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Re: [Owfs-developers] Issues with FTDI based USB-Serial dongle & DS2480B
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From: Johan S. <jo...@st...> - 2014-09-23 19:40:43
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I'm all for auto-detection, when it is possible to do so reliably. As you mentioned in the other reply, randomly poking at stuff is neither reliable or safe.. So, the question is what we can do to make it as smooth for the user as possible.. A possibly a new approach, with OS-specific resolving you mentioned: If user specifies --link /dev/ttyS0, -d /dev/ttyS0 or other, we could try OS-specific lookups to find what serial hardware it is using. For example, if we can find out that it is a FTDI based device, we could try to use ft_ftdi instead of ft_serial. If we cannot find out, we just fall back to regular TTY access. If user specifies --link 2:3, -d 3:4, --link usb:NNSERIAL or such, we look for that specific USB device. If it is a FTDI device, we use ft_ftdi. Else, we can either fail, or for device-types which are serial, we could try to reverse-lookup TTY using OS-specific approach. Note: on FreeBSD there are separate /dev permissions for accessing the TTY and the USB device. Not sure if Linux has the same. Or, a more intrusive approach, clean up all parameters and go a generic device-option: --device <type>[ <port-or-address>]. Examples: --device link /dev/ttyS0 (would also possibly try to use OS specific resolving) --device link usb:3:4 --device link usb:NNSERIAL --device ds9097 /dev/ttyS0 --device ds9097 usb:3:4 --device ds9097 usb:NNSERIAL --device ds9097u /dev/ttyS0 --device i2c /dev/i2c-0 --device masterhub /dev/ttyS0 --device usb (this would search for DS9490R or PuceBaboon or any other USb which we can *reliably* identify) What would your optimal owfs usage model look like? For the record, here are the usbconfig --dump_device_desc data for my two FTDI devices: ugen1.3: <FT232R USB UART FTDI> at usbus1, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON (90mA) bLength = 0x0012 bDescriptorType = 0x0001 bcdUSB = 0x0200 bDeviceClass = 0x0000 bDeviceSubClass = 0x0000 bDeviceProtocol = 0x0000 bMaxPacketSize0 = 0x0008 idVendor = 0x0403 idProduct = 0x6001 bcdDevice = 0x0600 iManufacturer = 0x0001 <FTDI> iProduct = 0x0002 <FT232R USB UART> iSerialNumber = 0x0003 <A9xxxxxD> bNumConfigurations = 0x0001 ugen2.3: <USB FAST SERIAL ADAPTER FTDI> at usbus2, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON (44mA) bcdUSB = 0x0110 bcdDevice = 0x0400 iManufacturer = 0x0001 <FTDI> iProduct = 0x0002 <USB FAST SERIAL ADAPTER> iSerialNumber = 0x0003 <FTCDXXX> (skipped all other attributes which are identical) Johan On 9/22/14 18:23 , Paul Alfille wrote: > I notice in recent Linux (Fedora specifically) that USB devices get > pretty consistently listed by a reasonably consistent and recognizable > name in /dev/serial/by_id. > > I haven't looked to closely at all the USB fields yet, but some > devices have unique identifiers rather than the generic USB/serial. I > was hoping to scan for known patterns, apply any optimizations, and > then connect. The upcoming USB HobbyBoards hub will have that. > > My dream is that owfs will be as "automatic" as possible. Currently we > can automatically scan for: > i2c > DS9490R > HA7Net > OWSERVER-ENET > w1 > > Hardware serial will always be a problem, but some USB-serial might be > possible. > > Paul > > On Mon, Sep 22, 2014 at 2:59 AM, Johan Ström <jo...@st... > <mailto:jo...@st...>> wrote: > > > On 22/09/14 00:21, Robin Gilks wrote: > >> 1. Trying to resolve a serial port TTY name (i.e. /dev/cuaU1 on > FreeBSD) > >> to a potential USB device is probably doable, but not without a > lot of > >> effort and OS specific code. > >> I don't think it's worth trying to go down that road. > >> > > How about using udev on Linux (is there an equivalent on other OSes?) that > > creates a symlink to a device node with a unique name from the > type (FTDI) > > and bus number and OWFS looks for that specific device name. > > > > Just an idea (had to do that years ago with serial devices to > sort out a > > connection to a weather station and an IR blaster, never sure > what device > > names each would come up with!). > > > > > > I have a similar setup myself, using FreeBSD's devd. It uses my known, > hard-coded USB serials to set up a symlink from /dev/cua-linkusb to > /dev/cuaXXX when device is detected, to easier find which tty device I > should be using for what (I think I have ~4 serial ports on my box) > > However, this doesn't solve the auto-deteciton problem, the user still > needs to manually tell which USB device to be used, by serial-no or > otherwise. And if that has to be done, it could just as well be done > directly in owfs. > > ------------------------------------------------------------------------------ > Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer > Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS > Reports > Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper > Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer > http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk > _______________________________________________ > Owfs-developers mailing list > Owf...@li... > <mailto:Owf...@li...> > https://lists.sourceforge.net/lists/listinfo/owfs-developers > > > > > ------------------------------------------------------------------------------ > Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer > Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports > Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper > Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer > http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk > > > _______________________________________________ > Owfs-developers mailing list > Owf...@li... > https://lists.sourceforge.net/lists/listinfo/owfs-developers |
