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authorGeoff Lansberry <geoff@kuvee.com>2016-12-22 07:18:33 +0300
committerSamuel Ortiz <sameo@linux.intel.com>2017-04-05 12:04:03 +0300
commit49d22c70aaf07cd7e33346b247f5df3ddb072ee0 (patch)
treebcdc825cff97cf30ffed42b619274e241d5e25f8 /drivers/nfc
parent837eb4d21ecde7bde7a1fe523594fdf509055f3f (diff)
downloadlinux-49d22c70aaf07cd7e33346b247f5df3ddb072ee0.tar.xz
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>
Diffstat (limited to 'drivers/nfc')
-rw-r--r--drivers/nfc/trf7970a.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index ecb786283ffa..2d1c8ca6e679 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;
@@ -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 |