On Wed, Feb 05, 2003 at 09:35:01AM +0100, Thomas Jarosch wrote:
> I found Documentation/ioctl-numbers.txt for new-style ioctls.
> Currently I'm using 'N' with a range of 20 to 3F.
> Before a final release, I'll check if they're still unused.

Heh, good luck, I don't think I'll take a patch adding new ioctls
without a _very_ good reason.  Also, you'll need to make the necessary
64 bit thunking layer if somehow you convince me :)

> [FTDI Bit Bang mode]
> > It looks like this mode does not even look like a serial device anymore.
> > I'd recommend just using libusb to talk to the device to use this new
> > functionality (and to send new firmware to the device), that way you
> > don't have to mess with kernel programming at all.
> 
> Hehe, it's still serial, because you have to write out bytes
> to change the status of the pins. It's more like synchronous serial.
> If you switch one line from zero to one and back constantly,
> you even have a clock line to talk to other chips.

But it isn't serial data, so you don't need the tty layer.  Why not just
do it all though libusb/usbfs in userspace?

> I've finished the bit bang mode part yesterday and sent my
> patch to Bill Ryder. Though his @sgi.com email address seems
> to be down. I tried again at bryder at paradise dot net dot nz.
> Let's see what happens.
> 
> Today I'll go for the eeprom stuff. I guess there will be
> 7 ioctls at all. Though newer devices (BM type chips) support
> setting the latency, how long a byte is hold in the buffer
> if the buffer doesn't become full. This might be also
> interesting to tune serial communications.
> 
> IMHO the eeprom stuff belongs in the ftdi_sio driver,
> because I don't want people to mess around with the
> eeprom checksum generation in some user-space application.
> If the checksum is wrong, the chip silently ignores the eeprom.
> The eeprom is used to store VID/PID/max. power consumption etc.

No, that should be done in userspace, not kernelspace.

thanks,

greg k-h


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