Re: [PATCH 1/2] Documentation: devicetree: m25p80: add "nor-jedec" binding

On Thu, Mar 12, 2015 at 11:36 AM, Rafał Miłecki [off-list ref] wrote:

On 12 March 2015 at 11:19, Geert Uytterhoeven [off-list ref] wrote:

quoted

On Wed, Mar 11, 2015 at 10:57 PM, Brian Norris
[off-list ref] wrote:

quoted

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

For the casual reader, this suggests putting "nor-jedec" first, which is not
what we want. So I would write it like e.g.

"Should be the manufacturer and the name of the chip. Additionally,
 should contain "nor-jedec" for any SPI NOR flash that can be
 identified by the JEDEC READ ID opcode (0x95)."

I don't really like above. It suggests using manufacturer,name
always/in most cases. This is what we want to avoid. Let's use
"nor-jedec" wherever possible (when dealing with JEDEC compatible
flashes).

Why? It's a basic DT principle to always specify the real device.
One day you might find a deviation from the nor-jedec spec, which you cannot
handle if the device node doesn't claim compatibility with the real device.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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