From patchwork Sun Apr 23 18:59:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sonninen X-Patchwork-Id: 13221446 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C34AC6FD18 for ; Sun, 23 Apr 2023 19:00:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229619AbjDWTAH (ORCPT ); Sun, 23 Apr 2023 15:00:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjDWTAG (ORCPT ); Sun, 23 Apr 2023 15:00:06 -0400 Received: from meesny.iki.fi (meesny.iki.fi [IPv6:2001:67c:2b0:1c1::201]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E635A10D4; Sun, 23 Apr 2023 12:00:04 -0700 (PDT) Received: from dungeon.fi (dungeon.fi [IPv6:2a00:d880:11::2cc]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kasper) by meesny.iki.fi (Postfix) with ESMTPSA id 4Q4Hd831h3zySW; Sun, 23 Apr 2023 21:59:56 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1682276398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MxfAWl1kWp9CpnyDQXswuqjCQB/+/RxHWBjkeo+0fS4=; b=HKcNpldoL+e2BKjtWHb0Lm84sG+CQH5RUp+FBeW2ZKT75mHu2K2IFJc51Z8attlZsfFk4R +lurW3vuz/rW3/zPzJRZ+tJsIxCAC0vNx2o7NWrIiLU/oa9dMs2aJ29hIylkk7X17688BD E+aZi/RdfOrIFKc9dkHdaFG/NlaXNeg= ARC-Seal: i=1; s=meesny; d=iki.fi; t=1682276398; a=rsa-sha256; cv=none; b=CvV0oydI7Iemg+7pixuLzpfX9KbpzDFm9DeeNIeCV3NtaAhgV7zsEm1hECrfaA/kxIZaK3 NPkEWyWGPEQhmyI77RyaYNLRLqdzH8THyaBAETh5DPOy+Za/Z9qGxGhZqc+aMXPxvfXKUl CNgCnFYYMhN1oLtLQ9eKtrKb9rPPl9w= ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=kasper smtp.mailfrom=kasper@iki.fi ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=meesny; t=1682276398; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MxfAWl1kWp9CpnyDQXswuqjCQB/+/RxHWBjkeo+0fS4=; b=XUYW4vzkxfQONcnets2MrDFBDj3/+zME4FKIyCDYrOMQtGHb/xpasVuAKG2DehXjNqYwKf 1/Sizic1Tz6D3OBXwRmz5FZ8qd+JJcQX3I/K6wVDdwlQkxV2DFVrPG3gajlG3QNpIUsIyY xsaqDhrKjmfJQkNAm966bhIxlV60zys= Received: from gridbug.. (dktgsyyyyyyyyyyyyyybt-3.rev.dnainternet.fi [IPv6:2001:14ba:440a:f000::3]) by dungeon.fi (Postfix) with ESMTPSA id 1F6A93F244; Sun, 23 Apr 2023 21:59:55 +0300 (EEST) From: Jarkko Sonninen To: Jarkko Sonninen Cc: Johan Hovold , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls Date: Sun, 23 Apr 2023 21:59:28 +0300 Message-Id: <20230423185929.1595056-1-kasper@iki.fi> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Exar devices like XR21B1411 can control an RS485 transceiver by automatically asserting the RTS#/RS485 pin before sending data and deasserting it when the last stop bit has been transmitted. The polarity of the RST#/RS485 signal is configurable and the hardware also supports half-duplex turn-around delay and address matching mode. Add support for enabling and disabling RS-485 mode and configuring the RST#/RS485 signal polarity using the TIOCGRS485 and TIOCSRS485 ioctls. Support for half-duplex turn-around delay and address matching mode are left unimplemented for now. User enables RS-485 mode by setting SER_RS485_ENABLED flag in struct serial_rs485 flags. User should also set either SER_RS485_RTS_ON_SEND or SER_RS485_RTS_AFTER_SEND to select the behaviour of the RTS#/RS485 pin. Setting SER_RS485_RTS_ON_SEND will drive RTS#/RS485 high during transmission. As this is the typical application described by Exar, it is selected when user sets neither or both flags. Signed-off-by: Jarkko Sonninen --- Changes in v3: - In this version only rs485.flags are stored to state. - There is no locking as only one bit of the flags is used. - ioctl returns -ENOIOCTLCMD as the actual error handling is in tty code. Changes in v4: - Store struct rs485 to data - Add mutex to protect data->rs485. - Implement SER_RS485_RTS_ON_SEND or SER_RS485_RTS_AFTER_SEND flags - SER_RS485_RTS_ON_SEND is the default like in serial_core.c drivers/usb/serial/xr_serial.c | 93 +++++++++++++++++++++++++++++++++- 1 file changed, 92 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c index fdb0aae546c3..a2157619b63c 100644 --- a/drivers/usb/serial/xr_serial.c +++ b/drivers/usb/serial/xr_serial.c @@ -19,6 +19,7 @@ #include #include #include +#include struct xr_txrx_clk_mask { u16 tx; @@ -93,6 +94,7 @@ struct xr_txrx_clk_mask { #define XR_GPIO_MODE_SEL_DTR_DSR 0x2 #define XR_GPIO_MODE_SEL_RS485 0x3 #define XR_GPIO_MODE_SEL_RS485_ADDR 0x4 +#define XR_GPIO_MODE_RS485_TX_H 0x8 #define XR_GPIO_MODE_TX_TOGGLE 0x100 #define XR_GPIO_MODE_RX_TOGGLE 0x200 @@ -237,6 +239,8 @@ static const struct xr_type xr_types[] = { struct xr_data { const struct xr_type *type; u8 channel; /* zero-based index or interface number */ + struct serial_rs485 rs485; + struct mutex lock; }; static int xr_set_reg(struct usb_serial_port *port, u8 channel, u16 reg, u16 val) @@ -630,6 +634,7 @@ static void xr_set_flow_mode(struct tty_struct *tty, const struct xr_type *type = data->type; u16 flow, gpio_mode; int ret; + bool rs485_enabled; ret = xr_get_reg_uart(port, type->gpio_mode, &gpio_mode); if (ret) @@ -645,7 +650,17 @@ static void xr_set_flow_mode(struct tty_struct *tty, /* Set GPIO mode for controlling the pins manually by default. */ gpio_mode &= ~XR_GPIO_MODE_SEL_MASK; - if (C_CRTSCTS(tty) && C_BAUD(tty) != B0) { + rs485_enabled = !!(data->rs485.flags & SER_RS485_ENABLED); + if (rs485_enabled) { + dev_dbg(&port->dev, "Enabling RS-485\n"); + gpio_mode |= XR_GPIO_MODE_SEL_RS485; + if (data->rs485.flags & SER_RS485_RTS_ON_SEND) + gpio_mode |= XR_GPIO_MODE_RS485_TX_H; + else + gpio_mode &= ~XR_GPIO_MODE_RS485_TX_H; + } + + if (C_CRTSCTS(tty) && C_BAUD(tty) != B0 && !rs485_enabled) { dev_dbg(&port->dev, "Enabling hardware flow ctrl\n"); gpio_mode |= XR_GPIO_MODE_SEL_RTS_CTS; flow = XR_UART_FLOW_MODE_HW; @@ -809,6 +824,80 @@ static void xr_cdc_set_line_coding(struct tty_struct *tty, kfree(lc); } +static void xr_sanitize_serial_rs485(struct serial_rs485 *rs485) +{ + if (!(rs485->flags & SER_RS485_ENABLED)) { + memset(rs485, 0, sizeof(*rs485)); + return; + } + + /* Select RTS on send if the user hasn't selected the mode properly */ + if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) == + !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) { + rs485->flags |= SER_RS485_RTS_ON_SEND; + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; + } + + /* Only the flags are implemented at the moment */ + rs485->flags &= SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | + SER_RS485_RTS_AFTER_SEND; + rs485->delay_rts_before_send = 0; + rs485->delay_rts_after_send = 0; + memset(rs485->padding, 0, sizeof(rs485->padding)); +} + +static int xr_get_rs485_config(struct tty_struct *tty, + struct serial_rs485 *argp) +{ + struct usb_serial_port *port = tty->driver_data; + struct xr_data *data = usb_get_serial_port_data(port); + + mutex_lock(&data->lock); + if (copy_to_user(argp, &data->rs485, sizeof(data->rs485))) { + mutex_unlock(&data->lock); + return -EFAULT; + } + mutex_unlock(&data->lock); + + return 0; +} + +static int xr_set_rs485_config(struct tty_struct *tty, + struct serial_rs485 *argp) +{ + struct usb_serial_port *port = tty->driver_data; + struct xr_data *data = usb_get_serial_port_data(port); + struct serial_rs485 rs485; + + if (copy_from_user(&rs485, argp, sizeof(rs485))) + return -EFAULT; + xr_sanitize_serial_rs485(&rs485); + + mutex_lock(&data->lock); + data->rs485 = rs485; + xr_set_flow_mode(tty, port, NULL); + mutex_unlock(&data->lock); + + if (copy_to_user(argp, &rs485, sizeof(rs485))) + return -EFAULT; + + return 0; +} + +static int xr_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) +{ + void __user *argp = (void __user *)arg; + + switch (cmd) { + case TIOCGRS485: + return xr_get_rs485_config(tty, argp); + case TIOCSRS485: + return xr_set_rs485_config(tty, argp); + } + + return -ENOIOCTLCMD; +} + static void xr_set_termios(struct tty_struct *tty, struct usb_serial_port *port, const struct ktermios *old_termios) @@ -939,6 +1028,7 @@ static int xr_port_probe(struct usb_serial_port *port) return -ENOMEM; data->type = type; + mutex_init(&data->lock); desc = &port->serial->interface->cur_altsetting->desc; if (type_id == XR21V141X) @@ -1010,6 +1100,7 @@ static struct usb_serial_driver xr_device = { .set_termios = xr_set_termios, .tiocmget = xr_tiocmget, .tiocmset = xr_tiocmset, + .ioctl = xr_ioctl, .dtr_rts = xr_dtr_rts };