From patchwork Wed Aug 18 07:12:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 499576 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F166C43214 for ; Wed, 18 Aug 2021 07:12:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09E626108D for ; Wed, 18 Aug 2021 07:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239513AbhHRHNZ (ORCPT ); Wed, 18 Aug 2021 03:13:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239251AbhHRHNQ (ORCPT ); Wed, 18 Aug 2021 03:13:16 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3977DC0613D9 for ; Wed, 18 Aug 2021 00:12:42 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mGFkY-00050H-Sr; Wed, 18 Aug 2021 09:12:34 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mGFkY-0005NZ-K8; Wed, 18 Aug 2021 09:12:34 +0200 From: Oleksij Rempel To: Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" , Jakub Kicinski , Rob Herring Cc: Oleksij Rempel , linux-can@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, David Jander Subject: [PATCH v3 1/3] dt-bindings: can-controller: add support for termination-gpios Date: Wed, 18 Aug 2021 09:12:30 +0200 Message-Id: <20210818071232.20585-2-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210818071232.20585-1-o.rempel@pengutronix.de> References: <20210818071232.20585-1-o.rempel@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Some boards provide GPIO controllable termination resistor. Provide binding to make use of it. Signed-off-by: Oleksij Rempel Reviewed-by: Rob Herring --- .../devicetree/bindings/net/can/can-controller.yaml | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/devicetree/bindings/net/can/can-controller.yaml b/Documentation/devicetree/bindings/net/can/can-controller.yaml index 9cf2ae097156..1f0e98051074 100644 --- a/Documentation/devicetree/bindings/net/can/can-controller.yaml +++ b/Documentation/devicetree/bindings/net/can/can-controller.yaml @@ -13,6 +13,15 @@ properties: $nodename: pattern: "^can(@.*)?$" + termination-gpios: + description: GPIO pin to enable CAN bus termination. + maxItems: 1 + + termination-ohms: + description: The resistance value of the CAN bus termination resistor. + minimum: 1 + maximum: 65535 + additionalProperties: true ... From patchwork Wed Aug 18 07:12:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 499575 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 271DBC4338F for ; Wed, 18 Aug 2021 07:13:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E26461053 for ; Wed, 18 Aug 2021 07:13:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238897AbhHRHOB (ORCPT ); Wed, 18 Aug 2021 03:14:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239528AbhHRHNT (ORCPT ); Wed, 18 Aug 2021 03:13:19 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 413C4C06129F for ; Wed, 18 Aug 2021 00:12:42 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mGFkZ-00050o-Cv; Wed, 18 Aug 2021 09:12:35 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mGFkZ-0005Ob-3y; Wed, 18 Aug 2021 09:12:35 +0200 From: Oleksij Rempel To: Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" , Jakub Kicinski , Rob Herring Cc: Oleksij Rempel , linux-can@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, David Jander Subject: [PATCH v3 2/3] dt-bindings: can: fsl, flexcan: enable termination-* bindings Date: Wed, 18 Aug 2021 09:12:31 +0200 Message-Id: <20210818071232.20585-3-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210818071232.20585-1-o.rempel@pengutronix.de> References: <20210818071232.20585-1-o.rempel@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Enable termination-* binding and provide validation example for it. Signed-off-by: Oleksij Rempel --- .../bindings/net/can/fsl,flexcan.yaml | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml b/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml index 55bff1586b6f..3f0ee17c1461 100644 --- a/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml +++ b/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml @@ -119,6 +119,9 @@ properties: minimum: 0 maximum: 2 + termination-gpios: true + termination-ohms: true + required: - compatible - reg @@ -148,3 +151,17 @@ examples: fsl,stop-mode = <&gpr 0x34 28>; fsl,scu-index = /bits/ 8 <1>; }; + - | + #include + #include + + can@2090000 { + compatible = "fsl,imx6q-flexcan"; + reg = <0x02090000 0x4000>; + interrupts = <0 110 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&clks 1>, <&clks 2>; + clock-names = "ipg", "per"; + fsl,stop-mode = <&gpr 0x34 28>; + termination-gpios = <&gpio1 0 GPIO_ACTIVE_LOW>; + termination-ohms = <120>; + }; From patchwork Wed Aug 18 07:12:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 500311 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC1EAC43214 for ; Wed, 18 Aug 2021 07:13:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 87753610A3 for ; Wed, 18 Aug 2021 07:13:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240226AbhHRHN5 (ORCPT ); Wed, 18 Aug 2021 03:13:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239560AbhHRHNT (ORCPT ); Wed, 18 Aug 2021 03:13:19 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54A7EC0612A4 for ; Wed, 18 Aug 2021 00:12:42 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mGFkZ-00051F-Ue; Wed, 18 Aug 2021 09:12:35 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mGFkZ-0005Ow-Kd; Wed, 18 Aug 2021 09:12:35 +0200 From: Oleksij Rempel To: Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" , Jakub Kicinski , Rob Herring Cc: Oleksij Rempel , linux-can@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, David Jander Subject: [PATCH v3 3/3] can: dev: provide optional GPIO based termination support Date: Wed, 18 Aug 2021 09:12:32 +0200 Message-Id: <20210818071232.20585-4-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210818071232.20585-1-o.rempel@pengutronix.de> References: <20210818071232.20585-1-o.rempel@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org For CAN buses to work, a termination resistor has to be present at both ends of the bus. This resistor is usually 120 Ohms, other values may be required for special bus topologies. This patch adds support for a generic GPIO based CAN termination. The resistor value has to be specified via device tree, and it can only be attached to or detached from the bus. By default the termination is not active. Signed-off-by: Oleksij Rempel --- drivers/net/can/dev/dev.c | 66 +++++++++++++++++++++++++++++++++++++++ include/linux/can/dev.h | 8 +++++ 2 files changed, 74 insertions(+) diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index 311d8564d611..e3d840b81357 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #define MOD_DESC "CAN device driver interface" @@ -400,10 +401,69 @@ void close_candev(struct net_device *dev) } EXPORT_SYMBOL_GPL(close_candev); +static int can_set_termination(struct net_device *ndev, u16 term) +{ + struct can_priv *priv = netdev_priv(ndev); + int set; + + if (term == priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED]) + set = 1; + else + set = 0; + + gpiod_set_value(priv->termination_gpio, set); + + return 0; +} + +static int can_get_termination(struct net_device *ndev) +{ + struct can_priv *priv = netdev_priv(ndev); + struct device *dev = ndev->dev.parent; + struct gpio_desc *gpio; + u32 term; + int ret; + + /* Disabling termination by default is the safe choice: Else if many + * bus participants enable it, no communication is possible at all. + */ + gpio = devm_gpiod_get_optional(dev, "termination", GPIOD_OUT_LOW); + if (IS_ERR(gpio)) + return dev_err_probe(dev, PTR_ERR(gpio), + "Cannot get termination-gpios\n"); + + if (!gpio) + return 0; + + ret = device_property_read_u32(dev, "termination-ohms", &term); + if (ret) { + netdev_err(ndev, "Cannot get termination-ohms: %pe\n", + ERR_PTR(ret)); + return ret; + } + + if (term > U16_MAX) { + netdev_err(ndev, "Invalid termination-ohms value (%u > %u)\n", + term, U16_MAX); + return -EINVAL; + } + + priv->termination_const_cnt = ARRAY_SIZE(priv->termination_gpio_ohms); + priv->termination_const = priv->termination_gpio_ohms; + priv->termination_gpio = gpio; + priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_DISABLED] = + CAN_TERMINATION_DISABLED; + priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED] = term; + priv->do_set_termination = can_set_termination; + + return 0; +} + /* Register the CAN network device */ int register_candev(struct net_device *dev) { struct can_priv *priv = netdev_priv(dev); + int err; /* Ensure termination_const, termination_const_cnt and * do_set_termination consistency. All must be either set or @@ -419,6 +479,12 @@ int register_candev(struct net_device *dev) if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt) return -EINVAL; + if (!priv->termination_const) { + err = can_get_termination(dev); + if (err) + return err; + } + dev->rtnl_link_ops = &can_link_ops; netif_carrier_off(dev); diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h index 27b275e463da..2413253e54c7 100644 --- a/include/linux/can/dev.h +++ b/include/linux/can/dev.h @@ -32,6 +32,12 @@ enum can_mode { CAN_MODE_SLEEP }; +enum can_termination_gpio { + CAN_TERMINATION_GPIO_DISABLED = 0, + CAN_TERMINATION_GPIO_ENABLED, + CAN_TERMINATION_GPIO_MAX, +}; + /* * CAN common private data */ @@ -55,6 +61,8 @@ struct can_priv { unsigned int termination_const_cnt; const u16 *termination_const; u16 termination; + struct gpio_desc *termination_gpio; + u16 termination_gpio_ohms[CAN_TERMINATION_GPIO_MAX]; enum can_state state;