From aff0564aa7b2118a1d76dc0118dfdbf4beaf4b8c Mon Sep 17 00:00:00 2001 From: "Mark A. Greer" Date: Tue, 2 Sep 2014 15:12:26 -0700 Subject: NFC: trf7970a: Clear possible spurious interrupt before transmitting The trf7970a occasionally generates spurious interrupts which can confuse the driver. To help alleviate this, clear any interrupts by reading the 'IRQ Status Register' before starting a new transaction. Signed-off-by: Mark A. Greer Signed-off-by: Samuel Ortiz --- drivers/nfc/trf7970a.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c index b67946c18b40..e7f22a44dc52 100644 --- a/drivers/nfc/trf7970a.c +++ b/drivers/nfc/trf7970a.c @@ -1120,6 +1120,7 @@ static int trf7970a_in_send_cmd(struct nfc_digital_dev *ddev, char *prefix; unsigned int len; int ret; + u8 status; dev_dbg(trf->dev, "New request - state: %d, timeout: %d ms, len: %d\n", trf->state, timeout, skb->len); @@ -1195,6 +1196,11 @@ static int trf7970a_in_send_cmd(struct nfc_digital_dev *ddev, len = min_t(int, skb->len, TRF7970A_FIFO_SIZE); + /* Clear possible spurious interrupt */ + ret = trf7970a_read_irqstatus(trf, &status); + if (ret) + goto out_err; + ret = trf7970a_transmit(trf, skb, len); if (ret) { kfree_skb(trf->rx_skb); -- cgit v1.2.3