Documentation: devicetree: m25p80: add "nor-jedec" binding

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=8ff16cf77ce314c20d7bd57c788f5b7719b450e1
Commit:     8ff16cf77ce314c20d7bd57c788f5b7719b450e1
Parent:     2a6a28e7922c07c116ba8f2aa3682c03ef8be678
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Fri Mar 27 10:29:49 2015 -0700
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Sun Apr 5 18:56:21 2015 -0700

    Documentation: devicetree: m25p80: add "nor-jedec" binding
    
    Almost all flash that are "compatible" with m25p80 support the JEDEC
    READ ID opcode (0x9F), 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.
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Cc: Rafał Miłecki <zajec5 at gmail.com>
    Reviewed-by: Marek Vasut <marex at denx.de>
---
 Documentation/devicetree/bindings/mtd/m25p80.txt | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/m25p80.txt b/Documentation/devicetree/bindings/mtd/m25p80.txt
index 4611aa8..f20b111 100644
--- a/Documentation/devicetree/bindings/mtd/m25p80.txt
+++ b/Documentation/devicetree/bindings/mtd/m25p80.txt
@@ -3,10 +3,13 @@
 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
-               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
-               of supported chips.
+- compatible : 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 "m25p_ids"
+               table in drivers/mtd/devices/m25p80.c for the list of supported
+               chips.
+               Must also include "nor-jedec" for any SPI NOR flash that can be
+               identified by the JEDEC READ ID opcode (0x9F).
 - 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 at 0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
-		compatible = "spansion,m25p80";
+		compatible = "spansion,m25p80", "nor-jedec";
 		reg = <0>;
 		spi-max-frequency = <40000000>;
 		m25p,fast-read;