linux/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
Mark A. Greer ab714817d7 NFC: trf7970a: Handle extra byte in response to Type 5 RMB commands
The current versions of the trf7970a has an erratum where it returns
an extra byte in the response to 'Read Multiple Block' (RMB) commands.
This command is issued to Type 5 tags (i.e., ISO/IEC 15693 tags) by
the neard daemon.

To handle this, define a new Device Tree property,
't5t-rmb-extra-byte-quirk', which indicates that the associated
trf7970a device has this erratum.  The trf7970a device driver
will then ensure that the response length to RMB commands is
reduced by one byte (for devices with the erratum).

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2015-06-08 23:16:31 +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.
- t5t-rmb-extra-byte-quirk: Specify that the trf7970a has the erratum
where an extra byte is returned by Read Multiple Block commands issued
to Type 5 tags.
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;
t5t-rmb-extra-byte-quirk;
status = "okay";
};
};