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 brgl@bgdev.pl --- Documentation/admin-guide/gpio/gpio-sim.rst | 67 ++ drivers/gpio/Kconfig | 8 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-sim.c | 990 ++++++++++++++++++++ 4 files changed, 1066 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..7f2080f520d6 --- /dev/null +++ b/Documentation/admin-guide/gpio/gpio-sim.rst @@ -0,0 +1,67 @@ +.. 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'. + +In order to instantiate a new simulated chip, the user needs to mkdir() a new +directory gpio-sim/. Inside each new directory, there's a set of attributes +that can be used to configure the new chip. Additionally the user can mkdir() +subdirectories inside the chip's directory that allow to pass additional +configuration for specific lines. The name of those subdirectories must take +the form of: 'line<offset>' (e.g. 'line0', 'line20', etc.) as the name will be +used by the module to assign the config to the specific line at given offset. + +Once the confiuration is complete, the 'active' attribute must be set to 1 in +order to instantiate the chip. It can be set back to 0 to destroy the simulated +chip. + +Currently supported chip 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 + +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. + +Supported line configuration attributes are: + + name - a string defining the name of this line as used by the + "gpio-line-names" device property + +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 + +Other standard GPIO properties (like "gpio-line-names", "ngpios" or 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 072ed610f9c6..5c3b29bddc5b 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1693,6 +1693,14 @@ config GPIO_VIRTIO These virtual GPIOs can be routed to real GPIOs or attached to simulators on the host (like QEMU).

+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 71ee9fc2ff83..f21577de2474 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -133,6 +133,7 @@ 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..2a1c548548a0 --- /dev/null +++ b/drivers/gpio/gpio-sim.c @@ -0,0 +1,990 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO testing driver based on configfs. + * + * Copyright (C) 2021 Bartosz Golaszewski brgl@bgdev.pl + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/bitmap.h> +#include <linux/configfs.h> +#include <linux/device.h> +#include <linux/gpio/driver.h> +#include <linux/idr.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/irq_sim.h> +#include <linux/list.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/string_helpers.h> +#include <linux/sysfs.h> + +#include "gpiolib.h" + +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 = sysfs_emit(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; + sysfs_attr_init(&dev_attr->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 = "control"; + 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, "ngpios", &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); + + return gpio_sim_setup_sysfs(chip); +} + +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", + .of_match_table = gpio_sim_of_match, + }, + .probe = gpio_sim_probe, +}; + +struct gpio_sim_chip_ctx { + struct config_group group; + + /* + * 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; + int id; + + /* + * 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; + + struct list_head line_ctx_list; +}; + +struct gpio_sim_line_ctx { + struct config_item item; + struct list_head list; + + /* + * We could have used the ci_parent field of the config_item but + * configfs is stupid and calls the item's release callback after + * already having cleared the parent pointer even though the parent + * is guaranteed to survive the child... + * + * So we need to store the pointer to the parent struct here. + */ + struct gpio_sim_chip_ctx *parent; + + /* Same as the chip context. */ + struct mutex lock; + + unsigned int offset; + char *name; +}; + +static struct gpio_sim_chip_ctx *to_gpio_sim_chip_ctx(struct config_item *item) +{ + struct config_group *group = container_of(item, struct config_group, + cg_item); + + return container_of(group, struct gpio_sim_chip_ctx, group); +} + +static struct gpio_sim_line_ctx *to_gpio_sim_line_ctx(struct config_item *item) +{ + return container_of(item, struct gpio_sim_line_ctx, item); +} + +static bool gpio_sim_chip_live(struct gpio_sim_chip_ctx *ctx) +{ + return !!ctx->pdev; +} + +static char *gpio_sim_strdup_trimmed(const char *str, size_t count) +{ + char *dup, *trimmed, *ret; + + dup = kstrndup(str, count, GFP_KERNEL); + if (!dup) + return NULL; + + trimmed = strstrip(dup); + ret = kstrdup(trimmed, GFP_KERNEL); + kfree(dup); + return ret; +} + +static ssize_t gpio_sim_config_chip_dev_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + struct platform_device *pdev; + int ret; + + mutex_lock(&ctx->lock); + pdev = ctx->pdev; + if (pdev) + ret = sprintf(page, "%s\n", dev_name(&pdev->dev)); + else + ret = sprintf(page, "gpio-sim.%d\n", ctx->id); + mutex_unlock(&ctx->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_config_chip_, dev_name); + +static ssize_t gpio_sim_config_chip_chip_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + struct gpio_sim_chip *chip = NULL; + int ret; + + mutex_lock(&ctx->lock); + if (gpio_sim_chip_live(ctx)) + chip = dev_get_drvdata(&ctx->pdev->dev); + + if (chip) + ret = sprintf(page, "%s\n", dev_name(&chip->gc.gpiodev->dev)); + else + ret = sprintf(page, "none\n"); + mutex_unlock(&ctx->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_config_chip_, chip_name); + +static ssize_t +gpio_sim_config_chip_label_show(struct config_item *item, char *page) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + int ret; + + mutex_lock(&ctx->lock); + ret = sprintf(page, "%s\n", ctx->label); + mutex_unlock(&ctx->lock); + + return ret; +} + +static ssize_t gpio_sim_config_chip_label_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + char *trimmed; + int ret; + + mutex_lock(&ctx->lock); + + if (gpio_sim_chip_live(ctx)) { + mutex_unlock(&ctx->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&ctx->lock); + return -ENOMEM; + } + + ret = snprintf(ctx->label, sizeof(ctx->label), "%s", trimmed); + kfree(trimmed); + if (ret < 0) { + mutex_unlock(&ctx->lock); + return ret; + } + + mutex_unlock(&ctx->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_config_chip_, label); + +static ssize_t +gpio_sim_config_chip_num_lines_show(struct config_item *item, char *page) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + int ret; + + mutex_lock(&ctx->lock); + ret = sprintf(page, "%u\n", ctx->num_lines); + mutex_unlock(&ctx->lock); + + return ret; +} + +static ssize_t +gpio_sim_config_chip_num_lines_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + unsigned int num_lines; + int ret; + + mutex_lock(&ctx->lock); + + if (gpio_sim_chip_live(ctx)) { + mutex_unlock(&ctx->lock); + return -EBUSY; + } + + ret = kstrtouint(page, 10, &num_lines); + if (ret) { + mutex_unlock(&ctx->lock); + return ret; + } + + if (num_lines == 0) { + mutex_unlock(&ctx->lock); + return -EINVAL; + } + + ctx->num_lines = num_lines; + + mutex_unlock(&ctx->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_config_chip_, num_lines); + +static ssize_t +gpio_sim_config_chip_live_show(struct config_item *item, char *page) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + int ret; + + mutex_lock(&ctx->lock); + ret = sprintf(page, "%c\n", gpio_sim_chip_live(ctx) ? '1' : '0'); + mutex_unlock(&ctx->lock); + + return ret; +} + +static char **gpio_sim_make_line_names(struct gpio_sim_chip_ctx *chip_ctx, + unsigned int *line_names_size) +{ + struct gpio_sim_line_ctx *line_ctx; + unsigned int max_offset = 0; + bool has_line_names = false; + char **line_names; + + list_for_each_entry(line_ctx, &chip_ctx->line_ctx_list, list) { + if (line_ctx->name) { + if (line_ctx->offset > max_offset) + max_offset = line_ctx->offset; + + /* + * max_offset can stay at 0 so it's not an indicator + * of whether line names were configured at all. + */ + has_line_names = true; + } + } + + if (!has_line_names) + /* + * This is not an error - NULL means, there are no line + * names configured. + */ + return NULL; + + *line_names_size = max_offset + 1; + + line_names = kcalloc(*line_names_size, sizeof(*line_names), GFP_KERNEL); + if (!line_names) + return ERR_PTR(-ENOMEM); + + list_for_each_entry(line_ctx, &chip_ctx->line_ctx_list, list) { + if (line_ctx->name) + line_names[line_ctx->offset] = line_ctx->name; + } + + return line_names; +} + +static int gpio_sim_activate_chip_unlocked(struct gpio_sim_chip_ctx *ctx) +{ + unsigned int prop_idx = 0, line_names_size = 0; + struct platform_device_info pdevinfo; + struct property_entry properties[4]; /* Max 3 properties + sentinel. */ + struct fwnode_handle *fwnode; + struct platform_device *pdev; + char **line_names; + + memset(&pdevinfo, 0, sizeof(pdevinfo)); + memset(properties, 0, sizeof(properties)); + + properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", + ctx->num_lines); + + if (ctx->label[0] != '\0') + properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label", + ctx->label); + + line_names = gpio_sim_make_line_names(ctx, &line_names_size); + if (IS_ERR(line_names)) + return PTR_ERR(line_names); + + if (line_names) + properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( + "gpio-line-names", + line_names, line_names_size); + + fwnode = fwnode_create_software_node(properties, NULL); + /* + * fwnode_create_software_node() makes a deep copy of the properties, + * so no need to store the array of line names. + */ + kfree_strarray(line_names, line_names_size); + if (IS_ERR(fwnode)) + return PTR_ERR(fwnode); + + pdevinfo.name = "gpio-sim"; + pdevinfo.fwnode = fwnode; + pdevinfo.id = ctx->id; + + pdev = platform_device_register_full(&pdevinfo); + if (IS_ERR(pdev)) { + fwnode_remove_software_node(fwnode); + return PTR_ERR(pdev); + } + + ctx->pdev = pdev; + + return 0; +} + +static void gpio_sim_deactivate_chip_unlocked(struct gpio_sim_chip_ctx *ctx) +{ + struct fwnode_handle *fwnode; + + fwnode = dev_fwnode(&ctx->pdev->dev); + platform_device_unregister(ctx->pdev); + fwnode_remove_software_node(fwnode); + ctx->pdev = NULL; +} + +static ssize_t +gpio_sim_config_chip_live_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + int live, ret; + + ret = kstrtouint(page, 10, &live); + if (ret) + return ret; + + mutex_lock(&ctx->lock); + + if ((live == 0 && !gpio_sim_chip_live(ctx)) || + (live == 1 && gpio_sim_chip_live(ctx))) + ret = -EPERM; + else if (live == 1) + ret = gpio_sim_activate_chip_unlocked(ctx); + else if (live == 0) + gpio_sim_deactivate_chip_unlocked(ctx); + else + ret = -EINVAL; + + mutex_unlock(&ctx->lock); + + return ret ?: count; +} + +CONFIGFS_ATTR(gpio_sim_config_chip_, live); + +static struct configfs_attribute *gpio_sim_config_chip_attrs[] = { + &gpio_sim_config_chip_attr_dev_name, + &gpio_sim_config_chip_attr_chip_name, + &gpio_sim_config_chip_attr_label, + &gpio_sim_config_chip_attr_num_lines, + &gpio_sim_config_chip_attr_live, + NULL +}; + +static ssize_t +gpio_sim_config_line_name_show(struct config_item *item, char *page) +{ + struct gpio_sim_line_ctx *ctx = to_gpio_sim_line_ctx(item); + int ret; + + mutex_lock(&ctx->lock); + ret = sprintf(page, "%s\n", ctx->name ?: ""); + mutex_unlock(&ctx->lock); + + return ret; +} + +static ssize_t gpio_sim_config_line_name_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_line_ctx *line_ctx = to_gpio_sim_line_ctx(item); + struct gpio_sim_chip_ctx *chip_ctx = line_ctx->parent; + char *trimmed; + + mutex_lock(&chip_ctx->lock); + + if (gpio_sim_chip_live(chip_ctx)) { + mutex_unlock(&chip_ctx->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&chip_ctx->lock); + return -ENOMEM; + } + + mutex_lock(&line_ctx->lock); + + kfree(line_ctx->name); + line_ctx->name = trimmed; + + mutex_unlock(&line_ctx->lock); + mutex_unlock(&chip_ctx->lock); + + return count; +} + +CONFIGFS_ATTR(gpio_sim_config_line_, name); + +static struct configfs_attribute *gpio_sim_line_config_attrs[] = { + &gpio_sim_config_line_attr_name, + NULL, +}; + +static void gpio_sim_line_item_release(struct config_item *item) +{ + struct gpio_sim_line_ctx *line_ctx = to_gpio_sim_line_ctx(item); + struct gpio_sim_chip_ctx *chip_ctx = line_ctx->parent; + + mutex_lock(&chip_ctx->lock); + list_del(&line_ctx->list); + mutex_unlock(&chip_ctx->lock); + + mutex_destroy(&line_ctx->lock); + kfree(line_ctx->name); + kfree(line_ctx); +} + +static struct configfs_item_operations gpio_sim_config_line_item_ops = { + .release = gpio_sim_line_item_release, +}; + +static const struct config_item_type gpio_sim_line_config_type = { + .ct_item_ops = &gpio_sim_config_line_item_ops, + .ct_attrs = gpio_sim_line_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_item * +gpio_sim_config_make_line_item(struct config_group *group, const char *name) +{ + struct gpio_sim_chip_ctx *chip_ctx; + struct gpio_sim_line_ctx *line_ctx; + unsigned int offset; + int ret, nchar; + + ret = sscanf(name, "line%u%n", &offset, &nchar); + if (ret != 1 || nchar != strlen(name)) + return ERR_PTR(-EINVAL); + + chip_ctx = to_gpio_sim_chip_ctx(&group->cg_item); + + mutex_lock(&chip_ctx->lock); + + if (gpio_sim_chip_live(chip_ctx)) { + mutex_unlock(&chip_ctx->lock); + return ERR_PTR(-EBUSY); + } + + line_ctx = kzalloc(sizeof(*line_ctx), GFP_KERNEL); + if (!line_ctx) { + mutex_unlock(&chip_ctx->lock); + return ERR_PTR(-ENOMEM); + } + + config_item_init_type_name(&line_ctx->item, name, + &gpio_sim_line_config_type); + + line_ctx->parent = chip_ctx; + line_ctx->offset = offset; + list_add_tail(&line_ctx->list, &chip_ctx->line_ctx_list); + mutex_init(&line_ctx->lock); + + mutex_unlock(&chip_ctx->lock); + + return &line_ctx->item; +} + +static void gpio_sim_chip_item_release(struct config_item *item) +{ + struct gpio_sim_chip_ctx *ctx = to_gpio_sim_chip_ctx(item); + + if (gpio_sim_chip_live(ctx)) + gpio_sim_deactivate_chip_unlocked(ctx); + + mutex_destroy(&ctx->lock); + ida_free(&gpio_sim_ida, ctx->id); + kfree(ctx); +} + +static struct configfs_item_operations gpio_sim_config_chip_item_ops = { + .release = gpio_sim_chip_item_release, +}; + +static struct configfs_group_operations gpio_sim_config_chip_group_ops = { + .make_item = gpio_sim_config_make_line_item, +}; + +static const struct config_item_type gpio_sim_chip_group_config_type = { + .ct_item_ops = &gpio_sim_config_chip_item_ops, + .ct_group_ops = &gpio_sim_config_chip_group_ops, + .ct_attrs = gpio_sim_config_chip_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_group * +gpio_sim_config_make_chip_group(struct config_group *group, const char *name) +{ + struct gpio_sim_chip_ctx *ctx; + int id; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return ERR_PTR(-ENOMEM); + + id = ida_alloc(&gpio_sim_ida, GFP_KERNEL); + if (id < 0) { + kfree(ctx); + return ERR_PTR(id); + } + + config_group_init_type_name(&ctx->group, name, + &gpio_sim_chip_group_config_type); + ctx->num_lines = 1; + ctx->id = id; + mutex_init(&ctx->lock); + INIT_LIST_HEAD(&ctx->line_ctx_list); + + return &ctx->group; +} + +static struct configfs_group_operations gpio_sim_config_group_ops = { + .make_group = gpio_sim_config_make_chip_group, +}; + +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 <brgl@bgdev.pl"); +MODULE_DESCRIPTION("GPIO Simulator Module"); +MODULE_LICENSE("GPL");

Add a simple program that allows to retrieve chip properties from the GPIO character device. This will be used in gpio-sim selftests.

Signed-off-by: Bartosz Golaszewski brgl@bgdev.pl --- tools/testing/selftests/gpio/.gitignore | 1 + tools/testing/selftests/gpio/Makefile | 2 +- tools/testing/selftests/gpio/gpio-chip-info.c | 57 +++++++++++++++++++ 3 files changed, 59 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/gpio/gpio-chip-info.c

diff --git a/tools/testing/selftests/gpio/.gitignore b/tools/testing/selftests/gpio/.gitignore index a4969f7ee020..4ea4f58dab1a 100644 --- a/tools/testing/selftests/gpio/.gitignore +++ b/tools/testing/selftests/gpio/.gitignore @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only gpio-mockup-cdev +gpio-chip-info diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile index 39f2bbe8dd3d..84b48547f94c 100644 --- a/tools/testing/selftests/gpio/Makefile +++ b/tools/testing/selftests/gpio/Makefile @@ -2,6 +2,6 @@

TEST_PROGS := gpio-mockup.sh TEST_FILES := gpio-mockup-sysfs.sh -TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev +TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info

include ../lib.mk diff --git a/tools/testing/selftests/gpio/gpio-chip-info.c b/tools/testing/selftests/gpio/gpio-chip-info.c new file mode 100644 index 000000000000..8f2d2e23e9f6 --- /dev/null +++ b/tools/testing/selftests/gpio/gpio-chip-info.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO character device helper for reading chip information. + * + * Copyright (C) 2021 Bartosz Golaszewski brgl@bgdev.pl + */ + +#include <fcntl.h> +#include <linux/gpio.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/types.h> + +static void print_usage(void) +{ + printf("usage:\n"); + printf(" gpio-chip-info <chip path> [name|label|num-lines]\n"); +} + +int main(int argc, char **argv) +{ + struct gpiochip_info info; + int fd, ret; + + if (argc !=3) { + print_usage(); + return EXIT_FAILURE; + } + + fd = open(argv[1], O_RDWR); + if (fd < 0) { + perror("unable to open the GPIO chip"); + return EXIT_FAILURE; + } + + memset(&info, 0, sizeof(info)); + ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info); + if (ret) { + perror("chip info ioctl failed"); + return EXIT_FAILURE; + } + + if (strcmp(argv[2], "name") == 0) { + printf("%s\n", info.name); + } else if (strcmp(argv[2], "label") == 0) { + printf("%s\n", info.label); + } else if (strcmp(argv[2], "num-lines") == 0) { + printf("%u\n", info.lines); + } else { + fprintf(stderr, "unknown command: %s\n", argv[2]); + return EXIT_FAILURE; + } + + return EXIT_SUCCESS; +}

Add a set of tests for the new gpio-sim module. This is a pure shell test-suite and uses the helper programs available in the gpio selftests directory. These test-cases only test the functionalities exposed by the gpio-sim driver, not those handled by core gpiolib code.

Signed-off-by: Bartosz Golaszewski brgl@bgdev.pl --- tools/testing/selftests/gpio/Makefile | 2 +- tools/testing/selftests/gpio/config | 1 + tools/testing/selftests/gpio/gpio-sim.sh | 266 +++++++++++++++++++++++ 3 files changed, 268 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/gpio/gpio-sim.sh

diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile index d7d8f1985d99..4c6df61c76a8 100644 --- a/tools/testing/selftests/gpio/Makefile +++ b/tools/testing/selftests/gpio/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0

-TEST_PROGS := gpio-mockup.sh +TEST_PROGS := gpio-mockup.sh gpio-sim.sh TEST_FILES := gpio-mockup-sysfs.sh TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info gpio-line-name

diff --git a/tools/testing/selftests/gpio/config b/tools/testing/selftests/gpio/config index ce100342c20b..409a8532facc 100644 --- a/tools/testing/selftests/gpio/config +++ b/tools/testing/selftests/gpio/config @@ -1,3 +1,4 @@ CONFIG_GPIOLIB=y CONFIG_GPIO_CDEV=y CONFIG_GPIO_MOCKUP=m +CONFIG_GPIO_SIM=m diff --git a/tools/testing/selftests/gpio/gpio-sim.sh b/tools/testing/selftests/gpio/gpio-sim.sh new file mode 100755 index 000000000000..99ce808d772a --- /dev/null +++ b/tools/testing/selftests/gpio/gpio-sim.sh @@ -0,0 +1,266 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2021 Bartosz Golaszewski brgl@bgdev.pl + +BASE_DIR=`dirname $0` +CONFIGFS_DIR="/sys/kernel/config/gpio-sim" +MODULE="gpio-sim" + +fail() { + echo "$*" >&2 + echo "GPIO $MODULE test FAIL" + exit 1 +} + +skip() { + echo "$*" >&2 + echo "GPIO $MODULE test SKIP" + exit 4 +} + +remove_chip() { + local CHIP=$1 + + LINES=`ls $CONFIGFS_DIR/$CHIP/ | egrep ^line` + if [ "$?" == 0 ]; then + for LINE in $LINES; do + rmdir $CONFIGFS_DIR/$CHIP/$LINE || fail "Unable to remove the line" + done + fi + + rmdir $CONFIGFS_DIR/$CHIP || fail "Unable to remove the chip" +} + +configfs_cleanup() { + for CHIP in `ls $CONFIGFS_DIR/`; do + remove_chip $CHIP + done +} + +create_chip() { + local CHIP=$1 + local CHIP_DIR="$CONFIGFS_DIR/$CHIP" + + mkdir $CHIP_DIR +} + +set_label() { + local CHIP=$1 + local LABEL=$2 + + echo $LABEL > $CONFIGFS_DIR/$CHIP/label || fail "Unable to set the chip label" +} + +set_num_lines() { + local CHIP=$1 + local NUM_LINES=$2 + + echo $NUM_LINES > $CONFIGFS_DIR/$CHIP/num_lines || fail "Unable to set the number of lines" +} + +set_line_name() { + local CHIP=$1 + local OFFSET=$2 + local NAME=$3 + local LINE_DIR=$CONFIGFS_DIR/$CHIP/line$OFFSET + + test -d $LINE_DIR || mkdir $LINE_DIR + echo $NAME > $LINE_DIR/name || fail "Unable to set the line name" +} + +enable_chip() { + local CHIP=$1 + + echo 1 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to enable the chip" +} + +disable_chip() { + local CHIP=$1 + + echo 0 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to disable the chip" +} + +configfs_chip_name() { + local CHIP="$1" + + cat $CONFIGFS_DIR/$CHIP/chip_name 2> /dev/null || return 1 +} + +configfs_dev_name() { + local CHIP="$1" + + cat $CONFIGFS_DIR/$CHIP/dev_name 2> /dev/null || return 1 +} + +get_chip_num_lines() { + local CHIP="$1" + + $BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP` num-lines +} + +get_chip_label() { + local CHIP="$1" + + $BASE_DIR/gpio-chip-info /dev/`configfs_chip_name $CHIP` label +} + +get_line_name() { + local CHIP="$1" + local OFFSET="$2" + + $BASE_DIR/gpio-line-name /dev/`configfs_chip_name $CHIP` $OFFSET +} + +sysfs_set_pull() { + local CHIP="$1" + local OFFSET="$2" + local PULL="$3" + local SYSFSPATH="/sys/devices/platform/`configfs_dev_name $CHIP`/control/gpio$OFFSET" + + echo $PULL > $SYSFSPATH || fail "Unable to set line pull in sysfs" +} + +# Load the gpio-sim module. This will pull in configfs if needed too. +modprobe gpio-sim || skip "unable to load the gpio-sim module" +# Make sure configfs is mounted at /sys/kernel/config. Wait a bit if needed. +for IDX in `seq 5`; do + if [ "$IDX" -eq "5" ]; then + skip "configfs not mounted at /sys/kernel/config" + fi + + mountpoint -q /sys/kernel/config && break + sleep 0.1 +done +# If the module was already loaded: remove all previous chips +configfs_cleanup + +trap "exit 1" SIGTERM SIGINT +trap configfs_cleanup EXIT + +echo "1. chip_name and dev_name attributes" + +echo "1.1. Chip name is communicated to user" +create_chip chip +enable_chip chip +test -n `cat $CONFIGFS_DIR/chip/chip_name` || fail "chip_name doesn't work" +remove_chip chip + +echo "1.2. chip_name returns 'none' if the chip is still pending" +create_chip chip +test "`cat $CONFIGFS_DIR/chip/chip_name`" = "none" || fail "chip_name doesn't return 'none' for a pending chip" +remove_chip chip + +echo "1.3. Device name is communicated to user" +create_chip chip +enable_chip chip +test -n `cat $CONFIGFS_DIR/chip/dev_name` || fail "dev_name doesn't work" +remove_chip chip + +echo "2. Creating and configuring simulated chips" + +echo "2.1. Default number of lines is 1" +create_chip chip +enable_chip chip +test "`get_chip_num_lines chip`" = "1" || fail "default number of lines is not 1" +remove_chip chip + +echo "2.2. Number of lines can be specified" +create_chip chip +set_num_lines chip 16 +enable_chip chip +test "`get_chip_num_lines chip`" = "16" || fail "number of lines is not 16" +remove_chip chip + +echo "2.3. Label can be set" +create_chip chip +set_label chip foobar +enable_chip chip +test "`get_chip_label chip`" = "foobar" || fail "label is incorrect" +remove_chip chip + +echo "2.4. Label can be left empty" +create_chip chip +enable_chip chip +test -z "`cat $CONFIGFS_DIR/chip/label`" || fail "label is not empty" +remove_chip chip + +echo "2.5. Line names can be configured" +create_chip chip +set_num_lines chip 16 +set_line_name chip 0 foo +set_line_name chip 2 bar +enable_chip chip +test "`get_line_name chip 0`" = "foo" || fail "line name is incorrect" +test "`get_line_name chip 2`" = "bar" || fail "line name is incorrect" +remove_chip chip + +echo "2.6. Line name can remain unused" +create_chip chip +set_num_lines chip 2 +set_line_name chip 5 foobar +enable_chip chip +test "`get_line_name chip 0`" = "" || fail "line name is incorrect" +test "`get_line_name chip 1`" = "" || fail "line name is incorrect" +remove_chip chip + +echo "2.7. Line configfs directory names are sanitized" +create_chip chip +mkdir $CONFIGFS_DIR/chip/line12foobar 2> /dev/null && fail "invalid configfs line name accepted" +mkdir $CONFIGFS_DIR/chip/line_no_offset 2> /dev/null && fail "invalid configfs line name accepted" +remove_chip chip + +echo "2.8. Multiple chips can be created" +CHIPS="chip0 chip1 chip2" +for CHIP in $CHIPS; do + create_chip $CHIP + enable_chip $CHIP +done +for CHIP in $CHIPS; do + remove_chip $CHIP +done + +echo "3. Controlling simulated chips" + +echo "3.3. Pull can be set over sysfs" +create_chip chip +set_num_lines chip 8 +enable_chip chip +sysfs_set_pull chip 0 1 +$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip` 0 +test "$?" = "1" || fail "pull set incorrectly" +sysfs_set_pull chip 0 0 +$BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip` 1 +test "$?" = "0" || fail "pull set incorrectly" +remove_chip chip + +echo "3.4. Incorrect input in sysfs is rejected" +create_chip chip +set_num_lines chip 8 +enable_chip chip +SYSFS_PATH="/sys/devices/platform/`configfs_dev_name chip`/control/gpio0" +echo 2 > $SYSFS_PATH 2> /dev/null && fail "invalid input not detected" +remove_chip chip + +echo "4. Simulated GPIO chips are functional" + +echo "4.1. Values can be read from sysfs" +create_chip chip +set_num_lines chip 8 +enable_chip chip +SYSFS_PATH="/sys/devices/platform/`configfs_dev_name chip`/control/gpio0" +test `cat $SYSFS_PATH` = "0" || fail "incorrect value read from sysfs" +$BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip` 0 & +sleep 0.1 # FIXME Any better way? +test `cat $SYSFS_PATH` = "1" || fail "incorrect value read from sysfs" +kill $! +remove_chip chip + +echo "4.2. Bias settings work correctly" +create_chip chip +set_num_lines chip 8 +enable_chip chip +$BASE_DIR/gpio-mockup-cdev -b pull-up /dev/`configfs_chip_name chip` 0 +test `cat $SYSFS_PATH` = "1" || fail "bias setting does not work" +remove_chip chip + +echo "GPIO $MODULE test PASS"