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/*
* Copyright 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <libusb.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define CHECK(expression) \
({ \
int error__ = (expression); \
\
if (error__ != 0) { \
fprintf(stderr, \
"libusb error: %s:%d %s\n", \
__FILE__, \
__LINE__, \
libusb_error_name(error__)); \
return error__; \
} \
\
error__; \
})
#define TRANSFER_TIMEOUT_MS 100
static int gpio_write(libusb_device_handle *device,
uint32_t set_mask,
uint32_t clear_mask)
{
uint8_t command[8];
int transferred;
command[0] = (set_mask >> 0) & 0xff;
command[1] = (set_mask >> 8) & 0xff;
command[2] = (set_mask >> 16) & 0xff;
command[3] = (set_mask >> 24) & 0xff;
command[4] = (clear_mask >> 0) & 0xff;
command[5] = (clear_mask >> 8) & 0xff;
command[6] = (clear_mask >> 16) & 0xff;
command[7] = (clear_mask >> 24) & 0xff;
CHECK(libusb_bulk_transfer(device,
LIBUSB_ENDPOINT_OUT | 2,
command,
sizeof(command),
&transferred,
TRANSFER_TIMEOUT_MS));
if (transferred != sizeof(command)) {
fprintf(stderr,
"Failed to transfer full command "
"(sent %d of %d bytes)\n",
transferred,
(int)sizeof(command));
return LIBUSB_ERROR_OTHER;
}
return 0;
}
static int gpio_read(libusb_device_handle *device, uint32_t *mask)
{
uint8_t response[4];
int transferred;
/*
* The first query does triggers the sampling of the GPIO values, the
* second query reads them back.
*/
CHECK(libusb_bulk_transfer(device,
LIBUSB_ENDPOINT_IN | 2,
response,
sizeof(response),
&transferred,
TRANSFER_TIMEOUT_MS));
CHECK(libusb_bulk_transfer(device,
LIBUSB_ENDPOINT_IN | 2,
response,
sizeof(response),
&transferred,
TRANSFER_TIMEOUT_MS));
if (transferred != sizeof(response)) {
fprintf(stderr,
"Failed to transfer full response "
"(read %d of %d bytes)\n",
transferred,
(int)sizeof(response));
return LIBUSB_ERROR_OTHER;
}
*mask = (response[0] << 0 |
response[1] << 8 |
response[2] << 16 |
response[3] << 24);
return 0;
}
int main(int argc, char **argv)
{
libusb_context *context;
libusb_device_handle *device;
uint16_t vendor_id = 0x18d1; /* Google */
uint16_t product_id = 0x500f; /* discovery-stm32f072 */
int interface = 1; /* gpio interface */
if (!(argc == 2 && strcmp(argv[1], "read") == 0) &&
!(argc == 4 && strcmp(argv[1], "write") == 0)) {
puts("Usage: usb_gpio read\n"
" usb_gpio write <set_mask> <clear_mask>\n");
return 1;
}
CHECK(libusb_init(&context));
device = libusb_open_device_with_vid_pid(context,
vendor_id,
product_id);
if (device == NULL) {
fprintf(stderr,
"Unable to find device 0x%04x:0x%04x\n",
vendor_id,
product_id);
return 1;
}
CHECK(libusb_set_auto_detach_kernel_driver(device, 1));
CHECK(libusb_claim_interface(device, interface));
if (argc == 2 && strcmp(argv[1], "read") == 0) {
uint32_t mask;
CHECK(gpio_read(device, &mask));
printf("GPIO mask: 0x%08x\n", mask);
}
if (argc == 4 && strcmp(argv[1], "write") == 0) {
uint32_t set_mask = strtol(argv[2], NULL, 0);
uint32_t clear_mask = strtol(argv[3], NULL, 0);
CHECK(gpio_write(device, set_mask, clear_mask));
}
libusb_close(device);
libusb_exit(context);
return 0;
}
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