From patchwork Fri Jun 19 14:19:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Codrin Ciubotariu X-Patchwork-Id: 207485 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=-9.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 0E4D1C433E2 for ; Fri, 19 Jun 2020 14:20:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDAC621556 for ; Fri, 19 Jun 2020 14:20:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=microchip.com header.i=@microchip.com header.b="aV2DOjK+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733043AbgFSOUi (ORCPT ); Fri, 19 Jun 2020 10:20:38 -0400 Received: from esa4.microchip.iphmx.com ([68.232.154.123]:7074 "EHLO esa4.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732960AbgFSOUh (ORCPT ); Fri, 19 Jun 2020 10:20:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1592576437; x=1624112437; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=uI1UnBBrQLzZH0Mkfly9+1y3fM2YZcptYMawirVUvR8=; b=aV2DOjK+6B5op7eis/yRF7eJYKmvMF+M7whIMNhbEgP+BdmST4LYWNC2 7dt2mYrlEhYM2YtzQ/Bnt8o1+qiBLzGMSCl3puoU/MD6xHc3Kd99Gvc/+ bL0sToFcevJJlIAoiyEUxzUMHfGMm1y1yOASU+TVisCqPh0uKJMn+pirq /FkfBwgrlYuxWdYUprvmPQWVlk7c2jPng5jUQktvyJSQ0cSJCo/kBouPr nyW2i3gxbgd/uLELL2+CjyudJloINMTAOFUwLBW0XziJKSV13q5CYPV67 q3UnFL2+OJpLet4ekNzOXqeJNOlK+fFI5XQHqINA5IvENisFMEY9kiIXy A==; IronPort-SDR: mvNZWlag1ym8Kr8AAds/dx0clS7q35JjuHLtGMklZfl7/wEHXAp0rqLKFGDKQOvLpp5cddlbA8 Fjb1E5isi1WLhcWkmadmqMhcppC6owviTCsCbFVpAyT6VFHcxJP48hpcjjNsfnF87soCtg3ZDR K6OI/X5SYIShOOBsvIF7P2gI+k83zWHn/wWTrygpceK8+sfE5ovUUvhSIpLjQJNouPXvnp+9do isJ5FnI7NJ+TW+kfp5h3kGc34/LAZXpZh4bWPfaO/2dGUTLrxA+2KHtop04o91cM3QZyk7Y3nt 7uI= X-IronPort-AV: E=Sophos;i="5.75,255,1589266800"; d="scan'208";a="77180771" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 19 Jun 2020 07:20:29 -0700 Received: from chn-vm-ex02.mchp-main.com (10.10.85.144) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 19 Jun 2020 07:20:28 -0700 Received: from rob-ult-m19940.microchip.com (10.10.115.15) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server id 15.1.1979.3 via Frontend Transport; Fri, 19 Jun 2020 07:20:02 -0700 From: Codrin Ciubotariu To: , , , CC: , , , , , , , Codrin Ciubotariu Subject: [RFC PATCH 2/4] i2c: core: add generic I2C GPIO recovery Date: Fri, 19 Jun 2020 17:19:02 +0300 Message-ID: <20200619141904.910889-3-codrin.ciubotariu@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200619141904.910889-1-codrin.ciubotariu@microchip.com> References: <20200619141904.910889-1-codrin.ciubotariu@microchip.com> MIME-Version: 1.0 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Multiple I2C bus drivers use similar bindings to obtain information needed for I2C recovery. For example, for platforms using device-tree, the properties look something like this: &i2c { ... pinctrl-names = "default", "gpio"; // or pinctrl-names = "default", "recovery"; pinctrl-0 = <&pinctrl_i2c_default>; pinctrl-1 = <&pinctrl_i2c_gpio>; sda-gpios = <&pio 0 GPIO_ACTIVE_HIGH>; scl-gpios = <&pio 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>; ... } For this reason, we can add this common initialization in the core. This way, other I2C bus drivers will be able to support GPIO recovery just by providing a pointer to platform's pinctrl and calling i2c_recover_bus() when SDA is stuck low. Signed-off-by: Codrin Ciubotariu --- drivers/i2c/i2c-core-base.c | 119 ++++++++++++++++++++++++++++++++++++ include/linux/i2c.h | 11 ++++ 2 files changed, 130 insertions(+) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index d1f278f73011..4ee29fec4e93 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -179,6 +180,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; int i = 0, scl = 1, ret = 0; + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); if (bri->prepare_recovery) bri->prepare_recovery(adap); @@ -236,6 +239,8 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) if (bri->unprepare_recovery) bri->unprepare_recovery(adap); + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); return ret; } @@ -251,6 +256,118 @@ int i2c_recover_bus(struct i2c_adapter *adap) } EXPORT_SYMBOL_GPL(i2c_recover_bus); +static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct pinctrl *p = bri->pinctrl; + + /* + * we can't change states without pinctrl, so remove the states if + * available + */ + if (!p) { + bri->pins_default = NULL; + bri->pins_gpio = NULL; + return; + } + + if (!bri->pins_default) { + bri->pins_default = pinctrl_lookup_state(p, + PINCTRL_STATE_DEFAULT); + if (IS_ERR(bri->pins_default)) { + dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n"); + bri->pins_default = NULL; + + goto cleanup_pinctrl; + } + } + if (!bri->pins_gpio) { + bri->pins_gpio = pinctrl_lookup_state(p, "gpio"); + if (IS_ERR(bri->pins_gpio)) + bri->pins_gpio = pinctrl_lookup_state(p, "recovery"); + + if (IS_ERR(bri->pins_gpio)) { + dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n"); + bri->pins_gpio = NULL; + + goto cleanup_pinctrl; + } + } + +cleanup_pinctrl: + /* for pinctrl state changes, we need all the information */ + if (!bri->pins_default || !bri->pins_gpio) { + bri->pinctrl = NULL; + bri->pins_default = NULL; + bri->pins_gpio = NULL; + } else { + dev_info(dev, "using pinctrl states for GPIO recovery"); + } +} + +static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + struct device *dev = &adap->dev; + struct gpio_desc *gpiod; + int ret = 0; + + /* don't touch the recovery information if the driver is not using + * generic SCL recovery + */ + if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery) + return 0; + + /* + * pins might be taken as GPIO, so we might as well inform pinctrl about + * this and move the state to GPIO + */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_gpio); + + /* + * if there is incomplete or no recovery information, see if generic + * GPIO recovery is available + */ + if (!bri->scl_gpiod) { + gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) { + bri->scl_gpiod = gpiod; + bri->recover_bus = i2c_generic_scl_recovery; + dev_info(dev, "using generic GPIOs for recovery\n"); + } + } + + /* SDA GPIOD line is optional, so we care about DEFER only */ + if (!bri->sda_gpiod) { + gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN); + if (PTR_ERR(gpiod) == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto cleanup_pinctrl_state; + } + if (!IS_ERR(gpiod)) + bri->sda_gpiod = gpiod; + } + +cleanup_pinctrl_state: + /* change the state of the pins back to their default state */ + if (bri->pinctrl) + pinctrl_select_state(bri->pinctrl, bri->pins_default); + + return ret; +} + +static int i2c_gpio_init_recovery(struct i2c_adapter *adap) +{ + i2c_gpio_init_pinctrl_recovery(adap); + return i2c_gpio_init_generic_recovery(adap); +} + static void i2c_init_recovery(struct i2c_adapter *adap) { struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; @@ -259,6 +376,8 @@ static void i2c_init_recovery(struct i2c_adapter *adap) if (!bri) return; + i2c_gpio_init_recovery(adap); + if (!bri->recover_bus) { err_str = "no recover_bus() found"; goto err; diff --git a/include/linux/i2c.h b/include/linux/i2c.h index c10617bb980a..c62c9b48f719 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -611,6 +611,14 @@ struct i2c_timings { * may configure padmux here for SDA/SCL line or something else they want. * @scl_gpiod: gpiod of the SCL line. Only required for GPIO recovery. * @sda_gpiod: gpiod of the SDA line. Only required for GPIO recovery. + * @pinctrl: pinctrl used by GPIO recovery to change the state of the I2C pins. + * Optional. + * @pins_default: default state of SCL/SDA lines, when they are assigned to the + * I2C bus. Optional. Populated internally for GPIO recovery, if a state with + * the name PINCTRL_STATE_DEFAULT is found and pinctrl is valid. + * @pins_gpio: recovery state of SCL/SDA lines, when they are used as GPIOs. + * Optional. Populated internally for GPIO recovery, if this state is called + * "gpio" or "recovery" and pinctrl is valid. */ struct i2c_bus_recovery_info { int (*recover_bus)(struct i2c_adapter *adap); @@ -627,6 +635,9 @@ struct i2c_bus_recovery_info { /* gpio recovery */ struct gpio_desc *scl_gpiod; struct gpio_desc *sda_gpiod; + struct pinctrl *pinctrl; + struct pinctrl_state *pins_default; + struct pinctrl_state *pins_gpio; }; int i2c_recover_bus(struct i2c_adapter *adap);