2017-07-19 8:46 GMT+02:00 Clemens Ladisch <clemens@xxxxxxxxxx>:
The HID interface is managed by another driver. The kernel driver
already knows how to write to these registers with a control request
instead (see below). Could you check if a control read request works,
or if the response still goes through the HID pipe?
I've tried that, but unfortunately it didn't work. The input request reads zero bytes.
Well, I think that means I'll have to use my workarount with libhidapi.
Below is my code. I don't feel very confident on all those bmRequestType, bRequest, wValue and other parameters, I just used the ones from your example. May be later I will be able to sniff the communication of the card with its proprietary Windows driver, and if I get a different results I'll revert back to you.
int cm106_read(libusb_device_handle *handle, char reg, uint16_t *data)
{
int res;
unsigned char buf[4] = {0x30, // 0x20 to write, 0x30 to read
0x00, // DATAL
0x00, // DATAH
reg}; // Register address
if ((res = libusb_control_transfer(handle, LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_ENDPOINT,
LIBUSB_REQUEST_SET_CONFIGURATION, 0, 0, buf, 4, 0)) != 4)
if ((res = libusb_control_transfer(handle, LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_ENDPOINT,
LIBUSB_REQUEST_SET_CONFIGURATION, 0, 0, buf, 4, 0)) < 0) // <-- THIS FUNCTION RETURNS 0
return res;
if (res != 3)
{
{
fprintf(stderr, "DEBUG Invalid response length"
return -1;
}
if (buf[0] & 0xe0 != 0x20) // No register data in the input
{
fprintf(stderr, "DEBUG data: %02X %02X %02X\n", buf[0], buf[1], buf[2]);
return -1;
}
*data = "" << 8) + buf[1];
return 0;
}
if (buf[0] & 0xe0 != 0x20) // No register data in the input
{
fprintf(stderr, "DEBUG data: %02X %02X %02X\n", buf[0], buf[1], buf[2]);
return -1;
}
*data = "" << 8) + buf[1];
return 0;
}
// Just for completeness, the below function successfully writes the data into cm106 registers
int cm106_write(libusb_device_handle *handle, char reg, uint16_t data)
{
unsigned char buf[4] = {0x20, // 0x20 to write, 0x30 to read
data & 0xff, // DATAL
(data >> 8) & 0xff, // DATAH
reg}; // Register address
return libusb_control_transfer(handle, LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_ENDPOINT,
LIBUSB_REQUEST_SET_CONFIGURATION, 0, 0, buf, 4, 0);
}
{
unsigned char buf[4] = {0x20, // 0x20 to write, 0x30 to read
data & 0xff, // DATAL
(data >> 8) & 0xff, // DATAH
reg}; // Register address
return libusb_control_transfer(handle, LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_ENDPOINT,
LIBUSB_REQUEST_SET_CONFIGURATION, 0, 0, buf, 4, 0);
}
Thank you for your support!
Best regards
Denis Shulyaka
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