diff options
Diffstat (limited to 'drivers/gpio/gpio-mockup.c')
-rw-r--r-- | drivers/gpio/gpio-mockup.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c new file mode 100644 index 0000000000..b32063ac84 --- /dev/null +++ b/drivers/gpio/gpio-mockup.c @@ -0,0 +1,615 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO Testing Device Driver + * + * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com> + * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com> + * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/debugfs.h> +#include <linux/gpio/driver.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/irq_sim.h> +#include <linux/irqdomain.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include <linux/string_helpers.h> +#include <linux/uaccess.h> + +#include "gpiolib.h" + +#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) + */ +struct gpio_mockup_line_status { + int dir; + int value; + int pull; +}; + +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; + struct gpio_desc *desc; + 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; + + mutex_lock(&chip->lock); + val = __gpio_mockup_get(chip, offset); + mutex_unlock(&chip->lock); + + 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; + + mutex_lock(&chip->lock); + for_each_set_bit(bit, mask, gc->ngpio) { + val = __gpio_mockup_get(chip, bit); + __assign_bit(bit, bits, val); + } + mutex_unlock(&chip->lock); + + 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); + + mutex_lock(&chip->lock); + __gpio_mockup_set(chip, offset, value); + mutex_unlock(&chip->lock); +} + +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; + + mutex_lock(&chip->lock); + for_each_set_bit(bit, mask, gc->ngpio) + __gpio_mockup_set(chip, bit, test_bit(bit, bits)); + mutex_unlock(&chip->lock); +} + +static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip, + unsigned int offset, int value) +{ + struct gpio_chip *gc = &chip->gc; + struct gpio_desc *desc = gpiochip_get_desc(gc, offset); + int curr, irq, irq_type, ret = 0; + + mutex_lock(&chip->lock); + + if (test_bit(FLAG_REQUESTED, &desc->flags) && + !test_bit(FLAG_IS_OUT, &desc->flags)) { + 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 (!test_bit(FLAG_REQUESTED, &desc->flags) || + !test_bit(FLAG_IS_OUT, &desc->flags)) + __gpio_mockup_set(chip, offset, value); + +out: + chip->lines[offset].pull = value; + mutex_unlock(&chip->lock); + 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); + + mutex_lock(&chip->lock); + chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT; + __gpio_mockup_set(chip, offset, value); + mutex_unlock(&chip->lock); + + return 0; +} + +static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN; + mutex_unlock(&chip->lock); + + 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; + + mutex_lock(&chip->lock); + direction = chip->lines[offset].dir; + mutex_unlock(&chip->lock); + + 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 void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + __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, + .llseek = no_llseek, + .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; + devname = dev_name(&gc->gpiodev->dev); + + 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; + priv->desc = gpiochip_get_desc(gc, 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->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 <base GPIO - number of GPIOS> 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 <kamlakant.patel@broadcom.com>"); +MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>"); +MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>"); +MODULE_DESCRIPTION("GPIO Testing driver"); +MODULE_LICENSE("GPL v2"); |