Hi Rob, sorry it took me so long to reply, I had to set up mutt first ;) On Mon, Sep 10, 2018 at 04:47:22PM -0500, Rob Herring wrote: > On Sat, Sep 8, 2018 at 8:20 AM Bernhard Frauendienst > <kernel@xxxxxxxxxxxxxxxxx> wrote: > > > > Some mtd drivers like physmap variants have support for concatenating > > multiple mtd devices, but there is no generic way to define such a > > concat device from within the device tree. > > That is the generic way, but I suppose that only works for parallel > memory mapped devices. So is it just spi-nor that you need to support? I'm no expert in this domain, or regarding OpenWRT, but as far as I can tell this only concerns spi-nor devices. It definitely does in my specific use-case. > Can we just make reg take multiple chip selects just like the existing > support takes multiple reg entries? That sounds like an interesting idea, but I'm afraid it's not a trivial change, as far as I can tell from looking at spi.c. The 'reg' property is currently read in of_spi_parse_dt which gets passed the spi device created in of_register_spi_device. The latter would have to create multiple devices from a single OF node, and pass the chipselect value to of_spi_parse_dt, which would have to parse the same node multiple times, which feels a bit strange. To make things worse, of_register_spi_device returns the created device, although that value seems unused in the current tree (except for error checks). Am I correct to assume that this change in method signature could be accteptable since both functions are not exported? Regards, Bernhard
