On Wed, Mar 11, 2015 at 09:57:25PM +0000, Brian Norris wrote:
> Almost all flash that are "compatible" with m25p80 support the JEDEC
> READ ID opcode (0x95), and in fact, that is often the only thing that is
> used to differentiate them. Let's add a compatible string that
> represents this lowest common denominator of compatibility.
>
> Device trees can still specify manufacturer/device names in addition,
> but (until some reason is found to differentiate between them through
> device tree) software will likely want to bind just against the generic
> name, and avoid unnecessarily growing its device ID binding tables.
>
> This is related to the work of commit a5b7616c55e1 ("mtd:
> m25p80,spi-nor: Fix module aliases for m25p80"), which showed that
> maintaining these device tables as stable device-tree/modalias binding
> tables is not a worthwhile burden for mostly-comptatible flash.
>
> At the same time, let's update the binding doc to point to the
> m25p_ids[] ID list instead of spi_nor_ids[]. The former can be used for
> device tree bindings, but the latter cannot. In the future, we should
> pare down the m25p_ids[] list to only those IDs which are actually used
> in device trees.
We really should not be referring to C files for the binding. The right
fix is to define the list in the binding document.
Mark.
>
> Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx>
> Cc: Rafał Miłecki <zajec5@xxxxxxxxx>
> ---
> Documentation/devicetree/bindings/mtd/m25p80.txt | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mtd/m25p80.txt b/Documentation/devicetree/bindings/mtd/m25p80.txt
> index 4611aa83531b..1b2997d4cee4 100644
> --- a/Documentation/devicetree/bindings/mtd/m25p80.txt
> +++ b/Documentation/devicetree/bindings/mtd/m25p80.txt
> @@ -3,9 +3,12 @@
> Required properties:
> - #address-cells, #size-cells : Must be present if the device has sub-nodes
> representing partitions.
> -- compatible : Should be the manufacturer and the name of the chip. Bear in mind
> +- compatible : Should be "nor-jedec" for any SPI NOR flash that can be
> + identified by the JEDEC READ ID opcode (0x95).
> + Additionally, may include a device-specific string consisting of
> + the manufacturer and name of the chip. Bear in mind
> the DT binding is not Linux-only, but in case of Linux, see the
> - "spi_nor_ids" table in drivers/mtd/spi-nor/spi-nor.c for the list
> + "m25p_ids" table in drivers/mtd/devices/m25p80.c for the list
> of supported chips.
> - reg : Chip-Select number
> - spi-max-frequency : Maximum frequency of the SPI bus the chip can operate at
> @@ -22,7 +25,7 @@ Example:
> flash: m25p80@0 {
> #address-cells = <1>;
> #size-cells = <1>;
> - compatible = "spansion,m25p80";
> + compatible = "spansion,m25p80", "nor-jedec";
> reg = <0>;
> spi-max-frequency = <40000000>;
> m25p,fast-read;
> --
> 1.9.1
>
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