[PATCH 6/7] pinctrl: tegra: Add DT binding for io pads control

[Laxman Dewangan <ldewangan@nvidia.com>]

NVIDIA Tegra210 supports the IO pads which can operate at 1.8V
or 3.3V I/O voltage levels. Also IO pads can be configured for
power down state if it is not in used. SW needs to configure the
voltage level of IO pads based on IO rail voltage and its power
state based on platform usage.

Add DT binding document for detailing the DT properties for
configuring IO pads voltage levels and its power state.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 .../bindings/pinctrl/nvidia,tegra210-io-pad.txt    | 102 +++++++++++++++++++++
 .../dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h  |  24 +++++
 2 files changed, 126 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-io-pad.txt
 create mode 100644 include/dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h

diff --git a/Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-io-pad.txt b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-io-pad.txt
new file mode 100644
index 0000000..97cdd4f
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-io-pad.txt
@@ -0,0 +1,102 @@
+NVIDIA Tegra210 PMC IO pad controller
+
+NVIDIA Tegra210 supports IO pads which can operate at 1.8V or 3.3V I/O
+power rail voltages. SW needs to configure the voltage level of IO pads
+based on platform specific power tree.
+
+The voltage configurations of IO pads should be done in boot if it is not
+going to change other wise dynamically based on IO rail voltage on that
+IO pads.
+
+The node for the Tegra210 io-pad driver must be sub node of pmc@0,7000e400.
+
+Required properties:
+- compatible: "nvidia,tegra210-io-pad"
+
+Please refer to <pinctrl-bindings.txt> in this directory for details of the
+common pinctrl bindings used by client devices, including the meaning of the
+phrase "pin configuration node".
+
+Tegra's pin configuration nodes act as a container for an arbitrary number of
+subnodes. Each of these subnodes represents some desired configuration for an
+IO pads, or a list of IO pads. This configuration can include the voltage and
+power enable/disable control
+
+The name of each subnode is not important; all subnodes should be enumerated
+and processed purely based on their content. Each subnode only affects those
+parameters that are explicitly listed. Unspecified is represented as an absent
+property,
+
+See the TRM to determine which properties and values apply to each IO pads.
+Macro values for property values are defined in
+<dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h>
+
+The voltage supported on the pads are 1.8V and 3.3V. The enums are defined as:
+	For 1.8V, use TEGRA210_IO_RAIL_1800000UV
+	For 3.3V, use TEGRA210_IO_RAIL_3300000UV
+
+Required subnode-properties:
+==========================
+- pins : An array of strings. Each string contains the name of an IO pads. Valid
+	 values for these names are listed below.
+
+Optional subnode-properties:
+==========================
+-nvidia,io-rail-voltage:	Integer. The voltage level of IO pads. The
+				valid values are 1.8V and 3.3V. Macros are
+				defined for these voltage levels in
+				<dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h>
+					Use TEGRA210_IO_RAIL_1800000UV for 1.8V
+					Use TEGRA210_IO_RAIL_3300000UV for 3.3V
+
+-nvidia,io-pad-deep-power-down: Integer, representing the deep power down state
+				of the IO pads. If this is enable then IO pads
+				will be in power down state and interface is not
+				enabled for any transaction. This is power
+				saving mode of the IO pads. The macros are
+				defined for enable/disable in
+				<dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h>
+				  TEGRA210_IO_PAD_DEEP_POWER_DOWN_DISABLE for
+					disable.
+				  TEGRA210_IO_PAD_DEEP_POWER_DOWN_ENABLE for
+					enable.
+Valid values for pin are:
+	audio, audio-hv, cam, csia, csib, csic, csid, csie, csif,
+	dbg, debug-nonao, dmic, dp, dsi, dsib, dsic, dsid, emmc, emmc2,
+	gpio, hdmi, hsic, lvds, mipi-bias, pex-bias, pex-clk1, pex-clk2,
+	pex-ctrl, sdmmc1, sdmmc3, spi, spi-hv, uart, usb-bias, usb0,
+	usb1, usb2, usb3.
+
+All IO pads do not support the 1.8V/3.3V configurations. Valid values for
+nvidia,io-rail-voltage are:
+	audio-hv, dmic, gpio, sdmmc1, sdmmc3, spi-hv.
+
+All above IO pads supports the deep power down state.
+
+Example:
+	#include <dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h>
+	pmc@0,7000e400 {
+		pmc-pad-control {
+			compatible = "nvidia,tegra210-io-pad";
+			pinctrl-names = "default";
+			pinctrl-0 = <&tegra_io_pad_volt_default>;
+			tegra_io_pad_volt_default: common {
+				audio {
+					pins = "audio";
+					nvidia,io-pad-deep-power-down = <TEGRA210_IO_PAD_DEEP_POWER_DOWN_DISABLE>;
+				};
+				audio-hv {
+					pins = "audio-hv";
+					nvidia,io-rail-voltage = <TEGRA210_IO_RAIL_1800000UV>;
+				};
+				gpio {
+					pins = "gpio";
+					nvidia,io-rail-voltage = <TEGRA210_IO_RAIL_1800000UV>;
+				};
+				rest {
+					pins = "dmic", "sdmmc1", "sdmmc3";
+					nvidia,io-rail-voltage = <TEGRA210_IO_RAIL_1800000UV>;
+				};
+			};
+		};
+	};
diff --git a/include/dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h b/include/dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h
new file mode 100644
index 0000000..e32166b
--- /dev/null
+++ b/include/dt-bindings/pinctrl/pinctrl-tegra210-io-pad.h
@@ -0,0 +1,24 @@
+/*
+ * This header provides constants for Tegra210 IO pads pinctrl bindings.
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#ifndef _DT_BINDINGS_PINCTRL_TEGRA210_IO_PAD_H
+#define _DT_BINDINGS_PINCTRL_TEGRA210_IO_PAD_H
+
+/* Voltage levels of Tegra210 IO rails. */
+#define TEGRA210_IO_RAIL_1800000UV		0
+#define TEGRA210_IO_RAIL_3300000UV		1
+
+/* Deep power down state enable/disable for Tegra210 IO pads */
+#define TEGRA210_IO_PAD_DEEP_POWER_DOWN_DISABLE	0
+#define TEGRA210_IO_PAD_DEEP_POWER_DOWN_ENABLE	1
+
+#endif
-- 
2.1.4