[PATCH v3 06/13] USB: ch341: add support for parity, frame length, stop bits

[Grigori Goronzy]

With the new reinitialization method, configuring parity, different
frame lengths and different stop bit settings work as expected on
both CH340G and CH341A.  This has been extensively tested with a
logic analyzer.

v2: only set mark/space when parity is enabled, simplifications,
patch termios HW flags.

Tested-by: Ryan Barber <rfb@xxxxxxxxxxxxx>
Signed-off-by: Grigori Goronzy <greg@xxxxxxxxxxxx>
---
 drivers/usb/serial/ch341.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 6181616..99b4621 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -341,7 +341,6 @@ static void ch341_set_termios(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
 	struct ch341_private *priv = usb_get_serial_port_data(port);
-	unsigned baud_rate;
 	unsigned long flags;
 	unsigned char ctrl;
 	int r;
@@ -350,13 +349,39 @@ static void ch341_set_termios(struct tty_struct *tty,
 	if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
 		return;
 
-	baud_rate = tty_get_baud_rate(tty);
+	priv->baud_rate = tty_get_baud_rate(tty);
 
-	priv->baud_rate = baud_rate;
+	ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
 
-	ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
+	switch (C_CSIZE(tty)) {
+	case CS5:
+		ctrl |= CH341_LCR_CS5;
+		break;
+	case CS6:
+		ctrl |= CH341_LCR_CS6;
+		break;
+	case CS7:
+		ctrl |= CH341_LCR_CS7;
+		break;
+	default:
+		tty->termios.c_cflag |= CS8;
+	case CS8:
+		ctrl |= CH341_LCR_CS8;
+		break;
+	}
+
+	if (C_PARENB(tty)) {
+		ctrl |= CH341_LCR_ENABLE_PAR;
+		if (C_PARODD(tty))
+			ctrl |= CH341_LCR_PAR_EVEN;
+		if (C_CMSPAR(tty))
+			ctrl |= CH341_LCR_MARK_SPACE;
+	}
+
+	if (C_CSTOPB(tty))
+		ctrl |= CH341_LCR_STOP_BITS_2;
 
-	if (baud_rate) {
+	if (priv->baud_rate) {
 		spin_lock_irqsave(&priv->lock, flags);
 		priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 		spin_unlock_irqrestore(&priv->lock, flags);
@@ -373,11 +398,6 @@ static void ch341_set_termios(struct tty_struct *tty,
 
 	ch341_set_handshake(port->serial->dev, priv->line_control);
 
-	/* Unimplemented:
-	 * (cflag & CSIZE) : data bits [5, 8]
-	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
-	 * (cflag & CSTOPB) : stop bits [1, 2]
-	 */
 }
 
 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
-- 
1.9.1