Re: [PATCH v4 06/13] USB: ch341: add support for parity, frame length, stop bits

Johan Hovold
2016-04-29T13:12:48Z

On Fri, Apr 15, 2016 at 11:14:09PM +0200, Grigori Goronzy wrote:
> 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.
> v3: fix parity odd/even regression.
>
> Tested-by: Ryan Barber <rfb@skyscraper.nu>
> Signed-off-by: Grigori Goronzy <greg@chown.ath.cx>
> ---
> 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..2fbec4a 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;

This is an unrelated change.

> + 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;

CSIZE is 2-bits wide, so this shouldn't be needed. (If it were, you'd
need to clear the bits first.)

> + 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) {
> + 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)

Looks good otherwise.

Thanks,
Johan