[PATCH v3 2/3] NFC: trf7970a: Add device tree option of 1.8 Volt IO voltage
From: Geoff Lansberry <hidden>
Date: 2016-12-22 04:19:32
Also in:
linux-wireless, lkml, netdev
Subsystem:
networking drivers, nfc subsystem, open firmware and flattened device tree bindings, the rest, ti trf7970a nfc driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Heidelberg, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds, Mark Greer
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 <redacted> --- .../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