NFC: trf7970a: Don't turn off RF if its already off

Don't try to turn off of RF transmitter is its
already off.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index e4671e54424a..429146b7e6d8 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -859,6 +859,10 @@ err_out:
 
 static void trf7970a_switch_rf_off(struct trf7970a *trf)
 {
+        if ((trf->state == TRF7970A_ST_PWR_OFF) ||
+                        (trf->state == TRF7970A_ST_RF_OFF))
+                return;
+
         dev_dbg(trf->dev, "Switching rf off\n");
 
         trf->chip_status_ctrl &= ~TRF7970A_CHIP_STATUS_RF_ON;