From patchwork Mon Jun 19 14:36:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Svyatoslav Ryhel X-Patchwork-Id: 694229 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 D9A3CC001DB for ; Mon, 19 Jun 2023 14:36:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229448AbjFSOgg (ORCPT ); Mon, 19 Jun 2023 10:36:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231365AbjFSOgf (ORCPT ); Mon, 19 Jun 2023 10:36:35 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB4B9F1; Mon, 19 Jun 2023 07:36:33 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id 4fb4d7f45d1cf-51a52a7d859so2632284a12.0; Mon, 19 Jun 2023 07:36:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687185392; x=1689777392; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=4OVGDWOuJSyIvhv2zllppmtukXlypQms5ZS/sCOsd9I=; b=SxUArd5NolAI7dAmIyLzHJYBt8SlUFsWWW+TD0qZGUxnno7SasZF8MD7aQDjqfj0JB rXLAVFCpITH+RH8k/VjQGt1mYxyS+RHtFmBgo41hm/grWNilYeKoJcrS7c0ffX7puQy7 DoNcye+jOIxNJUUX3cZE7T96aSh2QeWW2z08tv/WAYkSnsZu4XQeUdVrfjAsqJzHueur lLLyeXRw/yreth9HeRUtMwOmbuXx+aflr60o9dOWjd9ljI5KiI/5IsjpdD38vrHJTOYn C4w96Bx4k7H7qOoOQHmhYpdEU2fvQhNt0oSDOH8OTkqdGuFdE+GqSrEGwj8Yr4srzhQi oEkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687185392; x=1689777392; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4OVGDWOuJSyIvhv2zllppmtukXlypQms5ZS/sCOsd9I=; b=NRgq57YtUuS1Jww4/kpkpUvHSkSh1qntPo4LcVQBTHs3wU9eoSyoTBxWdwpaBCUWc7 nDG7EQmiJDpVn9EK7CoM6KrNi7AtVMNWOc1fmH6Nz/zX6xtiSTt96cbmlXaUOjQpe9Bd QQEbr9CGgeuGqnEjD3pP2Ny2Yt9eqC4LahgkYVWqlDBuahLZGoPV/ZikKKN8OYfYeuzZ QswpeeYGjSDoD+wFpalyqhuoUCKmwChaQWmMDTS8FfGUZiOCBhcLjqBLcA2lufi3Uv2A NZk4ugA4pJjX0BL1hsW83YiVaGWo9xHLqRfKoRdtNDJx+1L4bul7sY9rQKfUlDkTPevU 77GA== X-Gm-Message-State: AC+VfDzX4MW2sanH2WN9qt7fNU9ePEUPyMFDib5BOg0CfyRolwpTYX0g y6IJcOaqDlHzw47DVDM7ff4= X-Google-Smtp-Source: ACHHUZ5V9PNA+PJ+tXs2Z55xVnovq5HejvSxKARzTNd0g49MMvZMkVPMppR694U0pJkTAmpEQugcgw== X-Received: by 2002:a05:6402:2683:b0:51a:4c1e:c94a with SMTP id w3-20020a056402268300b0051a4c1ec94amr4439451edd.2.1687185392143; Mon, 19 Jun 2023 07:36:32 -0700 (PDT) Received: from xeon.. ([188.163.112.79]) by smtp.gmail.com with ESMTPSA id r13-20020aa7d58d000000b00514b2a9ce60sm13073283edq.81.2023.06.19.07.36.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jun 2023 07:36:31 -0700 (PDT) From: Svyatoslav Ryhel To: Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Wolfram Sang , =?utf-8?b?TWljaGHFgiBNaXJvc8WCYXc=?= , Svyatoslav Ryhel Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1 2/2] i2c: Add GPIO-based hotplug gate Date: Mon, 19 Jun 2023 17:36:11 +0300 Message-Id: <20230619143611.24482-3-clamor95@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230619143611.24482-1-clamor95@gmail.com> References: <20230619143611.24482-1-clamor95@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Michał Mirosław Implement driver for hot-plugged I2C busses, where some devices on a bus are hot-pluggable and their presence is indicated by GPIO line. Co-developed-by: Ion Agorria Signed-off-by: Ion Agorria Signed-off-by: Michał Mirosław Signed-off-by: Svyatoslav Ryhel --- drivers/i2c/Kconfig | 11 ++ drivers/i2c/Makefile | 1 + drivers/i2c/i2c-hotplug-gpio.c | 266 +++++++++++++++++++++++++++++++++ 3 files changed, 278 insertions(+) create mode 100644 drivers/i2c/i2c-hotplug-gpio.c diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 438905e2a1d0..3e3f7675ea4a 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -98,6 +98,17 @@ config I2C_SMBUS source "drivers/i2c/algos/Kconfig" source "drivers/i2c/busses/Kconfig" +config I2C_HOTPLUG_GPIO + tristate "Hot-plugged I2C bus detected by GPIO" + depends on GPIOLIB + depends on OF + help + If you say yes to this option, support will be included for + hot-plugging I2C devices with presence detected by GPIO pin value. + + This driver can also be built as a module. If so, the module + will be called i2c-hotplug-gpio. + config I2C_STUB tristate "I2C/SMBus Test Stub" depends on m diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index c1d493dc9bac..9fd44310835a 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o obj-$(CONFIG_I2C_MUX) += i2c-mux.o obj-y += algos/ busses/ muxes/ +obj-$(CONFIG_I2C_HOTPLUG_GPIO) += i2c-hotplug-gpio.o obj-$(CONFIG_I2C_STUB) += i2c-stub.o obj-$(CONFIG_I2C_SLAVE_EEPROM) += i2c-slave-eeprom.o obj-$(CONFIG_I2C_SLAVE_TESTUNIT) += i2c-slave-testunit.o diff --git a/drivers/i2c/i2c-hotplug-gpio.c b/drivers/i2c/i2c-hotplug-gpio.c new file mode 100644 index 000000000000..18c2d7f44d29 --- /dev/null +++ b/drivers/i2c/i2c-hotplug-gpio.c @@ -0,0 +1,266 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * I2C hotplug gate controlled by GPIO + */ + +#include +#include +#include +#include +#include +#include +#include + +struct i2c_hotplug_priv { + struct i2c_adapter adap; + struct i2c_adapter *parent; + struct device *dev; + struct gpio_desc *gpio; + int irq; +}; + +static inline struct i2c_adapter *i2c_hotplug_parent(struct i2c_adapter *adap) +{ + struct i2c_hotplug_priv *priv = container_of(adap, struct i2c_hotplug_priv, adap); + + return priv->parent; +} + +static int i2c_hotplug_master_xfer(struct i2c_adapter *adap, + struct i2c_msg msgs[], int num) +{ + struct i2c_adapter *parent = i2c_hotplug_parent(adap); + + return parent->algo->master_xfer(parent, msgs, num); +} + +static int i2c_hotplug_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int protocol, + union i2c_smbus_data *data) +{ + struct i2c_adapter *parent = i2c_hotplug_parent(adap); + + return parent->algo->smbus_xfer(parent, addr, flags, read_write, + command, protocol, data); +} + +static u32 i2c_hotplug_functionality(struct i2c_adapter *adap) +{ + u32 parent_func = i2c_get_functionality(i2c_hotplug_parent(adap)); + + return parent_func & ~I2C_FUNC_SLAVE; +} + +static const struct i2c_algorithm i2c_hotplug_algo_i2c = { + .master_xfer = i2c_hotplug_master_xfer, + .functionality = i2c_hotplug_functionality, +}; + +static const struct i2c_algorithm i2c_hotplug_algo_smbus = { + .smbus_xfer = i2c_hotplug_smbus_xfer, + .functionality = i2c_hotplug_functionality, +}; + +static const struct i2c_algorithm i2c_hotplug_algo_both = { + .master_xfer = i2c_hotplug_master_xfer, + .smbus_xfer = i2c_hotplug_smbus_xfer, + .functionality = i2c_hotplug_functionality, +}; + +static const struct i2c_algorithm *const i2c_hotplug_algo[2][2] = { + /* non-I2C */ + { NULL, &i2c_hotplug_algo_smbus }, + /* I2C */ + { &i2c_hotplug_algo_i2c, &i2c_hotplug_algo_both } +}; + +static void i2c_hotplug_lock_bus(struct i2c_adapter *adap, unsigned int flags) +{ + i2c_lock_bus(i2c_hotplug_parent(adap), flags); +} + +static int i2c_hotplug_trylock_bus(struct i2c_adapter *adap, + unsigned int flags) +{ + return i2c_trylock_bus(i2c_hotplug_parent(adap), flags); +} + +static void i2c_hotplug_unlock_bus(struct i2c_adapter *adap, + unsigned int flags) +{ + i2c_unlock_bus(i2c_hotplug_parent(adap), flags); +} + +static const struct i2c_lock_operations i2c_hotplug_lock_ops = { + .lock_bus = i2c_hotplug_lock_bus, + .trylock_bus = i2c_hotplug_trylock_bus, + .unlock_bus = i2c_hotplug_unlock_bus, +}; + +static int i2c_hotplug_recover_bus(struct i2c_adapter *adap) +{ + return i2c_recover_bus(i2c_hotplug_parent(adap)); +} + +static struct i2c_bus_recovery_info i2c_hotplug_recovery_info = { + .recover_bus = i2c_hotplug_recover_bus, +}; + +static int i2c_hotplug_activate(struct i2c_hotplug_priv *priv) +{ + int ret; + + if (priv->adap.algo_data) + return 0; + + /* + * Store the dev data in adapter dev, since + * previous i2c_del_adapter might have wiped it. + */ + priv->adap.dev.parent = priv->dev; + priv->adap.dev.of_node = priv->dev->of_node; + + dev_dbg(priv->adap.dev.parent, "connection detected"); + + ret = i2c_add_adapter(&priv->adap); + if (!ret) + priv->adap.algo_data = (void *)1; + + return ret; +} + +static void i2c_hotplug_deactivate(struct i2c_hotplug_priv *priv) +{ + if (!priv->adap.algo_data) + return; + + dev_dbg(priv->adap.dev.parent, "disconnection detected"); + + i2c_del_adapter(&priv->adap); + priv->adap.algo_data = NULL; +} + +static irqreturn_t i2c_hotplug_interrupt(int irq, void *dev_id) +{ + struct i2c_hotplug_priv *priv = dev_id; + + /* debounce */ + msleep(20); + + if (gpiod_get_value_cansleep(priv->gpio)) + i2c_hotplug_activate(priv); + else + i2c_hotplug_deactivate(priv); + + return IRQ_HANDLED; +} + +static void devm_i2c_put_adapter(void *adapter) +{ + i2c_put_adapter(adapter); +} + +static int i2c_hotplug_gpio_probe(struct platform_device *pdev) +{ + struct device_node *parent_np; + struct i2c_adapter *parent; + struct i2c_hotplug_priv *priv; + bool is_i2c, is_smbus; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + platform_set_drvdata(pdev, priv); + priv->dev = &pdev->dev; + + parent_np = of_parse_phandle(pdev->dev.of_node, "i2c-parent", 0); + if (IS_ERR(parent_np)) + return dev_err_probe(&pdev->dev, PTR_ERR(parent_np), + "cannot parse i2c-parent\n"); + + parent = of_find_i2c_adapter_by_node(parent_np); + of_node_put(parent_np); + if (IS_ERR(parent)) + return dev_err_probe(&pdev->dev, PTR_ERR(parent), + "failed to get parent I2C adapter\n"); + priv->parent = parent; + + ret = devm_add_action_or_reset(&pdev->dev, devm_i2c_put_adapter, + parent); + if (ret) + return ret; + + priv->gpio = devm_gpiod_get(&pdev->dev, "detect", GPIOD_IN); + if (IS_ERR(priv->gpio)) + return dev_err_probe(&pdev->dev, PTR_ERR(priv->gpio), + "failed to get detect GPIO\n"); + + is_i2c = parent->algo->master_xfer; + is_smbus = parent->algo->smbus_xfer; + + snprintf(priv->adap.name, sizeof(priv->adap.name), + "i2c-hotplug (master i2c-%d)", i2c_adapter_id(parent)); + priv->adap.owner = THIS_MODULE; + priv->adap.algo = i2c_hotplug_algo[is_i2c][is_smbus]; + priv->adap.algo_data = NULL; + priv->adap.lock_ops = &i2c_hotplug_lock_ops; + priv->adap.class = parent->class; + priv->adap.retries = parent->retries; + priv->adap.timeout = parent->timeout; + priv->adap.quirks = parent->quirks; + if (parent->bus_recovery_info) + priv->adap.bus_recovery_info = &i2c_hotplug_recovery_info; + + if (!priv->adap.algo) + return -EINVAL; + + priv->irq = platform_get_irq(pdev, 0); + if (priv->irq < 0) + return dev_err_probe(&pdev->dev, priv->irq, + "failed to get IRQ %d\n", priv->irq); + + ret = devm_request_threaded_irq(&pdev->dev, priv->irq, NULL, + i2c_hotplug_interrupt, + IRQF_ONESHOT | IRQF_SHARED, + "i2c-hotplug", priv); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "failed to register IRQ %d\n", priv->irq); + + irq_wake_thread(priv->irq, priv); + + return 0; +} + +static int i2c_hotplug_gpio_remove(struct platform_device *pdev) +{ + struct i2c_hotplug_priv *priv = platform_get_drvdata(pdev); + + i2c_hotplug_deactivate(priv); + + return 0; +} + +static const struct of_device_id i2c_hotplug_gpio_of_match[] = { + { .compatible = "i2c-hotplug-gpio" }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_hotplug_gpio_of_match); + +static struct platform_driver i2c_hotplug_gpio_driver = { + .probe = i2c_hotplug_gpio_probe, + .remove = i2c_hotplug_gpio_remove, + .driver = { + .name = "i2c-hotplug-gpio", + .of_match_table = i2c_hotplug_gpio_of_match, + }, +}; + +module_platform_driver(i2c_hotplug_gpio_driver); + +MODULE_DESCRIPTION("Hot-plugged I2C bus detected by GPIO"); +MODULE_AUTHOR("Michał Mirosław "); +MODULE_LICENSE("GPL");