diff options
| author | Mark A. Greer <mgreer@animalcreek.com> | 2014-09-03 00:12:42 +0200 |
|---|---|---|
| committer | Samuel Ortiz <sameo@linux.intel.com> | 2014-09-07 23:13:45 +0200 |
| commit | 851ee3cbf850501104e76683e439a4061f378a96 (patch) | |
| tree | 698b971d53ad0a2876e1eb3b1e85bd53f42eafdc /drivers/nfc | |
| parent | NFC: trf7970a: trf7970a_init() turns off the RF transmitter (diff) | |
| download | linux-851ee3cbf850501104e76683e439a4061f378a96.tar.xz linux-851ee3cbf850501104e76683e439a4061f378a96.zip | |
NFC: trf7970a: Don't turn on RF if there is already an RF field
Currently, the trf7970a driver blindly turns on its
RF field when configuring its framing. This isn't
a good idea if there is already a device generating
an RF field. Instead, check if there is already an
RF field present before turning on this device's RF
field and, if there is, return EBUSY.
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'drivers/nfc')
| -rw-r--r-- | drivers/nfc/trf7970a.c | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index ab6e276be6a6..0f09278ec37a 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -164,8 +164,8 @@ #define TRF7970A_CMD_CLOSE_SLOT 0x15 #define TRF7970A_CMD_BLOCK_RX 0x16 #define TRF7970A_CMD_ENABLE_RX 0x17 -#define TRF7970A_CMD_TEST_EXT_RF 0x18 -#define TRF7970A_CMD_TEST_INT_RF 0x19 +#define TRF7970A_CMD_TEST_INT_RF 0x18 +#define TRF7970A_CMD_TEST_EXT_RF 0x19 #define TRF7970A_CMD_RX_GAIN_ADJUST 0x1a /* Bits determining whether its a direct command or register R/W, @@ -280,6 +280,10 @@ TRF7970A_IRQ_STATUS_PARITY_ERROR | \ TRF7970A_IRQ_STATUS_CRC_ERROR) +#define TRF7970A_RSSI_OSC_STATUS_RSSI_MASK (BIT(2) | BIT(1) | BIT(0)) +#define TRF7970A_RSSI_OSC_STATUS_RSSI_X_MASK (BIT(5) | BIT(4) | BIT(3)) +#define TRF7970A_RSSI_OSC_STATUS_RSSI_OSC_OK BIT(6) + #define TRF7970A_SPECIAL_FCN_REG1_COL_7_6 BIT(0) #define TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL BIT(1) #define TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX BIT(2) @@ -989,9 +993,43 @@ static int trf7970a_in_config_rf_tech(struct trf7970a *trf, int tech) return ret; } +static int trf7970a_is_rf_field(struct trf7970a *trf, bool *is_rf_field) +{ + int ret; + u8 rssi; + + ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL, + trf->chip_status_ctrl | TRF7970A_CHIP_STATUS_REC_ON); + if (ret) + return ret; + + ret = trf7970a_cmd(trf, TRF7970A_CMD_TEST_EXT_RF); + if (ret) + return ret; + + usleep_range(50, 60); + + ret = trf7970a_read(trf, TRF7970A_RSSI_OSC_STATUS, &rssi); + if (ret) + return ret; + + ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL, + trf->chip_status_ctrl); + if (ret) + return ret; + + if (rssi & TRF7970A_RSSI_OSC_STATUS_RSSI_MASK) + *is_rf_field = true; + else + *is_rf_field = false; + + return 0; +} + static int trf7970a_in_config_framing(struct trf7970a *trf, int framing) { u8 iso_ctrl = trf->iso_ctrl_tech; + bool is_rf_field = false; int ret; dev_dbg(trf->dev, "framing: %d\n", framing); @@ -1024,6 +1062,15 @@ static int trf7970a_in_config_framing(struct trf7970a *trf, int framing) trf->framing = framing; + if (!(trf->chip_status_ctrl & TRF7970A_CHIP_STATUS_RF_ON)) { + ret = trf7970a_is_rf_field(trf, &is_rf_field); + if (ret) + return ret; + + if (is_rf_field) + return -EBUSY; + } + if (iso_ctrl != trf->iso_ctrl) { ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl); if (ret) |