The TRF7970A has configuration options for supporting hardware designs
with 1.8 Volt or 3.3 Volt IO. This commit adds a device tree option,
using a fixed regulator binding, for setting the io voltage to match
the hardware configuration. If no option is supplied it defaults to
3.3 volt configuration.
Signed-off-by: Geoff Lansberry <geoff@xxxxxxxxx>
---
.../devicetree/bindings/net/nfc/trf7970a.txt | 2 ++
drivers/nfc/trf7970a.c | 26 +++++++++++++++++++++-
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 8b01fc81..b5777d8 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-supply: Regulator specifying voltage for vdd-io
- clock-frequency: Set to specify that the input frequency to the trf7970a is 13560000Hz or 27120000Hz
Example (for ARM-based BeagleBone with TRF7970A on SPI1):
@@ -40,6 +41,7 @@ Example (for ARM-based BeagleBone with TRF7970A on SPI1):
<&gpio2 5 GPIO_ACTIVE_LOW>;
vin-supply = <&ldo3_reg>;
vin-voltage-override = <5000000>;
+ vdd-io-supply = <&ldo2_reg>;
autosuspend-delay = <30000>;
irq-status-read-quirk;
en2-rf-quirk;
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index b1cd4ef..e3c72c6 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -444,6 +444,7 @@ struct trf7970a {
u8 iso_ctrl_tech;
u8 modulator_sys_clk_ctrl;
u8 special_fcn_reg1;
+ u8 io_ctrl;
unsigned int guard_time;
int technology;
int framing;
@@ -1051,6 +1052,11 @@ static int trf7970a_init(struct trf7970a *trf)
if (ret)
goto err_out;
+ ret = trf7970a_write(trf, TRF7970A_REG_IO_CTRL,
+ trf->io_ctrl | TRF7970A_REG_IO_CTRL_VRS(0x1));
+ if (ret)
+ goto err_out;
+
ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL, 0);
if (ret)
goto err_out;
@@ -1767,7 +1773,7 @@ static int _trf7970a_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
goto out_err;
ret = trf7970a_write(trf, TRF7970A_REG_IO_CTRL,
- TRF7970A_REG_IO_CTRL_VRS(0x1));
+ trf->io_ctrl | TRF7970A_REG_IO_CTRL_VRS(0x1));
if (ret)
goto out_err;
@@ -2105,6 +2111,24 @@ static int trf7970a_probe(struct spi_device *spi)
if (uvolts > 4000000)
trf->chip_status_ctrl = TRF7970A_CHIP_STATUS_VRS5_3;
+ trf->regulator = devm_regulator_get(&spi->dev, "vdd-io");
+ if (IS_ERR(trf->regulator)) {
+ ret = PTR_ERR(trf->regulator);
+ dev_err(trf->dev, "Can't get VDD_IO regulator: %d\n", ret);
+ goto err_destroy_lock;
+ }
+
+ ret = regulator_enable(trf->regulator);
+ if (ret) {
+ dev_err(trf->dev, "Can't enable VDD_IO: %d\n", ret);
+ goto err_destroy_lock;
+ }
+
+ if (regulator_get_voltage(trf->regulator) == 1800000) {
+ trf->io_ctrl = TRF7970A_REG_IO_CTRL_IO_LOW;
+ dev_dbg(trf->dev, "trf7970a config vdd_io to 1.8V\n");
+ }
+
trf->ddev = nfc_digital_allocate_device(&trf7970a_nfc_ops,
TRF7970A_SUPPORTED_PROTOCOLS,
NFC_DIGITAL_DRV_CAPS_IN_CRC |
--
2.7.4
