Re: [PATCH v4 2/2] doc: dt: mtd: add a DT property to enable the use of 4byte-address op codes

From: Rob Herring
Date: Thu Mar 31 2016 - 10:20:06 EST


On Tue, Mar 29, 2016 at 02:24:13PM +0200, Cyrille Pitchen wrote:
> This patch adds a new optional DT property which enables an alternative
> way of supporting memory size above 16MiB (128Mib). This new mechanism
> translates the regular 3byte-address op codes into their 4byte-address
> version whereas the old/default mecanism makes the SPI memory enter its
> 4byte-address mode, which has annoying side effects for early bootloaders.
>
> We cannot discover at run time whether the SPI NOR memory supports the
> 4byte-address op codes. For instance both Macronix MX25L25635E and
> MX25L25673G share the same JEDEC ID (C22019 without any extension byte).
> However the first one doesn't support 4byte-address op codes whereas the
> second one does.
>
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
> ---
> Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt | 11 +++++++++++
> 1 file changed, 11 insertions(+)

Acked-by: Rob Herring <robh@xxxxxxxxxx>