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Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node

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Brian Norris <computersforpeace@gmail.com> writes:

>> > 
>> > Do some sorts of chipselects come into play here ? Ie. you can have one master
>> > with multiple NAND chips connected to it.
>> 
>> Most NAND controllers support interacting with several chips (or
>> dies in case your chip embeds several NAND dies), but I keep thinking
>> each physical chip should have its own instance of nand_chip + mtd_info.
>> If you want to have a single mtd device aggregating several chips you
>> can use mtdconcat.
>> 
>> This leaves the multi-dies chip case, and IHMO we should represent those
>> chips as a single entity, and I guess that's the purpose of the
>> ->numchips field in nand_chip (if your chip embeds 2 dies with 2 CS
>> lines, then ->numchips should be 2).
> Yes, I think that's some of the intention there. And so even in that
> case, a multi-die chip gets represented as a single struct nand_chip.

Isn't there the case of a single NAND controller with 2 identical chips, each a
8 bit NAND chip, and the controller aggregating them to offer the OS a single
16-bit NAND chip ?

In this case, the controller (pxa3xx is a good example) will be programmed to
handle both chips at the same time, and calculate CRC on both chips, etc ... I
hope the assertion "physical chip should have its own instance of nand_chip +
mtd_info" does take into account this example.

I don't know if there is actually any user of this for either pxa3xx or another
controller, nor if there is any value in this.

Cheers.

-- 
Robert
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[PATCH 0/5] mtd: migrate 'of_node' handling to core, not in mtd_part_parser_data Brian Norris <computersforpeace@gmail.com> - 2015-10-27 03:40 +0100
  [PATCH 3/5] mtd: spi-nor: drop unnecessary partition parser data Brian Norris <computersforpeace@gmail.com> - 2015-10-27 03:40 +0100
  [PATCH 4/5] mtd: drop unnecessary partition parser data Brian Norris <computersforpeace@gmail.com> - 2015-10-27 03:40 +0100
  [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Brian Norris <computersforpeace@gmail.com> - 2015-10-27 03:40 +0100
    Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-27 08:50 +0100
      Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Brian Norris <computersforpeace@gmail.com> - 2015-10-27 19:00 +0100
        Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Brian Norris <computersforpeace@gmail.com> - 2015-10-28 02:10 +0100
          Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-28 09:10 +0100
        Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-28 09:00 +0100
          Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Marek Vasut <marex@denx.de> - 2015-10-28 17:20 +0100
            Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-28 17:40 +0100
              Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Brian Norris <computersforpeace@gmail.com> - 2015-10-28 18:20 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Robert Jarzmik <robert.jarzmik@free.fr> - 2015-10-28 22:10 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Marek Vasut <marex@denx.de> - 2015-10-28 23:50 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Robert Jarzmik <robert.jarzmik@free.fr> - 2015-10-29 07:40 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-29 08:30 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Marek Vasut <marex@denx.de> - 2015-10-29 18:30 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from  master device node Boris Brezillon <boris.brezillon@free-electrons.com> - 2015-10-29 18:40 +0100
                Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Robert Jarzmik <robert.jarzmik@free.fr> - 2015-10-29 21:40 +0100
              Re: [PATCH 1/5] mtd: ofpart: grab device tree node directly from master device node Marek Vasut <marex@denx.de> - 2015-10-28 21:40 +0100
  [PATCH 5/5] mtd: drop 'of_node' partition parser data Brian Norris <computersforpeace@gmail.com> - 2015-10-27 03:40 +0100

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