Re: [PATCH v6] mtd: support BB SRAM on ICP DAS LP-8x4x

Rob Herring
2016-02-23T19:48:36Z

On Tue, Feb 23, 2016 at 09:58:01PM +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>
> CC: Rob Herring <robh@kernel.org>
>
> v5..v6
> * replace wildcards in compatible and module name
> * drop obsolete mtd_part_parser_data.of_node
>
> 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/icpdas-lp8841-sram.txt | 23 +++

Acked-by: Rob Herring <robh@kernel.org>

> drivers/mtd/devices/Kconfig | 14 ++
> drivers/mtd/devices/Makefile | 1 +
> drivers/mtd/devices/sram_lp8841.c | 198 +++++++++++++++++++++
> 4 files changed, 236 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/icpdas-lp8841-sram.txt
> create mode 100644 drivers/mtd/devices/sram_lp8841.c