Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754139AbcDCQEg (ORCPT ); Sun, 3 Apr 2016 12:04:36 -0400 Received: from palmtree.beeroclock.net ([178.79.160.154]:40306 "EHLO palmtree.beeroclock.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753969AbcDCQEf (ORCPT ); Sun, 3 Apr 2016 12:04:35 -0400 Content-Type: multipart/mixed; boundary="===============5408899418638152248==" MIME-Version: 1.0 Subject: Re: [PATCH v2 14/14] USB: ch341: implement tx_empty callback From: Karl Palsson To: "Grigori Goronzy" Cc: "Greg Kroah-Hartman" , "Johan Hovold" , Linux Kernel Mailing List , Linux USB Mailing List In-Reply-To: <1459616843-23829-15-git-send-email-greg@chown.ath.cx> References: <1459616843-23829-15-git-send-email-greg@chown.ath.cx> Message-Id: <20160403160238-28920-57566-mailpile@palmtree-beeroclock-net> Date: Sun, 03 Apr 2016 16:03:10 -0000 OpenPGP: id=9F020B9C40DA5E6F2CAF63B319A8B50FD4D5CAF6; preference=signencrypt Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2854 Lines: 85 --===============5408899418638152248== Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Grigori Goronzy wrote: > The status bit was found with USB captures of the Windows > driver and some luck. Tested on CH340G and CH341A. By my reversing, bit 0x4, is "multiple status changes since last interrupt" > > Signed-off-by: Grigori Goronzy > --- > drivers/usb/serial/ch341.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/serial/ch341.c > b/drivers/usb/serial/ch341.c index 6981e2ad..adf7d79 100644 > --- a/drivers/usb/serial/ch341.c > +++ b/drivers/usb/serial/ch341.c > @@ -82,6 +82,8 @@ > #define CH341_LCR_CS6 0x01 > #define CH341_LCR_CS5 0x00 > > +#define CH341_STATUS_TXBUSY 0x01 > + > static const struct usb_device_id id_table[] = { > { USB_DEVICE(0x4348, 0x5523) }, > { USB_DEVICE(0x1a86, 0x7523) }, > @@ -95,6 +97,7 @@ struct ch341_private { > unsigned baud_rate; /* set baud rate */ > u8 line_control; /* set line control value RTS/DTR */ > u8 line_status; /* active status of modem control inputs */ > + u8 uart_status; /* generic UART status bits */ > }; > > static void ch341_set_termios(struct tty_struct *tty, > @@ -187,7 +190,8 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) > if (r == 2) { > r = 0; > spin_lock_irqsave(&priv->lock, flags); > - priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; > + priv->line_status = (~buffer[0]) & CH341_BITS_MODEM_STAT; > + priv->uart_status = buffer[1]; > spin_unlock_irqrestore(&priv->lock, flags); > } else { > r = -EPROTO; > @@ -198,6 +202,18 @@ out: > return r; > } > > +static bool ch341_tx_empty(struct usb_serial_port *port) > +{ > + int r; > + struct ch341_private *priv = usb_get_serial_port_data(port); > + > + r = ch341_get_status(port->serial->dev, priv); > + if (r < 0) > + return true; > + > + return !(priv->uart_status & CH341_STATUS_TXBUSY); > +} > + > /* -------------------------------------------------------------------------- */ > > static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) > @@ -606,6 +622,7 @@ static struct usb_serial_driver ch341_device = { > .carrier_raised = ch341_carrier_raised, > .close = ch341_close, > .set_termios = ch341_set_termios, > + .tx_empty = ch341_tx_empty, > .break_ctl = ch341_break_ctl, > .tiocmget = ch341_tiocmget, > .tiocmset = ch341_tiocmset, > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-usb" in the body of a message to > majordomo@vger.kernel.org More majordomo info at > http://vger.kernel.org/majordomo-info.html --===============5408899418638152248==--