Messages in this thread | | | Date | Fri, 29 Apr 2016 15:23:39 +0200 | From | Johan Hovold <> | Subject | Re: [PATCH v4 08/13] USB: ch341: add support for RTS/CTS flow control |
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On Fri, Apr 15, 2016 at 11:14:11PM +0200, Grigori Goronzy wrote:
No commit message?
> v2: use correct flag variable. > v3: fix compilation > > Signed-off-by: Grigori Goronzy <greg@chown.ath.cx> > --- > drivers/usb/serial/ch341.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c > index e475677..7ca21a1 100644 > --- a/drivers/usb/serial/ch341.c > +++ b/drivers/usb/serial/ch341.c > @@ -68,6 +68,7 @@ > #define CH341_REQ_READ_REG 0x95 > #define CH341_REG_BREAK1 0x05 > #define CH341_REG_LCR 0x18 > +#define CH341_REG_RTSCTS 0x27 > #define CH341_NBREAK_BITS_REG1 0x01 > > #define CH341_LCR_ENABLE_RX 0x80 > @@ -399,6 +400,16 @@ static void ch341_set_termios(struct tty_struct *tty, > > ch341_set_handshake(port->serial->dev, priv->line_control); > > + if (C_CRTSCTS(tty)) { > + r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, > + CH341_REG_RTSCTS | ((uint16_t)CH341_REG_RTSCTS << 8),
(u16)
> + 0x0101);
You should also coordinate this with B0 handling (e.g. disable hard-flow control and make sure that RTS is deasserted on ->B0 transitions).
> + if (r < 0) { > + dev_err(&port->dev, "%s - USB control write error (%d)\n", > + __func__, r);
Please spell out what went wrong
"failed to enable flow control: %d\n"
> + tty->termios.c_cflag &= ~CRTSCTS; > + } > + }
What about disabling flow control?
> } > > static void ch341_break_ctl(struct tty_struct *tty, int break_state)
Thanks, Johan
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