diff options
Diffstat (limited to 'drivers/nfc')
| -rw-r--r-- | drivers/nfc/trf7970a.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index 3cc7001d7d2f..870867d645e0 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -36,7 +36,13 @@ * The trf7970a is very timing sensitive and the VIN, EN2, and EN * pins must asserted in that order and with specific delays in between. * The delays used in the driver were provided by TI and have been - * confirmed to work with this driver. + * confirmed to work with this driver. There is a bug with the current + * version of the trf7970a that requires that EN2 remain low no matter + * what. If it goes high, it will generate an RF field even when in + * passive target mode. TI has indicated that the chip will work okay + * when EN2 is left low. The 'en2-rf-quirk' device tree property + * indicates that trf7970a currently being used has the erratum and + * that EN2 must be kept low. * * Timeouts are implemented using the delayed workqueue kernel facility. * Timeouts are required so things don't hang when there is no response @@ -133,6 +139,7 @@ * read continuous command for IRQ Status and Collision Position registers. */ #define TRF7970A_QUIRK_IRQ_STATUS_READ BIT(0) +#define TRF7970A_QUIRK_EN2_MUST_STAY_LOW BIT(1) /* Direct commands */ #define TRF7970A_CMD_IDLE 0x00 @@ -1309,6 +1316,9 @@ static int trf7970a_probe(struct spi_device *spi) return ret; } + if (of_property_read_bool(np, "en2-rf-quirk")) + trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW; + ret = devm_request_threaded_irq(trf->dev, spi->irq, NULL, trf7970a_irq, IRQF_TRIGGER_RISING | IRQF_ONESHOT, "trf7970a", trf); @@ -1455,8 +1465,11 @@ static int trf7970a_pm_runtime_resume(struct device *dev) usleep_range(5000, 6000); - gpio_set_value(trf->en2_gpio, 1); - usleep_range(1000, 2000); + if (!(trf->quirks & TRF7970A_QUIRK_EN2_MUST_STAY_LOW)) { + gpio_set_value(trf->en2_gpio, 1); + usleep_range(1000, 2000); + } + gpio_set_value(trf->en_gpio, 1); usleep_range(20000, 21000); |