> -----Original Message----- > From: Jan Kandziora [mailto:j...@gmx.de] > Sent: Saturday, 11 February 2017 11:08 AM > To: OWFS (One-wire file system) discussion and help <owfs- > develop...@lists.sourceforge.net> > Subject: Re: [Owfs-developers] Hiding incompatible device variants > > Am 10.02.2017 um 22:04 schrieb Alastair D'Silva: > > Hi folks, > > > > I've written a 1Wire slave implementation for ARM (which I will be > > open sourcing), in order to implement some functionality that does not > > exist in the 1Wire world (multichannel RGBW control). > > > > Given the small amount of address space available in the family, I > > figured the best course of action for further implementations would be > > to keep the family code, and add a command to allow the master to > > query the device specifics. > > > What is your device emulating? A DS2408? There is some code inside OWFS'
I do have a working DS2408 emulation, but that was more to test that I have the low level protocol correct. This is a new device, with new commands. > DS2408 codebase which handles the various HD44780 displays connected to > the DS2408. It's ugly, it's error-prone and it's hard to debug. > Please don't require us to put even more quirks into the existing driver > sources. Agreed, what I was thinking of was adding an init/term function and a struct that represents a device instance (rather than a whole family of devices), and adding a DeviceEntryExtended2 to set that up. That way, the driver can query the device when inited, find out it's real type, and pass the appropriate filetype table (probably from a separate .c file), so we don't have the horrible overloading that exists in the DS2408 driver. What I'm stuck on is that none of the existing infrastructure seems to have a concept of a device instance, only types of devices, and I'm not sure it can be easily retrofitted. Regardless of whether I have a second level of device types, I don't think I can do without a struct to have device instance state. My use case is this: - The implementation library allows an arbitrary number of channels - I have a command which returns the number of channels - I would only like to display files for the permitted channels - I would like to avoid querying the device every time a directory listing is done If you have any ideas, I'm all ears. Maybe querying the device for it's state when necessary wouldn't be disastrous... > If you make your own device, please give it its own family code and create > your own driver source file in the owlib tree. We are going to face at most > twenty fundamentally different designs of homebrewn devices and there's > plenty of unused address space for that. That feels a lot like "640kb ought to be enough for everyone"... <later> > By the way, if you do an onewire LED driver, the feature I adore most is > synchronous control over a whole bus. So multiple LED units can be pre- > programmed to dim in a controlled fashion starting at a single point in time. > > You had to implement a new command similar to "Convert T" to achieve this. > That would break any existing driver but is extremly simple to implement in > your own driver (and the simultanenous code, of course). That sounds like a great idea, thanks. These are the commands I have implemented currently: ALL_OFF (sets all the channels on the device off, maybe a candidate for a simultaneous command?) COUNT_CHANNELS returns the number of available channels to the master SET_CHANNEL fades a channel to a specified RGBW value over a specified time GET_CHANNEL gets the current RGBW value of a channel, and the fade time remaining It should be relatively straightforward to add a COMMIT command which only starts fading the requested channels once received. Do you have any other suggestions? ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
