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

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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 - t5t-rmb-extra-byte-quirk: Specify that the trf7970a has the erratum
where an extra byte is returned by Read Multiple Block commands issued where an extra byte is returned by Read Multiple Block commands issued
to Type 5 tags. 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 - 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): 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>; <&gpio2 5 GPIO_ACTIVE_LOW>;
vin-supply = <&ldo3_reg>; vin-supply = <&ldo3_reg>;
vin-voltage-override = <5000000>; vin-voltage-override = <5000000>;
vdd-io-supply = <&ldo2_reg>;
autosuspend-delay = <30000>; autosuspend-delay = <30000>;
irq-status-read-quirk; irq-status-read-quirk;
en2-rf-quirk; en2-rf-quirk;

26
drivers/nfc/trf7970a.c
View file

@ -444,6 +444,7 @@ struct trf7970a {
u8 iso_ctrl_tech; u8 iso_ctrl_tech;
u8 modulator_sys_clk_ctrl; u8 modulator_sys_clk_ctrl;
u8 special_fcn_reg1; u8 special_fcn_reg1;
u8 io_ctrl;
unsigned int guard_time; unsigned int guard_time;
int technology; int technology;
int framing; int framing;
@ -1051,6 +1052,11 @@ static int trf7970a_init(struct trf7970a *trf)
if (ret) if (ret)
goto err_out; 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); ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL, 0);
if (ret) if (ret)
goto err_out; goto err_out;
@ -1767,7 +1773,7 @@ static int _trf7970a_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
goto out_err; goto out_err;
ret = trf7970a_write(trf, TRF7970A_REG_IO_CTRL, 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) if (ret)
goto out_err; goto out_err;
@ -2107,6 +2113,24 @@ static int trf7970a_probe(struct spi_device *spi)
if (uvolts > 4000000) if (uvolts > 4000000)
trf->chip_status_ctrl = TRF7970A_CHIP_STATUS_VRS5_3; 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, trf->ddev = nfc_digital_allocate_device(&trf7970a_nfc_ops,
TRF7970A_SUPPORTED_PROTOCOLS, TRF7970A_SUPPORTED_PROTOCOLS,
NFC_DIGITAL_DRV_CAPS_IN_CRC | NFC_DIGITAL_DRV_CAPS_IN_CRC |