On Sun, Sep 03, 2017 at 02:37:49PM +0100, Jonathan Cameron wrote: > +cc Mark Brown and linux-spi to address question about how to represent > a hardwired chip select. See below for why I think that is what we should > be representing rather than the fact it puts it in 'continuous mode'. There's a good chance that if you just send me mail with a not obviously related subject line it might get discarded unread, people CC me on lots of things that are of questionable relevance. > > >> > + - microchip,continuous-conversion (boolean): > > >> > + Only applicable to MCP3550/1/3: These ADCs have long > > >> > + conversion times and therefore support "continuous > > >> > + conversion mode" to allow retrieval of conversions > > >> > + at any time without observing a delay. The mode is > > >> > + enabled by permanently driving CS low, e.g. by wiring > > >> > + it to ground. > hmm. This is odd. We probably need to make the SPI subsystem aware of this. > It is possible to ask for exclusive use of an SPI bus and I think we should > be doing this here. It may be wired low on your board, but it may be wired to This sounds like SPI_NO_CS, though it's vanishingly rare for it to be implemented as there's a lot of ways for it to go wrong electrically - it's a lot simpler to just have a chip select and minimise the number of times it gets asserted.
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