Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753658AbcDBRRi (ORCPT ); Sat, 2 Apr 2016 13:17:38 -0400 Received: from pygmy.kinoho.net ([134.0.27.24]:38048 "EHLO pygmy.kinoho.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752006AbcDBRRd (ORCPT ); Sat, 2 Apr 2016 13:17:33 -0400 From: Grigori Goronzy To: Johan Hovold Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Grigori Goronzy Subject: [PATCH v2 14/14] USB: ch341: implement tx_empty callback Date: Sat, 2 Apr 2016 19:07:23 +0200 Message-Id: <1459616843-23829-15-git-send-email-greg@chown.ath.cx> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1459616843-23829-1-git-send-email-greg@chown.ath.cx> References: <1459616843-23829-1-git-send-email-greg@chown.ath.cx> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2234 Lines: 68 The status bit was found with USB captures of the Windows driver and some luck. Tested on CH340G and CH341A. 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