[v2,01/10] serial: st-asc: Ignore the parity error bit if 8-bit mode is enabled

Message ID 20170127172804.23881-2-lee.jones@linaro.org
State Accepted
Commit 5ab066e5465b2984a45e205f33896b2ec1620c37
Headers show
Series
  • serial: st-asc: Allow handling of RTS line
Related show

Commit Message

Lee Jones Jan. 27, 2017, 5:27 p.m.
The datasheet states:

"If the MODE field selects an 8-bit frame then this [parity error] bit
 is undefined. Software should ignore this bit when reading 8-bit frames."

Acked-by: Peter Griffin <peter.griffin@linaro.org>

Signed-off-by: Lee Jones <lee.jones@linaro.org>

---
 drivers/tty/serial/st-asc.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

-- 
2.9.3


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Patch

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 379e5bd..69e6232 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -287,9 +287,19 @@  static void asc_transmit_chars(struct uart_port *port)
 static void asc_receive_chars(struct uart_port *port)
 {
 	struct tty_port *tport = &port->state->port;
-	unsigned long status;
+	unsigned long status, mode;
 	unsigned long c = 0;
 	char flag;
+	bool ignore_pe = false;
+
+	/*
+	 * Datasheet states: If the MODE field selects an 8-bit frame then
+	 * this [parity error] bit is undefined. Software should ignore this
+	 * bit when reading 8-bit frames.
+	 */
+	mode = asc_in(port, ASC_CTL) & ASC_CTL_MODE_MSK;
+	if (mode == ASC_CTL_MODE_8BIT || mode == ASC_CTL_MODE_8BIT_PAR)
+		ignore_pe = true;
 
 	if (port->irq_wake)
 		pm_wakeup_event(tport->tty->dev, 0);
@@ -299,8 +309,8 @@  static void asc_receive_chars(struct uart_port *port)
 		flag = TTY_NORMAL;
 		port->icount.rx++;
 
-		if ((c & (ASC_RXBUF_FE | ASC_RXBUF_PE)) ||
-			status & ASC_STA_OE) {
+		if (status & ASC_STA_OE || c & ASC_RXBUF_FE ||
+		    (c & ASC_RXBUF_PE && !ignore_pe)) {
 
 			if (c & ASC_RXBUF_FE) {
 				if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) {