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1/*
2 * GPIO Testing Device Driver
3 *
4 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
5 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com>
6 * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
7 *
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.
12 *
13 */
14
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_sim.h>
24#include <linux/debugfs.h>
25#include <linux/uaccess.h>
26
27#include "gpiolib.h"
28
29#define GPIO_MOCKUP_NAME "gpio-mockup"
30#define GPIO_MOCKUP_MAX_GC 10
31/*
32 * We're storing two values per chip: the GPIO base and the number
33 * of GPIO lines.
34 */
35#define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
36
37#define gpio_mockup_err(...) pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)
38
39enum {
40 GPIO_MOCKUP_DIR_OUT = 0,
41 GPIO_MOCKUP_DIR_IN = 1,
42};
43
44/*
45 * struct gpio_pin_status - structure describing a GPIO status
46 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
47 * @value: Configures status of the gpio as 0(low) or 1(high)
48 */
49struct gpio_mockup_line_status {
50 int dir;
51 int value;
52};
53
54struct gpio_mockup_chip {
55 struct gpio_chip gc;
56 struct gpio_mockup_line_status *lines;
57 struct irq_sim irqsim;
58 struct dentry *dbg_dir;
59};
60
61struct gpio_mockup_dbgfs_private {
62 struct gpio_mockup_chip *chip;
63 struct gpio_desc *desc;
64 int offset;
65};
66
67struct gpio_mockup_platform_data {
68 int base;
69 int ngpio;
70 int index;
71 bool named_lines;
72};
73
74static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
75static int gpio_mockup_num_ranges;
76module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
77
78static bool gpio_mockup_named_lines;
79module_param_named(gpio_mockup_named_lines,
80 gpio_mockup_named_lines, bool, 0400);
81
82static struct dentry *gpio_mockup_dbg_dir;
83
84static int gpio_mockup_range_base(unsigned int index)
85{
86 return gpio_mockup_ranges[index * 2];
87}
88
89static int gpio_mockup_range_ngpio(unsigned int index)
90{
91 return gpio_mockup_ranges[index * 2 + 1];
92}
93
94static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
95{
96 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
97
98 return chip->lines[offset].value;
99}
100
101static void gpio_mockup_set(struct gpio_chip *gc,
102 unsigned int offset, int value)
103{
104 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
105
106 chip->lines[offset].value = !!value;
107}
108
109static void gpio_mockup_set_multiple(struct gpio_chip *gc,
110 unsigned long *mask, unsigned long *bits)
111{
112 unsigned int bit;
113
114 for_each_set_bit(bit, mask, gc->ngpio)
115 gpio_mockup_set(gc, bit, test_bit(bit, bits));
116
117}
118
119static int gpio_mockup_dirout(struct gpio_chip *gc,
120 unsigned int offset, int value)
121{
122 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
123
124 gpio_mockup_set(gc, offset, value);
125 chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
126
127 return 0;
128}
129
130static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
131{
132 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
133
134 chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
135
136 return 0;
137}
138
139static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
140{
141 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
142
143 return chip->lines[offset].dir;
144}
145
146static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
147{
148 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
149
150 return irq_sim_irqnum(&chip->irqsim, offset);
151}
152
153static ssize_t gpio_mockup_event_write(struct file *file,
154 const char __user *usr_buf,
155 size_t size, loff_t *ppos)
156{
157 struct gpio_mockup_dbgfs_private *priv;
158 struct gpio_mockup_chip *chip;
159 struct seq_file *sfile;
160 struct gpio_desc *desc;
161 int rv, val;
162
163 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
164 if (rv)
165 return rv;
166 if (val != 0 && val != 1)
167 return -EINVAL;
168
169 sfile = file->private_data;
170 priv = sfile->private;
171 desc = priv->desc;
172 chip = priv->chip;
173
174 gpiod_set_value_cansleep(desc, val);
175 irq_sim_fire(&chip->irqsim, priv->offset);
176
177 return size;
178}
179
180static int gpio_mockup_event_open(struct inode *inode, struct file *file)
181{
182 return single_open(file, NULL, inode->i_private);
183}
184
185static const struct file_operations gpio_mockup_event_ops = {
186 .owner = THIS_MODULE,
187 .open = gpio_mockup_event_open,
188 .write = gpio_mockup_event_write,
189 .llseek = no_llseek,
190};
191
192static void gpio_mockup_debugfs_setup(struct device *dev,
193 struct gpio_mockup_chip *chip)
194{
195 struct gpio_mockup_dbgfs_private *priv;
196 struct dentry *evfile, *link;
197 struct gpio_chip *gc;
198 const char *devname;
199 char *name;
200 int i;
201
202 gc = &chip->gc;
203 devname = dev_name(&gc->gpiodev->dev);
204
205 chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir);
206 if (IS_ERR_OR_NULL(chip->dbg_dir))
207 goto err;
208
209 link = debugfs_create_symlink(gc->label, gpio_mockup_dbg_dir, devname);
210 if (IS_ERR_OR_NULL(link))
211 goto err;
212
213 for (i = 0; i < gc->ngpio; i++) {
214 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
215 if (!name)
216 goto err;
217
218 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
219 if (!priv)
220 goto err;
221
222 priv->chip = chip;
223 priv->offset = i;
224 priv->desc = &gc->gpiodev->descs[i];
225
226 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
227 &gpio_mockup_event_ops);
228 if (IS_ERR_OR_NULL(evfile))
229 goto err;
230 }
231
232 return;
233
234err:
235 dev_err(dev, "error creating debugfs event files\n");
236}
237
238static int gpio_mockup_name_lines(struct device *dev,
239 struct gpio_mockup_chip *chip)
240{
241 struct gpio_chip *gc = &chip->gc;
242 char **names;
243 int i;
244
245 names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
246 if (!names)
247 return -ENOMEM;
248
249 for (i = 0; i < gc->ngpio; i++) {
250 names[i] = devm_kasprintf(dev, GFP_KERNEL,
251 "%s-%d", gc->label, i);
252 if (!names[i])
253 return -ENOMEM;
254 }
255
256 gc->names = (const char *const *)names;
257
258 return 0;
259}
260
261static int gpio_mockup_probe(struct platform_device *pdev)
262{
263 struct gpio_mockup_platform_data *pdata;
264 struct gpio_mockup_chip *chip;
265 struct gpio_chip *gc;
266 int rv, base, ngpio;
267 struct device *dev;
268 char *name;
269
270 dev = &pdev->dev;
271 pdata = dev_get_platdata(dev);
272 base = pdata->base;
273 ngpio = pdata->ngpio;
274
275 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
276 if (!chip)
277 return -ENOMEM;
278
279 name = devm_kasprintf(dev, GFP_KERNEL, "%s-%c",
280 pdev->name, pdata->index);
281 if (!name)
282 return -ENOMEM;
283
284 gc = &chip->gc;
285 gc->base = base;
286 gc->ngpio = ngpio;
287 gc->label = name;
288 gc->owner = THIS_MODULE;
289 gc->parent = dev;
290 gc->get = gpio_mockup_get;
291 gc->set = gpio_mockup_set;
292 gc->set_multiple = gpio_mockup_set_multiple;
293 gc->direction_output = gpio_mockup_dirout;
294 gc->direction_input = gpio_mockup_dirin;
295 gc->get_direction = gpio_mockup_get_direction;
296 gc->to_irq = gpio_mockup_to_irq;
297
298 chip->lines = devm_kcalloc(dev, gc->ngpio,
299 sizeof(*chip->lines), GFP_KERNEL);
300 if (!chip->lines)
301 return -ENOMEM;
302
303 if (pdata->named_lines) {
304 rv = gpio_mockup_name_lines(dev, chip);
305 if (rv)
306 return rv;
307 }
308
309 rv = devm_irq_sim_init(dev, &chip->irqsim, gc->ngpio);
310 if (rv < 0)
311 return rv;
312
313 rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
314 if (rv)
315 return rv;
316
317 if (!IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
318 gpio_mockup_debugfs_setup(dev, chip);
319
320 return 0;
321}
322
323static struct platform_driver gpio_mockup_driver = {
324 .driver = {
325 .name = GPIO_MOCKUP_NAME,
326 },
327 .probe = gpio_mockup_probe,
328};
329
330static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
331
332static void gpio_mockup_unregister_pdevs(void)
333{
334 struct platform_device *pdev;
335 int i;
336
337 for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
338 pdev = gpio_mockup_pdevs[i];
339
340 if (pdev)
341 platform_device_unregister(pdev);
342 }
343}
344
345static int __init gpio_mockup_init(void)
346{
347 int i, num_chips, err = 0, index = 'A';
348 struct gpio_mockup_platform_data pdata;
349 struct platform_device *pdev;
350
351 if ((gpio_mockup_num_ranges < 2) ||
352 (gpio_mockup_num_ranges % 2) ||
353 (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES))
354 return -EINVAL;
355
356 /* Each chip is described by two values. */
357 num_chips = gpio_mockup_num_ranges / 2;
358
359 /*
360 * The second value in the <base GPIO - number of GPIOS> pair must
361 * always be greater than 0.
362 */
363 for (i = 0; i < num_chips; i++) {
364 if (gpio_mockup_range_ngpio(i) < 0)
365 return -EINVAL;
366 }
367
368 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
369 if (IS_ERR_OR_NULL(gpio_mockup_dbg_dir))
370 gpio_mockup_err("error creating debugfs directory\n");
371
372 err = platform_driver_register(&gpio_mockup_driver);
373 if (err) {
374 gpio_mockup_err("error registering platform driver\n");
375 return err;
376 }
377
378 for (i = 0; i < num_chips; i++) {
379 pdata.index = index++;
380 pdata.base = gpio_mockup_range_base(i);
381 pdata.ngpio = pdata.base < 0
382 ? gpio_mockup_range_ngpio(i)
383 : gpio_mockup_range_ngpio(i) - pdata.base;
384 pdata.named_lines = gpio_mockup_named_lines;
385
386 pdev = platform_device_register_resndata(NULL,
387 GPIO_MOCKUP_NAME,
388 i, NULL, 0, &pdata,
389 sizeof(pdata));
390 if (IS_ERR(pdev)) {
391 gpio_mockup_err("error registering device");
392 platform_driver_unregister(&gpio_mockup_driver);
393 gpio_mockup_unregister_pdevs();
394 return PTR_ERR(pdev);
395 }
396
397 gpio_mockup_pdevs[i] = pdev;
398 }
399
400 return 0;
401}
402
403static void __exit gpio_mockup_exit(void)
404{
405 debugfs_remove_recursive(gpio_mockup_dbg_dir);
406 platform_driver_unregister(&gpio_mockup_driver);
407 gpio_mockup_unregister_pdevs();
408}
409
410module_init(gpio_mockup_init);
411module_exit(gpio_mockup_exit);
412
413MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
414MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>");
415MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
416MODULE_DESCRIPTION("GPIO Testing driver");
417MODULE_LICENSE("GPL v2");