Hi, On Fri, Apr 4, 2014 at 5:54 PM, Peter Crosthwaite <peter.crosthwaite@xxxxxxxxxx> wrote: > On Fri, Apr 4, 2014 at 10:14 PM, Harini Katakam > <harinikatakamlinux@xxxxxxxxx> wrote: >> Hi Mark, >> >> On Fri, Apr 4, 2014 at 3:39 PM, Mark Brown <broonie@xxxxxxxxxx> wrote: >>> On Fri, Apr 04, 2014 at 08:30:38AM +0530, Harini Katakam wrote: >>>> On Fri, Apr 4, 2014 at 3:04 AM, Mark Brown <broonie@xxxxxxxxxx> wrote: >>>> > On Thu, Apr 03, 2014 at 04:40:31PM +0530, Harini Katakam wrote: >>> >>>> >> +Optional properties: >>>> >> +- num-cs : Number of chip selects used. >>> >>>> > How does this translate to the hardware? >>> >>>> This IP can drive 4 slaves. >>>> The CS line to be driven is selected in spi device structure and >>>> that is driven by the software. >>> >>> So why specify this in the binding at all? If the device always has the >>> same number of chip selects it's redundant. >> >> I'm sorry, I should have explained that better. >> The IP can support upto 4 chip selects. >> The num-cs value here is the number of chip selects actually used on the board. >> > > Just to clarify - do you mean SoC or board level? > I mean board level. One more reason it will be useful to keep this property is because there is support for adding a decoder where extended slaves can be selected through the IP's control register. (This is not currently implemented in the driver but will be in the future.) Regards, Harini -- 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
