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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * GPIO Testing Device Driver
4 *
5 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
6 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com>
7 * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
8 */
9
10#include <linux/debugfs.h>
11#include <linux/gpio/consumer.h>
12#include <linux/gpio/driver.h>
13#include <linux/init.h>
14#include <linux/interrupt.h>
15#include <linux/irq.h>
16#include <linux/irq_sim.h>
17#include <linux/irqdomain.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/property.h>
21#include <linux/slab.h>
22#include <linux/uaccess.h>
23
24#include "gpiolib.h"
25
26#define GPIO_MOCKUP_NAME "gpio-mockup"
27#define GPIO_MOCKUP_MAX_GC 10
28/*
29 * We're storing two values per chip: the GPIO base and the number
30 * of GPIO lines.
31 */
32#define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
33/* Maximum of three properties + the sentinel. */
34#define GPIO_MOCKUP_MAX_PROP 4
35
36#define gpio_mockup_err(...) pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)
37
38/*
39 * struct gpio_pin_status - structure describing a GPIO status
40 * @dir: Configures direction of gpio as "in" or "out"
41 * @value: Configures status of the gpio as 0(low) or 1(high)
42 */
43struct gpio_mockup_line_status {
44 int dir;
45 int value;
46 int pull;
47};
48
49struct gpio_mockup_chip {
50 struct gpio_chip gc;
51 struct gpio_mockup_line_status *lines;
52 struct irq_domain *irq_sim_domain;
53 struct dentry *dbg_dir;
54 struct mutex lock;
55};
56
57struct gpio_mockup_dbgfs_private {
58 struct gpio_mockup_chip *chip;
59 struct gpio_desc *desc;
60 unsigned int offset;
61};
62
63static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
64static int gpio_mockup_num_ranges;
65module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
66
67static bool gpio_mockup_named_lines;
68module_param_named(gpio_mockup_named_lines,
69 gpio_mockup_named_lines, bool, 0400);
70
71static struct dentry *gpio_mockup_dbg_dir;
72
73static int gpio_mockup_range_base(unsigned int index)
74{
75 return gpio_mockup_ranges[index * 2];
76}
77
78static int gpio_mockup_range_ngpio(unsigned int index)
79{
80 return gpio_mockup_ranges[index * 2 + 1];
81}
82
83static int __gpio_mockup_get(struct gpio_mockup_chip *chip,
84 unsigned int offset)
85{
86 return chip->lines[offset].value;
87}
88
89static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
90{
91 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
92 int val;
93
94 mutex_lock(&chip->lock);
95 val = __gpio_mockup_get(chip, offset);
96 mutex_unlock(&chip->lock);
97
98 return val;
99}
100
101static int gpio_mockup_get_multiple(struct gpio_chip *gc,
102 unsigned long *mask, unsigned long *bits)
103{
104 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
105 unsigned int bit, val;
106
107 mutex_lock(&chip->lock);
108 for_each_set_bit(bit, mask, gc->ngpio) {
109 val = __gpio_mockup_get(chip, bit);
110 __assign_bit(bit, bits, val);
111 }
112 mutex_unlock(&chip->lock);
113
114 return 0;
115}
116
117static void __gpio_mockup_set(struct gpio_mockup_chip *chip,
118 unsigned int offset, int value)
119{
120 chip->lines[offset].value = !!value;
121}
122
123static void gpio_mockup_set(struct gpio_chip *gc,
124 unsigned int offset, int value)
125{
126 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
127
128 mutex_lock(&chip->lock);
129 __gpio_mockup_set(chip, offset, value);
130 mutex_unlock(&chip->lock);
131}
132
133static void gpio_mockup_set_multiple(struct gpio_chip *gc,
134 unsigned long *mask, unsigned long *bits)
135{
136 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
137 unsigned int bit;
138
139 mutex_lock(&chip->lock);
140 for_each_set_bit(bit, mask, gc->ngpio)
141 __gpio_mockup_set(chip, bit, test_bit(bit, bits));
142 mutex_unlock(&chip->lock);
143}
144
145static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
146 unsigned int offset, int value)
147{
148 int curr, irq, irq_type, ret = 0;
149 struct gpio_desc *desc;
150 struct gpio_chip *gc;
151
152 gc = &chip->gc;
153 desc = &gc->gpiodev->descs[offset];
154
155 mutex_lock(&chip->lock);
156
157 if (test_bit(FLAG_REQUESTED, &desc->flags) &&
158 !test_bit(FLAG_IS_OUT, &desc->flags)) {
159 curr = __gpio_mockup_get(chip, offset);
160 if (curr == value)
161 goto out;
162
163 irq = irq_find_mapping(chip->irq_sim_domain, offset);
164 if (!irq)
165 /*
166 * This is fine - it just means, nobody is listening
167 * for interrupts on this line, otherwise
168 * irq_create_mapping() would have been called from
169 * the to_irq() callback.
170 */
171 goto set_value;
172
173 irq_type = irq_get_trigger_type(irq);
174
175 if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
176 (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
177 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
178 true);
179 if (ret)
180 goto out;
181 }
182 }
183
184set_value:
185 /* Change the value unless we're actively driving the line. */
186 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
187 !test_bit(FLAG_IS_OUT, &desc->flags))
188 __gpio_mockup_set(chip, offset, value);
189
190out:
191 chip->lines[offset].pull = value;
192 mutex_unlock(&chip->lock);
193 return ret;
194}
195
196static int gpio_mockup_set_config(struct gpio_chip *gc,
197 unsigned int offset, unsigned long config)
198{
199 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
200
201 switch (pinconf_to_config_param(config)) {
202 case PIN_CONFIG_BIAS_PULL_UP:
203 return gpio_mockup_apply_pull(chip, offset, 1);
204 case PIN_CONFIG_BIAS_PULL_DOWN:
205 return gpio_mockup_apply_pull(chip, offset, 0);
206 default:
207 break;
208 }
209 return -ENOTSUPP;
210}
211
212static int gpio_mockup_dirout(struct gpio_chip *gc,
213 unsigned int offset, int value)
214{
215 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
216
217 mutex_lock(&chip->lock);
218 chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT;
219 __gpio_mockup_set(chip, offset, value);
220 mutex_unlock(&chip->lock);
221
222 return 0;
223}
224
225static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
226{
227 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
228
229 mutex_lock(&chip->lock);
230 chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN;
231 mutex_unlock(&chip->lock);
232
233 return 0;
234}
235
236static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
237{
238 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
239 int direction;
240
241 mutex_lock(&chip->lock);
242 direction = chip->lines[offset].dir;
243 mutex_unlock(&chip->lock);
244
245 return direction;
246}
247
248static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
249{
250 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
251
252 return irq_create_mapping(chip->irq_sim_domain, offset);
253}
254
255static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
256{
257 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
258
259 __gpio_mockup_set(chip, offset, chip->lines[offset].pull);
260}
261
262static ssize_t gpio_mockup_debugfs_read(struct file *file,
263 char __user *usr_buf,
264 size_t size, loff_t *ppos)
265{
266 struct gpio_mockup_dbgfs_private *priv;
267 struct gpio_mockup_chip *chip;
268 struct seq_file *sfile;
269 struct gpio_chip *gc;
270 int val, cnt;
271 char buf[3];
272
273 if (*ppos != 0)
274 return 0;
275
276 sfile = file->private_data;
277 priv = sfile->private;
278 chip = priv->chip;
279 gc = &chip->gc;
280
281 val = gpio_mockup_get(gc, priv->offset);
282 cnt = snprintf(buf, sizeof(buf), "%d\n", val);
283
284 return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt);
285}
286
287static ssize_t gpio_mockup_debugfs_write(struct file *file,
288 const char __user *usr_buf,
289 size_t size, loff_t *ppos)
290{
291 struct gpio_mockup_dbgfs_private *priv;
292 int rv, val;
293 struct seq_file *sfile;
294
295 if (*ppos != 0)
296 return -EINVAL;
297
298 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
299 if (rv)
300 return rv;
301 if (val != 0 && val != 1)
302 return -EINVAL;
303
304 sfile = file->private_data;
305 priv = sfile->private;
306 rv = gpio_mockup_apply_pull(priv->chip, priv->offset, val);
307 if (rv)
308 return rv;
309
310 return size;
311}
312
313static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
314{
315 return single_open(file, NULL, inode->i_private);
316}
317
318/*
319 * Each mockup chip is represented by a directory named after the chip's device
320 * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
321 * a file using the line's offset as the name under the chip's directory.
322 *
323 * Reading from the line's file yields the current *value*, writing to the
324 * line's file changes the current *pull*. Default pull for mockup lines is
325 * down.
326 *
327 * Examples:
328 * - when a line pulled down is requested in output mode and driven high, its
329 * value will return to 0 once it's released
330 * - when the line is requested in output mode and driven high, writing 0 to
331 * the corresponding debugfs file will change the pull to down but the
332 * reported value will still be 1 until the line is released
333 * - line requested in input mode always reports the same value as its pull
334 * configuration
335 * - when the line is requested in input mode and monitored for events, writing
336 * the same value to the debugfs file will be a noop, while writing the
337 * opposite value will generate a dummy interrupt with an appropriate edge
338 */
339static const struct file_operations gpio_mockup_debugfs_ops = {
340 .owner = THIS_MODULE,
341 .open = gpio_mockup_debugfs_open,
342 .read = gpio_mockup_debugfs_read,
343 .write = gpio_mockup_debugfs_write,
344 .llseek = no_llseek,
345 .release = single_release,
346};
347
348static void gpio_mockup_debugfs_setup(struct device *dev,
349 struct gpio_mockup_chip *chip)
350{
351 struct gpio_mockup_dbgfs_private *priv;
352 struct gpio_chip *gc;
353 const char *devname;
354 char *name;
355 int i;
356
357 gc = &chip->gc;
358 devname = dev_name(&gc->gpiodev->dev);
359
360 chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir);
361
362 for (i = 0; i < gc->ngpio; i++) {
363 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
364 if (!name)
365 return;
366
367 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
368 if (!priv)
369 return;
370
371 priv->chip = chip;
372 priv->offset = i;
373 priv->desc = &gc->gpiodev->descs[i];
374
375 debugfs_create_file(name, 0200, chip->dbg_dir, priv,
376 &gpio_mockup_debugfs_ops);
377 }
378
379 return;
380}
381
382static int gpio_mockup_name_lines(struct device *dev,
383 struct gpio_mockup_chip *chip)
384{
385 struct gpio_chip *gc = &chip->gc;
386 char **names;
387 int i;
388
389 names = devm_kcalloc(dev, gc->ngpio, sizeof(char *), GFP_KERNEL);
390 if (!names)
391 return -ENOMEM;
392
393 for (i = 0; i < gc->ngpio; i++) {
394 names[i] = devm_kasprintf(dev, GFP_KERNEL,
395 "%s-%d", gc->label, i);
396 if (!names[i])
397 return -ENOMEM;
398 }
399
400 gc->names = (const char *const *)names;
401
402 return 0;
403}
404
405static void gpio_mockup_dispose_mappings(void *data)
406{
407 struct gpio_mockup_chip *chip = data;
408 struct gpio_chip *gc = &chip->gc;
409 int i, irq;
410
411 for (i = 0; i < gc->ngpio; i++) {
412 irq = irq_find_mapping(chip->irq_sim_domain, i);
413 if (irq)
414 irq_dispose_mapping(irq);
415 }
416}
417
418static int gpio_mockup_probe(struct platform_device *pdev)
419{
420 struct gpio_mockup_chip *chip;
421 struct gpio_chip *gc;
422 struct device *dev;
423 const char *name;
424 int rv, base, i;
425 u16 ngpio;
426
427 dev = &pdev->dev;
428
429 rv = device_property_read_u32(dev, "gpio-base", &base);
430 if (rv)
431 base = -1;
432
433 rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
434 if (rv)
435 return rv;
436
437 rv = device_property_read_string(dev, "chip-name", &name);
438 if (rv)
439 name = NULL;
440
441 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
442 if (!chip)
443 return -ENOMEM;
444
445 if (!name) {
446 name = devm_kasprintf(dev, GFP_KERNEL,
447 "%s-%c", pdev->name, pdev->id + 'A');
448 if (!name)
449 return -ENOMEM;
450 }
451
452 mutex_init(&chip->lock);
453
454 gc = &chip->gc;
455 gc->base = base;
456 gc->ngpio = ngpio;
457 gc->label = name;
458 gc->owner = THIS_MODULE;
459 gc->parent = dev;
460 gc->get = gpio_mockup_get;
461 gc->set = gpio_mockup_set;
462 gc->get_multiple = gpio_mockup_get_multiple;
463 gc->set_multiple = gpio_mockup_set_multiple;
464 gc->direction_output = gpio_mockup_dirout;
465 gc->direction_input = gpio_mockup_dirin;
466 gc->get_direction = gpio_mockup_get_direction;
467 gc->set_config = gpio_mockup_set_config;
468 gc->to_irq = gpio_mockup_to_irq;
469 gc->free = gpio_mockup_free;
470
471 chip->lines = devm_kcalloc(dev, gc->ngpio,
472 sizeof(*chip->lines), GFP_KERNEL);
473 if (!chip->lines)
474 return -ENOMEM;
475
476 for (i = 0; i < gc->ngpio; i++)
477 chip->lines[i].dir = GPIO_LINE_DIRECTION_IN;
478
479 if (device_property_read_bool(dev, "named-gpio-lines")) {
480 rv = gpio_mockup_name_lines(dev, chip);
481 if (rv)
482 return rv;
483 }
484
485 chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
486 gc->ngpio);
487 if (IS_ERR(chip->irq_sim_domain))
488 return PTR_ERR(chip->irq_sim_domain);
489
490 rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip);
491 if (rv)
492 return rv;
493
494 rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
495 if (rv)
496 return rv;
497
498 gpio_mockup_debugfs_setup(dev, chip);
499
500 return 0;
501}
502
503static struct platform_driver gpio_mockup_driver = {
504 .driver = {
505 .name = GPIO_MOCKUP_NAME,
506 },
507 .probe = gpio_mockup_probe,
508};
509
510static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
511
512static void gpio_mockup_unregister_pdevs(void)
513{
514 struct platform_device *pdev;
515 int i;
516
517 for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
518 pdev = gpio_mockup_pdevs[i];
519
520 if (pdev)
521 platform_device_unregister(pdev);
522 }
523}
524
525static int __init gpio_mockup_init(void)
526{
527 struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
528 int i, prop, num_chips, err = 0, base;
529 struct platform_device_info pdevinfo;
530 struct platform_device *pdev;
531 u16 ngpio;
532
533 if ((gpio_mockup_num_ranges < 2) ||
534 (gpio_mockup_num_ranges % 2) ||
535 (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES))
536 return -EINVAL;
537
538 /* Each chip is described by two values. */
539 num_chips = gpio_mockup_num_ranges / 2;
540
541 /*
542 * The second value in the <base GPIO - number of GPIOS> pair must
543 * always be greater than 0.
544 */
545 for (i = 0; i < num_chips; i++) {
546 if (gpio_mockup_range_ngpio(i) < 0)
547 return -EINVAL;
548 }
549
550 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
551
552 err = platform_driver_register(&gpio_mockup_driver);
553 if (err) {
554 gpio_mockup_err("error registering platform driver\n");
555 debugfs_remove_recursive(gpio_mockup_dbg_dir);
556 return err;
557 }
558
559 for (i = 0; i < num_chips; i++) {
560 memset(properties, 0, sizeof(properties));
561 memset(&pdevinfo, 0, sizeof(pdevinfo));
562 prop = 0;
563
564 base = gpio_mockup_range_base(i);
565 if (base >= 0)
566 properties[prop++] = PROPERTY_ENTRY_U32("gpio-base",
567 base);
568
569 ngpio = base < 0 ? gpio_mockup_range_ngpio(i)
570 : gpio_mockup_range_ngpio(i) - base;
571 properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
572
573 if (gpio_mockup_named_lines)
574 properties[prop++] = PROPERTY_ENTRY_BOOL(
575 "named-gpio-lines");
576
577 pdevinfo.name = GPIO_MOCKUP_NAME;
578 pdevinfo.id = i;
579 pdevinfo.properties = properties;
580
581 pdev = platform_device_register_full(&pdevinfo);
582 if (IS_ERR(pdev)) {
583 gpio_mockup_err("error registering device");
584 platform_driver_unregister(&gpio_mockup_driver);
585 gpio_mockup_unregister_pdevs();
586 debugfs_remove_recursive(gpio_mockup_dbg_dir);
587 return PTR_ERR(pdev);
588 }
589
590 gpio_mockup_pdevs[i] = pdev;
591 }
592
593 return 0;
594}
595
596static void __exit gpio_mockup_exit(void)
597{
598 debugfs_remove_recursive(gpio_mockup_dbg_dir);
599 platform_driver_unregister(&gpio_mockup_driver);
600 gpio_mockup_unregister_pdevs();
601}
602
603module_init(gpio_mockup_init);
604module_exit(gpio_mockup_exit);
605
606MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
607MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>");
608MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
609MODULE_DESCRIPTION("GPIO Testing driver");
610MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * GPIO Testing Device Driver
4 *
5 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
6 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamv2005@gmail.com>
7 * Copyright (C) 2017 Bartosz Golaszewski <brgl@bgdev.pl>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/cleanup.h>
13#include <linux/debugfs.h>
14#include <linux/device.h>
15#include <linux/gpio/driver.h>
16#include <linux/interrupt.h>
17#include <linux/irq.h>
18#include <linux/irq_sim.h>
19#include <linux/irqdomain.h>
20#include <linux/mod_devicetable.h>
21#include <linux/module.h>
22#include <linux/platform_device.h>
23#include <linux/property.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/string_helpers.h>
27#include <linux/uaccess.h>
28
29#define GPIO_MOCKUP_MAX_GC 10
30/*
31 * We're storing two values per chip: the GPIO base and the number
32 * of GPIO lines.
33 */
34#define GPIO_MOCKUP_MAX_RANGES (GPIO_MOCKUP_MAX_GC * 2)
35/* Maximum of four properties + the sentinel. */
36#define GPIO_MOCKUP_MAX_PROP 5
37
38/*
39 * struct gpio_pin_status - structure describing a GPIO status
40 * @dir: Configures direction of gpio as "in" or "out"
41 * @value: Configures status of the gpio as 0(low) or 1(high)
42 * @pull: Configures the current pull of the GPIO as 0 (pull-down) or
43 * 1 (pull-up)
44 * @requested: Request status of this GPIO
45 */
46struct gpio_mockup_line_status {
47 int dir;
48 int value;
49 int pull;
50 bool requested;
51};
52
53struct gpio_mockup_chip {
54 struct gpio_chip gc;
55 struct gpio_mockup_line_status *lines;
56 struct irq_domain *irq_sim_domain;
57 struct dentry *dbg_dir;
58 struct mutex lock;
59};
60
61struct gpio_mockup_dbgfs_private {
62 struct gpio_mockup_chip *chip;
63 unsigned int offset;
64};
65
66static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
67static int gpio_mockup_num_ranges;
68module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
69
70static bool gpio_mockup_named_lines;
71module_param_named(gpio_mockup_named_lines,
72 gpio_mockup_named_lines, bool, 0400);
73
74static struct dentry *gpio_mockup_dbg_dir;
75
76static int gpio_mockup_range_base(unsigned int index)
77{
78 return gpio_mockup_ranges[index * 2];
79}
80
81static int gpio_mockup_range_ngpio(unsigned int index)
82{
83 return gpio_mockup_ranges[index * 2 + 1];
84}
85
86static int __gpio_mockup_get(struct gpio_mockup_chip *chip,
87 unsigned int offset)
88{
89 return chip->lines[offset].value;
90}
91
92static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
93{
94 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
95 int val;
96
97 scoped_guard(mutex, &chip->lock)
98 val = __gpio_mockup_get(chip, offset);
99
100 return val;
101}
102
103static int gpio_mockup_get_multiple(struct gpio_chip *gc,
104 unsigned long *mask, unsigned long *bits)
105{
106 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
107 unsigned int bit, val;
108
109 scoped_guard(mutex, &chip->lock) {
110 for_each_set_bit(bit, mask, gc->ngpio) {
111 val = __gpio_mockup_get(chip, bit);
112 __assign_bit(bit, bits, val);
113 }
114 }
115
116 return 0;
117}
118
119static void __gpio_mockup_set(struct gpio_mockup_chip *chip,
120 unsigned int offset, int value)
121{
122 chip->lines[offset].value = !!value;
123}
124
125static void gpio_mockup_set(struct gpio_chip *gc,
126 unsigned int offset, int value)
127{
128 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
129
130 guard(mutex)(&chip->lock);
131
132 __gpio_mockup_set(chip, offset, value);
133}
134
135static void gpio_mockup_set_multiple(struct gpio_chip *gc,
136 unsigned long *mask, unsigned long *bits)
137{
138 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
139 unsigned int bit;
140
141 guard(mutex)(&chip->lock);
142
143 for_each_set_bit(bit, mask, gc->ngpio)
144 __gpio_mockup_set(chip, bit, test_bit(bit, bits));
145}
146
147static int gpio_mockup_apply_pull(struct gpio_mockup_chip *chip,
148 unsigned int offset, int value)
149{
150 struct gpio_mockup_line_status *line = &chip->lines[offset];
151 int curr, irq, irq_type, ret = 0;
152
153 guard(mutex)(&chip->lock);
154
155 if (line->requested && line->dir == GPIO_LINE_DIRECTION_IN) {
156 curr = __gpio_mockup_get(chip, offset);
157 if (curr == value)
158 goto out;
159
160 irq = irq_find_mapping(chip->irq_sim_domain, offset);
161 if (!irq)
162 /*
163 * This is fine - it just means, nobody is listening
164 * for interrupts on this line, otherwise
165 * irq_create_mapping() would have been called from
166 * the to_irq() callback.
167 */
168 goto set_value;
169
170 irq_type = irq_get_trigger_type(irq);
171
172 if ((value == 1 && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
173 (value == 0 && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
174 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
175 true);
176 if (ret)
177 goto out;
178 }
179 }
180
181set_value:
182 /* Change the value unless we're actively driving the line. */
183 if (!line->requested || line->dir == GPIO_LINE_DIRECTION_IN)
184 __gpio_mockup_set(chip, offset, value);
185
186out:
187 chip->lines[offset].pull = value;
188 return ret;
189}
190
191static int gpio_mockup_set_config(struct gpio_chip *gc,
192 unsigned int offset, unsigned long config)
193{
194 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
195
196 switch (pinconf_to_config_param(config)) {
197 case PIN_CONFIG_BIAS_PULL_UP:
198 return gpio_mockup_apply_pull(chip, offset, 1);
199 case PIN_CONFIG_BIAS_PULL_DOWN:
200 return gpio_mockup_apply_pull(chip, offset, 0);
201 default:
202 break;
203 }
204 return -ENOTSUPP;
205}
206
207static int gpio_mockup_dirout(struct gpio_chip *gc,
208 unsigned int offset, int value)
209{
210 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
211
212 scoped_guard(mutex, &chip->lock) {
213 chip->lines[offset].dir = GPIO_LINE_DIRECTION_OUT;
214 __gpio_mockup_set(chip, offset, value);
215 }
216
217 return 0;
218}
219
220static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
221{
222 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
223
224 scoped_guard(mutex, &chip->lock)
225 chip->lines[offset].dir = GPIO_LINE_DIRECTION_IN;
226
227 return 0;
228}
229
230static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
231{
232 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
233 int direction;
234
235 scoped_guard(mutex, &chip->lock)
236 direction = chip->lines[offset].dir;
237
238 return direction;
239}
240
241static int gpio_mockup_to_irq(struct gpio_chip *gc, unsigned int offset)
242{
243 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
244
245 return irq_create_mapping(chip->irq_sim_domain, offset);
246}
247
248static int gpio_mockup_request(struct gpio_chip *gc, unsigned int offset)
249{
250 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
251
252 scoped_guard(mutex, &chip->lock)
253 chip->lines[offset].requested = true;
254
255 return 0;
256}
257
258static void gpio_mockup_free(struct gpio_chip *gc, unsigned int offset)
259{
260 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
261
262 guard(mutex)(&chip->lock);
263
264 chip->lines[offset].requested = false;
265 __gpio_mockup_set(chip, offset, chip->lines[offset].pull);
266}
267
268static ssize_t gpio_mockup_debugfs_read(struct file *file,
269 char __user *usr_buf,
270 size_t size, loff_t *ppos)
271{
272 struct gpio_mockup_dbgfs_private *priv;
273 struct gpio_mockup_chip *chip;
274 struct seq_file *sfile;
275 struct gpio_chip *gc;
276 int val, cnt;
277 char buf[3];
278
279 if (*ppos != 0)
280 return 0;
281
282 sfile = file->private_data;
283 priv = sfile->private;
284 chip = priv->chip;
285 gc = &chip->gc;
286
287 val = gpio_mockup_get(gc, priv->offset);
288 cnt = snprintf(buf, sizeof(buf), "%d\n", val);
289
290 return simple_read_from_buffer(usr_buf, size, ppos, buf, cnt);
291}
292
293static ssize_t gpio_mockup_debugfs_write(struct file *file,
294 const char __user *usr_buf,
295 size_t size, loff_t *ppos)
296{
297 struct gpio_mockup_dbgfs_private *priv;
298 int rv, val;
299 struct seq_file *sfile;
300
301 if (*ppos != 0)
302 return -EINVAL;
303
304 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
305 if (rv)
306 return rv;
307 if (val != 0 && val != 1)
308 return -EINVAL;
309
310 sfile = file->private_data;
311 priv = sfile->private;
312 rv = gpio_mockup_apply_pull(priv->chip, priv->offset, val);
313 if (rv)
314 return rv;
315
316 return size;
317}
318
319static int gpio_mockup_debugfs_open(struct inode *inode, struct file *file)
320{
321 return single_open(file, NULL, inode->i_private);
322}
323
324/*
325 * Each mockup chip is represented by a directory named after the chip's device
326 * name under /sys/kernel/debug/gpio-mockup/. Each line is represented by
327 * a file using the line's offset as the name under the chip's directory.
328 *
329 * Reading from the line's file yields the current *value*, writing to the
330 * line's file changes the current *pull*. Default pull for mockup lines is
331 * down.
332 *
333 * Examples:
334 * - when a line pulled down is requested in output mode and driven high, its
335 * value will return to 0 once it's released
336 * - when the line is requested in output mode and driven high, writing 0 to
337 * the corresponding debugfs file will change the pull to down but the
338 * reported value will still be 1 until the line is released
339 * - line requested in input mode always reports the same value as its pull
340 * configuration
341 * - when the line is requested in input mode and monitored for events, writing
342 * the same value to the debugfs file will be a noop, while writing the
343 * opposite value will generate a dummy interrupt with an appropriate edge
344 */
345static const struct file_operations gpio_mockup_debugfs_ops = {
346 .owner = THIS_MODULE,
347 .open = gpio_mockup_debugfs_open,
348 .read = gpio_mockup_debugfs_read,
349 .write = gpio_mockup_debugfs_write,
350 .llseek = no_llseek,
351 .release = single_release,
352};
353
354static void gpio_mockup_debugfs_setup(struct device *dev,
355 struct gpio_mockup_chip *chip)
356{
357 struct gpio_mockup_dbgfs_private *priv;
358 struct gpio_chip *gc;
359 const char *devname;
360 char *name;
361 int i;
362
363 gc = &chip->gc;
364
365 /*
366 * There can only be a single GPIO device per platform device in
367 * gpio-mockup so using device_find_any_child() is OK.
368 */
369 struct device *child __free(put_device) = device_find_any_child(dev);
370 if (!child)
371 return;
372
373 devname = dev_name(child);
374 chip->dbg_dir = debugfs_create_dir(devname, gpio_mockup_dbg_dir);
375
376 for (i = 0; i < gc->ngpio; i++) {
377 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
378 if (!name)
379 return;
380
381 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
382 if (!priv)
383 return;
384
385 priv->chip = chip;
386 priv->offset = i;
387
388 debugfs_create_file(name, 0600, chip->dbg_dir, priv,
389 &gpio_mockup_debugfs_ops);
390 }
391}
392
393static void gpio_mockup_debugfs_cleanup(void *data)
394{
395 struct gpio_mockup_chip *chip = data;
396
397 debugfs_remove_recursive(chip->dbg_dir);
398}
399
400static void gpio_mockup_dispose_mappings(void *data)
401{
402 struct gpio_mockup_chip *chip = data;
403 struct gpio_chip *gc = &chip->gc;
404 int i, irq;
405
406 for (i = 0; i < gc->ngpio; i++) {
407 irq = irq_find_mapping(chip->irq_sim_domain, i);
408 if (irq)
409 irq_dispose_mapping(irq);
410 }
411}
412
413static int gpio_mockup_probe(struct platform_device *pdev)
414{
415 struct gpio_mockup_chip *chip;
416 struct gpio_chip *gc;
417 struct device *dev;
418 const char *name;
419 int rv, base, i;
420 u16 ngpio;
421
422 dev = &pdev->dev;
423
424 rv = device_property_read_u32(dev, "gpio-base", &base);
425 if (rv)
426 base = -1;
427
428 rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
429 if (rv)
430 return rv;
431
432 rv = device_property_read_string(dev, "chip-label", &name);
433 if (rv)
434 name = dev_name(dev);
435
436 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
437 if (!chip)
438 return -ENOMEM;
439
440 mutex_init(&chip->lock);
441
442 gc = &chip->gc;
443 gc->base = base;
444 gc->ngpio = ngpio;
445 gc->label = name;
446 gc->owner = THIS_MODULE;
447 gc->parent = dev;
448 gc->get = gpio_mockup_get;
449 gc->set = gpio_mockup_set;
450 gc->get_multiple = gpio_mockup_get_multiple;
451 gc->set_multiple = gpio_mockup_set_multiple;
452 gc->direction_output = gpio_mockup_dirout;
453 gc->direction_input = gpio_mockup_dirin;
454 gc->get_direction = gpio_mockup_get_direction;
455 gc->set_config = gpio_mockup_set_config;
456 gc->to_irq = gpio_mockup_to_irq;
457 gc->request = gpio_mockup_request;
458 gc->free = gpio_mockup_free;
459
460 chip->lines = devm_kcalloc(dev, gc->ngpio,
461 sizeof(*chip->lines), GFP_KERNEL);
462 if (!chip->lines)
463 return -ENOMEM;
464
465 for (i = 0; i < gc->ngpio; i++)
466 chip->lines[i].dir = GPIO_LINE_DIRECTION_IN;
467
468 chip->irq_sim_domain = devm_irq_domain_create_sim(dev, NULL,
469 gc->ngpio);
470 if (IS_ERR(chip->irq_sim_domain))
471 return PTR_ERR(chip->irq_sim_domain);
472
473 rv = devm_add_action_or_reset(dev, gpio_mockup_dispose_mappings, chip);
474 if (rv)
475 return rv;
476
477 rv = devm_gpiochip_add_data(dev, &chip->gc, chip);
478 if (rv)
479 return rv;
480
481 gpio_mockup_debugfs_setup(dev, chip);
482
483 return devm_add_action_or_reset(dev, gpio_mockup_debugfs_cleanup, chip);
484}
485
486static const struct of_device_id gpio_mockup_of_match[] = {
487 { .compatible = "gpio-mockup", },
488 {},
489};
490MODULE_DEVICE_TABLE(of, gpio_mockup_of_match);
491
492static struct platform_driver gpio_mockup_driver = {
493 .driver = {
494 .name = "gpio-mockup",
495 .of_match_table = gpio_mockup_of_match,
496 },
497 .probe = gpio_mockup_probe,
498};
499
500static struct platform_device *gpio_mockup_pdevs[GPIO_MOCKUP_MAX_GC];
501
502static void gpio_mockup_unregister_pdevs(void)
503{
504 struct platform_device *pdev;
505 struct fwnode_handle *fwnode;
506 int i;
507
508 for (i = 0; i < GPIO_MOCKUP_MAX_GC; i++) {
509 pdev = gpio_mockup_pdevs[i];
510 if (!pdev)
511 continue;
512
513 fwnode = dev_fwnode(&pdev->dev);
514 platform_device_unregister(pdev);
515 fwnode_remove_software_node(fwnode);
516 }
517}
518
519static int __init gpio_mockup_register_chip(int idx)
520{
521 struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
522 struct platform_device_info pdevinfo;
523 struct platform_device *pdev;
524 struct fwnode_handle *fwnode;
525 char **line_names = NULL;
526 char chip_label[32];
527 int prop = 0, base;
528 u16 ngpio;
529
530 memset(properties, 0, sizeof(properties));
531 memset(&pdevinfo, 0, sizeof(pdevinfo));
532
533 snprintf(chip_label, sizeof(chip_label), "gpio-mockup-%c", idx + 'A');
534 properties[prop++] = PROPERTY_ENTRY_STRING("chip-label", chip_label);
535
536 base = gpio_mockup_range_base(idx);
537 if (base >= 0)
538 properties[prop++] = PROPERTY_ENTRY_U32("gpio-base", base);
539
540 ngpio = base < 0 ? gpio_mockup_range_ngpio(idx)
541 : gpio_mockup_range_ngpio(idx) - base;
542 properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
543
544 if (gpio_mockup_named_lines) {
545 line_names = kasprintf_strarray(GFP_KERNEL, chip_label, ngpio);
546 if (!line_names)
547 return -ENOMEM;
548
549 properties[prop++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
550 "gpio-line-names", line_names, ngpio);
551 }
552
553 fwnode = fwnode_create_software_node(properties, NULL);
554 if (IS_ERR(fwnode)) {
555 kfree_strarray(line_names, ngpio);
556 return PTR_ERR(fwnode);
557 }
558
559 pdevinfo.name = "gpio-mockup";
560 pdevinfo.id = idx;
561 pdevinfo.fwnode = fwnode;
562
563 pdev = platform_device_register_full(&pdevinfo);
564 kfree_strarray(line_names, ngpio);
565 if (IS_ERR(pdev)) {
566 fwnode_remove_software_node(fwnode);
567 pr_err("error registering device");
568 return PTR_ERR(pdev);
569 }
570
571 gpio_mockup_pdevs[idx] = pdev;
572
573 return 0;
574}
575
576static int __init gpio_mockup_init(void)
577{
578 int i, num_chips, err;
579
580 if ((gpio_mockup_num_ranges % 2) ||
581 (gpio_mockup_num_ranges > GPIO_MOCKUP_MAX_RANGES))
582 return -EINVAL;
583
584 /* Each chip is described by two values. */
585 num_chips = gpio_mockup_num_ranges / 2;
586
587 /*
588 * The second value in the <base GPIO - number of GPIOS> pair must
589 * always be greater than 0.
590 */
591 for (i = 0; i < num_chips; i++) {
592 if (gpio_mockup_range_ngpio(i) < 0)
593 return -EINVAL;
594 }
595
596 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup", NULL);
597
598 err = platform_driver_register(&gpio_mockup_driver);
599 if (err) {
600 pr_err("error registering platform driver\n");
601 debugfs_remove_recursive(gpio_mockup_dbg_dir);
602 return err;
603 }
604
605 for (i = 0; i < num_chips; i++) {
606 err = gpio_mockup_register_chip(i);
607 if (err) {
608 platform_driver_unregister(&gpio_mockup_driver);
609 gpio_mockup_unregister_pdevs();
610 debugfs_remove_recursive(gpio_mockup_dbg_dir);
611 return err;
612 }
613 }
614
615 return 0;
616}
617
618static void __exit gpio_mockup_exit(void)
619{
620 gpio_mockup_unregister_pdevs();
621 debugfs_remove_recursive(gpio_mockup_dbg_dir);
622 platform_driver_unregister(&gpio_mockup_driver);
623}
624
625module_init(gpio_mockup_init);
626module_exit(gpio_mockup_exit);
627
628MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
629MODULE_AUTHOR("Bamvor Jian Zhang <bamv2005@gmail.com>");
630MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
631MODULE_DESCRIPTION("GPIO Testing driver");
632MODULE_LICENSE("GPL v2");