[PATCH v2 1/2] Documentation: dt: reset: Add syscon reset binding

From: Andrew F. Davis
Date: Thu Mar 10 2016 - 16:46:42 EST


Add syscon reset controller binding. This will hook to the reset
framework and use syscon/regmap to set reset bits. This allows
reset control of individual SoC subsytems and devices with
memory-mapped reset registers in a common register memory
space.

Signed-off-by: Andrew F. Davis <afd@xxxxxx>
[s-anna@xxxxxx: revise the binding format]
Signed-off-by: Suman Anna <s-anna@xxxxxx>
---
.../devicetree/bindings/reset/syscon-reset.txt | 114 +++++++++++++++++++++
include/dt-bindings/reset/syscon.h | 23 +++++
2 files changed, 137 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reset/syscon-reset.txt
create mode 100644 include/dt-bindings/reset/syscon.h

diff --git a/Documentation/devicetree/bindings/reset/syscon-reset.txt b/Documentation/devicetree/bindings/reset/syscon-reset.txt
new file mode 100644
index 0000000..02bc9e3
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/syscon-reset.txt
@@ -0,0 +1,114 @@
+SysCon Reset Controller
+=======================
+
+Almost all SoCs have hardware modules that require reset control in addition
+to clock and power control for their functionality. The reset control is
+typically provided by means of memory-mapped I/O registers. These registers are
+sometimes a part of a larger register space region implementing various
+functionalities. This register range is best represented as a syscon node to
+allow multiple entities to access their relevant registers in the common
+register space.
+
+A SysCon Reset Controller node defines a device that uses a syscon node
+and provides reset management functionality for various hardware modules
+present on the SoC.
+
+SysCon Reset Controller Node
+============================
+Each of the reset provider/controller nodes should be a child of a syscon
+node and have the following properties.
+
+Required properties:
+--------------------
+ - compatible : Should be "syscon-reset"
+ - #reset-cells : Should be 1. Please see the reset consumer node below
+ for usage details
+ - #address-cells : Should be 1
+ - #size-cells : Should be 0
+
+SysCon Reset Child Node
+============================
+Each reset provider/controller node should have a child node for each reset
+it would like to expose to consumers.
+
+Required properties:
+--------------------
+ - reg : This reset's number, this will be used to reference
+ this reset by consumers of this reset
+ - reset-control : Contains the reset control register information
+ Should contain 3 cells defined as:
+ Cell #1 : register offset of the reset
+ control/status register from the syscon
+ register base
+ Cell #2 : bit shift value for the reset in the
+ respective reset control/status register
+ Cell #3 : polarity of the reset bit. Should be 1 or
+ RESET_ASSERT_SET for resets that are
+ asserted when the bit is set, 0 or
+ RESET_ASSERT_CLEAR for resets that are
+ asserted when the bit is cleared
+
+Optional properties:
+--------------------
+ - reset-status : Contains the reset status register information. The
+ contents of this property are the equivalent to
+ reset-control as defined above. If this property is
+ not present and the toggle flag is not set, the
+ reset register is assumed to be the same as the
+ control register
+ - toggle : Mark this reset as a toggle only reset, this is used
+ when no status register is available.
+
+SysCon Reset Consumer Nodes
+===========================
+Each of the reset consumer nodes should have the following properties,
+in addition to their own properties.
+
+Required properties:
+--------------------
+ - resets : A phandle and a reset specifier, the reset specifier should
+ be a numerical address matching the desired reset as set
+ by the reg property defined above.
+
+Please also refer to Documentation/devicetree/bindings/reset/reset.txt for
+common reset controller usage by consumers.
+
+Example:
+--------
+The following example demonstrates a syscon node, the reset controller node
+using the syscon node, and a consumer (a DSP device) on the TI Keystone 2
+Hawking SoC.
+
+/ {
+ soc {
+ psc: power-sleep-controller@02350000 {
+ compatible = "syscon", "simple-mfd";
+ reg = <0x02350000 0x1000>;
+
+ pscrst: psc-reset {
+ compatible = "syscon-reset";
+ #reset-cells = <1>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ dsp@0 {
+ reg = <0>;
+ reset-control = <0xa3c 8 RESET_ASSERT_CLEAR>;
+ reset-status = <0x83c 8 RESET_ASSERT_CLEAR>;
+ };
+
+ imu@1 {
+ reg = <1>;
+ reset-control = <0xa40 5 RESET_ASSERT_SET>;
+ toggle;
+ };
+ };
+ };
+
+ dsp0: dsp0 {
+ ...
+ resets = <&pscrst 0>;
+ ...
+ };
+ };
+};
diff --git a/include/dt-bindings/reset/syscon.h b/include/dt-bindings/reset/syscon.h
new file mode 100644
index 0000000..9927779
--- /dev/null
+++ b/include/dt-bindings/reset/syscon.h
@@ -0,0 +1,23 @@
+/*
+ * Syscon Reset definitions
+ *
+ * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __DT_BINDINGS_RESET_SYSCON_H__
+#define __DT_BINDINGS_RESET_SYSCON_H__
+
+#define RESET_ASSERT_CLEAR 0x0
+#define RESET_ASSERT_SET 0x1
+
+#endif
--
2.7.2