On Mon, Dec 19, 2016 at 5:35 PM, Rob Herring [off-list ref] wrote:

On Thu, Dec 15, 2016 at 05:30:43PM -0500, Geoff Lansberry wrote:

quoted

From: Geoff Lansberry <redacted>

---
 Documentation/devicetree/bindings/net/nfc/trf7970a.txt |  2 ++
 drivers/nfc/trf7970a.c                                 | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 9dda879..208f045 100644
--- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
+++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt

@@ -21,6 +21,7 @@ Optional SoC Specific Properties:
 - 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.
+- vdd_io_1v8: Set to specify that the trf7970a io voltage should be set to 1.8V

Use the regulator binding and provide a fixed 1.8V supply.

quoted

 - crystal_27mhz: Set to specify that the input frequency to the trf7970a is 27.12MHz

@@ -45,6 +46,7 @@ Example (for ARM-based BeagleBone with TRF7970A on SPI1):
              irq-status-read-quirk;
              en2-rf-quirk;
              t5t-rmb-extra-byte-quirk;
+             vdd_io_1v8;
              crystal_27mhz;
              status = "okay";
      };

Rob - using the regulator binding is new to me, but I've given it a
shot and just sent you another set of patches for your inspection.
Please let me know if this is what you had in mind.

Geoff