diff options
| author | Mark A. Greer <mgreer@animalcreek.com> | 2014-09-02 15:12:24 -0700 |
|---|---|---|
| committer | Samuel Ortiz <sameo@linux.intel.com> | 2014-09-07 23:13:43 +0200 |
| commit | 4e64eff837fb682dfb2a1188fb036d75ec57375c (patch) | |
| tree | d28e1807b9f0c7a694975b7464574fbaecfc5a57 /drivers/nfc/trf7970a.c | |
| parent | a08e54549e743ea3704da939f92caf3eaa8471d3 (diff) | |
NFC: trf7970a: Add RF technology specific guard times
When turning on the RF field, the driver must wait
an RF-technology-specific amount of time (known as
the guard time) before modulating the field.
Currently, the driver waits 5 ms but that is too
short for NFCF and too long for ISO/IEC 15693.
Fix this by determining the guard time when the
RF technology is set and delaying that amount
of time when turning on the RF field.
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'drivers/nfc/trf7970a.c')
| -rw-r--r-- | drivers/nfc/trf7970a.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index ce9686c44350..22485e703849 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -134,6 +134,12 @@ #define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT 3 #define TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF 20 +/* Guard times for various RF technologies (in us) */ +#define TRF7970A_GUARD_TIME_NFCA 5000 +#define TRF7970A_GUARD_TIME_NFCB 5000 +#define TRF7970A_GUARD_TIME_NFCF 20000 +#define TRF7970A_GUARD_TIME_15693 1000 + /* Quirks */ /* Erratum: When reading IRQ Status register on trf7970a, we must issue a * read continuous command for IRQ Status and Collision Position registers. @@ -351,6 +357,7 @@ struct trf7970a { u8 iso_ctrl_tech; u8 modulator_sys_clk_ctrl; u8 special_fcn_reg1; + unsigned int guard_time; int technology; int framing; u8 tx_cmd; @@ -887,22 +894,27 @@ static int trf7970a_config_rf_tech(struct trf7970a *trf, int tech) case NFC_DIGITAL_RF_TECH_106A: trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443A_106; trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK; + trf->guard_time = TRF7970A_GUARD_TIME_NFCA; break; case NFC_DIGITAL_RF_TECH_106B: trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443B_106; trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10; + trf->guard_time = TRF7970A_GUARD_TIME_NFCB; break; case NFC_DIGITAL_RF_TECH_212F: trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_212; trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10; + trf->guard_time = TRF7970A_GUARD_TIME_NFCF; break; case NFC_DIGITAL_RF_TECH_424F: trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_424; trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10; + trf->guard_time = TRF7970A_GUARD_TIME_NFCF; break; case NFC_DIGITAL_RF_TECH_ISO15693: trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648; trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK; + trf->guard_time = TRF7970A_GUARD_TIME_15693; break; default: dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech); @@ -971,7 +983,7 @@ static int trf7970a_config_framing(struct trf7970a *trf, int framing) trf->chip_status_ctrl |= TRF7970A_CHIP_STATUS_RF_ON; - usleep_range(5000, 6000); + usleep_range(trf->guard_time, trf->guard_time + 1000); } return 0; |