From patchwork Sat Jul 29 16:08:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Svyatoslav Ryhel X-Patchwork-Id: 128166 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:918b:0:b0:3e4:2afc:c1 with SMTP id s11csp1171350vqg; Sat, 29 Jul 2023 11:56:35 -0700 (PDT) X-Google-Smtp-Source: APBJJlGqBmeP/jaWzmQXRJmmF2SSrwRyEiI8y4EtaOHEpEhBE47S43xhf3p7SOjzIsMoYp7sWQPa X-Received: by 2002:a17:902:b598:b0:1b8:4607:c3d7 with SMTP id a24-20020a170902b59800b001b84607c3d7mr5233278pls.41.1690656995241; Sat, 29 Jul 2023 11:56:35 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690656995; cv=none; d=google.com; s=arc-20160816; b=Az7XrK8r5O0sY3isEM7oAYM+fEnJXvQAqBWnIfDIWeAxaK6K+H42cdsdYfHvQYhIxI nems0FGOoK5WnF/6wTGXyuRsYKnzWrWB99hnWcY1h1FlYUEDy/hMUqK5vE4dC7CyLblc VGbzA31zboO/gDk4NSonOX0AD83xOiv4bQeNCwNjOXtCcyNL0jPvGjNnEmh+iZmj/4Bg A3l4xpxfKx37BAs5epD0iY/gVKUuTeAAU1N1xM3XyK6/WbOdisCSChnaRLJK+ohhdptn gNIm2R/f3k2fJODuHhQOihaAjBbscbfJZhdGAUubM8iFwtjVDJ8nJmhmi8zgw7n3aXFN nIIA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=w4vDNLM3XLifOUeIHk+++zlMfUYzj741T6wp3kNlkXU=; fh=bzppE1/iAplbw1xybVAfgEEAUsBu29MZ3J9baXku07w=; b=MnfYjXrIH/r+Yo7j8S7PtdqEYeAP6Z/JkqkcYTwlG6c45M3FLiHmzlDACcGwQKaxaG ZYhd0IsQwdkQL2SegmGL6vGjo7kUI61budwl4UxZmjAM2jLtLydIvrHRsRyg8gzm2a/A xvrVR39DdiYFtYL0TMRR39Jddmd2l0nRk0pg8z1TxijgRzCDa/0toLi1ECo+tG2yx3bq O7qxbcmMjaMbXvP2F6cEAhjx8gYjYMSkNAd76CTnwsEZsoQftZ8ed5YZR6xgc6z6EUMO eOhgSvw8WFFx30SURSzg4UKMf3HEKcVnfPG31zEMKFeWmOxDL2Lx6RdNDatpXyKQ8pn+ WjXg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20221208 header.b=C82RAcDO; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. 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([188.163.112.48]) by smtp.gmail.com with ESMTPSA id f10-20020a2ea0ca000000b002b6daa3fa2csm1346886ljm.69.2023.07.29.09.09.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Jul 2023 09:09:25 -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 v3 1/2] dt-bindings: i2c: add binding for i2c-hotplug-gpio Date: Sat, 29 Jul 2023 19:08:56 +0300 Message-Id: <20230729160857.6332-2-clamor95@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230729160857.6332-1-clamor95@gmail.com> References: <20230729160857.6332-1-clamor95@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772782349522849141 X-GMAIL-MSGID: 1772782349522849141 Document device tree schema which describes hot-pluggable via GPIO i2c bus. Signed-off-by: Svyatoslav Ryhel --- .../bindings/i2c/i2c-hotplug-gpio.yaml | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml diff --git a/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml new file mode 100644 index 000000000000..21f2b74ca6c1 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-hotplug-gpio.yaml @@ -0,0 +1,65 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-hotplug-gpio.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: GPIO detected hot-plugged I2C bus + +maintainers: + - Michał Mirosław + +description: + Driver for hot-plugged I2C busses, where some devices on a bus + are hot-pluggable and their presence is indicated by GPIO line. + +properties: + compatible: + items: + - const: i2c-hotplug-gpio + + '#address-cells': + const: 1 + + '#size-cells': + const: 0 + + interrupts-extended: + minItems: 1 + + detect-gpios: + maxItems: 1 + + i2c-parent: + maxItems: 1 + +required: + - compatible + - '#address-cells' + - '#size-cells' + - interrupts-extended + - detect-gpios + - i2c-parent + +unevaluatedProperties: false + +examples: + - | + /* + * Asus Transformers use I2C hotplug for attachable dock keyboard + */ + #include + #include + + i2c-dock { + compatible = "i2c-hotplug-gpio"; + + #address-cells = <1>; + #size-cells = <0>; + + interrupts-extended = <&gpio 164 IRQ_TYPE_EDGE_BOTH>; + detect-gpios = <&gpio 164 GPIO_ACTIVE_LOW>; + + i2c-parent = <&gen2_i2c>; + }; +... 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([188.163.112.48]) by smtp.gmail.com with ESMTPSA id f10-20020a2ea0ca000000b002b6daa3fa2csm1346886ljm.69.2023.07.29.09.09.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Jul 2023 09:09:26 -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 v3 2/2] i2c: Add GPIO-based hotplug gate Date: Sat, 29 Jul 2023 19:08:57 +0300 Message-Id: <20230729160857.6332-3-clamor95@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230729160857.6332-1-clamor95@gmail.com> References: <20230729160857.6332-1-clamor95@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772781495910217708 X-GMAIL-MSGID: 1772781495910217708 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. This feature is mainly used by the ASUS Transformers family. The Transformers have a connector that's used for USB, charging or for attaching a dock-keyboard (which also has a battery and a touchpad). This connector probably (can't be verified since no datasheets or special equipment is available) has an I2C bus lines and a "detect" line (pulled low on the dock side) among the pins. I guess there is either no additional chip or a transparent bridge/buffer chip, but nothing that could be controlled by software. For DT this setup could be modelled like an I2C gate or 2-port mux with enable joining two I2C buses (one "closer" to the CPU as a parent). 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");