USB: serial: ch341: add support for parity, frame length, stop bits

With the new reinitialization method, configuring parity, different
frame lengths and different stop bit settings should work as expected
on both CH340G and CH341A. Tested on a loopback-connected CH340G
with a logic analyzer in a number of different configurations.

Based on a patch by Grigori Goronzy

Signed-off-by: Aidan Thornton <makosoft@gmail.com>
Reviewed-by: Grigori Goronzy <greg@chown.ath.cx>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 096bc070635a5fa90ccc85653ec6b197715e0429..af9edbedfd28b50e531bac199fb55682f244cfc0 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -356,8 +356,33 @@ static void ch341_set_termios(struct tty_struct *tty,
        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;
+       case CS8:
+               ctrl |= CH341_LCR_CS8;
+               break;
+       }
+
+       if (C_PARENB(tty)) {
+               ctrl |= CH341_LCR_ENABLE_PAR;
+               if (C_PARODD(tty) == 0)
+                       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) {
                spin_lock_irqsave(&priv->lock, flags);
@@ -376,11 +401,6 @@ 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)