2 * GPIO Testing Device Driver
4 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
5 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
6 * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/gpio/driver.h>
18 #include <linux/gpio/consumer.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21 #include <linux/interrupt.h>
22 #include <linux/irq.h>
23 #include <linux/irq_work.h>
24 #include <linux/debugfs.h>
25 #include <linux/uaccess.h>
29 #define GPIO_MOCKUP_NAME "gpio-mockup"
30 #define GPIO_MOCKUP_MAX_GC 10
32 * We're storing two values per chip: the GPIO base and the number
35 #define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
38 GPIO_MOCKUP_DIR_OUT = 0,
39 GPIO_MOCKUP_DIR_IN = 1,
43 * struct gpio_pin_status - structure describing a GPIO status
44 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
45 * @value: Configures status of the gpio as 0(low) or 1(high)
47 struct gpio_mockup_line_status {
53 struct gpio_mockup_irq_context {
58 struct gpio_mockup_chip {
60 struct gpio_mockup_line_status *lines;
61 struct gpio_mockup_irq_context irq_ctx;
62 struct dentry *dbg_dir;
65 struct gpio_mockup_dbgfs_private {
66 struct gpio_mockup_chip *chip;
67 struct gpio_desc *desc;
71 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
72 static int gpio_mockup_params_nr;
73 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);
75 static bool gpio_mockup_named_lines;
76 module_param_named(gpio_mockup_named_lines,
77 gpio_mockup_named_lines, bool, 0400);
79 static const char gpio_mockup_name_start = 'A';
80 static struct dentry *gpio_mockup_dbg_dir;
82 static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
84 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
86 return chip->lines[offset].value;
89 static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
92 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
94 chip->lines[offset].value = !!value;
97 static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
100 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
102 gpio_mockup_set(gc, offset, value);
103 chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
108 static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
110 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
112 chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
117 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
119 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
121 return chip->lines[offset].dir;
124 static int gpio_mockup_name_lines(struct device *dev,
125 struct gpio_mockup_chip *chip)
127 struct gpio_chip *gc = &chip->gc;
131 names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
135 for (i = 0; i < gc->ngpio; i++) {
136 names[i] = devm_kasprintf(dev, GFP_KERNEL,
137 "%s-%d", gc->label, i);
142 gc->names = (const char *const *)names;
147 static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
149 return chip->irq_base + offset;
152 static void gpio_mockup_irqmask(struct irq_data *data)
154 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
155 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
157 chip->lines[data->irq - gc->irq_base].irq_enabled = false;
160 static void gpio_mockup_irqunmask(struct irq_data *data)
162 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
163 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
165 chip->lines[data->irq - gc->irq_base].irq_enabled = true;
168 static struct irq_chip gpio_mockup_irqchip = {
169 .name = GPIO_MOCKUP_NAME,
170 .irq_mask = gpio_mockup_irqmask,
171 .irq_unmask = gpio_mockup_irqunmask,
174 static void gpio_mockup_handle_irq(struct irq_work *work)
176 struct gpio_mockup_irq_context *irq_ctx;
178 irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
179 handle_simple_irq(irq_to_desc(irq_ctx->irq));
182 static int gpio_mockup_irqchip_setup(struct device *dev,
183 struct gpio_mockup_chip *chip)
185 struct gpio_chip *gc = &chip->gc;
188 irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
192 gc->irq_base = irq_base;
193 gc->irqchip = &gpio_mockup_irqchip;
195 for (i = 0; i < gc->ngpio; i++) {
196 irq_set_chip(irq_base + i, gc->irqchip);
197 irq_set_chip_data(irq_base + i, gc);
198 irq_set_handler(irq_base + i, &handle_simple_irq);
199 irq_modify_status(irq_base + i,
200 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
203 init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
208 static ssize_t gpio_mockup_event_write(struct file *file,
209 const char __user *usr_buf,
210 size_t size, loff_t *ppos)
212 struct gpio_mockup_dbgfs_private *priv;
213 struct gpio_mockup_chip *chip;
214 struct seq_file *sfile;
215 struct gpio_desc *desc;
216 struct gpio_chip *gc;
219 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
222 if (val != 0 && val != 1)
225 sfile = file->private_data;
226 priv = sfile->private;
231 if (chip->lines[priv->offset].irq_enabled) {
232 gpiod_set_value_cansleep(desc, val);
233 priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
234 irq_work_queue(&priv->chip->irq_ctx.work);
240 static int gpio_mockup_event_open(struct inode *inode, struct file *file)
242 return single_open(file, NULL, inode->i_private);
245 static const struct file_operations gpio_mockup_event_ops = {
246 .owner = THIS_MODULE,
247 .open = gpio_mockup_event_open,
248 .write = gpio_mockup_event_write,
252 static void gpio_mockup_debugfs_setup(struct device *dev,
253 struct gpio_mockup_chip *chip)
255 struct gpio_mockup_dbgfs_private *priv;
256 struct dentry *evfile;
257 struct gpio_chip *gc;
263 chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
267 for (i = 0; i < gc->ngpio; i++) {
268 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
272 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
278 priv->desc = &gc->gpiodev->descs[i];
280 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
281 &gpio_mockup_event_ops);
289 dev_err(dev, "error creating debugfs directory\n");
292 static int gpio_mockup_add(struct device *dev,
293 struct gpio_mockup_chip *chip,
294 const char *name, int base, int ngpio)
296 struct gpio_chip *gc = &chip->gc;
302 gc->owner = THIS_MODULE;
304 gc->get = gpio_mockup_get;
305 gc->set = gpio_mockup_set;
306 gc->direction_output = gpio_mockup_dirout;
307 gc->direction_input = gpio_mockup_dirin;
308 gc->get_direction = gpio_mockup_get_direction;
309 gc->to_irq = gpio_mockup_to_irq;
311 chip->lines = devm_kcalloc(dev, gc->ngpio,
312 sizeof(*chip->lines), GFP_KERNEL);
316 if (gpio_mockup_named_lines) {
317 ret = gpio_mockup_name_lines(dev, chip);
322 ret = gpio_mockup_irqchip_setup(dev, chip);
326 ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
330 if (gpio_mockup_dbg_dir)
331 gpio_mockup_debugfs_setup(dev, chip);
336 static int gpio_mockup_probe(struct platform_device *pdev)
338 int ret, i, base, ngpio, num_chips;
339 struct device *dev = &pdev->dev;
340 struct gpio_mockup_chip *chips;
343 if (gpio_mockup_params_nr < 2 || (gpio_mockup_params_nr % 2))
346 /* Each chip is described by two values. */
347 num_chips = gpio_mockup_params_nr / 2;
349 chips = devm_kcalloc(dev, num_chips, sizeof(*chips), GFP_KERNEL);
353 platform_set_drvdata(pdev, chips);
355 for (i = 0; i < num_chips; i++) {
356 base = gpio_mockup_ranges[i * 2];
359 ngpio = gpio_mockup_ranges[i * 2 + 1];
361 ngpio = gpio_mockup_ranges[i * 2 + 1] - base;
364 chip_name = devm_kasprintf(dev, GFP_KERNEL,
365 "%s-%c", GPIO_MOCKUP_NAME,
366 gpio_mockup_name_start + i);
370 ret = gpio_mockup_add(dev, &chips[i],
371 chip_name, base, ngpio);
378 "adding gpiochip failed: %d (base: %d, ngpio: %d)\n",
379 ret, base, base < 0 ? ngpio : base + ngpio);
388 static struct platform_driver gpio_mockup_driver = {
390 .name = GPIO_MOCKUP_NAME,
392 .probe = gpio_mockup_probe,
395 static struct platform_device *pdev;
396 static int __init mock_device_init(void)
400 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
401 if (!gpio_mockup_dbg_dir)
402 pr_err("%s: error creating debugfs directory\n",
405 pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
409 err = platform_device_add(pdev);
411 platform_device_put(pdev);
415 err = platform_driver_register(&gpio_mockup_driver);
417 platform_device_unregister(pdev);
424 static void __exit mock_device_exit(void)
426 debugfs_remove_recursive(gpio_mockup_dbg_dir);
427 platform_driver_unregister(&gpio_mockup_driver);
428 platform_device_unregister(pdev);
431 module_init(mock_device_init);
432 module_exit(mock_device_exit);
434 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
435 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
436 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
437 MODULE_DESCRIPTION("GPIO Testing driver");
438 MODULE_LICENSE("GPL v2");