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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 148CBC43334 for ; Mon, 27 Jun 2022 11:47:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:Message-ID: In-Reply-To:Subject:cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=dev36NCHSIgNbxQ7NKHUExxPb/ftJlI784jo6tKP0FE=; b=ujow79jWmgUM11 5eekIvat788E2uYA50156IdnMxrge82ZDjEcRqAyL860DNTwiEMGCHMgeq74RfRjhIIlcT16/tpKb cedmjO2nTHT/KGX5l6/9LB8B+44kKPEfzEVKLNkF21tLO48zGH4anLwL11m8zmGwxmonNI5ZBVHNj EiDsuPtke8HReJP1ZV0eKvBYGEigJ8ZKqOekgQOkDozG50X/rAqBX4tspP92iK4cxDQwxGJS8YSNa btMoajfR6JXQ3NAURnlr7TFLmUIPci6DP0a7Y6+2iTrSOb9pK2mV65JamNbONG8CQVaruRHFPkqsd Qu090NAzWLvO+gAA6Nnw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o5nC3-000eNR-9B; Mon, 27 Jun 2022 11:46:15 +0000 Received: from mga12.intel.com ([192.55.52.136]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o5nBz-000eLh-P3 for linux-arm-kernel@lists.infradead.org; Mon, 27 Jun 2022 11:46:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656330371; x=1687866371; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=038ViQj4OdJMOtsCH8E05gcJKrV6mUvMiaaLGQCFo14=; b=IfO4UacPKCgNBE3RBXnvxsk4U3a+J0PlmSzMy1YF6VtWJkfS33GCBq8u h1m5JzSR9dukJdRP5i6R6NChFBNgWYt4/oQeYf9Ge2lByt/eb6JRnDlzv s1dhVzNeTCk5+lCj+ktfmqfEHXRR3pT3bt32P9CaPSFDJZ2sEygvxOfEs eUqqmqWihWzxqZ2PKOiw09SHEUjOJ4LcGUJ12ScUUU+I5Sxjo/MeFx9RQ /KLE4lWinCyLosO7kUg3NAiraa35e/niyxi0OkOxjEvnJBL597mISGZy4 WOoLnC1Eazg5KrweWEFPuN0/k341KeCB1VmZfdcQK7r3S2uw2FeSVdC0C g==; X-IronPort-AV: E=McAfee;i="6400,9594,10390"; a="261236309" X-IronPort-AV: E=Sophos;i="5.92,226,1650956400"; d="scan'208";a="261236309" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 04:46:09 -0700 X-IronPort-AV: E=Sophos;i="5.92,226,1650956400"; d="scan'208";a="646396113" Received: from gretavix-mobl3.amr.corp.intel.com ([10.249.43.78]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 04:46:07 -0700 Date: Mon, 27 Jun 2022 14:46:07 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: Chanho Park cc: Krzysztof Kozlowski , Greg Kroah-Hartman , Jiri Slaby , Alim Akhtar , Hector Martin , Jaewon Kim , Vincent Whitchurch , linux-samsung-soc@vger.kernel.org, linux-serial , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] tty: serial: samsung_tty: loopback mode support In-Reply-To: <20220627032353.8868-1-chanho61.park@samsung.com> Message-ID: References: <20220627032353.8868-1-chanho61.park@samsung.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220627_044611_902491_C22A194D X-CRM114-Status: GOOD ( 19.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 27 Jun 2022, Chanho Park wrote: > Internal loopback mode can be supported by setting > S3C2443_UCON_LOOPBACK bit. The mode & bit can be supported since > s3c2410 and later SoCs. In that case, why is the LOOPBACK define named 2443 and not 2410??? The change looks fine otherwise. I note though that many of the current drivers won't return TOICM_LOOP from ->get_mctrl() but I don't think it's exactly wrong to return it either. Perhaps lack of returning it is due to Documentation/driver-api/serial/driver.rst not including TOICM_LOOP in get_mctrl's list of information but only in set_mctrl's one. -- i. > We can test it by linux-serial-test program[1] > with -k option. It will set TIOCM_LOOP mode during test. > > -k, --loopback Use internal hardware loop back > > [1]: https://github.com/cbrake/linux-serial-test > Signed-off-by: Chanho Park > --- > drivers/tty/serial/samsung_tty.c | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c > index d5ca904def34..d7d035cd95c0 100644 > --- a/drivers/tty/serial/samsung_tty.c > +++ b/drivers/tty/serial/samsung_tty.c > @@ -1002,16 +1002,22 @@ static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port) > static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port) > { > unsigned int umstat = rd_reg(port, S3C2410_UMSTAT); > + unsigned int ucon = rd_reg(port, S3C2410_UCON); > + unsigned int mctrl = TIOCM_CAR | TIOCM_DSR; > > if (umstat & S3C2410_UMSTAT_CTS) > - return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; > - else > - return TIOCM_CAR | TIOCM_DSR; > + mctrl |= TIOCM_CTS; > + > + if (ucon & S3C2443_UCON_LOOPBACK) > + mctrl |= TIOCM_LOOP; > + > + return mctrl; > } > > static void s3c24xx_serial_set_mctrl(struct uart_port *port, unsigned int mctrl) > { > unsigned int umcon = rd_regl(port, S3C2410_UMCON); > + unsigned int ucon = rd_reg(port, S3C2410_UCON); > > if (mctrl & TIOCM_RTS) > umcon |= S3C2410_UMCOM_RTS_LOW; > @@ -1019,6 +1025,13 @@ static void s3c24xx_serial_set_mctrl(struct uart_port *port, unsigned int mctrl) > umcon &= ~S3C2410_UMCOM_RTS_LOW; > > wr_regl(port, S3C2410_UMCON, umcon); > + > + if (mctrl & TIOCM_LOOP) > + ucon |= S3C2443_UCON_LOOPBACK; > + else > + ucon &= ~S3C2443_UCON_LOOPBACK; > + > + wr_regl(port, S3C2410_UCON, ucon); > } > > static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state) > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel