/* * 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> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * */ #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_OUT = 0, GPIO_MOCKUP_DIR_IN = 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"); 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(); 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");