From mboxrd@z Thu Jan 1 00:00:00 1970 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 9169EC43334 for ; Sat, 25 Jun 2022 10:40:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232677AbiFYKkZ (ORCPT ); Sat, 25 Jun 2022 06:40:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232651AbiFYKkX (ORCPT ); Sat, 25 Jun 2022 06:40:23 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 079D313F90; Sat, 25 Jun 2022 03:40:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656153623; x=1687689623; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=AVgIL2E9QEAvAwfWoBXfauto0LB7PQrrTcs8Zw/nbNA=; b=ayG0qF1AhtB8wQpRZ+PbtLpuiH0srWlnGqD00I1vlUTmr5GN/LM/2puy 6qo339oqvuwD0887Zd7wvDqbgPKbPGTZhEyC3CLaR7rlNQKpxEHudwYeS 5ITTk9+KUpqwGlM7tr2vjWPoqBcWQdLXbi1jiGHMWX0kMf+5G9yJAt36N X+zWKyNmDSucY5cGLNKVeUKRE3h5YQRctSi4xzWuPCQXPfzsWwaKGcDhC 991oRFdWT84YdAi1UWnqPgK1mu+hAMesnheb8yPiGCb7IlMeFowlpQspL RGY42l1oT2LYyy63fKibcsDMgzKOBIjnz62mbruoVFQJiXU8DKeJg9wVh Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10388"; a="342861243" X-IronPort-AV: E=Sophos;i="5.92,222,1650956400"; d="scan'208";a="342861243" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2022 03:40:22 -0700 X-IronPort-AV: E=Sophos;i="5.92,222,1650956400"; d="scan'208";a="645655106" Received: from selvaku-mobl.ger.corp.intel.com ([10.252.60.244]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jun 2022 03:40:18 -0700 Date: Sat, 25 Jun 2022 13:40:16 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: Lino Sanfilippo cc: Greg Kroah-Hartman , Jiri Slaby , robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, Andy Shevchenko , vz@mleia.com, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-serial , LKML , lukas@wunner.de, p.rosenberger@kunbus.com, Lino Sanfilippo Subject: Re: [PATCH 2/8] serial: core, 8250: set RS485 termination gpio in serial core In-Reply-To: <20220622154659.8710-3-LinoSanfilippo@gmx.de> Message-ID: <83762813-70ec-93c3-4015-5676ce9534fd@linux.intel.com> References: <20220622154659.8710-1-LinoSanfilippo@gmx.de> <20220622154659.8710-3-LinoSanfilippo@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 22 Jun 2022, Lino Sanfilippo wrote: > From: Lino Sanfilippo > > In serial8250_em485_config() the termination GPIO is set with the uart_port > spinlock held. This is an issue if setting the GPIO line can sleep (e.g. > since the concerning GPIO expander is connected via SPI or I2C). > > Fix this by setting the termination line outside of the uart_port spinlock > in the serial core. > > This also makes setting the termination GPIO generic for all uart drivers. > > Signed-off-by: Lino Sanfilippo > --- > drivers/tty/serial/8250/8250_port.c | 3 --- > drivers/tty/serial/serial_core.c | 12 ++++++++++++ > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 3e3d784aa628..5245c179cc51 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -675,9 +675,6 @@ int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485) > rs485->flags &= ~SER_RS485_RTS_AFTER_SEND; > } > > - gpiod_set_value(port->rs485_term_gpio, > - rs485->flags & SER_RS485_TERMINATE_BUS); > - > /* > * Both serial8250_em485_init() and serial8250_em485_destroy() > * are idempotent. > diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c > index 015f4e1da647..b387376e6fa2 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -1352,12 +1352,23 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 > memset(rs485->padding, 0, sizeof(rs485->padding)); > } > > +static void uart_set_rs485_termination(struct uart_port *port, > + const struct serial_rs485 *rs485) > +{ > + if (!port->rs485_term_gpio || !(rs485->flags & SER_RS485_ENABLED)) > + return; > + > + gpiod_set_value_cansleep(port->rs485_term_gpio, > + !!(rs485->flags & SER_RS485_TERMINATE_BUS)); > +} > + > int uart_rs485_config(struct uart_port *port) > { > struct serial_rs485 *rs485 = &port->rs485; > int ret; > > uart_sanitize_serial_rs485(port, rs485); > + uart_set_rs485_termination(port, rs485); > > ret = port->rs485_config(port, rs485); > if (ret) > @@ -1400,6 +1411,7 @@ static int uart_set_rs485_config(struct uart_port *port, > if (ret) > return ret; > uart_sanitize_serial_rs485(port, &rs485); > + uart_set_rs485_termination(port, &rs485); > > spin_lock_irqsave(&port->lock, flags); > ret = port->rs485_config(port, &rs485); When port->rs485_config(port, &rs485) returns non-zero, the input got partially applied? -- i.