NFC: trf7970a: Handle low-watermark IRQ when transmitting
Commit 4dd836e46c3d ("NFC: trf7970a: Reset FIFO when
'End of TX' Interrupt Occurs") fixes the issue that
it was meant to fix but adds the unfortunate side
effect of causing the driver to report an error
when the TX low-watermark level is passed during
transmits. This can be fixed by checking whether
the IRQ status indicates that the low-watermark
has been passed when transmitting. If it has been
passed and the FIFO is empty, then its safe to reset
the FIFO. Otherwise, silently continue since another
TX interrupt will be generated and the FIFO will be
reset then.
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index e9e961f..6d2b06d 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -667,7 +667,7 @@
{
struct trf7970a *trf = dev_id;
int ret;
- u8 status;
+ u8 status, fifo_bytes;
mutex_lock(&trf->lock);
@@ -720,6 +720,16 @@
trf->ignore_timeout =
!cancel_delayed_work(&trf->timeout_work);
trf7970a_drain_fifo(trf, status);
+ } else if (status & TRF7970A_IRQ_STATUS_FIFO) {
+ ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS,
+ &fifo_bytes);
+
+ fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;
+
+ if (ret)
+ trf7970a_send_err_upstream(trf, ret);
+ else if (!fifo_bytes)
+ trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
} else if (status == TRF7970A_IRQ_STATUS_TX) {
trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
} else {