* AT91's Analog to Digital Converter (ADC)
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Required properties:
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- compatible: Should be "atmel,<chip>-adc"
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<chip> can be "at91sam9260", "at91sam9g45" or "at91sam9x5"
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- reg: Should contain ADC registers location and length
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- interrupts: Should contain the IRQ line for the ADC
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- clock-names: tuple listing input clock names.
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Required elements: "adc_clk", "adc_op_clk".
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- clocks: phandles to input clocks.
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- atmel,adc-channels-used: Bitmask of the channels muxed and enabled for this
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device
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- atmel,adc-startup-time: Startup Time of the ADC in microseconds as
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defined in the datasheet
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- atmel,adc-vref: Reference voltage in millivolts for the conversions
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- atmel,adc-res: List of resolutions in bits supported by the ADC. List size
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must be two at least.
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- atmel,adc-res-names: Contains one identifier string for each resolution
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in atmel,adc-res property. "lowres" and "highres"
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identifiers are required.
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Optional properties:
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- atmel,adc-use-external-triggers: Boolean to enable the external triggers
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- atmel,adc-use-res: String corresponding to an identifier from
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atmel,adc-res-names property. If not specified, the highest
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resolution will be used.
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- atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
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- atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
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- atmel,adc-ts-wires: Number of touchscreen wires. Should be 4 or 5. If this
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value is set, then the adc driver will enable touchscreen
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support.
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NOTE: when adc touchscreen is enabled, the adc hardware trigger will be
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disabled. Since touchscreen will occupy the trigger register.
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- atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
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makes touch detection more precise.
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Optional trigger Nodes:
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- Required properties:
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* trigger-name: Name of the trigger exposed to the user
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* trigger-value: Value to put in the Trigger register
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to activate this trigger
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- Optional properties:
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* trigger-external: Is the trigger an external trigger?
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Examples:
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adc0: adc@fffb0000 {
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#address-cells = <1>;
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#size-cells = <0>;
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compatible = "atmel,at91sam9260-adc";
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reg = <0xfffb0000 0x100>;
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interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0>;
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clocks = <&adc_clk>, <&adc_op_clk>;
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clock-names = "adc_clk", "adc_op_clk";
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atmel,adc-channels-used = <0xff>;
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atmel,adc-startup-time = <40>;
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atmel,adc-use-external-triggers;
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atmel,adc-vref = <3300>;
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atmel,adc-res = <8 10>;
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atmel,adc-res-names = "lowres", "highres";
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atmel,adc-use-res = "lowres";
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trigger0 {
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trigger-name = "external-rising";
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trigger-value = <0x1>;
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trigger-external;
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};
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trigger1 {
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trigger-name = "external-falling";
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trigger-value = <0x2>;
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trigger-external;
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};
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trigger2 {
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trigger-name = "external-any";
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trigger-value = <0x3>;
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trigger-external;
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};
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trigger3 {
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trigger-name = "continuous";
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trigger-value = <0x6>;
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};
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};
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