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Commit 49d22c70 authored by Geoff Lansberry's avatar Geoff Lansberry Committed by Samuel Ortiz
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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: default avatarRob Herring <robh@kernel.org>
Acked-by: default avatarMark Greer <mgreer@animalcreek.com>
Signed-off-by: default avatarGeoff Lansberry <geoff@kuvee.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 837eb4d2

Documentation/devicetree/bindings/net/nfc/trf7970a.txt

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/nfc/trf7970a.c

+25 −1
Original line number Diff line number Diff line
@@ -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 |