2014-02-17 17:11 GMT+01:00 Paolo Bonzini <[email protected]>:
> Il 17/02/2014 16:33, Alex David ha scritto:
>
> If you need more than one bus, you need a new device exposing the
>> I2C bus, besides the new sensor devices. USB-I2C could be one such
>> device.
>>
>> So let me see if I understood well. USB-I2C (host QEMU device) seems a
>> good idea, I could normally do : qemu-system-i386 -device
>> usb-I2c,chardev=foo -device usb-i2c,chardev=bar -chardev
>> socket,path=/tmp/test0,server,nowait,id=foo -chardev
>> socket,path=/tmp/test1,server,nowait,id=bar.
>>
>
> Almost. For QOM:
>
> -device usb-i2c,id=usb-i2c-0
> -device i2c-my-sensor,address=0x48,bus=usb-i2c-0.0
>
> For chardev:
>
> -device usb-i2c,id=usb-i2c-0
> -chardev socket,path=/tmp/test0,server,nowait,id=chr-foo-0
> -device i2c-my-sensor,address=0x48,bus=usb-i2c-0.0,chardev=chr-foo-0
>
> Repeat for the other buses, replacing -0 with -1 and -2.
>
>
> I need a "USB-I2C guest kernel driver" that would register a bus (i2c-1
>> for chardev foo, i2c-2 for chardev bar etc...), I guess ?
>>
>
> It exists already, drivers/i2c/busses/i2c-tiny-usb.c.
>
I'm now trying to write this new USB-I2C device, I look through some of the
code (dev-serial, dev-...), I used dev-serial code and removed the code
that wanted to declare a chardev (I don't need one to create my bus, right
?).
Now I'm wondering, how will be i2c-tiny-usb launched and declare a new
/dev/i2c-N, with my device. I found :
static struct usb_device_id i2c_tiny_usb_table [] = {
{ USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
{ USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
{ } /* Terminating entry */
};
So I figured my USB-I2C should register using these numbers ?
static const USBDesc desc_i2c = {
.id = {
.idVendor = 0x0403,
.idProduct = 0xc631,
.bcdDevice = 0x0400,
.iManufacturer = STR_MANUFACTURER,
.iProduct = STR_PRODUCT_I2C,
.iSerialNumber = STR_SERIALNUMBER,
},
.full = &desc_device,
.str = desc_strings,
};
However, this doesn't work, after a $ qemu-system-i386
debian_wheezy_i386_standard.qcow2 -usb -device USB-I2C,id=usb-i2c-0, the
driver doesn't seem to be used (/sys/class/i2c-dev/i2c-0/name isn't for
it...), even if I modprobe i2c-tiny-usb...
The dmesg shows it doesn't go into the "probe" function.
What did I miss ?
