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>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/irq_work.h>
23 #include <linux/debugfs.h>
24 #include <linux/uaccess.h>
28 #define GPIO_MOCKUP_NAME "gpio-mockup"
29 #define GPIO_MOCKUP_MAX_GC 10
31 * We're storing two values per chip: the GPIO base and the number
34 #define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
37 GPIO_MOCKUP_DIR_OUT = 0,
38 GPIO_MOCKUP_DIR_IN = 1,
42 * struct gpio_pin_status - structure describing a GPIO status
43 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
44 * @value: Configures status of the gpio as 0(low) or 1(high)
46 struct gpio_mockup_line_status {
52 struct gpio_mockup_irq_context {
57 struct gpio_mockup_chip {
59 struct gpio_mockup_line_status *lines;
60 struct gpio_mockup_irq_context irq_ctx;
61 struct dentry *dbg_dir;
64 struct gpio_mockup_dbgfs_private {
65 struct gpio_mockup_chip *chip;
66 struct gpio_desc *desc;
70 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
71 static int gpio_mockup_params_nr;
72 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);
74 static bool gpio_mockup_named_lines;
75 module_param_named(gpio_mockup_named_lines,
76 gpio_mockup_named_lines, bool, 0400);
78 static const char gpio_mockup_name_start = 'A';
79 static struct dentry *gpio_mockup_dbg_dir;
81 static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
83 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
85 return chip->lines[offset].value;
88 static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
91 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
93 chip->lines[offset].value = !!value;
96 static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
99 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
101 gpio_mockup_set(gc, offset, value);
102 chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
107 static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
109 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
111 chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
116 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
118 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
120 return chip->lines[offset].dir;
123 static int gpio_mockup_name_lines(struct device *dev,
124 struct gpio_mockup_chip *chip)
126 struct gpio_chip *gc = &chip->gc;
130 names = devm_kzalloc(dev, sizeof(char *) * gc->ngpio, GFP_KERNEL);
134 for (i = 0; i < gc->ngpio; i++) {
135 names[i] = devm_kasprintf(dev, GFP_KERNEL,
136 "%s-%d", gc->label, i);
141 gc->names = (const char *const *)names;
146 static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
148 return chip->irq_base + offset;
151 static void gpio_mockup_irqmask(struct irq_data *data)
153 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
154 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
156 chip->lines[data->irq - gc->irq_base].irq_enabled = false;
159 static void gpio_mockup_irqunmask(struct irq_data *data)
161 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
162 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
164 chip->lines[data->irq - gc->irq_base].irq_enabled = true;
167 static struct irq_chip gpio_mockup_irqchip = {
168 .name = GPIO_MOCKUP_NAME,
169 .irq_mask = gpio_mockup_irqmask,
170 .irq_unmask = gpio_mockup_irqunmask,
173 static void gpio_mockup_handle_irq(struct irq_work *work)
175 struct gpio_mockup_irq_context *irq_ctx;
177 irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
178 handle_simple_irq(irq_to_desc(irq_ctx->irq));
181 static int gpio_mockup_irqchip_setup(struct device *dev,
182 struct gpio_mockup_chip *chip)
184 struct gpio_chip *gc = &chip->gc;
187 irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
191 gc->irq_base = irq_base;
192 gc->irqchip = &gpio_mockup_irqchip;
194 for (i = 0; i < gc->ngpio; i++) {
195 irq_set_chip(irq_base + i, gc->irqchip);
196 irq_set_chip_data(irq_base + i, gc);
197 irq_set_handler(irq_base + i, &handle_simple_irq);
198 irq_modify_status(irq_base + i,
199 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
202 init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
207 static ssize_t gpio_mockup_event_write(struct file *file,
208 const char __user *usr_buf,
209 size_t size, loff_t *ppos)
211 struct gpio_mockup_dbgfs_private *priv;
212 struct gpio_mockup_chip *chip;
213 struct seq_file *sfile;
214 struct gpio_desc *desc;
215 struct gpio_chip *gc;
218 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
221 if (val != 0 && val != 1)
224 sfile = file->private_data;
225 priv = sfile->private;
230 if (chip->lines[priv->offset].irq_enabled) {
231 gpiod_set_value_cansleep(desc, val);
232 priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
233 irq_work_queue(&priv->chip->irq_ctx.work);
239 static int gpio_mockup_event_open(struct inode *inode, struct file *file)
241 return single_open(file, NULL, inode->i_private);
244 static const struct file_operations gpio_mockup_event_ops = {
245 .owner = THIS_MODULE,
246 .open = gpio_mockup_event_open,
247 .write = gpio_mockup_event_write,
251 static void gpio_mockup_debugfs_setup(struct device *dev,
252 struct gpio_mockup_chip *chip)
254 struct gpio_mockup_dbgfs_private *priv;
255 struct dentry *evfile;
256 struct gpio_chip *gc;
262 chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
266 for (i = 0; i < gc->ngpio; i++) {
267 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
271 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
277 priv->desc = &gc->gpiodev->descs[i];
279 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
280 &gpio_mockup_event_ops);
288 dev_err(dev, "error creating debugfs directory\n");
291 static int gpio_mockup_add(struct device *dev,
292 struct gpio_mockup_chip *chip,
293 const char *name, int base, int ngpio)
295 struct gpio_chip *gc = &chip->gc;
301 gc->owner = THIS_MODULE;
303 gc->get = gpio_mockup_get;
304 gc->set = gpio_mockup_set;
305 gc->direction_output = gpio_mockup_dirout;
306 gc->direction_input = gpio_mockup_dirin;
307 gc->get_direction = gpio_mockup_get_direction;
308 gc->to_irq = gpio_mockup_to_irq;
310 chip->lines = devm_kzalloc(dev, sizeof(*chip->lines) * gc->ngpio,
315 if (gpio_mockup_named_lines) {
316 ret = gpio_mockup_name_lines(dev, chip);
321 ret = gpio_mockup_irqchip_setup(dev, chip);
325 ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
329 if (gpio_mockup_dbg_dir)
330 gpio_mockup_debugfs_setup(dev, chip);
335 static int gpio_mockup_probe(struct platform_device *pdev)
337 int ret, i, base, ngpio, num_chips;
338 struct device *dev = &pdev->dev;
339 struct gpio_mockup_chip *chips;
342 if (gpio_mockup_params_nr < 2 || (gpio_mockup_params_nr % 2))
345 /* Each chip is described by two values. */
346 num_chips = gpio_mockup_params_nr / 2;
348 chips = devm_kzalloc(dev, sizeof(*chips) * num_chips, GFP_KERNEL);
352 platform_set_drvdata(pdev, chips);
354 for (i = 0; i < num_chips; i++) {
355 base = gpio_mockup_ranges[i * 2];
358 ngpio = gpio_mockup_ranges[i * 2 + 1];
360 ngpio = gpio_mockup_ranges[i * 2 + 1] - base;
363 chip_name = devm_kasprintf(dev, GFP_KERNEL,
364 "%s-%c", GPIO_MOCKUP_NAME,
365 gpio_mockup_name_start + i);
369 ret = gpio_mockup_add(dev, &chips[i],
370 chip_name, base, ngpio);
376 dev_err(dev, "gpio<%d..%d> add failed\n",
377 base, base < 0 ? ngpio : base + ngpio);
386 static struct platform_driver gpio_mockup_driver = {
388 .name = GPIO_MOCKUP_NAME,
390 .probe = gpio_mockup_probe,
393 static struct platform_device *pdev;
394 static int __init mock_device_init(void)
398 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
399 if (!gpio_mockup_dbg_dir)
400 pr_err("%s: error creating debugfs directory\n",
403 pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
407 err = platform_device_add(pdev);
409 platform_device_put(pdev);
413 err = platform_driver_register(&gpio_mockup_driver);
415 platform_device_unregister(pdev);
422 static void __exit mock_device_exit(void)
424 debugfs_remove_recursive(gpio_mockup_dbg_dir);
425 platform_driver_unregister(&gpio_mockup_driver);
426 platform_device_unregister(pdev);
429 module_init(mock_device_init);
430 module_exit(mock_device_exit);
432 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
433 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
434 MODULE_DESCRIPTION("GPIO Testing driver");
435 MODULE_LICENSE("GPL v2");