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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
To:     linux-mtd@lists.infradead.org
Cc:     Dinh Nguyen <dinguyen@kernel.org>, Marek Vasut <marex@denx.de>,
        Ley Foon Tan <ley.foon.tan@intel.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Richard Weinberger <richard@nod.at>,
        Rob Herring <robh+dt@kernel.org>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 3/5] dt-bindings: mtd: denali_dt: document reset property
Date:   Fri, 20 Dec 2019 20:31:53 +0900
Message-Id: <20191220113155.28177-4-yamada.masahiro@socionext.com>
In-Reply-To: <20191220113155.28177-1-yamada.masahiro@socionext.com>
References: <20191220113155.28177-1-yamada.masahiro@socionext.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

According to the Denali NAND Flash Memory Controller User's Guide,
this IP has two reset signals.

  rst_n:     reset most of FFs in the controller core
  reg_rst_n: reset all FFs in the register interface, and in the
             initialization sequencer

This commit specifies these reset signals.

It is possible to control them separately from the IP point of view
although they might be often tied up together in actual SoC integration.

At least for the upstream platforms, Altera/Intel SOCFPGA and Socionext
UniPhier, the reset controller seems to provide only 1-bit control for
the NAND controller. If it is the case, the resets property should
reference to the same phandles for "nand" and "reg" resets, like this:

    resets = <&nand_rst>, <&nand_rst>;
    reset-names = "nand", "reg";

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Rob Herring <robh@kernel.org>
---

Changes in v3: None
Changes in v2:
  - Split into two patches

 Documentation/devicetree/bindings/mtd/denali-nand.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/denali-nand.txt b/Documentation/devicetree/bindings/mtd/denali-nand.txt
index b32aed1db46d..98916a84bbf6 100644
--- a/Documentation/devicetree/bindings/mtd/denali-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/denali-nand.txt
@@ -14,6 +14,11 @@ Required properties:
     interface clock, and the ECC circuit clock.
   - clock-names: should contain "nand", "nand_x", "ecc"
 
+Optional properties:
+  - resets: may contain phandles to the controller core reset, the register
+    reset
+  - reset-names: may contain "nand", "reg"
+
 Sub-nodes:
   Sub-nodes represent available NAND chips.
 
@@ -46,6 +51,8 @@ nand: nand@ff900000 {
 	reg-names = "nand_data", "denali_reg";
 	clocks = <&nand_clk>, <&nand_x_clk>, <&nand_ecc_clk>;
 	clock-names = "nand", "nand_x", "ecc";
+	resets = <&nand_rst>, <&nand_reg_rst>;
+	reset-names = "nand", "reg";
 	interrupts = <0 144 4>;
 
 	nand@0 {
-- 
2.17.1