[PATCH RFC 1/3] Devicetree: Add pl353 smc controller devicetree binding information

[Gupta, Pekon]

>From: Punnaiah Choudary Kalluri [mailto:punnaiah.choudary.kalluri at xilinx.com]
>
>Add pl353 static memory controller devicetree binding information.
>
>Signed-off-by: Punnaiah Choudary Kalluri <punnaia at xilinx.com>
>---
> .../bindings/memory-controllers/pl353-smc.txt      |   53 ++++++++++++++++++++
> 1 files changed, 53 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
>
>diff --git a/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt b/Documentation/devicetree/bindings/memory-
>controllers/pl353-smc.txt
>new file mode 100644
>index 0000000..623c1c6
>--- /dev/null
>+++ b/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
>@@ -0,0 +1,53 @@
>+Device tree bindings for ARM PL353 static memory controller
>+
>+PL353 static memory controller supports two kinds of memory
>+interfaces.i.e NAND and SRAM/NOR interfaces.
>+The actual devices are instantiated from the child nodes of pl353 smc node.
>+
>+Required properties:
>+- compatible		: Should be "arm,pl353-smc-r2p1"
>+- reg			: Controller registers map and length.
>+- clock-names		: List of input clock names - "ref_clk", "aper_clk"
>+			  (See clock bindings for details).
>+- clocks		: Clock phandles (see clock bindings for details).
>+- address-cells	: Address cells, must be 1.
>+- size-cells		: Size cells. Must be 1.
>+
>+Child nodes:
>+ For NAND the "arm,pl353-nand-r2p1" and for NOR the "cfi-flash" drivers are
>+supported as child nodes.
>+
>+Mandatory timing properties for child nodes:
>+- arm,nand-cycle-t0	: Read cycle time(t_rc).
>+- arm,nand-cycle-t1	: Write cycle time(t_wc).
>+- arm,nand-cycle-t2	: re_n assertion delay(t_rea).
>+- arm,nand-cycle-t3	: we_n de-assertion delay(t_wp).
>+- arm,nand-cycle-t4	: Status read time(t_clr)
>+- arm,nand-cycle-t5	: ID read time(t_ar)
>+- arm,nand-cycle-t6	: busy to re_n(t_rr)
>+

It would be good to have DT-bindings with meaningful names,
and suffixed with timing units like "ns" | "ps".
Also, as many of these timing parameters are common across NAND device
vendors, so why not get them added to  generic NAND bindings list.
	Documentation/devicetree/bindings/mtd/nand.txt

Another driver using similar bindings for NAND device timings
	[RFC 13/47] mtd: nand: stm_nand_bch: provide Device Tree support
	http://lists.infradead.org/pipermail/linux-mtd/2014-March/052890.html


with regards, pekon