On 30.11.2014 16:42, Huang Shijie wrote: > On Sat, Nov 29, 2014 at 10:53:26PM -0800, Brian Norris wrote: >> On Sat, Nov 29, 2014 at 10:40:50AM +0800, Huang Shijie wrote: >>> On Fri, Nov 28, 2014 at 08:01:41AM +0100, Stefan Roese wrote: >>>> On 28.11.2014 02:48, Huang Shijie wrote: >>>>> On Thu, Nov 27, 2014 at 03:18:49PM +0100, Stefan Roese wrote: >>>>>> This sentence "We support only one NAND chip now" is not true any more. >>>>>> Multiple chips are supported. So lets remove this sentence to not >>>>> >>>>> The gpmi can only supports one chip. Of course, there are maybe two dies >>>>> in this single chip. >>>> >>>> Now I'm a bit confused. The i.MX6 supports 4 chips select signals. And isn't >>>> "two dies in this single chip" not practically the same as connecting 2 (or >>>> more) chips (same device) to multiple chip selects of the SoC? Where is the >>>> difference here? >>> The "one chip" here is means the "one package" (TSOP or BGA ....). >> >> Then why is this even in the DT binding doc? Isn't that a board-level >> constraint (and not a chip property) which should be obvious to the >> user? If so, then should we just drop the language? Or at a minimum, >> make it more specific so it doesn't confuse readers. > > yes. It is okay to send a patch to make it more clear. > >> >>> (In logic, "two dies in this single chip" is same as connecting 2 chips >>> to the gpmi.) >> >> ...which means that logically, you can connect more than one chip to the >> GPMI, right? > The gpmi can only connect with one physical chip now, but there maybe > two DIEs in this chip. I really fail to see why you make this distinction between two chips on a die and two external chips. For the SoC this should really look identical, right? Please explain again, why exactly only two chips on one die are supported. BTW: We have a custom i.MX6DL based board with 2 NAND chips connected. And Linux seems to support both chips just fine. Here the boot log: [ 1.085812] nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xdc [ 1.092218] nand: Micron MT29F4G08ABADAH4 [ 1.096245] nand: 512MiB, SLC, page size: 2048, OOB size: 64 [ 1.102171] nand: 2 chips detected [ 1.106156] gpmi-nand 112000.gpmi-nand: enable the asynchronous EDO mode 5 [ 1.113094] Scanning device for bad blocks Comments welcome... Thanks, Stefan -- 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
