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NFC: trf7970a: Add device tree option of 1.8 Volt IO voltage 

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.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Geoff Lansberry <geoff@kuvee.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Geoff Lansberry 2016-12-21 23:18:33 -05:00 committed by Samuel Ortiz
parent 837eb4d21e
commit 49d22c70aa
2 changed files with 27 additions and 1 deletions
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2
Documentation/devicetree/bindings/net/nfc/trf7970a.txt
View File

@ -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;

26
drivers/nfc/trf7970a.c
View File

@ -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;
@ -2107,6 +2113,24 @@ 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 |