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 DB434C43334 for ; Mon, 4 Jul 2022 09:56:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232902AbiGDJ4J (ORCPT ); Mon, 4 Jul 2022 05:56:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230136AbiGDJ4I (ORCPT ); Mon, 4 Jul 2022 05:56:08 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3B0BDEC9; Mon, 4 Jul 2022 02:56:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656928567; x=1688464567; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=wqdKh+YT2kwmBentxY6WWvFarS1Y974WhBuHLSKpX8k=; b=eOZsXb49Yf9yLqlbb9EKagxY4AOKv9qAdS7CmpFbjCRINgPslAzPeCjP QtCWQnC/Jn0b6G2EnwfxgGKuKCv2/MPpTCN+HW2eZ9vJvny0uCFGl3ddH LmJsDCkLxh6hQj8h0quOaaiYXPleFkGaMHBeaQTvGAa9rE3q1UZdJhsP7 H5FrO69hIsSDxj9B8fakPnzjjfjgmnbUVY5Y+bkeOYQ8giy0YR6QruosG 1wMXnFCv8OkyBk+/bVKCN78Zr57MKC4GTQlChBL4r40xOq4j44dTp5qzf 6CXbogZIyFHhFrXuL7x07OjH8rZaKXRFQz2bogNg8Si7j0FrRUJhx5Pol Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10397"; a="347067904" X-IronPort-AV: E=Sophos;i="5.92,243,1650956400"; d="scan'208";a="347067904" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2022 02:56:06 -0700 X-IronPort-AV: E=Sophos;i="5.92,243,1650956400"; d="scan'208";a="649513813" Received: from bclindho-mobl.ger.corp.intel.com ([10.252.49.27]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2022 02:56:02 -0700 Date: Mon, 4 Jul 2022 12:55:59 +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 , p.rosenberger@kunbus.com, Lino Sanfilippo Subject: Re: [PATCH v2 1/9] serial: core: only get RS485 termination GPIO if supported In-Reply-To: <20220703170039.2058202-2-LinoSanfilippo@gmx.de> Message-ID: <9bc128a9-7ce3-d1e-dad6-ca91a5564ea8@linux.intel.com> References: <20220703170039.2058202-1-LinoSanfilippo@gmx.de> <20220703170039.2058202-2-LinoSanfilippo@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Sun, 3 Jul 2022, Lino Sanfilippo wrote: > From: Lino Sanfilippo > > In uart_get_rs485_mode() only try to get a termination GPIO if RS485 bus > termination is supported by the driver. This prevents from allocating > and holding a GPIO descriptor for the drivers lifetimg that will never be > used. > > Signed-off-by: Lino Sanfilippo > --- > > NOTE: > This patch follows the design decision that "rs485_supported" is > set by the driver at initialization and cannot be modified > afterwards. However the better approach would be to let the serial > core modify the termination GPIO support setting based on the > existence of a termination GPIO. If "rs485_supported" is not a > read-only value any more in future the logic implemented in this > patch should be adjusted accordingly. > > drivers/tty/serial/serial_core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c > index 85ef7ef00b82..3768663dfa4d 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -3404,6 +3404,16 @@ int uart_get_rs485_mode(struct uart_port *port) > */ > port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term", > GPIOD_OUT_LOW); > + > + if (port->rs485_term_gpio && > + !(port->rs485_supported->flags & SER_RS485_TERMINATE_BUS)) { > + dev_warn(port->dev, > + "%s (%d): RS485 termination gpio not supported by driver\n", > + port->name, port->line); > + devm_gpiod_put(dev, port->rs485_term_gpio); > + port->rs485_term_gpio = NULL; > + } > + > if (IS_ERR(port->rs485_term_gpio)) { > ret = PTR_ERR(port->rs485_term_gpio); > port->rs485_term_gpio = NULL; I sent a series to embed supported_rs485 to uart_port and manage SER_RS485_TERMINATE_BUS properly so I think this won't be necessary with that? -- i.