From patchwork Fri Jun 21 13:36:11 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 2762961 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 65FE69F756 for ; Fri, 21 Jun 2013 13:56:21 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 33BED20211 for ; Fri, 21 Jun 2013 13:56:20 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B876A201C7 for ; Fri, 21 Jun 2013 13:56:18 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uq1X2-0007Fp-By; Fri, 21 Jun 2013 13:37:43 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uq1W5-00032t-VW; Fri, 21 Jun 2013 13:36:41 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Uq1W2-000327-0g for linux-arm-kernel@lists.infradead.org; Fri, 21 Jun 2013 13:36:39 +0000 Received: from dude.hi.pengutronix.de ([10.1.0.7] helo=dude.pengutronix.de) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1Uq1Vc-0007Jq-CJ; Fri, 21 Jun 2013 15:36:12 +0200 From: Philipp Zabel To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH] ARM i.MX53: Fix UART pad configuration Date: Fri, 21 Jun 2013 15:36:11 +0200 Message-Id: <1371821771-23450-1-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.8.3.1 X-SA-Exim-Connect-IP: 10.1.0.7 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130621_093638_847507_9415A160 X-CRM114-Status: GOOD ( 12.45 ) X-Spam-Score: -3.4 (---) Cc: Fabio Estevam , Shawn Guo , Philipp Zabel , kernel@pengutronix.de X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The current default pad configuration for UART RX and TX pads sets a 360k pull-down and writes 1 to a reserved bit (1 << 0). It doesn't seem right to me that in idle state, the UART has to keep the signal high against a pull-down resistor. This patch instead sets a 100k pull-up, which incidentally corresponds to the register reset value for all but one (MX53_PAD_KEY_ROW0__UART4_RXD_MUX) pad, and removes the write to the reserved bit. Signed-off-by: Philipp Zabel --- Or is there a valid reason to set a pull-down on those pads and to write 1 to the reserved bit? --- arch/arm/boot/dts/imx53.dtsi | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/arch/arm/boot/dts/imx53.dtsi b/arch/arm/boot/dts/imx53.dtsi index 5d77f00..fee0c0e 100644 --- a/arch/arm/boot/dts/imx53.dtsi +++ b/arch/arm/boot/dts/imx53.dtsi @@ -523,15 +523,15 @@ uart1 { pinctrl_uart1_1: uart1grp-1 { fsl,pins = < - MX53_PAD_CSI0_DAT10__UART1_TXD_MUX 0x1c5 - MX53_PAD_CSI0_DAT11__UART1_RXD_MUX 0x1c5 + MX53_PAD_CSI0_DAT10__UART1_TXD_MUX 0x1e4 + MX53_PAD_CSI0_DAT11__UART1_RXD_MUX 0x1e4 >; }; pinctrl_uart1_2: uart1grp-2 { fsl,pins = < - MX53_PAD_PATA_DIOW__UART1_TXD_MUX 0x1c5 - MX53_PAD_PATA_DMACK__UART1_RXD_MUX 0x1c5 + MX53_PAD_PATA_DIOW__UART1_TXD_MUX 0x1e4 + MX53_PAD_PATA_DMACK__UART1_RXD_MUX 0x1e4 >; }; }; @@ -539,8 +539,8 @@ uart2 { pinctrl_uart2_1: uart2grp-1 { fsl,pins = < - MX53_PAD_PATA_BUFFER_EN__UART2_RXD_MUX 0x1c5 - MX53_PAD_PATA_DMARQ__UART2_TXD_MUX 0x1c5 + MX53_PAD_PATA_BUFFER_EN__UART2_RXD_MUX 0x1e4 + MX53_PAD_PATA_DMARQ__UART2_TXD_MUX 0x1e4 >; }; }; @@ -548,17 +548,17 @@ uart3 { pinctrl_uart3_1: uart3grp-1 { fsl,pins = < - MX53_PAD_PATA_CS_0__UART3_TXD_MUX 0x1c5 - MX53_PAD_PATA_CS_1__UART3_RXD_MUX 0x1c5 - MX53_PAD_PATA_DA_1__UART3_CTS 0x1c5 - MX53_PAD_PATA_DA_2__UART3_RTS 0x1c5 + MX53_PAD_PATA_CS_0__UART3_TXD_MUX 0x1e4 + MX53_PAD_PATA_CS_1__UART3_RXD_MUX 0x1e4 + MX53_PAD_PATA_DA_1__UART3_CTS 0x1e4 + MX53_PAD_PATA_DA_2__UART3_RTS 0x1e4 >; }; pinctrl_uart3_2: uart3grp-2 { fsl,pins = < - MX53_PAD_PATA_CS_0__UART3_TXD_MUX 0x1c5 - MX53_PAD_PATA_CS_1__UART3_RXD_MUX 0x1c5 + MX53_PAD_PATA_CS_0__UART3_TXD_MUX 0x1e4 + MX53_PAD_PATA_CS_1__UART3_RXD_MUX 0x1e4 >; }; @@ -567,8 +567,8 @@ uart4 { pinctrl_uart4_1: uart4grp-1 { fsl,pins = < - MX53_PAD_KEY_COL0__UART4_TXD_MUX 0x1c5 - MX53_PAD_KEY_ROW0__UART4_RXD_MUX 0x1c5 + MX53_PAD_KEY_COL0__UART4_TXD_MUX 0x1e4 + MX53_PAD_KEY_ROW0__UART4_RXD_MUX 0x1e4 >; }; }; @@ -576,8 +576,8 @@ uart5 { pinctrl_uart5_1: uart5grp-1 { fsl,pins = < - MX53_PAD_KEY_COL1__UART5_TXD_MUX 0x1c5 - MX53_PAD_KEY_ROW1__UART5_RXD_MUX 0x1c5 + MX53_PAD_KEY_COL1__UART5_TXD_MUX 0x1e4 + MX53_PAD_KEY_ROW1__UART5_RXD_MUX 0x1e4 >; }; };