Grant Likely wrote: > On Thu, Mar 26, 2009 at 9:33 AM, Wolfgang Grandegger <w...@grandegger.com> > wrote: >> Grant Likely wrote: >>> Does using the reg property give the driver enough information to >>> reliably program the MAR for NAND connections that use the address >>> line chip select scheme? Related to that, should the binding include >> In principle yes: >> >> if (i > 0) >> offset[i] = resource[i].start - resource[0].start; > > Ewww. That's ugly.
Yep. >>> a property that explicitly states that an address line chip select >>> scheme is being used? >> That's why I'm still in favor of: >> >> fsl,upm-multi-chip-offsets = <0x200 0x400> >> >> That would state that the address line chip select scheme is used with >> the specified offsets. It also allows for a more elegant solution >> (code-wise). > > Alright. Then at the very least the property name should reflect that > address lines CS is used to reduce the chance of confusion with > another multi-chip scheme. Something like > fsl,upm-addr-line-cs-offsets maybe? > > Here is another thought. The binding is describing that address lines > are used to activate CS lines. Offset for chip access purposes is > derived from the address line, but it doesn't directly describe the > hardware. The following may be a better description of the hardware. > > fsl,upm-addr-line-cs = <9 10>; The TQM8548 hardware has some logic connected to the two address lines allowing to select up to 4 chips with two address lines: fsl,upm-addr-line-cs-offsets = <0x0 0x200 0x400 0x600> That's the more general solution. Wolfgang. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev