From patchwork Tue Mar 9 20:59:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 397025 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,DKIM_SIGNED, DKIM_VALID, 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 A7E71C433E6 for ; Tue, 9 Mar 2021 21:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7744865250 for ; Tue, 9 Mar 2021 21:00:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232063AbhCIVAN (ORCPT ); Tue, 9 Mar 2021 16:00:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231970AbhCIU7m (ORCPT ); Tue, 9 Mar 2021 15:59:42 -0500 Received: from mail-wr1-x431.google.com (mail-wr1-x431.google.com [IPv6:2a00:1450:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66973C06175F for ; Tue, 9 Mar 2021 12:59:41 -0800 (PST) Received: by mail-wr1-x431.google.com with SMTP id l11so15126925wrp.7 for ; Tue, 09 Mar 2021 12:59:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ItiZOkb9LXwdXIAzNxaU55PAysGpACGNcO54wLmkmU0=; b=DU8DyLD+0C8D3ukYtrlE783YpBa0ILCNShFqQF2Gk1krfu7VdOB45AAvmiurTutyEm gpoa0AVs2u7qX+lGg7wz5GJi299gJFAih+i8mud90+J6n1nCA/ktMT026EGas2sXe4Yy TxO0cOdh9dTrGVUUG2gx0yaTeuWycJCIL2Isugf4lTeCWU0HnwBh6c2ImjcgI1u9HQ+4 xhKylfkRLqIm98DhdVIQUMqDWKnpGb/LVVx/mr/B8x42d6bVNVQYtAKklNcRp8TneJkR KZ+6s+jj72QbTLJJUuh41vZxd+neW6yO4VvT6lBVoVNR1L1AobX8aSEZrSoHsBO/dFBu kBoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ItiZOkb9LXwdXIAzNxaU55PAysGpACGNcO54wLmkmU0=; b=uD5k6JSBD5LiFzp1o3UQUmnZ/rEPXequdX0sMkT33UCWoSr+w79A19xN+JTUeBWqmU Vs7ARkLTTbcvAzguOuVk6Kaix/p3PTsp+r7kflmwKPgJgH6KToPqxZWhCQWii8EwbleT i7brNcI6dbaQhYpobSHqcSIYy5fBo5AYnGgpQkmHKC2MPnlRBd2VPsdB6YHLrrTd0aAx QGWsd49eamufO6Pkdim3gjEF6Oq9sHCs3BWv1ETSQJYysuJO0x9UQtq+y1eMvILReVva zD4EguaKLcjPjbabYvSTeHh90wwCtij9Tl8qEsoEuqI7XduL0L0u5FQ2SZqoPn/sE5SF 9e0g== X-Gm-Message-State: AOAM533yoNKMaQh0xVObbR4kSzFdI03mxGvvocFW2NjmeFhv3AVSp0TT F4HDdUx+N3/2aJQybLQyPG1RAg== X-Google-Smtp-Source: ABdhPJzAvqvQ14Pa7hGqRwzPSN++HYdTTN5BKp0V9kjwj51LgN+D0zRlgoIv2A0IeKPLO3VpKdtaaw== X-Received: by 2002:adf:f711:: with SMTP id r17mr30431852wrp.358.1615323580008; Tue, 09 Mar 2021 12:59:40 -0800 (PST) Received: from debian-brgl.home (amarseille-656-1-4-167.w90-8.abo.wanadoo.fr. [90.8.158.167]) by smtp.gmail.com with ESMTPSA id j6sm5501305wmq.16.2021.03.09.12.59.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Mar 2021 12:59:39 -0800 (PST) From: Bartosz Golaszewski To: Joel Becker , Christoph Hellwig , Shuah Khan , Linus Walleij , Andy Shevchenko , =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= , Geert Uytterhoeven , Kent Gibson , Jonathan Corbet , Greg Kroah-Hartman Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v3 08/11] gpio: sim: new testing module Date: Tue, 9 Mar 2021 21:59:18 +0100 Message-Id: <20210309205921.15992-9-brgl@bgdev.pl> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210309205921.15992-1-brgl@bgdev.pl> References: <20210309205921.15992-1-brgl@bgdev.pl> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Bartosz Golaszewski Implement a new, modern GPIO testing module controlled by configfs attributes instead of module parameters. The goal of this driver is to provide a replacement for gpio-mockup that will be easily extensible with new features and doesn't require reloading the module to change the setup. Signed-off-by: Bartosz Golaszewski Reviewed-by: Linus Walleij --- Documentation/admin-guide/gpio/gpio-sim.rst | 72 ++ drivers/gpio/Kconfig | 8 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sim.c | 879 ++++++++++++++++++++ 4 files changed, 960 insertions(+) create mode 100644 Documentation/admin-guide/gpio/gpio-sim.rst create mode 100644 drivers/gpio/gpio-sim.c diff --git a/Documentation/admin-guide/gpio/gpio-sim.rst b/Documentation/admin-guide/gpio/gpio-sim.rst new file mode 100644 index 000000000000..08eac487e35e --- /dev/null +++ b/Documentation/admin-guide/gpio/gpio-sim.rst @@ -0,0 +1,72 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +Configfs GPIO Simulator +======================= + +The configfs GPIO Simulator (gpio-sim) provides a way to create simulated GPIO +chips for testing purposes. The lines exposed by these chips can be accessed +using the standard GPIO character device interface as well as manipulated +using sysfs attributes. + +Creating simulated chips +------------------------ + +The gpio-sim module registers a configfs subsystem called 'gpio-sim'. It's a +subsystem with committable items which means two subdirectories are created in +the filesystem: pending and live. For more information on configfs and +committable items, please refer to Documentation/filesystems/configfs.rst. + +In order to instantiate a new simulated chip, the user needs to mkdir() a new +directory in pending/. Inside each new directory, there's a set of attributes +that can be used to configure the new chip. Once the configuration is complete, +the user needs to use rename() to move the chip to the live/ directory. This +creates and registers the new device. + +In order to destroy a simulated chip, it has to be moved back to pending first +and then removed using rmdir(). + +Currently supported configuration attributes are: + + num_lines - an unsigned integer value defining the number of GPIO lines to + export + + label - a string defining the label for the GPIO chip + + line_names - a list of GPIO line names in the form of quoted strings + separated by commas, e.g.: '"foo", "bar", "", "foobar"'. The + number of strings doesn't have to be equal to the value set in + the num_lines attribute. If it's lower than the number of lines, + the remaining lines are unnamed. If it's larger, the superfluous + lines are ignored. A name of the form: '""' means the line + should be unnamed. + +Additionally two read-only attributes named 'chip_name' and 'dev_name' are +exposed in order to provide users with a mapping from configfs directories to +the actual devices created in the kernel. The former returns the name of the +GPIO device as assigned by gpiolib (i.e. "gpiochip0", "gpiochip1", etc.). The +latter returns the parent device name as defined by the gpio-sim driver (i.e. +"gpio-sim.0", "gpio-sim.1", etc.). This allows user-space to map the configfs +items both to the correct character device file as well as the associated entry +in sysfs. + +Simulated GPIO chips can also be defined in device-tree. The compatible string +must be: "gpio-simulator". Supported properties are: + + "gpio-sim,label" - chip label + + "gpio-sim,nr-gpios" - number of lines + +Other standard GPIO properties (like "gpio-line-names" and gpio-hog) are also +supported. + +Manipulating simulated lines +---------------------------- + +Each simulated GPIO chip creates a sysfs attribute group under its device +directory called 'line-ctrl'. Inside each group, there's a separate attribute +for each GPIO line. The name of the attribute is of the form 'gpioX' where X +is the line's offset in the chip. + +Reading from a line attribute returns the current value. Writing to it (0 or 1) +changes the configuration of the simulated pull-up/pull-down resistor +(1 - pull-up, 0 - pull-down). diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index e3607ec4c2e8..b6b6150d0d04 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1633,6 +1633,14 @@ config GPIO_MOCKUP tools/testing/selftests/gpio/gpio-mockup.sh. Reference the usage in it. +config GPIO_SIM + tristate "GPIO Simulator Module" + select IRQ_SIM + select CONFIGFS_FS + help + This enables the GPIO simulator - a configfs-based GPIO testing + driver. + endmenu endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index c58a90a3c3b1..d717aa85f8e1 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -130,6 +130,7 @@ obj-$(CONFIG_GPIO_SAMA5D2_PIOBU) += gpio-sama5d2-piobu.o obj-$(CONFIG_GPIO_SCH311X) += gpio-sch311x.o obj-$(CONFIG_GPIO_SCH) += gpio-sch.o obj-$(CONFIG_GPIO_SIFIVE) += gpio-sifive.o +obj-$(CONFIG_GPIO_SIM) += gpio-sim.o obj-$(CONFIG_GPIO_SIOX) += gpio-siox.o obj-$(CONFIG_GPIO_SL28CPLD) += gpio-sl28cpld.o obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c new file mode 100644 index 000000000000..253f5b4bd1f5 --- /dev/null +++ b/drivers/gpio/gpio-sim.c @@ -0,0 +1,879 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO testing driver based on configfs. + * + * Copyright (C) 2021 Bartosz Golaszewski + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpiolib.h" + +/* + * This normally should correspond with the number of attributes exposed over + * configfs + sentinel. + */ +#define GPIO_SIM_MAX_PROP 4 + +static DEFINE_IDA(gpio_sim_ida); + +struct gpio_sim_chip { + struct gpio_chip gc; + unsigned long *directions; + unsigned long *values; + unsigned long *pulls; + struct irq_domain *irq_sim; + struct mutex lock; + struct attribute_group attr_group; +}; + +struct gpio_sim_attribute { + struct device_attribute dev_attr; + unsigned int offset; +}; + +static struct gpio_sim_attribute * +to_gpio_sim_attr(struct device_attribute *dev_attr) +{ + return container_of(dev_attr, struct gpio_sim_attribute, dev_attr); +} + +static int gpio_sim_apply_pull(struct gpio_sim_chip *chip, + unsigned int offset, int value) +{ + int curr_val, irq, irq_type, ret; + struct gpio_desc *desc; + struct gpio_chip *gc; + + gc = &chip->gc; + desc = &gc->gpiodev->descs[offset]; + + mutex_lock(&chip->lock); + + if (test_bit(FLAG_REQUESTED, &desc->flags) && + !test_bit(FLAG_IS_OUT, &desc->flags)) { + curr_val = !!test_bit(offset, chip->values); + if (curr_val == value) + goto set_pull; + + /* + * This is fine - it just means, nobody is listening + * for interrupts on this line, otherwise + * irq_create_mapping() would have been called from + * the to_irq() callback. + */ + irq = irq_find_mapping(chip->irq_sim, offset); + if (!irq) + goto set_value; + + irq_type = irq_get_trigger_type(irq); + + if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) || + (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) { + ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, + true); + if (ret) + goto set_pull; + } + } + +set_value: + /* Change the value unless we're actively driving the line. */ + if (!test_bit(FLAG_REQUESTED, &desc->flags) || + !test_bit(FLAG_IS_OUT, &desc->flags)) + __assign_bit(offset, chip->values, value); + +set_pull: + __assign_bit(offset, chip->pulls, value); + mutex_unlock(&chip->lock); + return 0; +} + +static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + int ret; + + mutex_lock(&chip->lock); + ret = !!test_bit(offset, chip->values); + mutex_unlock(&chip->lock); + + return ret; +} + +static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __assign_bit(offset, chip->values, value); + mutex_unlock(&chip->lock); +} + +static int gpio_sim_get_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + bitmap_copy(bits, chip->values, gc->ngpio); + mutex_unlock(&chip->lock); + + return 0; +} + +static void gpio_sim_set_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + bitmap_copy(chip->values, bits, gc->ngpio); + mutex_unlock(&chip->lock); +} + +static int gpio_sim_direction_output(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __clear_bit(offset, chip->directions); + __assign_bit(offset, chip->values, value); + mutex_unlock(&chip->lock); + + return 0; +} + +static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __set_bit(offset, chip->directions); + mutex_unlock(&chip->lock); + + return 0; +} + +static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + int direction; + + mutex_lock(&chip->lock); + direction = !!test_bit(offset, chip->directions); + mutex_unlock(&chip->lock); + + return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT; +} + +static int gpio_sim_set_config(struct gpio_chip *gc, + unsigned int offset, unsigned long config) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + switch (pinconf_to_config_param(config)) { + case PIN_CONFIG_BIAS_PULL_UP: + return gpio_sim_apply_pull(chip, offset, 1); + case PIN_CONFIG_BIAS_PULL_DOWN: + return gpio_sim_apply_pull(chip, offset, 0); + default: + break; + } + + return -ENOTSUPP; +} + +static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + return irq_create_mapping(chip->irq_sim, offset); +} + +static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __assign_bit(offset, chip->values, !!test_bit(offset, chip->pulls)); + mutex_unlock(&chip->lock); +} + +static ssize_t gpio_sim_sysfs_line_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); + struct gpio_sim_chip *chip = dev_get_drvdata(dev); + int ret; + + mutex_lock(&chip->lock); + ret = sprintf(buf, "%u\n", !!test_bit(line_attr->offset, chip->values)); + mutex_unlock(&chip->lock); + + return ret; +} + +static ssize_t gpio_sim_sysfs_line_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); + struct gpio_sim_chip *chip = dev_get_drvdata(dev); + int ret, val; + + if (len > 2 || (buf[0] != '0' && buf[0] != '1')) + return -EINVAL; + + val = buf[0] == '0' ? 0 : 1; + + ret = gpio_sim_apply_pull(chip, line_attr->offset, val); + if (ret) + return ret; + + return len; +} + +static void gpio_sim_mutex_destroy(void *data) +{ + struct mutex *lock = data; + + mutex_destroy(lock); +} + +static void gpio_sim_sysfs_remove(void *data) +{ + struct gpio_sim_chip *chip = data; + + sysfs_remove_group(&chip->gc.parent->kobj, &chip->attr_group); +} + +static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip) +{ + unsigned int i, num_lines = chip->gc.ngpio; + struct device *dev = chip->gc.parent; + struct gpio_sim_attribute *line_attr; + struct device_attribute *dev_attr; + struct attribute **attrs; + int ret; + + attrs = devm_kcalloc(dev, sizeof(*attrs), num_lines + 1, GFP_KERNEL); + if (!attrs) + return -ENOMEM; + + for (i = 0; i < num_lines; i++) { + line_attr = devm_kzalloc(dev, sizeof(*line_attr), GFP_KERNEL); + if (!line_attr) + return -ENOMEM; + + line_attr->offset = i; + + dev_attr = &line_attr->dev_attr; + + dev_attr->attr.name = devm_kasprintf(dev, GFP_KERNEL, + "gpio%u", i); + if (!dev_attr->attr.name) + return -ENOMEM; + + dev_attr->attr.mode = 0644; + + dev_attr->show = gpio_sim_sysfs_line_show; + dev_attr->store = gpio_sim_sysfs_line_store; + + attrs[i] = &dev_attr->attr; + } + + chip->attr_group.name = "line-ctrl"; + chip->attr_group.attrs = attrs; + + ret = sysfs_create_group(&dev->kobj, &chip->attr_group); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip); +} + +static int gpio_sim_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct gpio_sim_chip *chip; + struct gpio_chip *gc; + const char *label; + u32 num_lines; + int ret; + + ret = device_property_read_u32(dev, "gpio-sim,nr-gpios", &num_lines); + if (ret) + return ret; + + ret = device_property_read_string(dev, "gpio-sim,label", &label); + if (ret) + label = dev_name(dev); + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->directions = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL); + if (!chip->directions) + return -ENOMEM; + + /* Default to input mode. */ + bitmap_fill(chip->directions, num_lines); + + chip->values = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); + if (!chip->values) + return -ENOMEM; + + chip->pulls = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); + if (!chip->pulls) + return -ENOMEM; + + chip->irq_sim = devm_irq_domain_create_sim(dev, NULL, num_lines); + if (IS_ERR(chip->irq_sim)) + return PTR_ERR(chip->irq_sim); + + mutex_init(&chip->lock); + ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy, + &chip->lock); + if (ret) + return ret; + + gc = &chip->gc; + gc->base = -1; + gc->ngpio = num_lines; + gc->label = label; + gc->owner = THIS_MODULE; + gc->parent = dev; + gc->get = gpio_sim_get; + gc->set = gpio_sim_set; + gc->get_multiple = gpio_sim_get_multiple; + gc->set_multiple = gpio_sim_set_multiple; + gc->direction_output = gpio_sim_direction_output; + gc->direction_input = gpio_sim_direction_input; + gc->get_direction = gpio_sim_get_direction; + gc->set_config = gpio_sim_set_config; + gc->to_irq = gpio_sim_to_irq; + gc->free = gpio_sim_free; + + ret = devm_gpiochip_add_data(dev, gc, chip); + if (ret) + return ret; + + /* Used by sysfs and configfs callbacks. */ + dev_set_drvdata(dev, chip); + + ret = gpio_sim_setup_sysfs(chip); + if (ret) + return ret; + + return 0; +} + +static const struct of_device_id gpio_sim_of_match[] = { + { .compatible = "gpio-simulator" }, + { } +}; +MODULE_DEVICE_TABLE(of, gpio_sim_of_match); + +static struct platform_driver gpio_sim_driver = { + .driver = { + .name = "gpio-sim", + }, + .probe = gpio_sim_probe, +}; + +struct gpio_sim_chip_config { + struct config_item item; + + /* + * If pdev is NULL, the item is 'pending' (waiting for configuration). + * Once the pointer is assigned, the device has been created and the + * item is 'live'. + */ + struct platform_device *pdev; + + /* + * Each configfs filesystem operation is protected with the subsystem + * mutex. Each separate attribute is protected with the buffer mutex. + * This structure however can be modified by callbacks of different + * attributes so we need another lock. + */ + struct mutex lock; + + char label[32]; + unsigned int num_lines; + char **line_names; + unsigned int num_line_names; +}; + +static struct gpio_sim_chip_config * +to_gpio_sim_chip_config(struct config_item *item) +{ + return container_of(item, struct gpio_sim_chip_config, item); +} + +static ssize_t gpio_sim_config_dev_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + struct platform_device *pdev; + int ret; + + mutex_lock(&config->lock); + pdev = config->pdev; + if (pdev) + ret = sprintf(page, "%s\n", dev_name(&pdev->dev)); + else + ret = sprintf(page, "n/a\n"); + mutex_unlock(&config->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_config_, dev_name); + +static ssize_t gpio_sim_config_chip_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + struct gpio_sim_chip *chip = NULL; + struct platform_device *pdev; + int ret; + + mutex_lock(&config->lock); + pdev = config->pdev; + if (pdev) + chip = dev_get_drvdata(&pdev->dev); + + if (chip) + ret = sprintf(page, "%s\n", dev_name(&chip->gc.gpiodev->dev)); + else + ret = sprintf(page, "n/a\n"); + mutex_unlock(&config->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_config_, chip_name); + +static ssize_t gpio_sim_config_label_show(struct config_item *item, char *page) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + int ret; + + mutex_lock(&config->lock); + ret = sprintf(page, "%s\n", config->label); + mutex_unlock(&config->lock); + + return ret; +} + +static ssize_t gpio_sim_config_label_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + char *dup, *trimmed; + int ret; + + mutex_lock(&config->lock); + + if (config->pdev) { + mutex_unlock(&config->lock); + return -EBUSY; + } + + dup = kstrndup(page, count, GFP_KERNEL); + if (!dup) { + mutex_unlock(&config->lock); + return -ENOMEM; + } + + trimmed = strstrip(dup); + ret = snprintf(config->label, sizeof(config->label), "%s", trimmed); + kfree(dup); + if (ret < 0) { + mutex_unlock(&config->lock); + return ret; + } + + mutex_unlock(&config->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_config_, label); + +static ssize_t gpio_sim_config_num_lines_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + int ret; + + mutex_lock(&config->lock); + ret = sprintf(page, "%u\n", config->num_lines); + mutex_unlock(&config->lock); + + return ret; +} + +static ssize_t gpio_sim_config_num_lines_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + unsigned int num_lines; + int ret; + + mutex_lock(&config->lock); + + if (config->pdev) { + mutex_unlock(&config->lock); + return -EBUSY; + } + + ret = kstrtouint(page, 10, &num_lines); + if (ret) { + mutex_unlock(&config->lock); + return ret; + } + + if (num_lines == 0) { + mutex_unlock(&config->lock); + return -EINVAL; + } + + config->num_lines = num_lines; + + mutex_unlock(&config->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_config_, num_lines); + +static ssize_t gpio_sim_config_line_names_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + int ret, i, written = 0; + + mutex_lock(&config->lock); + + if (!config->line_names) { + mutex_unlock(&config->lock); + return sprintf(page, "\n"); + } + + for (i = 0; i < config->num_line_names; i++) { + ret = sprintf(page + written, + i < config->num_line_names - 1 ? "\"%s\", " : "\"%s\"\n", + config->line_names[i] ?: ""); + if (ret < 0) { + mutex_unlock(&config->lock); + return ret; + } + + written += ret; + } + + mutex_unlock(&config->lock); + return written; +} + +static ssize_t gpio_sim_config_line_names_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + unsigned int num_new_names = 1, num_old_names, name_idx = 0; + bool in_quote = false, got_comma = true; + char **new_names, **old_names, *name, c; + const char *start = page; + size_t pos, name_len; + int err = -EINVAL; + + mutex_lock(&config->lock); + + if (config->pdev) { + mutex_unlock(&config->lock); + return -EBUSY; + } + + /* + * Line names are stored in a pointer array so that we can easily + * pass them down to the GPIO subsystem in a "gpio-line-names" + * property. + * + * Line names must be passed as a list of quoted names separated by + * commas, for example: '"foo", "bar", "foobar"'. + */ + + for (pos = 0; pos < count; pos++) { + /* + * Just count the commas and assume the number if strings + * equals the number of commas + 1. If the format is wrong + * we'll bail out anyway. + */ + if (page[pos] == ',') + num_new_names++; + } + + new_names = kcalloc(num_new_names, sizeof(char *), GFP_KERNEL); + if (!new_names) { + mutex_unlock(&config->lock); + return -ENOMEM; + } + + /* + * REVISIT There are more users in the kernel that want to split + * comma-separated strings into tokens. We should generalize it and + * put it into lib/. + */ + for (pos = 0; pos < count; pos++) { + c = page[pos]; + + if (in_quote) { + if (c == '"') { + /* This is the end of the name. */ + in_quote = got_comma = false; + name_len = (page + pos) - start; + if (name_len == 0) { + /* Name is empty (passed as ""). */ + name_idx++; + continue; + } + + name = kmemdup(start, name_len + 1, GFP_KERNEL); + if (!name) { + err = -ENOMEM; + goto err_out; + } + + name[name_len] = '\0'; + new_names[name_idx++] = name; + } + } else { + if (c == '"') { + /* Enforce separating names with commas. */ + if (!got_comma) + goto err_out; + + start = page + pos + 1; + in_quote = true; + } else if (c == ',') { + if (!got_comma) + got_comma = true; + else + /* Double commas are not allowed. */ + goto err_out; + } else if (!isspace(c)) { + goto err_out; + } + } + } + + /* + * End of input sanity checks, must not have a comma at the end and + * must have finished scanning the last name. + */ + if (in_quote || got_comma) + goto err_out; + + old_names = config->line_names; + num_old_names = config->num_line_names; + config->line_names = new_names; + config->num_line_names = num_new_names; + + mutex_unlock(&config->lock); + kfree_strarray(old_names, num_old_names); + return count; + +err_out: + mutex_unlock(&config->lock); + kfree_strarray(new_names, name_idx); + return err; +} + +CONFIGFS_ATTR(gpio_sim_config_, line_names); + +static struct configfs_attribute *gpio_sim_config_attrs[] = { + &gpio_sim_config_attr_dev_name, + &gpio_sim_config_attr_chip_name, + &gpio_sim_config_attr_label, + &gpio_sim_config_attr_num_lines, + &gpio_sim_config_attr_line_names, + NULL +}; + +static void gpio_sim_chip_config_release(struct config_item *item) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + + mutex_destroy(&config->lock); + kfree_strarray(config->line_names, config->num_line_names); + kfree(config); +} + +static struct configfs_item_operations gpio_sim_config_item_ops = { + .release = gpio_sim_chip_config_release, +}; + +static const struct config_item_type gpio_sim_chip_config_type = { + .ct_item_ops = &gpio_sim_config_item_ops, + .ct_attrs = gpio_sim_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_item * +gpio_sim_config_make_item(struct config_group *group, const char *name) +{ + struct gpio_sim_chip_config *config; + + config = kzalloc(sizeof(*config), GFP_KERNEL); + if (!config) + return ERR_PTR(-ENOMEM); + + config_item_init_type_name(&config->item, name, + &gpio_sim_chip_config_type); + config->num_lines = 1; + mutex_init(&config->lock); + + return &config->item; +} + +static int gpio_sim_config_commit_item(struct config_item *item) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + struct property_entry properties[GPIO_SIM_MAX_PROP]; + struct platform_device_info pdevinfo; + struct platform_device *pdev; + unsigned int prop_idx = 0; + + memset(&pdevinfo, 0, sizeof(pdevinfo)); + memset(properties, 0, sizeof(properties)); + + mutex_lock(&config->lock); + + properties[prop_idx++] = PROPERTY_ENTRY_U32("gpio-sim,nr-gpios", + config->num_lines); + + if (config->label[0] != '\0') + properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label", + config->label); + + if (config->line_names) + properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( + "gpio-line-names", + config->line_names, + config->num_line_names); + + pdevinfo.id = ida_alloc(&gpio_sim_ida, GFP_KERNEL); + if (pdevinfo.id < 0) { + mutex_unlock(&config->lock); + return pdevinfo.id; + } + + pdevinfo.name = "gpio-sim"; + pdevinfo.properties = properties; + + pdev = platform_device_register_full(&pdevinfo); + if (IS_ERR(pdev)) { + ida_free(&gpio_sim_ida, pdevinfo.id); + mutex_unlock(&config->lock); + return PTR_ERR(pdev); + } + + config->pdev = pdev; + mutex_unlock(&config->lock); + + return 0; +} + +static int gpio_sim_config_uncommit_item(struct config_item *item) +{ + struct gpio_sim_chip_config *config = to_gpio_sim_chip_config(item); + int id; + + mutex_lock(&config->lock); + id = config->pdev->id; + platform_device_unregister(config->pdev); + config->pdev = NULL; + mutex_unlock(&config->lock); + + ida_free(&gpio_sim_ida, id); + return 0; +} + +static struct configfs_group_operations gpio_sim_config_group_ops = { + .make_item = gpio_sim_config_make_item, + .commit_item = gpio_sim_config_commit_item, + .uncommit_item = gpio_sim_config_uncommit_item, +}; + +static const struct config_item_type gpio_sim_config_type = { + .ct_group_ops = &gpio_sim_config_group_ops, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem gpio_sim_config_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "gpio-sim", + .ci_type = &gpio_sim_config_type, + }, + }, +}; + +static int __init gpio_sim_init(void) +{ + int ret; + + ret = platform_driver_register(&gpio_sim_driver); + if (ret) { + pr_err("Error %d while registering the platform driver\n", ret); + return ret; + } + + config_group_init(&gpio_sim_config_subsys.su_group); + mutex_init(&gpio_sim_config_subsys.su_mutex); + ret = configfs_register_subsystem(&gpio_sim_config_subsys); + if (ret) { + pr_err("Error %d while registering the configfs subsystem %s\n", + ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf); + mutex_destroy(&gpio_sim_config_subsys.su_mutex); + platform_driver_unregister(&gpio_sim_driver); + return ret; + } + + return 0; +} +module_init(gpio_sim_init); + +static void __exit gpio_sim_exit(void) +{ + configfs_unregister_subsystem(&gpio_sim_config_subsys); + mutex_destroy(&gpio_sim_config_subsys.su_mutex); + platform_driver_unregister(&gpio_sim_driver); +} +module_exit(gpio_sim_exit); + +MODULE_AUTHOR("Bartosz Golaszewski "); +MODULE_DESCRIPTION("GPIO Simulator Module"); +MODULE_LICENSE("GPL");