linux-kernel - [PATCH 2/4] mtd: nand: atmel: Update DT documentation after splitting NFC and NAND

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Date:	Thu,  4 Dec 2014 23:30:12 +0100
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	David Woodhouse <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>,
	linux-mtd@...ts.infradead.org, Josh Wu <josh.wu@...el.com>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Andrew Victor <linux@...im.org.za>
Cc:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH 2/4] mtd: nand: atmel: Update DT documentation after splitting NFC and NAND

The NAND and NFC (NAND Flash Controller) were linked together with a
parent <-> child relationship.

This model has several drawbacks:
- it does not allow for multiple NAND chip handling while the controller
  support multi-chip (even though the driver is not ready yet)
- it mixes NAND partitions and NFC nodes at the same level (which is a bit
  disturbing)
- the introduction of the EBI bus implies defining NAND chips under the
  EBI node, and the ranges available under the EBI node should be
  restricted to EBI address space, while the NFC references several
  registers outside of these EBI ranges.

Move the NFC node outside of the NAND node, to get a more future-proof
model.

Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
---
 .../devicetree/bindings/mtd/atmel-nand.txt         | 46 ++++++++++++----------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
index 6edc3b6..8896850 100644
--- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
@@ -30,15 +30,19 @@ Optional properties:
   sector size 1024.
 - nand-bus-width : 8 or 16 bus width if not present 8
 - nand-on-flash-bbt: boolean to enable on flash bbt option if not present false
-- Nand Flash Controller(NFC) is a slave driver under Atmel nand flash
-  - Required properties:
-    - compatible : "atmel,sama5d3-nfc".
-    - reg : should specify the address and size used for NFC command registers,
-            NFC registers and NFC Sram. NFC Sram address and size can be absent
-            if don't want to use it.
-    - clocks: phandle to the peripheral clock
-  - Optional properties:
-    - atmel,write-by-sram: boolean to enable NFC write by sram.
+- atmel,nfc: phandle referencing the NAND Flash Controller, if available.
+
+The NAND Flash Controller (NFC) is an advanced NAND controller and should be
+used in conjunction with the NAND flash device.
+Required properties:
+ - compatible : "atmel,sama5d3-nfc".
+ - reg : should specify the address and size used for NFC command registers,
+         NFC registers and NFC Sram. NFC Sram address and size can be absent
+         if you don't want to use it.
+ - clocks: phandle to the peripheral clock
+
+Optional properties:
+ - atmel,write-by-sram: boolean to enable NFC write by sram.
 
 Examples:
 nand0: nand@...00000,0 {
@@ -89,21 +93,23 @@ nand0: nand@...00000 {
 };
 
 /* for NFC supported chips */
+nfc: nfc@...00000 {
+	compatible = "atmel,sama5d3-nfc";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	clocks = <&hsmc_clk>
+	reg = <
+		0x70000000 0x10000000	/* NFC Command Registers */
+		0xffffc000 0x00000070	/* NFC HSMC regs */
+		0x00200000 0x00100000	/* NFC SRAM banks */
+	>;
+};
+
 nand0: nand@...00000 {
 	compatible = "atmel,at91rm9200-nand";
 	#address-cells = <1>;
 	#size-cells = <1>;
 	ranges;
+	atmel,nfc = <&nfc>;
         ...
-        nfc@...00000 {
-		compatible = "atmel,sama5d3-nfc";
-		#address-cells = <1>;
-		#size-cells = <1>;
-		clocks = <&hsmc_clk>
-		reg = <
-			0x70000000 0x10000000	/* NFC Command Registers */
-			0xffffc000 0x00000070	/* NFC HSMC regs */
-			0x00200000 0x00100000	/* NFC SRAM banks */
-		>;
-	};
 };
-- 
1.9.1

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