diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/gpio/gpio-mockup.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c new file mode 100644 index 000000000..cab324eb7 --- /dev/null +++ b/drivers/gpio/gpio-mockup.c @@ -0,0 +1,414 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * 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> + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/gpio/driver.h> +#include <linux/gpio/consumer.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/irq_sim.h> +#include <linux/debugfs.h> +#include <linux/uaccess.h> + +#include "gpiolib.h" + +#define GPIO_MOCKUP_NAME "gpio-mockup" +#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) + +#define gpio_mockup_err(...) pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__) + +enum { + GPIO_MOCKUP_DIR_IN = 0, + GPIO_MOCKUP_DIR_OUT = 1, +}; + +/* + * struct gpio_pin_status - structure describing a GPIO status + * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out + * @value: Configures status of the gpio as 0(low) or 1(high) + */ +struct gpio_mockup_line_status { + int dir; + int value; +}; + +struct gpio_mockup_chip { + struct gpio_chip gc; + struct gpio_mockup_line_status *lines; + struct irq_sim irqsim; + struct dentry *dbg_dir; +}; + +struct gpio_mockup_dbgfs_private { + struct gpio_mockup_chip *chip; + struct gpio_desc *desc; + int offset; +}; + +struct gpio_mockup_platform_data { + int base; + int ngpio; + int index; + bool named_lines; +}; + +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_chip *gc, unsigned int offset) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + return chip->lines[offset].value; +} + +static void gpio_mockup_set(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + chip->lines[offset].value = !!value; +} + +static void gpio_mockup_set_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + unsigned int bit; + + for_each_set_bit(bit, mask, gc->ngpio) + gpio_mockup_set(gc, bit, test_bit(bit, bits)); + +} + +static int gpio_mockup_dirout(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + gpio_mockup_set(gc, offset, value); + chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT; + + return 0; +} + +static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + chip->lines[offset].dir = GPIO_MOCKUP_DIR_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); + + return !chip->lines[offset].dir; +} + +static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_mockup_chip *chip = gpiochip_get_data(gc); + + return irq_sim_irqnum(&chip->irqsim, offset); +} + +static ssize_t gpio_mockup_event_write(struct file *file, + const 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_desc *desc; + int rv, val; + + 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; + desc = priv->desc; + chip = priv->chip; + + gpiod_set_value_cansleep(desc, val); + irq_sim_fire(&chip->irqsim, priv->offset); + + return size; +} + +static int gpio_mockup_event_open(struct inode *inode, struct file *file) +{ + return single_open(file, NULL, inode->i_private); +} + +static const struct file_operations gpio_mockup_event_ops = { + .owner = THIS_MODULE, + .open = gpio_mockup_event_open, + .write = gpio_mockup_event_write, + .llseek = no_llseek, +}; + +static void gpio_mockup_debugfs_setup(struct device *dev, + struct gpio_mockup_chip *chip) +{ + struct gpio_mockup_dbgfs_private *priv; + struct dentry *evfile, *link; + 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); + if (IS_ERR_OR_NULL(chip->dbg_dir)) + goto err; + + link = debugfs_create_symlink(gc->label, gpio_mockup_dbg_dir, devname); + if (IS_ERR_OR_NULL(link)) + goto err; + + for (i = 0; i < gc->ngpio; i++) { + name = devm_kasprintf(dev, GFP_KERNEL, "%d", i); + if (!name) + goto err; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + goto err; + + priv->chip = chip; + priv->offset = i; + priv->desc = &gc->gpiodev->descs[i]; + + evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv, + &gpio_mockup_event_ops); + if (IS_ERR_OR_NULL(evfile)) + goto err; + } + + return; + +err: + dev_err(dev, "error creating debugfs event files\n"); +} + +static int gpio_mockup_name_lines(struct device *dev, + struct gpio_mockup_chip *chip) +{ + struct gpio_chip *gc = &chip->gc; + char **names; + int i; + + names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL); + if (!names) + return -ENOMEM; + + for (i = 0; i < gc->ngpio; i++) { + names[i] = devm_kasprintf(dev, GFP_KERNEL, + "%s-%d", gc->label, i); + if (!names[i]) + return -ENOMEM; + } + + gc->names = (const char *const *)names; + + return 0; +} + +static int gpio_mockup_probe(struct platform_device *pdev) +{ + struct gpio_mockup_platform_data *pdata; + struct gpio_mockup_chip *chip; + struct gpio_chip *gc; + int rv, base, ngpio; + struct device *dev; + char *name; + + dev = &pdev->dev; + pdata = dev_get_platdata(dev); + base = pdata->base; + ngpio = pdata->ngpio; + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + name = devm_kasprintf(dev, GFP_KERNEL, "%s-%c", + pdev->name, pdata->index); + if (!name) + return -ENOMEM; + + 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->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->to_irq = gpio_mockup_to_irq; + + chip->lines = devm_kcalloc(dev, gc->ngpio, + sizeof(*chip->lines), GFP_KERNEL); + if (!chip->lines) + return -ENOMEM; + + if (pdata->named_lines) { + rv = gpio_mockup_name_lines(dev, chip); + if (rv) + return rv; + } + + rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio); + if (rv < 0) + return rv; + + rv = devm_gpiochip_add_data(dev, &chip->gc, chip); + if (rv) + return rv; + + if (!IS_ERR_OR_NULL(gpio_mockup_dbg_dir)) + gpio_mockup_debugfs_setup(dev, chip); + + return 0; +} + +static struct platform_driver gpio_mockup_driver = { + .driver = { + .name = GPIO_MOCKUP_NAME, + }, + .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; + int i; + + for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) { + pdev = gpio_mockup_pdevs[i]; + + if (pdev) + platform_device_unregister(pdev); + } +} + +static int __init gpio_mockup_init(void) +{ + int i, num_chips, err = 0, index = 'A'; + struct gpio_mockup_platform_data pdata; + struct platform_device *pdev; + + if ((gpio_mockup_num_ranges < 2) || + (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-event", NULL); + if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir)) + gpio_mockup_err("error creating debugfs directory\n"); + + err = platform_driver_register(&gpio_mockup_driver); + if (err) { + gpio_mockup_err("error registering platform driver\n"); + debugfs_remove_recursive(gpio_mockup_dbg_dir); + return err; + } + + for (i = 0; i < num_chips; i++) { + pdata.index = index++; + pdata.base = gpio_mockup_range_base(i); + pdata.ngpio = pdata.base < 0 + ? gpio_mockup_range_ngpio(i) + : gpio_mockup_range_ngpio(i) - pdata.base; + pdata.named_lines = gpio_mockup_named_lines; + + pdev = platform_device_register_resndata(NULL, + GPIO_MOCKUP_NAME, + i, NULL, 0, &pdata, + sizeof(pdata)); + if (IS_ERR(pdev)) { + gpio_mockup_err("error registering device"); + platform_driver_unregister(&gpio_mockup_driver); + gpio_mockup_unregister_pdevs(); + debugfs_remove_recursive(gpio_mockup_dbg_dir); + return PTR_ERR(pdev); + } + + gpio_mockup_pdevs[i] = pdev; + } + + return 0; +} + +static void __exit gpio_mockup_exit(void) +{ + debugfs_remove_recursive(gpio_mockup_dbg_dir); + platform_driver_unregister(&gpio_mockup_driver); + gpio_mockup_unregister_pdevs(); +} + +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"); |