On Fri, Jun 30, 2017 at 8:53 AM, Jonathan Cameron <jic23@xxxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 30 Jun 2017 10:44:42 +0200 > Mike Looijmans <mike.looijmans@xxxxxxxx> wrote: > >> I'm writing an IIO driver for a custom IP, which is pretty simple: >> >> - Map the registers to memory and register IRQ routine >> - To start acquisition, write a value to the config register >> - On interrupt, read data register, push it into queue >> - To stop, write another value to config. >> >> Would it be useful to provide this as a generic driver in Linux, so that you >> can provide the config register and data register offsets and values in the >> devicetree? That would make it work on a lot of similar project without >> everyone coding the same thing. > > Hi Mike, > > I've brought in the devicetree bindings maintainers and list as well on this > discussion because in many ways it's more about the strategy on bindings > than the actual driver... Also Linus Walleij for any experience handing > the gpio-mmio driver which strikes me as fairly similar in aim. > > To the driver question, yes absolutely this would be a good thing to have. > The majority of ADCs out there are irritatingly more complex than what > you have. Everyone seems to feel obliged to put in their own 'special > sauce'. > > As for bindings, there are two options, either we > > 1) As you suggest push all differences between different parts into the > bindings. Note we'll still need a compatible list in the driver. > So this is something like gpio-mmio.c > > 2) Do something similar to the irq generic_chip (CONFIG_GENERIC_IRQ) > infrastructure and actually have very slim wrapper drivers around a > library. That allows those elements that are constrained by the > hardware to not need specifying in device tree bindings. > >> >> And a related question: Is there a driver that's close to this? > I can't immediately think of one, but it's possible that one > of the SoC ADC drivers is simple enough to describe this way. > > So Mark / Rob. You guys have experience with how the bindings > worked out for each approach. Which do you prefer? > Either approach is fine with me. The latter case. Specific bindings can map to a generic driver or evolve to a specific driver if the generic one becomes inadequate. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
