linux/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
Mark A. Greer 6afed0eb8c NFC: trf7970a: Document the 'en2-rf-quirk' DT property
Current versions of the trf7970a have an erratum where
the EN2 pin must be kept low.  If it isn't kept low,
it will generate an RF field even when in passive
target mode.  To work around this issue, create the
'en2-rf-quirk' device tree property to indicate that
the trf7970a that the driver is using has this erratum.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-01 00:06:56 +02:00

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* Texas Instruments TRF7970A RFID/NFC/15693 Transceiver
Required properties:
- compatible: Should be "ti,trf7970a".
- spi-max-frequency: Maximum SPI frequency (<= 2000000).
- interrupt-parent: phandle of parent interrupt handler.
- interrupts: A single interrupt specifier.
- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
TRF7970A.
- vin-supply: Regulator for supply voltage to VIN pin
Optional SoC Specific Properties:
- pinctrl-names: Contains only one value - "default".
- pintctrl-0: Specifies the pin control groups used for this controller.
- autosuspend-delay: Specify autosuspend delay in milliseconds.
- vin-voltage-override: Specify voltage of VIN pin in microvolts.
- irq-status-read-quirk: Specify that the trf7970a being used has the
"IRQ Status Read" erratum.
- en2-rf-quirk: Specify that the trf7970a being used has the "EN2 RF"
erratum.
Example (for ARM-based BeagleBone with TRF7970A on SPI1):
&spi1 {
status = "okay";
nfc@0 {
compatible = "ti,trf7970a";
reg = <0>;
pinctrl-names = "default";
pinctrl-0 = <&trf7970a_default>;
spi-max-frequency = <2000000>;
interrupt-parent = <&gpio2>;
interrupts = <14 0>;
ti,enable-gpios = <&gpio2 2 GPIO_ACTIVE_LOW>,
<&gpio2 5 GPIO_ACTIVE_LOW>;
vin-supply = <&ldo3_reg>;
vin-voltage-override = <5000000>;
autosuspend-delay = <30000>;
irq-status-read-quirk;
en2-rf-quirk;
status = "okay";
};
};