From 3bd14233aa0733fbc6c3f75ec928f1a393522644 Mon Sep 17 00:00:00 2001 From: "Mark A. Greer" Date: Thu, 7 Aug 2014 17:41:41 -0700 Subject: [PATCH] NFC: trf7970a: Add VIN voltage override support The trf7970a driver uses the voltage from the power/regulator subsystem to determine what the voltage on the VIN pin is. Normally, this is the right thing to do but sometimes the board that the trf7970a is on may change the voltage. This is the case for the trf7970atb board from Texas Instruments where it boosts the VIN voltage from 3.3V to 5V (see http://www.ti.com/tool/trf7970atb). To handle this, add support for the 'vin-voltage-override' device tree property which overrides the voltage value given by the regulator subsystem. When the DT property is not present, the value from the regulator subsystem is used. The value of 'vin-voltage-override' is in uVolts. Signed-off-by: Mark A. Greer Signed-off-by: Samuel Ortiz --- drivers/nfc/trf7970a.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index 3b78b031e617..5355d0e4c045 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -1251,6 +1251,12 @@ static int trf7970a_get_autosuspend_delay(struct device_node *np) return autosuspend_delay; } +static int trf7970a_get_vin_voltage_override(struct device_node *np, + u32 *vin_uvolts) +{ + return of_property_read_u32(np, "vin-voltage-override", vin_uvolts); +} + static int trf7970a_probe(struct spi_device *spi) { struct device_node *np = spi->dev.of_node; @@ -1326,7 +1332,9 @@ static int trf7970a_probe(struct spi_device *spi) goto err_destroy_lock; } - uvolts = regulator_get_voltage(trf->regulator); + ret = trf7970a_get_vin_voltage_override(np, &uvolts); + if (ret) + uvolts = regulator_get_voltage(trf->regulator); if (uvolts > 4000000) trf->chip_status_ctrl = TRF7970A_CHIP_STATUS_VRS5_3; -- 2.20.1