint8_t configuration;    /* The bConfigurationValue of the device */
+	uint8_t interface_number; /* The bInterfaceNumber of the device */
+	struct am7xxx_ops ops;
+};
+
+static int default_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power);
+static int picopix_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power);
+static int default_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom);
+static int picopix_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom);
+
+#define DEFAULT_OPS { \
+	.set_power_mode = default_set_power_mode, \
+	.set_zoom_mode = default_set_zoom_mode, \
+}
+
+static const struct am7xxx_usb_device_descriptor supported_devices[] = {
+	{
+		.name       = "Acer C110",
+		.vendor_id  = 0x1de1,
+		.product_id = 0xc101,
+		.configuration    = 2,
+		.interface_number = 0,
+		.ops = DEFAULT_OPS,
+	},
+	{
+		.name       = "Acer C112",
+		.vendor_id  = 0x1de1,
+		.product_id = 0x5501,
+		.configuration    = 2,
+		.interface_number = 0,
+		.ops = DEFAULT_OPS,
+	},
+	{
+		.name       ="Aiptek PocketCinema T25",
+		.vendor_id  = 0x08ca,
+		.product_id = 0x2144,
+		.configuration    = 2,
+		.interface_number = 0,
+		.ops = DEFAULT_OPS,
+	},
+	{
+		.name       = "Philips/Sagemcom PicoPix 1020",
+		.vendor_id  = 0x21e7,
+		.product_id = 0x000e,
+		.configuration    = 2,
+		.interface_number = 0,
+		.ops = DEFAULT_OPS,
+	},
+	{
+		.name       = "Philips/Sagemcom PicoPix 2055",
+		.vendor_id  = 0x21e7,
+		.product_id = 0x0016,
+		.configuration    = 2,
+		.interface_number = 0,
+		.ops = {
+			.set_power_mode = picopix_set_power_mode,
+			.set_zoom_mode = picopix_set_zoom_mode,
+		},
+	},
+	{
+		.name       = "Philips/Sagemcom PicoPix 2330",
+		.vendor_id  = 0x21e7,
+		.product_id = 0x0019,
+		.configuration    = 1,
+		.interface_number = 0,
+	},
+};
+
+/* The header size on the wire is known to be always 24 bytes, regardless of
+ * the memory configuration enforced by different architectures or compilers
+ * for struct am7xxx_header
+ */
+#define AM7XXX_HEADER_WIRE_SIZE 24
+
+struct _am7xxx_device {
+	libusb_device_handle *usb_device;
+	struct libusb_transfer *transfer;
+	int transfer_completed;
+	uint8_t buffer[AM7XXX_HEADER_WIRE_SIZE];
+	am7xxx_device_info *device_info;
+	am7xxx_context *ctx;
+	const struct am7xxx_usb_device_descriptor *desc;
+	am7xxx_device *next;
+};
+
+struct _am7xxx_context {
+	libusb_context *usb_context;
+	int log_level;
+	am7xxx_device *devices_list;
+};
+
+typedef enum {
+	AM7XXX_PACKET_TYPE_DEVINFO = 0x01,
+	AM7XXX_PACKET_TYPE_IMAGE   = 0x02,
+	AM7XXX_PACKET_TYPE_POWER   = 0x04,
+	AM7XXX_PACKET_TYPE_ZOOM    = 0x05,
+	AM7XXX_PACKET_TYPE_PICOPIX_POWER_LOW    = 0x15,
+	AM7XXX_PACKET_TYPE_PICOPIX_POWER_MEDIUM = 0x16,
+	AM7XXX_PACKET_TYPE_PICOPIX_POWER_HIGH   = 0x17,
+	AM7XXX_PACKET_TYPE_PICOPIX_ENABLE_TI    = 0x18,
+	AM7XXX_PACKET_TYPE_PICOPIX_DISABLE_TI   = 0x19,
+} am7xxx_packet_type;
+
+struct am7xxx_generic_header {
+	uint32_t field0;
+	uint32_t field1;
+	uint32_t field2;
+	uint32_t field3;
+};
+
+struct am7xxx_devinfo_header {
+	uint32_t native_width;
+	uint32_t native_height;
+	uint32_t unknown0;
+	uint32_t unknown1;
+};
+
+struct am7xxx_image_header {
+	uint32_t format;
+	uint32_t width;
+	uint32_t height;
+	uint32_t image_size;
+};
+
+struct am7xxx_power_header {
+	uint32_t bit2;
+	uint32_t bit1;
+	uint32_t bit0;
+};
+
+struct am7xxx_zoom_header {
+	uint32_t bit1;
+	uint32_t bit0;
+};
+
+/*
+ * Examples of packet headers:
+ *
+ * Image header:
+ * 02 00 00 00 00 10 3e 10 01 00 00 00 20 03 00 00 e0 01 00 00 53 E8 00 00
+ *
+ * Power header:
+ * 04 00 00 00 00 0c ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
+ */
+
+/* Direction of the communication from the host point of view */
+#define AM7XXX_DIRECTION_OUT 0 /* host -> device */
+#define AM7XXX_DIRECTION_IN  1 /* host <- device */
+
+struct am7xxx_header {
+	uint32_t packet_type;
+	uint8_t direction;
+	uint8_t header_data_len;
+	uint8_t unknown2;
+	uint8_t unknown3;
+	union {
+		struct am7xxx_generic_header data;
+		struct am7xxx_devinfo_header devinfo;
+		struct am7xxx_image_header image;
+		struct am7xxx_power_header power;
+		struct am7xxx_zoom_header zoom;
+	} header_data;
+};
+
+
+#ifdef DEBUG
+static void debug_dump_generic_header(am7xxx_context *ctx, struct am7xxx_generic_header *g)
+{
+	if (ctx == NULL || g == NULL)
+		return;
+
+	debug(ctx, "Generic header:\n");
+	debug(ctx, "\tfield0:  0x%08x (%u)\n", g->field0, g->field0);
+	debug(ctx, "\tfield1:  0x%08x (%u)\n", g->field1, g->field1);
+	debug(ctx, "\tfield2:  0x%08x (%u)\n", g->field2, g->field2);
+	debug(ctx, "\tfield3:  0x%08x (%u)\n", g->field3, g->field3);
+}
+
+static void debug_dump_devinfo_header(am7xxx_context *ctx, struct am7xxx_devinfo_header *d)
+{
+	if (ctx == NULL || d == NULL)
+		return;
+
+	debug(ctx, "Info header:\n");
+	debug(ctx, "\tnative_width:  0x%08x (%u)\n", d->native_width, d->native_width);
+	debug(ctx, "\tnative_height: 0x%08x (%u)\n", d->native_height, d->native_height);
+	debug(ctx, "\tunknown0:      0x%08x (%u)\n", d->unknown0, d->unknown0);
+	debug(ctx, "\tunknown1:      0x%08x (%u)\n", d->unknown1, d->unknown1);
+}
+
+static void debug_dump_image_header(am7xxx_context *ctx, struct am7xxx_image_header *i)
 {
-	if (i == NULL)
+	if (ctx == NULL || i == NULL)
 		return;
 
-	printf("Image header:\n");
-	printf("format:      0x%08x (%u)\n", i->format, i->format);
-	printf("width:       0x%08x (%u)\n", i->width, i->width);
-	printf("height:      0x%08x (%u)\n", i->height, i->height);
-	printf("image size:  0x%08x (%u)\n", i->image_size, i->image_size);
+	debug(ctx, "Image header:\n");
+	debug(ctx, "\tformat:     0x%08x (%u)\n", i->format, i->format);
+	debug(ctx, "\twidth:      0x%08x (%u)\n", i->width, i->width);
+	debug(ctx, "\theight:     0x%08x (%u)\n", i->height, i->height);
+	debug(ctx, "\timage size: 0x%08x (%u)\n", i->image_size, i->image_size);
 }
 
-static void dump_header(struct am7xxx_header *h)
+static void debug_dump_power_header(am7xxx_context *ctx, struct am7xxx_power_header *p)
 {
-	if (h == NULL)
+	if (ctx == NULL || p == NULL)
 		return;
 
-	printf("packet_type: 0x%08x (%u)\n", h->packet_type, h->packet_type);
-	printf("unknown0:    0x%02hhx (%hhu)\n", h->unknown0, h->unknown0);
-	printf("header_len:  0x%02hhx (%hhu)\n", h->header_len, h->header_len);
-	printf("unknown2:    0x%02hhx (%hhu)\n", h->unknown2, h->unknown2);
-	printf("unknown3:    0x%02hhx (%hhu)\n", h->unknown3, h->unknown3);
+	debug(ctx, "Power header:\n");
+	debug(ctx, "\tbit2: 0x%08x (%u)\n", p->bit2, p->bit2);
+	debug(ctx, "\tbit1: 0x%08x (%u)\n", p->bit1, p->bit1);
+	debug(ctx, "\tbit0: 0x%08x (%u)\n", p->bit0, p->bit0);
+}
+
+static void debug_dump_zoom_header(am7xxx_context *ctx, struct am7xxx_zoom_header *z)
+{
+	if (ctx == NULL || z == NULL)
+		return;
+
+	debug(ctx, "Zoom header:\n");
+	debug(ctx, "\tbit1: 0x%08x (%u)\n", z->bit1, z->bit1);
+	debug(ctx, "\tbit0: 0x%08x (%u)\n", z->bit0, z->bit0);
+}
+
+static void debug_dump_header(am7xxx_context *ctx, struct am7xxx_header *h)
+{
+	if (ctx == NULL || h == NULL)
+		return;
+
+	debug(ctx, "BEGIN\n");
+	debug(ctx, "packet_type:     0x%08x (%u)\n", h->packet_type, h->packet_type);
+	debug(ctx, "direction:       0x%02hhx (%hhu) (%s)\n", h->direction, h->direction,
+	      h->direction == AM7XXX_DIRECTION_IN ? "IN" :
+	      h->direction == AM7XXX_DIRECTION_OUT ? "OUT" :
+	      "UNKNOWN");
+	debug(ctx, "header_data_len: 0x%02hhx (%hhu)\n", h->header_data_len, h->header_data_len);
+	debug(ctx, "unknown2:        0x%02hhx (%hhu)\n", h->unknown2, h->unknown2);
+	debug(ctx, "unknown3:        0x%02hhx (%hhu)\n", h->unknown3, h->unknown3);
 
 	switch(h->packet_type) {
+	case AM7XXX_PACKET_TYPE_DEVINFO:
+		debug_dump_devinfo_header(ctx, &(h->header_data.devinfo));
+		break;
+
 	case AM7XXX_PACKET_TYPE_IMAGE:
-		dump_image_header(&(h->header_data.image));
+		debug_dump_image_header(ctx, &(h->header_data.image));
+		break;
+
+	case AM7XXX_PACKET_TYPE_POWER:
+		debug_dump_power_header(ctx, &(h->header_data.power));
+		break;
+
+	case AM7XXX_PACKET_TYPE_ZOOM:
+		debug_dump_zoom_header(ctx, &(h->header_data.zoom));
 		break;
 
 	default:
-		printf("Packet type not supported!\n");
+		debug(ctx, "Parsing data not supported for this packet type!\n");
+		debug_dump_generic_header(ctx, &(h->header_data.data));
 		break;
 	}
-
-	fflush(stdout);
+	debug(ctx, "END\n\n");
 }
 
 static inline unsigned int in_80chars(unsigned int i)
 {
-	return ((i+1) % (80/3));
+	/* The 3 below is the length of "xx " where xx is the hex string
+	 * representation of a byte */
+	return ((i + 1) % (80 / 3));
 }
 
-static void dump_buffer(uint8_t *buffer, unsigned int len)
+static void trace_dump_buffer(am7xxx_context *ctx, const char *message,
+			      uint8_t *buffer, unsigned int len)
 {
 	unsigned int i;
 
-	if (buffer == NULL || len == 0)
+	if (ctx == NULL || buffer == NULL || len == 0)
 		return;
 
+	trace(ctx, "\n");
+	if (message)
+		trace(ctx, "%s\n", message);
+
 	for (i = 0; i < len; i++) {
-		printf("%02hhX%c", buffer[i], (in_80chars(i) && (i < len - 1)) ? ' ' : '\n');
+		trace(ctx, "%02hhX%c", buffer[i], (in_80chars(i) && (i < len - 1)) ? ' ' : '\n');
 	}
-	fflush(stdout);
+	trace(ctx, "\n");
 }
+#else
+static void debug_dump_header(am7xxx_context *ctx, struct am7xxx_header *h)
+{
+	(void)ctx;
+	(void)h;
+}
+
+static void trace_dump_buffer(am7xxx_context *ctx, const char *message,
+			      uint8_t *buffer, unsigned int len)
+{
+	(void)ctx;
+	(void)message;
+	(void)buffer;
+	(void)len;
+}
+#endif /* DEBUG */
 
-static int send_data(am7xxx_device dev, uint8_t *buffer, unsigned int len)
+static int read_data(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
 {
 	int ret;
 	int transferred;
 
-	dump_buffer(buffer, len);
+	transferred = 0;
+	ret = libusb_bulk_transfer(dev->usb_device, 0x81, buffer, len, &transferred, 0);
+	if (ret != 0 || (unsigned int)transferred != len) {
+		error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
+		      libusb_error_name(ret), transferred, len);
+		return ret;
+	}
 
-	ret = libusb_bulk_transfer(dev, 1, buffer, len, &transferred, 0);
+	trace_dump_buffer(dev->ctx, "<-- received", buffer, len);
+
+	return 0;
+}
+
+static int send_data(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
+{
+	int ret;
+	int transferred;
+
+	trace_dump_buffer(dev->ctx, "sending -->", buffer, len);
+
+	transferred = 0;
+	ret = libusb_bulk_transfer(dev->usb_device, 0x1, buffer, len, &transferred, 0);
 	if (ret != 0 || (unsigned int)transferred != len) {
-		fprintf(stderr, "Error: ret: %d\ttransferred: %d (expected %u)\n",
-			ret, transferred, len);
+		error(dev->ctx, "%s. Transferred: %d (expected %u)\n",
+		      libusb_error_name(ret), transferred, len);
 		return ret;
 	}
 
 	return 0;
 }
 
-static int send_header(am7xxx_device dev, struct am7xxx_header *h)
+static void send_data_async_complete_cb(struct libusb_transfer *transfer)
 {
-	union {
-		struct am7xxx_header header;
-		uint8_t buffer[sizeof (struct am7xxx_header)];
-	} data;
+	am7xxx_device *dev = (am7xxx_device *)(transfer->user_data);
+	int *completed = &(dev->transfer_completed);
+	int transferred = transfer->actual_length;
+	int ret;
 
-	data.header = *h;
+	if (transferred != transfer->length) {
+		error(dev->ctx, "transferred: %d (expected %u)\n",
+		      transferred, transfer->length);
+	}
+
+	switch (transfer->status) {
+	case LIBUSB_TRANSFER_COMPLETED:
+		ret = 0;
+		break;
+	case LIBUSB_TRANSFER_TIMED_OUT:
+		ret = LIBUSB_ERROR_TIMEOUT;
+		break;
+	case LIBUSB_TRANSFER_STALL:
+		ret = LIBUSB_ERROR_PIPE;
+		break;
+	case LIBUSB_TRANSFER_OVERFLOW:
+		ret = LIBUSB_ERROR_OVERFLOW;
+		break;
+	case LIBUSB_TRANSFER_NO_DEVICE:
+		ret = LIBUSB_ERROR_NO_DEVICE;
+		break;
+	case LIBUSB_TRANSFER_ERROR:
+	case LIBUSB_TRANSFER_CANCELLED:
+		ret = LIBUSB_ERROR_IO;
+		break;
+	default:
+		error(dev->ctx, "unrecognised status code %d", transfer->status);
+		ret = LIBUSB_ERROR_OTHER;
+	}
+
+	if (ret < 0)
+		error(dev->ctx, "libusb transfer failed: %s",
+		      libusb_error_name(ret));
 
-	return send_data(dev, data.buffer, sizeof (struct am7xxx_header));
+	libusb_free_transfer(transfer);
+	transfer = NULL;
+
+	*completed = 1;
 }
 
-am7xxx_device am7xxx_init(void)
+static inline void wait_for_trasfer_completed(am7xxx_device *dev)
 {
-	am7xxx_device dev;
+	while (!dev->transfer_completed) {
+		int ret = libusb_handle_events_completed(dev->ctx->usb_context,
+							 &(dev->transfer_completed));
+		if (ret < 0) {
+			if (ret == LIBUSB_ERROR_INTERRUPTED)
+				continue;
+			error(dev->ctx, "libusb_handle_events failed: %s, cancelling transfer and retrying",
+			      libusb_error_name(ret));
+			libusb_cancel_transfer(dev->transfer);
+			continue;
+		}
+	}
+}
 
-	libusb_init(NULL);
-	libusb_set_debug(NULL, 3);
+static int send_data_async(am7xxx_device *dev, uint8_t *buffer, unsigned int len)
+{
+	int ret;
+	uint8_t *transfer_buffer;
 
-	dev = libusb_open_device_with_vid_pid(NULL,
-					      AM7XXX_VENDOR_ID,
-					      AM7XXX_PRODUCT_ID);
-	if (dev == NULL) {
+	dev->transfer = libusb_alloc_transfer(0);
+	if (dev->transfer == NULL) {
+		error(dev->ctx, "cannot allocate transfer (%s)\n",
+		      strerror(errno));
+		return -ENOMEM;
+	}
+
+	/* Make a copy of the buffer so the caller can safely reuse it just
+	 * after libusb_submit_transfer() has returned. This technique
+	 * requires more dynamic allocations compared to a proper
+	 * double-buffering approach but it takes a lot less code. */
+	transfer_buffer = malloc(len);
+	if (transfer_buffer == NULL) {
+		error(dev->ctx, "cannot allocate transfer buffer (%s)\n",
+		      strerror(errno));
+		ret = -ENOMEM;
+		goto err;
+	}
+	memcpy(transfer_buffer, buffer, len);
+
+	dev->transfer->flags |= LIBUSB_TRANSFER_FREE_BUFFER;
+	libusb_fill_bulk_transfer(dev->transfer, dev->usb_device, 0x1,
+				  transfer_buffer, len,
+				  send_data_async_complete_cb, dev, 0);
+
+	/* wait for the previous transfer to complete */
+	wait_for_trasfer_completed(dev);
+
+	trace_dump_buffer(dev->ctx, "sending -->", buffer, len);
+
+	dev->transfer_completed = 0;
+	ret = libusb_submit_transfer(dev->transfer);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+
+err:
+	libusb_free_transfer(dev->transfer);
+	dev->transfer = NULL;
+	return ret;
+}
+
+static void serialize_header(struct am7xxx_header *h, uint8_t *buffer)
+{
+	uint8_t **buffer_iterator = &buffer;
+
+	put_le32(h->packet_type, buffer_iterator);
+	put_8(h->direction, buffer_iterator);
+	put_8(h->header_data_len, buffer_iterator);
+	put_8(h->unknown2, buffer_iterator);
+	put_8(h->unknown3, buffer_iterator);
+	put_le32(h->header_data.data.field0, buffer_iterator);
+	put_le32(h->header_data.data.field1, buffer_iterator);
+	put_le32(h->header_data.data.field2, buffer_iterator);
+	put_le32(h->header_data.data.field3, buffer_iterator);
+}
+
+static void unserialize_header(uint8_t *buffer, struct am7xxx_header *h)
+{
+	uint8_t **buffer_iterator = &buffer;
+
+	h->packet_type = get_le32(buffer_iterator);
+	h->direction = get_8(buffer_iterator);
+	h->header_data_len = get_8(buffer_iterator);
+	h->unknown2 = get_8(buffer_iterator);
+	h->unknown3 = get_8(buffer_iterator);
+	h->header_data.data.field0 = get_le32(buffer_iterator);
+	h->header_data.data.field1 = get_le32(buffer_iterator);
+	h->header_data.data.field2 = get_le32(buffer_iterator);
+	h->header_data.data.field3 = get_le32(buffer_iterator);
+}
+
+static int read_header(am7xxx_device *dev, struct am7xxx_header *h)
+{
+	int ret;
+
+	ret = read_data(dev, dev->buffer, AM7XXX_HEADER_WIRE_SIZE);
+	if (ret < 0)
+		goto out;
+
+	unserialize_header(dev->buffer, h);
+
+	if (h->direction == AM7XXX_DIRECTION_IN) {
+		ret = 0;
+	} else {
+		error(dev->ctx,
+		      "Expected an AM7XXX_DIRECTION_IN packet, got one with direction = %d. Weird!\n",
+		      h->direction);
+		ret = -EINVAL;
+	}
+
+	debug_dump_header(dev->ctx, h);
+
+out:
+	return ret;
+}
+
+static int send_header(am7xxx_device *dev, struct am7xxx_header *h)
+{
+	int ret;
+
+	debug_dump_header(dev->ctx, h);
+
+	/* For symmetry with read_header() we should check here for
+	 * h->direction == AM7XXX_DIRECTION_OUT but we just ensure that in all
+	 * the callers and save some cycles here.
+	 */
+
+	serialize_header(h, dev->buffer);
+
+	ret = send_data(dev, dev->buffer, AM7XXX_HEADER_WIRE_SIZE);
+	if (ret < 0)
+		error(dev->ctx, "failed to send data\n");
+
+	return ret;
+}
+
+static int send_command(am7xxx_device *dev, am7xxx_packet_type type)
+{
+	struct am7xxx_header h = {
+		.packet_type     = type,
+		.direction       = AM7XXX_DIRECTION_OUT,
+		.header_data_len = 0x00,
+		.unknown2        = 0x3e,
+		.unknown3        = 0x10,
+		.header_data = {
+			.data = {
+				.field0 = 0,
+				.field1 = 0,
+				.field2 = 0,
+				.field3 = 0,
+			},
+		},
+	};
+
+	return send_header(dev, &h);
+}
+
+
+/* When level == AM7XXX_LOG_FATAL do not check the log_level from the context
+ * and print the message unconditionally, this makes it possible to print
+ * fatal messages even early on initialization, before the context has been
+ * set up */
+static void log_message(am7xxx_context *ctx,
+			int level,
+			const char *function_name,
+			int line,
+			const char *fmt,
+			...)
+{
+	va_list ap;
+
+	if (level == AM7XXX_LOG_FATAL || (ctx && level <= ctx->log_level)) {
+		if (function_name) {
+			fprintf(stderr, "%s", function_name);
+			if (line)
+				fprintf(stderr, "[%d]", line);
+			fprintf(stderr, ": ");
+		}
+
+		va_start(ap, fmt);
+		vfprintf(stderr, fmt, ap);
+		va_end(ap);
+	}
+
+	return;
+}
+
+static am7xxx_device *add_new_device(am7xxx_context *ctx,
+				     const struct am7xxx_usb_device_descriptor *desc)
+{
+	am7xxx_device **devices_list;
+	am7xxx_device *new_device;
+
+	if (ctx == NULL) {
+		fatal("context must not be NULL!\n");
+		return NULL;
+	}
+
+	new_device = malloc(sizeof(*new_device));
+	if (new_device == NULL) {
+		debug(ctx, "cannot allocate a new device (%s)\n", strerror(errno));
+		return NULL;
+	}
+	memset(new_device, 0, sizeof(*new_device));
+
+	new_device->ctx = ctx;
+	new_device->desc = desc;
+	new_device->transfer_completed = 1;
+
+	devices_list = &(ctx->devices_list);
+
+	if (*devices_list == NULL) {
+		*devices_list = new_device;
+	} else {
+		am7xxx_device *prev = *devices_list;
+		while (prev->next)
+			prev = prev->next;
+		prev->next = new_device;
+	}
+	return new_device;
+}
+
+static am7xxx_device *find_device(am7xxx_context *ctx,
+				  unsigned int device_index)
+{
+	unsigned int i = 0;
+	am7xxx_device *current;
+
+	if (ctx == NULL) {
+		fatal("context must not be NULL!\n");
+		return NULL;
+	}
+
+	current = ctx->devices_list;
+	while (current && i++ < device_index)
+		current = current->next;
+
+	return current;
+}
+
+static int open_device(am7xxx_context *ctx,
+		       unsigned int device_index,
+		       libusb_device *usb_dev,
+		       am7xxx_device **dev)
+{
+	int ret;
+	int current_configuration;
+
+	*dev = find_device(ctx, device_index);
+	if (*dev == NULL) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	/* the usb device has already been opened */
+	if ((*dev)->usb_device) {
+		ret = 1;
+		goto out;
+	}
+
+	ret = libusb_open(usb_dev, &((*dev)->usb_device));
+	if (ret < 0) {
+		debug(ctx, "libusb_open failed: %s\n", libusb_error_name(ret));
+		goto out;
+	}
+
+	/* XXX, the device is now open, if any of the calls below fail we need
+	 * to close it again before bailing out.
+	 */
+
+	current_configuration = -1;
+	ret = libusb_get_configuration((*dev)->usb_device,
+				       &current_configuration);
+	if (ret < 0) {
+		debug(ctx, "libusb_get_configuration failed: %s\n",
+		      libusb_error_name(ret));
+		goto out_libusb_close;
+	}
+
+	if (current_configuration != (*dev)->desc->configuration) {
+		/*
+		 * In principle, before setting a new configuration, kernel
+		 * drivers should be detached from _all_ interfaces; for
+		 * example calling something like the following "invented"
+		 * function _before_ setting the new configuration:
+		 *
+		 *   libusb_detach_all_kernel_drivers((*dev)->usb_device);
+		 *
+		 * However, in practice, this is not necessary for most
+		 * devices as they have only one configuration.
+		 *
+		 * When a device only has one configuration:
+		 *
+		 *   - if there was a kernel driver bound to the device, it
+		 *     had already set the configuration and the call below
+		 *     will be skipped;
+		 *
+		 *   - if no kernel driver was bound to the device, the call
+		 *     below will suceed.
+		 */
+		ret = libusb_set_configuration((*dev)->usb_device,
+					       (*dev)->desc->configuration);
+		if (ret < 0) {
+			debug(ctx, "libusb_set_configuration failed: %s\n",
+			      libusb_error_name(ret));
+			debug(ctx, "Cannot set configuration %hhu\n",
+			      (*dev)->desc->configuration);
+			goto out_libusb_close;
+		}
+	}
+
+	libusb_set_auto_detach_kernel_driver((*dev)->usb_device, 1);
+
+	ret = libusb_claim_interface((*dev)->usb_device,
+				     (*dev)->desc->interface_number);
+	if (ret < 0) {
+		debug(ctx, "libusb_claim_interface failed: %s\n",
+		      libusb_error_name(ret));
+		debug(ctx, "Cannot claim interface %hhu\n",
+		      (*dev)->desc->interface_number);
+		goto out_libusb_close;
+	}
+
+	/* Checking that the configuration has not changed, as suggested in
+	 * http://libusb.sourceforge.net/api-1.0/caveats.html
+	 */
+	current_configuration = -1;
+	ret = libusb_get_configuration((*dev)->usb_device,
+				       &current_configuration);
+	if (ret < 0) {
+		debug(ctx, "libusb_get_configuration after claim failed: %s\n",
+		      libusb_error_name(ret));
+		goto out_libusb_release_interface;
+	}
+
+	if (current_configuration != (*dev)->desc->configuration) {
+		debug(ctx, "libusb configuration changed (expected: %hhu, current: %d)\n",
+		      (*dev)->desc->configuration, current_configuration);
+		ret = -EINVAL;
+		goto out_libusb_release_interface;
+	}
+out:
+	return ret;
+
+out_libusb_release_interface:
+	libusb_release_interface((*dev)->usb_device,
+				 (*dev)->desc->interface_number);
+out_libusb_close:
+	libusb_close((*dev)->usb_device);
+	(*dev)->usb_device = NULL;
+	return ret;
+}
+
+typedef enum {
+	SCAN_OP_BUILD_DEVLIST,
+	SCAN_OP_OPEN_DEVICE,
+} scan_op;
+
+/**
+ * This is where the central logic of multi-device support is.
+ *
+ * When 'op' == SCAN_OP_BUILD_DEVLIST the parameters 'open_device_index' and
+ * 'dev' are ignored; the function returns 0 on success or a negative value
+ * on error.
+ *
+ * When 'op' == SCAN_OP_OPEN_DEVICE the function opens the supported USB
+ * device with index 'open_device_index' and returns the correspondent
+ * am7xxx_device in the 'dev' parameter; the function returns the value from
+ * open_device(), which is 0 on success, 1 if the device was already open or
+ * a negative value on error.
+ *
+ * NOTES:
+ * if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
+ * the caller might want to call am7xxx_shutdown() in order to remove
+ * devices possibly added before the failure.
+ */
+static int scan_devices(am7xxx_context *ctx, scan_op op,
+			unsigned int open_device_index, am7xxx_device **dev)
+{
+	ssize_t num_devices;
+	libusb_device **list;
+	unsigned int current_index;
+	int i;
+	int ret;
+
+	if (ctx == NULL) {
+		fatal("context must not be NULL!\n");
+		return -EINVAL;
+	}
+	if (op == SCAN_OP_BUILD_DEVLIST && ctx->devices_list != NULL) {
+		error(ctx, "device scan done already? Abort!\n");
+		return -EINVAL;
+	}
+
+	num_devices = libusb_get_device_list(ctx->usb_context, &list);
+	if (num_devices < 0) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	current_index = 0;
+	for (i = 0; i < num_devices; i++) {
+		struct libusb_device_descriptor desc;
+		unsigned int j;
+
+		ret = libusb_get_device_descriptor(list[i], &desc);
+		if (ret < 0)
+			continue;
+
+		for (j = 0; j < ARRAY_SIZE(supported_devices); j++) {
+			if (desc.idVendor == supported_devices[j].vendor_id &&
+			    desc.idProduct == supported_devices[j].product_id) {
+
+				if (op == SCAN_OP_BUILD_DEVLIST) {
+					am7xxx_device *new_device;
+					info(ctx, "am7xxx device found, index: %d, name: %s\n",
+					     current_index,
+					     supported_devices[j].name);
+					new_device = add_new_device(ctx, &supported_devices[j]);
+					if (new_device == NULL) {
+						/* XXX, the caller may want
+						 * to call am7xxx_shutdown() if
+						 * we fail here, as we may have
+						 * added some devices already
+						 */
+						debug(ctx, "Cannot create a new device\n");
+						ret = -ENODEV;
+						goto out;
+					}
+				} else if (op == SCAN_OP_OPEN_DEVICE &&
+					   current_index == open_device_index) {
+
+					ret = open_device(ctx,
+							  open_device_index,
+							  list[i],
+							  dev);
+					if (ret < 0)
+						debug(ctx, "open_device failed\n");
+
+					/* exit the loop unconditionally after
+					 * attempting to open the device
+					 * requested by the user */
+					goto out;
+				}
+				current_index++;
+			}
+		}
+	}
+
+	/* if we made it up to here when op == SCAN_OP_OPEN_DEVICE,
+	 * no devices to open had been found. */
+	if (op == SCAN_OP_OPEN_DEVICE) {
+		error(ctx, "Cannot find any device to open\n");
+		ret = -ENODEV;
+		goto out;
+	}
+
+	/* everything went fine when building the device list */
+	ret = 0;
+out:
+	libusb_free_device_list(list, 1);
+	return ret;
+}
+
+/* Device specific operations */
+
+static int default_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power)
+{
+	int ret;
+	struct am7xxx_header h = {
+		.packet_type     = AM7XXX_PACKET_TYPE_POWER,
+		.direction       = AM7XXX_DIRECTION_OUT,
+		.header_data_len = sizeof(struct am7xxx_power_header),
+		.unknown2        = 0x3e,
+		.unknown3        = 0x10,
+	};
+
+	switch(power) {
+	case AM7XXX_POWER_OFF:
+		h.header_data.power.bit2 = 0;
+		h.header_data.power.bit1 = 0;
+		h.header_data.power.bit0 = 0;
+		break;
+
+	case AM7XXX_POWER_LOW:
+		h.header_data.power.bit2 = 0;
+		h.header_data.power.bit1 = 0;
+		h.header_data.power.bit0 = 1;
+		break;
+
+	case AM7XXX_POWER_MIDDLE:
+		h.header_data.power.bit2 = 0;
+		h.header_data.power.bit1 = 1;
+		h.header_data.power.bit0 = 0;
+		break;
+
+	case AM7XXX_POWER_HIGH:
+		h.header_data.power.bit2 = 0;
+		h.header_data.power.bit1 = 1;
+		h.header_data.power.bit0 = 1;
+		break;
+
+	case AM7XXX_POWER_TURBO:
+		h.header_data.power.bit2 = 1;
+		h.header_data.power.bit1 = 0;
+		h.header_data.power.bit0 = 0;
+		break;
+
+	default:
+		error(dev->ctx, "Unsupported power mode.\n");
+		return -EINVAL;
+	};
+
+	ret = send_header(dev, &h);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int picopix_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power)
+{
+	switch(power) {
+	case AM7XXX_POWER_LOW:
+		return send_command(dev, AM7XXX_PACKET_TYPE_PICOPIX_POWER_LOW);
+
+	case AM7XXX_POWER_MIDDLE:
+		return send_command(dev, AM7XXX_PACKET_TYPE_PICOPIX_POWER_MEDIUM);
+
+	case AM7XXX_POWER_HIGH:
+		return send_command(dev, AM7XXX_PACKET_TYPE_PICOPIX_POWER_HIGH);
+
+	case AM7XXX_POWER_OFF:
+	case AM7XXX_POWER_TURBO:
+	default:
+		error(dev->ctx, "Unsupported power mode.\n");
+		return -EINVAL;
+	};
+}
+
+static int default_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom)
+{
+	int ret;
+	struct am7xxx_header h = {
+		.packet_type     = AM7XXX_PACKET_TYPE_ZOOM,
+		.direction       = AM7XXX_DIRECTION_OUT,
+		.header_data_len = sizeof(struct am7xxx_zoom_header),
+		.unknown2        = 0x3e,
+		.unknown3        = 0x10,
+	};
+
+	switch(zoom) {
+	case AM7XXX_ZOOM_ORIGINAL:
+		h.header_data.zoom.bit1 = 0;
+		h.header_data.zoom.bit0 = 0;
+		break;
+
+	case AM7XXX_ZOOM_H:
+		h.header_data.zoom.bit1 = 0;
+		h.header_data.zoom.bit0 = 1;
+		break;
+
+	case AM7XXX_ZOOM_H_V:
+		h.header_data.zoom.bit1 = 1;
+		h.header_data.zoom.bit0 = 0;
+		break;
+
+	case AM7XXX_ZOOM_TEST:
+		h.header_data.zoom.bit1 = 1;
+		h.header_data.zoom.bit0 = 1;
+		break;
+
+	case AM7XXX_ZOOM_TELE:
+	default:
+		error(dev->ctx, "Unsupported zoom mode.\n");
+		return -EINVAL;
+	};
+
+	ret = send_header(dev, &h);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int picopix_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom)
+{
+	int ret;
+	am7xxx_packet_type packet_type;
+
+	switch(zoom) {
+	case AM7XXX_ZOOM_ORIGINAL:
+		packet_type = AM7XXX_PACKET_TYPE_PICOPIX_DISABLE_TI;
+		break;
+
+	case AM7XXX_ZOOM_TELE:
+		packet_type = AM7XXX_PACKET_TYPE_PICOPIX_ENABLE_TI;
+		break;
+
+	case AM7XXX_ZOOM_H:
+	case AM7XXX_ZOOM_H_V:
+	case AM7XXX_ZOOM_TEST:
+	default:
+		error(dev->ctx, "Unsupported zoom mode.\n");
+		return -EINVAL;
+	};
+
+	ret = send_command(dev, packet_type);
+	if (ret < 0)
+		return ret;
+
+	/* The Windows drivers wait for 100ms and send the same command again,
+	 * probably to overcome a firmware deficiency */
+	ret = msleep(100);
+	if (ret < 0)
+		return ret;
+
+	return send_command(dev, packet_type);
+}
+
+/* Public API */
+
+AM7XXX_PUBLIC int am7xxx_init(am7xxx_context **ctx)
+{
+	int ret;
+
+	*ctx = malloc(sizeof(**ctx));
+	if (*ctx == NULL) {
+		fatal("cannot allocate the context (%s)\n", strerror(errno));
+		return -ENOMEM;
+	}
+	memset(*ctx, 0, sizeof(**ctx));
+
+	/* Set the highest log level during initialization */
+	(*ctx)->log_level = AM7XXX_LOG_TRACE;
+
+	ret = libusb_init(&((*ctx)->usb_context));
+	if (ret < 0) {
+		error(*ctx, "libusb_init failed: %s\n", libusb_error_name(ret));
+		goto out_free_context;
+	}
+
+	libusb_set_debug((*ctx)->usb_context, LIBUSB_LOG_LEVEL_INFO);
+
+	ret = scan_devices(*ctx, SCAN_OP_BUILD_DEVLIST , 0, NULL);
+	if (ret < 0) {
+		error(*ctx, "scan_devices() failed\n");
+		am7xxx_shutdown(*ctx);
+		goto out;
+	}
+
+	/* Set a quieter log level as default for normal operation */
+	(*ctx)->log_level = AM7XXX_LOG_ERROR;
+	return 0;
+
+out_free_context:
+	free(*ctx);
+	*ctx = NULL;
+out:
+	return ret;
+}
+
+AM7XXX_PUBLIC void am7xxx_shutdown(am7xxx_context *ctx)
+{
+	am7xxx_device *current;
+
+	if (ctx == NULL) {
+		fatal("context must not be NULL!\n");
+		return;
+	}
+
+	current = ctx->devices_list;
+	while (current) {
+		am7xxx_device *next = current->next;
+		am7xxx_close_device(current);
+		free(current->device_info);
+		free(current);
+		current = next;
+	}
+
+	libusb_exit(ctx->usb_context);
+	free(ctx);
+	ctx = NULL;
+}
+
+AM7XXX_PUBLIC void am7xxx_set_log_level(am7xxx_context *ctx, am7xxx_log_level log_level)
+{
+	ctx->log_level = log_level;
+}
+
+AM7XXX_PUBLIC int am7xxx_open_device(am7xxx_context *ctx, am7xxx_device **dev,
+		       unsigned int device_index)
+{
+	int ret;
+
+	if (ctx == NULL) {
+		fatal("context must not be NULL!\n");
+		return -EINVAL;
+	}
+
+	ret = scan_devices(ctx, SCAN_OP_OPEN_DEVICE, device_index, dev);
+	if (ret < 0) {
 		errno = ENODEV;
-		perror("libusb_open_device_with_vid_pid");
-		goto out_libusb_exit;
+		goto out;
+	} else if (ret > 0) {
+		warning(ctx, "device %d already open\n", device_index);
+		errno = EBUSY;
+		ret = -EBUSY;
+		goto out;
 	}
 
-	libusb_set_configuration(dev, 1);
-	libusb_claim_interface(dev, 0);
+	/* Philips/Sagemcom PicoPix projectors require that the DEVINFO packet
+	 * is the first one to be sent to the device in order for it to
+	 * successfully return the correct device information.
+	 *
+	 * NOTE: am7xxx_get_device_info() will fetch the actual device info
+	 * from the device only the very first time it's called for a given
+	 * device, otherwise, it'll return a cached version of the device info
+	 * (from a previous call to am7xxx_open_device(), for instance).
+	 */
+	ret = am7xxx_get_device_info(*dev, NULL);
+	if (ret < 0)
+		error(ctx, "cannot get device info\n");
 
-	return dev;
+out:
+	return ret;
+}
 
-out_libusb_exit:
-	libusb_exit(NULL);
-	return NULL;
+AM7XXX_PUBLIC int am7xxx_close_device(am7xxx_device *dev)
+{
+	if (dev == NULL) {
+		fatal("dev must not be NULL!\n");
+		return -EINVAL;
+	}
+	if (dev->usb_device) {
+		wait_for_trasfer_completed(dev);
+		libusb_release_interface(dev->usb_device, dev->desc->interface_number);
+		libusb_close(dev->usb_device);
+		dev->usb_device = NULL;
+	}
+	return 0;
 }
 
-void am7xxx_shutdown(am7xxx_device dev)
+AM7XXX_PUBLIC int am7xxx_get_device_info(am7xxx_device *dev,
+			   am7xxx_device_info *device_info)
 {
-	if (dev) {
-		libusb_close(dev);
-		libusb_exit(NULL);
+	int ret;
+	struct am7xxx_header h;
+
+	/* if there is a cached copy of the device info, just return that */
+	if (dev->device_info)
+		goto return_value;
+
+	ret = send_command(dev, AM7XXX_PACKET_TYPE_DEVINFO);
+	if (ret < 0)
+		return ret;
+
+	memset(&h, 0, sizeof(h));
+	ret = read_header(dev, &h);
+	if (ret < 0)
+		return ret;
+
+	if (h.packet_type != AM7XXX_PACKET_TYPE_DEVINFO) {
+		error(dev->ctx, "expected packet type: %d, got %d instead!\n",
+		      AM7XXX_PACKET_TYPE_DEVINFO, h.packet_type);
+		errno = ENOTSUP;
+		return -ENOTSUP;
 	}
+
+	dev->device_info = malloc(sizeof(*dev->device_info));
+	if (dev->device_info == NULL) {
+		error(dev->ctx, "cannot allocate a device info (%s)\n",
+		       strerror(errno));
+		return -ENOMEM;
+	}
+	memset(dev->device_info, 0, sizeof(*dev->device_info));
+
+	dev->device_info->native_width = h.header_data.devinfo.native_width;
+	dev->device_info->native_height = h.header_data.devinfo.native_height;
+#if 0
+	/* No reason to expose these in the public API until we know what they mean */
+	dev->device_info->unknown0 = h.header_data.devinfo.unknown0;
+	dev->device_info->unknown1 = h.header_data.devinfo.unknown1;
+#endif
+
+return_value:
+	if (device_info)
+		memcpy(device_info, dev->device_info, sizeof(*device_info));
+	return 0;
 }
 
-int am7xxx_send_image(am7xxx_device dev,
+AM7XXX_PUBLIC int am7xxx_calc_scaled_image_dimensions(am7xxx_device *dev,
+					unsigned int upscale,
+					unsigned int original_width,
+					unsigned int original_height,
+					unsigned int *scaled_width,
+					unsigned int *scaled_height)
+{
+	am7xxx_device_info device_info;
+	float width_ratio;
+	float height_ratio;
+	int ret;
+
+	ret = am7xxx_get_device_info(dev, &device_info);
+	if (ret < 0) {
+		error(dev->ctx, "cannot get device info\n");
+		return ret;
+	}
+
+	/*
+	 * Check if we need to rescale; if the input image fits the native
+	 * dimensions there is no need to, unless we want to upscale.
+	 */
+	if (!upscale &&
+	    original_width <= device_info.native_width &&
+	    original_height <= device_info.native_height ) {
+		debug(dev->ctx, "CASE 0, no rescaling, the original image fits already\n");
+		*scaled_width = original_width;
+		*scaled_height = original_height;
+		return 0;
+	}
+
+	/* Input dimensions relative to the device native dimensions */
+	width_ratio =  (float)original_width / device_info.native_width;
+	height_ratio = (float)original_height / device_info.native_height;
+
+	if (width_ratio > height_ratio) {
+		/*
+		 * The input is proportionally "wider" than the device viewport
+		 * so its height needs to be adjusted
+		 */
+		debug(dev->ctx, "CASE 1, original image wider, adjust the scaled height\n");
+		*scaled_width = device_info.native_width;
+		*scaled_height = (unsigned int)lroundf(original_height / width_ratio);
+	} else if (width_ratio < height_ratio) {
+		/*
+		 * The input is proportionally "taller" than the device viewport
+		 * so its width needs to be adjusted
+		 */
+		debug(dev->ctx, "CASE 2 original image taller, adjust the scaled width\n");
+		*scaled_width = (unsigned int)lroundf(original_width / height_ratio);
+		*scaled_height = device_info.native_height;
+	} else {
+		debug(dev->ctx, "CASE 3, just rescale, same aspect ratio already\n");
+		*scaled_width = device_info.native_width;
+		*scaled_height = device_info.native_height;
+	}
+	debug(dev->ctx, "scaled dimensions: %dx%d\n", *scaled_width, *scaled_height);
+
+	return 0;
+}
+
+AM7XXX_PUBLIC int am7xxx_send_image(am7xxx_device *dev,
 		      am7xxx_image_format format,
 		      unsigned int width,
 		      unsigned int height,
 		      uint8_t *image,
-		      unsigned int size)
+		      unsigned int image_size)
 {
 	int ret;
 	struct am7xxx_header h = {
-		.packet_type = htole32(AM7XXX_PACKET_TYPE_IMAGE),
-		.unknown0    = 0x00,
-		.header_len  = sizeof(struct am7xxx_image_header),
-		.unknown2    = 0x3e,
-		.unknown3    = 0x10,
+		.packet_type     = AM7XXX_PACKET_TYPE_IMAGE,
+		.direction       = AM7XXX_DIRECTION_OUT,
+		.header_data_len = sizeof(struct am7xxx_image_header),
+		.unknown2        = 0x3e,
+		.unknown3        = 0x10,
 		.header_data = {
 			.image = {
-				.format     = htole32(format),
-				.width      = htole32(width),
-				.height     = htole32(height),
-				.image_size = htole32(size),
+				.format     = format,
+				.width      = width,
+				.height     = height,
+				.image_size = image_size,
 			},
 		},
 	};
 
-	dump_header(&h);
-	printf("\n");
+	ret = send_header(dev, &h);
+	if (ret < 0)
+		return ret;
+
+	if (image == NULL || image_size == 0) {
+		warning(dev->ctx, "Not sending any data, check the 'image' or 'image_size' parameters\n");
+		return 0;
+	}
 
-	printf("Dump Buffers\n");
-	dump_buffer(reference_image_header, sizeof(struct am7xxx_header));
+	return send_data(dev, image, image_size);
+}
+
+AM7XXX_PUBLIC int am7xxx_send_image_async(am7xxx_device *dev,
+					  am7xxx_image_format format,
+					  unsigned int width,
+					  unsigned int height,
+					  uint8_t *image,
+					  unsigned int image_size)
+{
+	int ret;
+	struct am7xxx_header h = {
+		.packet_type     = AM7XXX_PACKET_TYPE_IMAGE,
+		.direction       = AM7XXX_DIRECTION_OUT,
+		.header_data_len = sizeof(struct am7xxx_image_header),
+		.unknown2        = 0x3e,
+		.unknown3        = 0x10,
+		.header_data = {
+			.image = {
+				.format     = format,
+				.width      = width,
+				.height     = height,
+				.image_size = image_size,
+			},
+		},
+	};
 
 	ret = send_header(dev, &h);
 	if (ret < 0)
 		return ret;
 
-	if (image == NULL || size == 0)
+	if (image == NULL || image_size == 0) {
+		warning(dev->ctx, "Not sending any data, check the 'image' or 'image_size' parameters\n");
 		return 0;
+	}
+
+	return send_data_async(dev, image, image_size);
+}
+
+AM7XXX_PUBLIC int am7xxx_set_power_mode(am7xxx_device *dev, am7xxx_power_mode power)
+{
+	if (dev->desc->ops.set_power_mode == NULL) {
+		warning(dev->ctx,
+			"setting power mode is unsupported on this device\n");
+		return 0;
+	}
+
+	return dev->desc->ops.set_power_mode(dev, power);
+}
+
+AM7XXX_PUBLIC int am7xxx_set_zoom_mode(am7xxx_device *dev, am7xxx_zoom_mode zoom)
+{
+	if (dev->desc->ops.set_zoom_mode == NULL) {
+		warning(dev->ctx,
+			"setting zoom mode is unsupported on this device\n");
+		return 0;
+	}
 
-	return send_data(dev, image, size);
+	return dev->desc->ops.set_zoom_mode(dev, zoom);
 }