1 files changed, 158 insertions, 0 deletions
diff --git a/extra/usb_gpio/usb_gpio.c b/extra/usb_gpio/usb_gpio.c
new file mode 100644
index 0000000000..6c6d464963
--- /dev/null
+++ b/extra/usb_gpio/usb_gpio.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 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     transfered;
+
+	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),
+				   &transfered,
+				   TRANSFER_TIMEOUT_MS));
+
+	if (transfered != sizeof(command)) {
+		fprintf(stderr,
+			"Failed to transfer full command "
+			"(sent %d of %d bytes)\n",
+			transfered,
+			(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     transfered;
+
+	/*
+	 * 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),
+				   &transfered,
+				   TRANSFER_TIMEOUT_MS));
+
+	CHECK(libusb_bulk_transfer(device,
+				   LIBUSB_ENDPOINT_IN | 2,
+				   response,
+				   sizeof(response),
+				   &transfered,
+				   TRANSFER_TIMEOUT_MS));
+
+	if (transfered != sizeof(response)) {
+		fprintf(stderr,
+			"Failed to transfer full response "
+			"(read %d of %d bytes)\n",
+			transfered,
+			(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;
+	uint16_t              product_id = 0x500f;
+
+	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, 0));
+
+	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;
+}