// SPDX-License-Identifier: GPL-2.0-or-later /* * GPIO Testing Device Driver * * Copyright (C) 2014 Kamlakant Patel * Copyright (C) 2015-2016 Bamvor Jian Zhang * Copyright (C) 2017 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 #define GPIO_MOCKUP_MAX_GC 10 /* * We're storing two values per chip: the GPIO base and the number * of GPIO lines. */ #define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2) /* Maximum of four properties + the sentinel. */ #define GPIO_MOCKUP_MAX_PROP 5 /* * struct gpio_pin_status - structure describing a GPIO status * @dir: Configures direction of gpio as "in" or "out" * @value: Configures status of the gpio as 0(low) or 1(high) * @pull: Configures the current pull of the GPIO as 0 (pull-down) or * 1 (pull-up) * @requested: Request status of this GPIO */ struct gpio_mockup_line_status { int dir; int value; int pull; bool requested; }; struct gpio_mockup_chip { struct gpio_chip gc; struct gpio_mockup_line_status *lines; struct irq_domain *irq_sim_domain; struct dentry *dbg_dir; struct mutex lock; }; struct gpio_mockup_dbgfs_private { struct gpio_mockup_chip *chip; unsigned int offset; }; static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES]; static int gpio_mockup_num_ranges; module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400); static bool gpio_mockup_named_lines; module_param_named(gpio_mockup_named_lines, gpio_mockup_named_lines, bool, 0400); static struct dentry *gpio_mockup_dbg_dir; static int gpio_mockup_range_base(unsigned int index) { return gpio_mockup_ranges[index * 2]; } static int gpio_mockup_range_ngpio(unsigned int index) { return gpio_mockup_ranges[index * 2 + 1]; } static int __gpio_mockup_get(struct gpio_mockup_chip *chip, unsigned int offset) { return chip->lines[offset].value; } static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); int val; scoped_guard(mutex, &chip->lock) val = __gpio_mockup_get(chip, offset); return val; } static int gpio_mockup_get_multiple(struct gpio_chip *gc, unsigned long *mask, unsigned long *bits) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); unsigned int bit, val; scoped_guard(mutex, &chip->lock) { for_each_set_bit(bit, mask, gc->ngpio) { val = __gpio_mockup_get(chip, bit); __assign_bit(bit, bits, val); } } return 0; } static void __gpio_mockup_set(struct gpio_mockup_chip *chip, unsigned int offset, int value) { chip->lines[offset].value = !!value; } static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset, int value) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); guard(mutex)(&chip->lock); __gpio_mockup_set(chip, offset, value); } static void gpio_mockup_set_multiple(struct gpio_chip *gc, unsigned long *mask, unsigned long *bits) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); unsigned int bit; guard(mutex)(&chip->lock); for_each_set_bit(bit, mask, gc->ngpio) __gpio_mockup_set(chip, bit, test_bit(bit, bits)); } static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip, unsigned int offset, int value) { struct gpio_mockup_line_status *line = &chip->lines[offset]; int curr, irq, irq_type, ret = 0; guard(mutex)(&chip->lock); if (line->requested && line->dir == GPIO_LINE_DIRECTION_IN) { curr = __gpio_mockup_get(chip, offset); if (curr == value) goto out; irq = irq_find_mapping(chip->irq_sim_domain, offset); if (!irq) /* * 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. */ goto set_value; irq_type = irq_get_trigger_type(irq); if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) || (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) { ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true); if (ret) goto out; } } set_value: /* Change the value unless we're actively driving the line. */ if (!line->requested || line->dir == GPIO_LINE_DIRECTION_IN) __gpio_mockup_set(chip, offset, value); out: chip->lines[offset].pull = value; return ret; } static int gpio_mockup_set_config(struct gpio_chip *gc, unsigned int offset, unsigned long config) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); switch (pinconf_to_config_param(config)) { case PIN_CONFIG_BIAS_PULL_UP: return gpio_mockup_apply_pull(chip, offset, 1); case PIN_CONFIG_BIAS_PULL_DOWN: return gpio_mockup_apply_pull(chip, offset, 0); default: break; } return -ENOTSUPP; } static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset, int value) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); scoped_guard(mutex, &chip->lock) { chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT; __gpio_mockup_set(chip, offset, value); } return 0; } static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); scoped_guard(mutex, &chip->lock) chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN; return 0; } static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); int direction; scoped_guard(mutex, &chip->lock) direction = chip->lines[offset].dir; return direction; } static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); return irq_create_mapping(chip->irq_sim_domain, offset); } static int gpio_mockup_request(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); scoped_guard(mutex, &chip->lock) chip->lines[offset].requested = true; return 0; } static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset) { struct gpio_mockup_chip *chip = gpiochip_get_data(gc); guard(mutex)(&chip->lock); chip->lines[offset].requested = false; __gpio_mockup_set(chip, offset, chip->lines[offset].pull); } static ssize_t gpio_mockup_debugfs_read(struct file *file, char __user *usr_buf, size_t size, loff_t *ppos) { struct gpio_mockup_dbgfs_private *priv; struct gpio_mockup_chip *chip; struct seq_file *sfile; struct gpio_chip *gc; int val, cnt; char buf[3]; if (*ppos != 0) return 0; sfile = file->private_data; priv = sfile->private; chip = priv->chip; gc = &chip->gc; val = gpio_mockup_get(gc, priv->offset); cnt = snprintf(buf, sizeof(buf), "%d\n", val); return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt); } static ssize_t gpio_mockup_debugfs_write(struct file *file, const char __user *usr_buf, size_t size, loff_t *ppos) { struct gpio_mockup_dbgfs_private *priv; int rv, val; struct seq_file *sfile; if (*ppos != 0) return -EINVAL; rv = kstrtoint_from_user(usr_buf, size, 0, &val); if (rv) return rv; if (val != 0 && val != 1) return -EINVAL; sfile = file->private_data; priv = sfile->private; rv = gpio_mockup_apply_pull(priv->chip, priv->offset, val); if (rv) return rv; return size; } static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file) { return single_open(file, NULL, inode->i_private); } /* * Each mockup chip is represented by a directory named after the chip's device * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by * a file using the line's offset as the name under the chip's directory. * * Reading from the line's file yields the current *value*, writing to the * line's file changes the current *pull*. Default pull for mockup lines is * down. * * Examples: * - when a line pulled down is requested in output mode and driven high, its * value will return to 0 once it's released * - when the line is requested in output mode and driven high, writing 0 to * the corresponding debugfs file will change the pull to down but the * reported value will still be 1 until the line is released * - line requested in input mode always reports the same value as its pull * configuration * - when the line is requested in input mode and monitored for events, writing * the same value to the debugfs file will be a noop, while writing the * opposite value will generate a dummy interrupt with an appropriate edge */ static const struct file_operations gpio_mockup_debugfs_ops = { .owner = THIS_MODULE, .open = gpio_mockup_debugfs_open, .read = gpio_mockup_debugfs_read, .write = gpio_mockup_debugfs_write, .release = single_release, }; static void gpio_mockup_debugfs_setup(struct device *dev, struct gpio_mockup_chip *chip) { struct gpio_mockup_dbgfs_private *priv; struct gpio_chip *gc; const char *devname; char *name; int i; gc = &chip->gc; /* * There can only be a single GPIO device per platform device in * gpio-mockup so using device_find_any_child() is OK. */ struct device *child __free(put_device) = device_find_any_child(dev); if (!child) return; devname = dev_name(child); chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir); for (i = 0; i < gc->ngpio; i++) { name = devm_kasprintf(dev, GFP_KERNEL, "%d", i); if (!name) return; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return; priv->chip = chip; priv->offset = i; debugfs_create_file(name, 0600, chip->dbg_dir, priv, &gpio_mockup_debugfs_ops); } } static void gpio_mockup_debugfs_cleanup(void *data) { struct gpio_mockup_chip *chip = data; debugfs_remove_recursive(chip->dbg_dir); } static void gpio_mockup_dispose_mappings(void *data) { struct gpio_mockup_chip *chip = data; struct gpio_chip *gc = &chip->gc; int i, irq; for (i = 0; i < gc->ngpio; i++) { irq = irq_find_mapping(chip->irq_sim_domain, i); if (irq) irq_dispose_mapping(irq); } } static int gpio_mockup_probe(struct platform_device *pdev) { struct gpio_mockup_chip *chip; struct gpio_chip *gc; struct device *dev; const char *name; int rv, base, i; u16 ngpio; dev = &pdev->dev; rv = device_property_read_u32(dev, "gpio-base", &base); if (rv) base = -1; rv = device_property_read_u16(dev, "nr-gpios", &ngpio); if (rv) return rv; rv = device_property_read_string(dev, "chip-label", &name); if (rv) name = dev_name(dev); chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; mutex_init(&chip->lock); gc = &chip->gc; gc->base = base; gc->ngpio = ngpio; gc->label = name; gc->owner = THIS_MODULE; gc->parent = dev; gc->get = gpio_mockup_get; gc->set = gpio_mockup_set; gc->get_multiple = gpio_mockup_get_multiple; gc->set_multiple = gpio_mockup_set_multiple; gc->direction_output = gpio_mockup_dirout; gc->direction_input = gpio_mockup_dirin; gc->get_direction = gpio_mockup_get_direction; gc->set_config = gpio_mockup_set_config; gc->to_irq = gpio_mockup_to_irq; gc->request = gpio_mockup_request; gc->free = gpio_mockup_free; chip->lines = devm_kcalloc(dev, gc->ngpio, sizeof(*chip->lines), GFP_KERNEL); if (!chip->lines) return -ENOMEM; for (i = 0; i < gc->ngpio; i++) chip->lines[i].dir = GPIO_LINE_DIRECTION_IN; chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL, gc->ngpio); if (IS_ERR(chip->irq_sim_domain)) return PTR_ERR(chip->irq_sim_domain); rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip); if (rv) return rv; rv = devm_gpiochip_add_data(dev, &chip->gc, chip); if (rv) return rv; gpio_mockup_debugfs_setup(dev, chip); return devm_add_action_or_reset(dev, gpio_mockup_debugfs_cleanup, chip); } static const struct of_device_id gpio_mockup_of_match[] = { { .compatible = "gpio-mockup", }, {}, }; MODULE_DEVICE_TABLE(of, gpio_mockup_of_match); static struct platform_driver gpio_mockup_driver = { .driver = { .name = "gpio-mockup", .of_match_table = gpio_mockup_of_match, }, .probe = gpio_mockup_probe, }; static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC]; static void gpio_mockup_unregister_pdevs(void) { struct platform_device *pdev; struct fwnode_handle *fwnode; int i; for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) { pdev = gpio_mockup_pdevs[i]; if (!pdev) continue; fwnode = dev_fwnode(&pdev->dev); platform_device_unregister(pdev); fwnode_remove_software_node(fwnode); } } static int __init gpio_mockup_register_chip(int idx) { struct property_entry properties[GPIO_MOCKUP_MAX_PROP]; struct platform_device_info pdevinfo; struct platform_device *pdev; struct fwnode_handle *fwnode; char **line_names = NULL; char chip_label[32]; int prop = 0, base; u16 ngpio; memset(properties, 0, sizeof(properties)); memset(&pdevinfo, 0, sizeof(pdevinfo)); snprintf(chip_label, sizeof(chip_label), "gpio-mockup-%c", idx + 'A'); properties[prop++] = PROPERTY_ENTRY_STRING("chip-label", chip_label); base = gpio_mockup_range_base(idx); if (base >= 0) properties[prop++] = PROPERTY_ENTRY_U32("gpio-base", base); ngpio = base < 0 ? gpio_mockup_range_ngpio(idx) : gpio_mockup_range_ngpio(idx) - base; properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio); if (gpio_mockup_named_lines) { line_names = kasprintf_strarray(GFP_KERNEL, chip_label, ngpio); if (!line_names) return -ENOMEM; properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( "gpio-line-names", line_names, ngpio); } fwnode = fwnode_create_software_node(properties, NULL); if (IS_ERR(fwnode)) { kfree_strarray(line_names, ngpio); return PTR_ERR(fwnode); } pdevinfo.name = "gpio-mockup"; pdevinfo.id = idx; pdevinfo.fwnode = fwnode; pdev = platform_device_register_full(&pdevinfo); kfree_strarray(line_names, ngpio); if (IS_ERR(pdev)) { fwnode_remove_software_node(fwnode); pr_err("error registering device"); return PTR_ERR(pdev); } gpio_mockup_pdevs[idx] = pdev; return 0; } static int __init gpio_mockup_init(void) { int i, num_chips, err; if ((gpio_mockup_num_ranges % 2) || (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES)) return -EINVAL; /* Each chip is described by two values. */ num_chips = gpio_mockup_num_ranges / 2; /* * The second value in the pair must * always be greater than 0. */ for (i = 0; i < num_chips; i++) { if (gpio_mockup_range_ngpio(i) < 0) return -EINVAL; } gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL); err = platform_driver_register(&gpio_mockup_driver); if (err) { pr_err("error registering platform driver\n"); debugfs_remove_recursive(gpio_mockup_dbg_dir); return err; } for (i = 0; i < num_chips; i++) { err = gpio_mockup_register_chip(i); if (err) { platform_driver_unregister(&gpio_mockup_driver); gpio_mockup_unregister_pdevs(); debugfs_remove_recursive(gpio_mockup_dbg_dir); return err; } } return 0; } static void __exit gpio_mockup_exit(void) { gpio_mockup_unregister_pdevs(); debugfs_remove_recursive(gpio_mockup_dbg_dir); platform_driver_unregister(&gpio_mockup_driver); } module_init(gpio_mockup_init); module_exit(gpio_mockup_exit); MODULE_AUTHOR("Kamlakant Patel "); MODULE_AUTHOR("Bamvor Jian Zhang "); MODULE_AUTHOR("Bartosz Golaszewski "); MODULE_DESCRIPTION("GPIO Testing driver"); MODULE_LICENSE("GPL v2");