On Thu, Dec 26, 2013 at 22:34 +0200, Baruch Siach wrote: > > That's what I meant. The "dummy-cs" should be an internal > chip-select that does not control any slave signal. [ ... ]
Ah, nevermind then, I simply misunderstood. :) It's good to see how much thought you already put into this topic. Thank you again for working on GPIO backed CS support for the DW-SPI controller! Regarding device tree bindings: Make sure to keep "arbitrary implementation details" out of the bindings, i.e. only put into bindings what's related to the hardware, or what _each_ potential user of this binding needs to do because of hardware features or hardware limitations, regardless whether this piece of software is an OS or not or which OS it may be. So the introduction of another dummy-cs property might be appropriate given the observed behaviour of the hardware. Alternatively one might just pick an arbitrary internal CS number at runtime (probably the highest internal number, i.e. the last one), which should not be a problem as long as this behaviour is documented -- GPIOs then can get used for this CS number and all numbers above, so no functionality is missing. Mind that this workaround then is a feature of the Linux driver, and not the DT binding. I'm just saying all of this because any DT properties you introduce not only need to get documented and reviewed, but even more so because compatibility needs to be kept in the future and changes are neither easy nor quick. virtually yours Gerhard Sittig -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr. 5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
