From nobody Thu Dec 18 18:02:29 2025 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 512CDC2BB3F for ; Mon, 20 Nov 2023 15:11:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233098AbjKTPLT (ORCPT ); Mon, 20 Nov 2023 10:11:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234098AbjKTPLJ (ORCPT ); Mon, 20 Nov 2023 10:11:09 -0500 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22D4BCB for ; Mon, 20 Nov 2023 07:11:04 -0800 (PST) Received: by mail-lf1-x131.google.com with SMTP id 2adb3069b0e04-507a98517f3so5795712e87.0 for ; Mon, 20 Nov 2023 07:11:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; t=1700493062; x=1701097862; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=g/SkPChN/mWBp/DhOux5JWgEaySNKwX36DC2y2cdDkg=; b=a0hIvYkktppxFCuqKimI1smolxt9iTxrvf3Dn4M0hb3jbGoWASIkALBb9cuHfRWjUp 66CaUrpTaLoxSW0jRpLpdXEx/Q6IvnyT5Yd6P++t09ylAvkbsRBFpZqs3xPQrvj9DX+P Ii1jJcuxxk+TDjx4i2EXNqjJT2ZhSvsRhycYY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700493062; x=1701097862; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=g/SkPChN/mWBp/DhOux5JWgEaySNKwX36DC2y2cdDkg=; b=tToG+4FrrKMst30BCgJlXFqwKaG1YVEE9s0tWEqtDFEPyDhuSr5VPiWH5mjVYCq1Ir mCae0jmvSvuh4QmKF9mUn6ujN8opzBZ8NlQUl2fbde/yMjT9dXbK8X1wnDAzg5bxpd9k Y6fwG4AiPLABNI/W/NABNKF6E14+R857ynXb/zHFW8aG6VPmHhcjl5w2keruBLLKoFwC 4vwt6iQTH20jKM3gtVMIeMwMCoWh2oe2s7S31xZucmxA7tOewj8TJQ088wZioUr3U47C C90TeoX8xVfRxoYWU4ojEit7TqSHEIZqaTgnYm+fsOFnAGL5vuolQx0Wbl3drx05B79A CRQw== X-Gm-Message-State: AOJu0Yy/bn7thWBT4AZAFqJCYVAzu8qZt94vFxT+lYjFXz5+kWOeZXIY SkhhrcFQO86V0X3MTy1LZdqP4A== X-Google-Smtp-Source: AGHT+IEhkfVIhtF+H9/XCs/MThWLVP4I2seY1s1dvQuePISEXOOnqAajhZYae0MYlMGFCGOHb2fCAw== X-Received: by 2002:a19:5517:0:b0:509:fbf:f235 with SMTP id n23-20020a195517000000b005090fbff235mr5971008lfe.6.1700493062235; Mon, 20 Nov 2023 07:11:02 -0800 (PST) Received: from prevas-ravi.prevas.se ([81.216.59.226]) by smtp.gmail.com with ESMTPSA id g29-20020a0565123b9d00b00502e2ab7118sm1207444lfv.50.2023.11.20.07.11.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Nov 2023 07:11:01 -0800 (PST) From: Rasmus Villemoes To: Greg Kroah-Hartman , Jiri Slaby Cc: devicetree@vger.kernel.org, Andy Shevchenko , Lukas Wunner , Rasmus Villemoes , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Subject: [PATCH 2/2] serial: core: implement support for rs485-mux-gpios Date: Mon, 20 Nov 2023 16:10:55 +0100 Message-Id: <20231120151056.148450-3-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.40.1.1.g1c60b9335d In-Reply-To: <20231120151056.148450-1-linux@rasmusvillemoes.dk> References: <20231120151056.148450-1-linux@rasmusvillemoes.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add code for handling a rs485-mux-gpio specified in device tree. Signed-off-by: Rasmus Villemoes Reviewed-by: Lino Sanfilippo --- drivers/tty/serial/serial_core.c | 35 ++++++++++++++++++++++++++++++-- include/linux/serial_core.h | 1 + 2 files changed, 34 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_c= ore.c index f1348a509552..410b17ea7444 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1402,14 +1402,20 @@ static void uart_set_rs485_termination(struct uart_= port *port, !!(rs485->flags & SER_RS485_TERMINATE_BUS)); } =20 +static void uart_set_rs485_mux(struct uart_port *port, const struct serial= _rs485 *rs485) +{ + gpiod_set_value_cansleep(port->rs485_mux_gpio, + !!(rs485->flags & SER_RS485_ENABLED)); +} + static int uart_rs485_config(struct uart_port *port) { struct serial_rs485 *rs485 =3D &port->rs485; unsigned long flags; - int ret; + int ret =3D 0; =20 if (!(rs485->flags & SER_RS485_ENABLED)) - return 0; + goto out; =20 uart_sanitize_serial_rs485(port, rs485); uart_set_rs485_termination(port, rs485); @@ -1420,6 +1426,9 @@ static int uart_rs485_config(struct uart_port *port) if (ret) memset(rs485, 0, sizeof(*rs485)); =20 +out: + uart_set_rs485_mux(port, rs485); + return ret; } =20 @@ -1457,6 +1466,14 @@ static int uart_set_rs485_config(struct tty_struct *= tty, struct uart_port *port, return ret; uart_sanitize_serial_rs485(port, &rs485); uart_set_rs485_termination(port, &rs485); + /* + * To avoid glitches on the transmit enable pin, the mux must + * be set before calling the driver's ->rs485_config when + * disabling rs485 mode, but after when enabling rs485 + * mode. + */ + if (!(rs485.flags & SER_RS485_ENABLED)) + uart_set_rs485_mux(port, &rs485); =20 uart_port_lock_irqsave(port, &flags); ret =3D port->rs485_config(port, &tty->termios, &rs485); @@ -1468,6 +1485,13 @@ static int uart_set_rs485_config(struct tty_struct *= tty, struct uart_port *port, port->ops->set_mctrl(port, port->mctrl); } uart_port_unlock_irqrestore(port, flags); + + /* + * The ->rs485_config might have failed. Regardless, set the + * mux according to the port's effective rs485 config. + */ + uart_set_rs485_mux(port, &port->rs485); + if (ret) return ret; =20 @@ -3621,6 +3645,13 @@ int uart_get_rs485_mode(struct uart_port *port) return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-= gpios\n"); port->rs485_rx_during_tx_gpio =3D desc; =20 + dflags =3D (rs485conf->flags & SER_RS485_ENABLED) ? GPIOD_OUT_HIGH : GPIO= D_OUT_LOW; + desc =3D devm_gpiod_get_optional(dev, "rs485-mux", dflags); + if (IS_ERR(desc)) + return dev_err_probe(dev, PTR_ERR(port->rs485_mux_gpio), + "Cannot get rs485-mux-gpios\n"); + port->rs485_mux_gpio =3D desc; + return 0; } EXPORT_SYMBOL_GPL(uart_get_rs485_mode); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 89f7b6c63598..943818209c49 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -584,6 +584,7 @@ struct uart_port { struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */ struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ struct gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the s= tate of RS485 RX during TX */ + struct gpio_desc *rs485_mux_gpio; /* gpio for selecting RS485 mode */ struct serial_iso7816 iso7816; void *private_data; /* generic platform data pointer */ }; --=20 2.40.1.1.g1c60b9335d