From patchwork Sat Jul 8 14:56:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sonninen X-Patchwork-Id: 701002 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 CCAF9EB64DD for ; Sat, 8 Jul 2023 14:57:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230190AbjGHO51 (ORCPT ); Sat, 8 Jul 2023 10:57:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229666AbjGHO50 (ORCPT ); Sat, 8 Jul 2023 10:57:26 -0400 Received: from lahtoruutu.iki.fi (lahtoruutu.iki.fi [IPv6:2a0b:5c81:1c1::37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71867D9; Sat, 8 Jul 2023 07:57:24 -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 lahtoruutu.iki.fi (Postfix) with ESMTPSA id 4Qytf74HF5z49Psw; Sat, 8 Jul 2023 17:57:19 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=lahtoruutu; t=1688828240; 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=Dx+yZDyoZEMezjVYd3PTEK6iSdWrjTFGImAbJdiYRVE=; b=BdhpdtzEd3Cu0xkFxtfzOhvqFCLAgStCVT2E+Cl9CBWJA0TmnbtuWan/5GUJX2l1NDpF03 h5DfCMBRDnnKTsqTEcXWS6LAj9mlQ/buizRRsfgV12QRJIqV1/GJpLdWoGpxRmFLIXmLE9 yNrzH75UO8q9pVyfofRl0r5+jkZq1TuMqkrrzezLN0HT/FCINrCf/YvC1AEzCIjt8koaSo ef+JqCa48QNe9VORZsbKVKzHJcQxvmUWjn5xxAjLFUPj+ZwrHkdhJRUmUAn9BPQeL1BJ+V /A8MZBVALvOqhl1jr//kuYQ2rAZw2WLJ23YAWJtX/zXar0oJ4KehQtVWl8qmSQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=iki.fi; s=lahtoruutu; t=1688828240; 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=Dx+yZDyoZEMezjVYd3PTEK6iSdWrjTFGImAbJdiYRVE=; b=Eus036bV69xgfrnpumuM12bQkuz/cA18+0MS2pLpvM7UKuWoHjwaWfJNGuoyPaSHJAuyZv 6MRU2Q813JDwNha1rNDwCt6s77gtV7ZsKw6uiAYcogDwe5Iodk2QZV+zCj1Lmd6VyUuOCg 74g8U4CoS4vNlhWUEO/tfp3baVzqgrViF2Ak3ml5ROngn0iPIauJ6e9BZvy+h9dfvhE8mj TBcDKUnZt0g2QL4M5btDLULz3osyHGU95wj7V0488GZqYMg7U93JqdjcHawGSrB8NTeGtA ngImx4FjntaiMpRSaZRgfse6XHxwFwvYaQqmXfiJzpHhq4pmepT8ARcOiuICAQ== ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=kasper smtp.mailfrom=kasper@iki.fi ARC-Seal: i=1; s=lahtoruutu; d=iki.fi; t=1688828240; a=rsa-sha256; cv=none; b=Bk2rD+wCoFfI1Wdne7kHdG5nJjwK0P4cDk8QkR+xs17okV3/3cGkAYlQ0XPkyewoSUISxr QbLIITQk48mIR6yGM9bmcLa5K2BEBL3ZsMTPcfUrjO0T9i4Si5V6Zm/nDdpWmpevPnq4tJ unUeRtAz5e9vFMgUSrI/S9Ew1JtdrhUL/nbyNPjSNIhMQB+6D3CdSGJBya3kL1mJHcohkW LB+OpWiTrTl6dVr+AcmlXYx+sJLhFXhL1pyuMmh0LROGUKfRkdOgK22yIn4jx9go+3684n Oag54yvOzJBJpjG4RHdxvK6L9EvFXDsENZVdNEbFQB9EZ2hMco4CzGKiVL23wA== Received: from gridbug.. (dkxv4fyyyyyyyyyyyyyby-3.rev.dnainternet.fi [IPv6:2001:14ba:44e3:8200::2]) by dungeon.fi (Postfix) with ESMTPSA id E7C113F57A; Sat, 8 Jul 2023 17:57:17 +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 v5] USB: serial: xr: Add TIOCGRS485 and TIOCSRS485 ioctls Date: Sat, 8 Jul 2023 17:56:50 +0300 Message-Id: <20230708145651.1860565-1-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_AFTER_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 Change in v5: - Use tty->termios_rwsem semaphore instead of own mutex - Set SER_RS485_RTS_AFTER_SEND as the default - Fix XR_GPIO_MODE_RS485_TX_H setting with SER_RS485_RTS_ON_SEND - Add missing __user directives drivers/usb/serial/xr_serial.c | 90 +++++++++++++++++++++++++++++++++- 1 file changed, 89 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c index 4ec7c5892b84..6a5a70e77969 100644 --- a/drivers/usb/serial/xr_serial.c +++ b/drivers/usb/serial/xr_serial.c @@ -93,6 +93,7 @@ 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 +238,7 @@ 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; }; static int xr_set_reg(struct usb_serial_port *port, u8 channel, u16 reg, u16 val) @@ -629,6 +631,7 @@ static void xr_set_flow_mode(struct tty_struct *tty, struct xr_data *data = usb_get_serial_port_data(port); const struct xr_type *type = data->type; u16 flow, gpio_mode; + bool rs485_enabled; int ret; ret = xr_get_reg_uart(port, type->gpio_mode, &gpio_mode); @@ -645,7 +648,17 @@ 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 +822,80 @@ 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 after 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_AFTER_SEND; + rs485->flags &= ~SER_RS485_RTS_ON_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 __user *argp) +{ + struct usb_serial_port *port = tty->driver_data; + struct xr_data *data = usb_get_serial_port_data(port); + + down_read(&tty->termios_rwsem); + if (copy_to_user(argp, &data->rs485, sizeof(data->rs485))) { + up_read(&tty->termios_rwsem); + return -EFAULT; + } + up_read(&tty->termios_rwsem); + + return 0; +} + +static int xr_set_rs485_config(struct tty_struct *tty, + struct serial_rs485 __user *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); + + down_write(&tty->termios_rwsem); + data->rs485 = rs485; + xr_set_flow_mode(tty, port, NULL); + up_write(&tty->termios_rwsem); + + 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) @@ -1010,6 +1097,7 @@ 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 };