Input: introduce palmas-pwrbutton

Many palmas family of PMICs have support for interrupt based power button.
This allows the device to notify the processor of external push button
events over the shared palmas interrupt. However, this event is generated
only during a "press" operation. Software is supposed to poll(sigh!) for
detecting a release event.

The PMIC also supports ability to power off independent of the software
decisions when the button is pressed for a long duration if the PMIC is
appropriately configured on the platform.

Even though the function is similar to twl4030_pwrbutton, it is
substantially different in operation to belong to a new driver of it's own.

Based on original work done by Girish S Ghongdemath <girishsg@ti.com>

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/ti,palmas-pwrbutton.txt b/Documentation/devicetree/bindings/input/ti,palmas-pwrbutton.txt
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+Texas Instruments Palmas family power button module
+
+This module is part of the Palmas family of PMICs. For more details
+about the whole chip see:
+Documentation/devicetree/bindings/mfd/palmas.txt.
+
+This module provides a simple power button event via an Interrupt.
+
+Required properties:
+- compatible: should be one of the following
+   - "ti,palmas-pwrbutton": For Palmas compatible power on button
+- interrupt-parent: Parent interrupt device, must be handle of palmas node.
+- interrupts: Interrupt number of power button submodule on device.
+
+Optional Properties:
+
+- ti,palmas-long-press-seconds: Duration in seconds which the power
+  button should be kept pressed for Palmas to power off automatically.
+  NOTE: This depends on OTP support and POWERHOLD signal configuration
+  on platform. Valid values are 6, 8, 10 and 12.
+- ti,palmas-pwron-debounce-milli-seconds: Duration in milliseconds
+  which the power button should be kept pressed for Palmas to register
+  a press for debouncing purposes. NOTE: This depends on specific
+  Palmas variation capability. Valid values are 15, 100, 500 and 1000.
+
+Example:
+
+&palmas {
+	palmas_pwr_button: pwrbutton {
+		compatible = "ti,palmas-pwrbutton";
+		interrupt-parent = <&tps659038>;
+		interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
+		ti,palmas-long-press-seconds = <12>;
+		ti,palmas-pwron-debounce-milli-seconds = <15>;
+	};
+};