[PATCH v5 4/8] Documentation: add the document for the SPI NOR framework

[Konstantin Tokarev]

24.02.2014, 15:26, "Huang Shijie" <b32955 at freescale.com>:
> This patch adds the document for the SPI NOR framework.
>
> Signed-off-by: Huang Shijie <b32955 at freescale.com>
> ---
>  Documentation/mtd/spi-nor.txt |   59 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 59 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/mtd/spi-nor.txt
>
> diff --git a/Documentation/mtd/spi-nor.txt b/Documentation/mtd/spi-nor.txt
> new file mode 100644
> index 0000000..b9585f8
> --- /dev/null
> +++ b/Documentation/mtd/spi-nor.txt
> @@ -0,0 +1,59 @@
> +                          SPI NOR framework
> +               ============================================
> +
> +Part I - why we need this framework?
> +-------------------------------------
> +
> +The SPI bus controller only deals with the byte stream.
> +Some controller does not works like a SPI bus controller, it works
> +like a SPI NOR controller instead, such as the Freescale's QuadSPI controller.
> +
> +The Freescale's QuadSPI controller should knows the NOR commands to
> +find the right LUT sequence. Unfortunately, the old code can not meet
> +this requirement.

should know

> +
> +Part II - How does the framework work?
> +-------------------------------------
> +
> +This framework just adds a new layer between the MTD and the SPI bus driver.
> +With this new layer, the SPI NOR controller driver does not depend on the
> +m25p80 code anymore.
> +
> +   Before this framework, the layer is like:
> +
> +                   MTD
> +         ------------------------
> +                  m25p80
> +         ------------------------
> +       SPI bus driver
> +         ------------------------
> +        SPI NOR chip
> +
> +   After this framework, the layer is like:
> +                   MTD
> +         ------------------------
> +              SPI NOR framework
> +         ------------------------
> +                  m25p80
> +         ------------------------
> +       SPI bus driver
> +         ------------------------
> +       SPI NOR chip
> +
> +  With the SPI NOR controller driver(Freescale QuadSPI), it looks like:
> +                   MTD
> +         ------------------------
> +              SPI NOR framework
> +         ------------------------
> +                fsl-quadSPI
> +         ------------------------
> +       SPI NOR chip
> +
> +Part III - How can the drivers use the framework
> +-------------------------------------
> +
> +The main API is the spi_nor_scan(). Before you call the hook, you should
> +initialize the necessary fields for spi_nor{}.
> +Please see the drivers/mtd/spi-nor/spi-nor.c for detail.
> +Please also reference to the fsl-quadspi.c when you want to write a new driver
> +for a SPI NOR controller.
> --
> 1.7.2.rc3
>
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Regards,
Konstantin