Texas Instruments AM335 Series Design Guide

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15
SPRAC74A–February 2017–Revised March 2017
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AM335x Low Power Design Guide
This peripheral could be turned off by changing line 3 to "disabled" giving a fragment that looks like the
following.
LCD Panel Disabled Device Tree Fragment
panel {
compatible = "ti,tilcdc,panel";
status = "disabled";
pinctrl-names = "default";
pinctrl-0 = <&lcd_pins_s0>;
panel-info {
...
};
display-timings {
...
};
};
Or, the module can be disabled with a subsequent reference using an ampersand and label:
LCD Panel Device Tree Reference
&panel {
status = "disabled";
};
3.1.4.2 Defining Pinmux States in Device Tree
In order to optimize power on the I/O supply rails during low-power modes (for example, standby,
suspend), each pin can be given a "sleep" configuration in addition to its run-time configuration. Sleep pin
states should be defined to align with external pulls to avoid contention. Pinctrl states are defined in the
board device tree for each peripheral and are used to configure the PAD_CONF registers found in the
control module of the device, which allow for selection of the MUXMODE of the pin and the operation of
the internal pull resistor. Typically, a device defines its pinctrl state for normal operation:
MDIO Device Tree Default Pin Configuration
davinci_mdio_default: davinci_mdio_default {
pinctrl-single,pins = <
/* MDIO */
0x148 (PIN_INPUT_PULLUP | SLEWCTRL_FAST | MUX_MODE0) /* mdio_data.mdio_data */
0x14c (PIN_OUTPUT_PULLUP | MUX_MODE0) /* mdio_clk.mdio_clk */
>;
};
In order to define a sleep state for the same device, another pinctrl state can be defined:
MDIO Device Tree Sleep Pinmux
davinci_mdio_sleep: davinci_mdio_sleep {
pinctrl-single,pins = <
/* MDIO reset value */
0x148 (PIN_INPUT_PULLDOWN | MUX_MODE7)
0x14c (PIN_INPUT_PULLDOWN | MUX_MODE7)
>;
};
Then, the two states for the driver are defined:
MDIO Device Tree Driver Fragment
&davinci_mdio {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&davinci_mdio_default>;
pinctrl-1 = <&davinci_mdio_sleep>;
status = "okay";
};

Texas Instruments AM335 Series Specifications

General

Brand	Texas Instruments
Model	AM335 Series
Category	Computer Hardware
Language	English