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    SubjectRe: [PATCH v5] mtd: support BB SRAM on ICP DAS LP-8x4x
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    On Sat, 2015-12-19 at 21:38 -0600, Rob Herring wrote:
    > On Tue, Dec 15, 2015 at 09:58:53PM +0300, Sergei Ianovich wrote:
    > > This provides an MTD device driver for 512kB of battery backed up
    > > SRAM
    > > on ICPDAS LP-8X4X programmable automation controllers.
    > >
    > > SRAM chip is connected via FPGA and is not accessible without a
    > > driver,
    > > unlike flash memory which is wired to CPU MMU.
    > >
    > > This SRAM becomes an excellent persisent storage of volatile process
    > > data like counter values and sensor statuses. Storing those data in
    > > flash or mmc card is not a viable solution.
    > >
    > > Signed-off-by: Sergei Ianovich <ynvich@gmail.com>
    > > Reviewed-by: Brian Norris <computersforpeace@gmail.com>
    > > ---
    > >    v4..v5
    > >    * remove .owner from struct platform_driver
    > >    * constify struct of_device_id
    > >     for further Brian Norris comments:
    > >    * drop unused property from doc file
    > >    * move defconfig update to a different file
    > >    * drop extra match w/ of_match_device()
    > >
    > >    v3..v4 for Brian Norris 'Reviewed-by'
    > >    * add doc file for DT binding
    > >    * move DTS binding to a different patch (8/21)
    > >    * drop unused include directive
    > >    * drop safely unused callback
    > >    * drop non-default partion probe types
    > >    * drop duplicate error checks
    > >    * drop duplicate error reporting
    > >    * fixed error message on MTD registeration
    > >    * fixed module removal routine
    > >
    > >    v2..v3
    > >    * no changes (except number 08/16 -> 10/21)
    > >
    > >    v0..v2
    > >    * use device tree
    > >    * use devm helpers where possible
    > >
    > >  .../devicetree/bindings/mtd/sram-lp8x4x.txt        |  20 +++
    > >  drivers/mtd/devices/Kconfig                        |  14 ++
    > >  drivers/mtd/devices/Makefile                       |   1 +
    > >  drivers/mtd/devices/sram_lp8x4x.c                  | 199
    > > +++++++++++++++++++++
    > >  4 files changed, 234 insertions(+)
    > >  create mode 100644 Documentation/devicetree/bindings/mtd/sram-
    > > lp8x4x.txt
    > >  create mode 100644 drivers/mtd/devices/sram_lp8x4x.c
    > >
    > > diff --git a/Documentation/devicetree/bindings/mtd/sram-lp8x4x.txt
    > > b/Documentation/devicetree/bindings/mtd/sram-lp8x4x.txt
    > > new file mode 100644
    > > index 0000000..476934f
    > > --- /dev/null
    > > +++ b/Documentation/devicetree/bindings/mtd/sram-lp8x4x.txt
    > > @@ -0,0 +1,20 @@
    > > +512kB battery backed up SRAM on LP-8x4x industrial computers
    > > +
    > > +Required properties:
    > > +- compatible : should be "icpdas,sram-lp8x4x"
    >
    > No wildcards please. Otherwise looks fine.

    There is a similar review comment from Arnd Bergmann in the discussion
    of `[PATCH v5] serial: support for 16550A serial ports on LP-8x4x`.

    I'll quote my latest clarification:
    > ... This driver will support ports on LP-8081, 
    > LP-8141, LP-8441, LP-8841. Last time I checked the vendor was announcing
    > a series with 3 as the last digit. They use lp8x4x name, eg. in
    > documentation like `LP-8x4x_ChangeLog.txt`. They ship their proprietary
    > SDK in `lp8x4x_sdk_for_linux.tar`. All of this implies that it is a
    > single board.

    I think the solution should be the same for all LP-8x4x drivers (IRQ,
    SRAM, SERIAL, IIO).


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