On Thu, Sep 12, 2013 at 12:48:31PM +0100, Mark Brown wrote: > On Thu, Sep 12, 2013 at 12:17:45PM +0100, David Woodhouse wrote: > > > Right. The issue here is that the LUT is currently *pre-populated*, with > > an incestuously-"known" set of commands that the slave is expected to > > support. > > So, to repeat my earlier question can someone tell me what a LUT is? It's a very common abbreviation - Look Up Table. More specifically, it's a set of registers which give the SPI controller a sequence of 16-bit commands to execute, which tell it what to do on the SPI bus. Each register contains two commands, and it executes them successively throughout the register set until it reaches a STOP command. These commands tell the SPI controller the width of the bus, a command to send on SPI, whether to read or write data and how much, etc. If you read the comments in patch 5, and the code, it's all explained there. I never saw this before until about an hour ago when I took an interest in it after your "what is a LUT" question, and it took less than 15 minutes to work the above out. -- 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
