summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-mockup.c
blob: 6a50f9f59c901b6d38069a67b5b9f7881e8a43b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
// SPDX-License-Identifier: GPL-2.0+
/*
 * 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>
 */

#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 <linux/property.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)
/* Maximum of three properties + the sentinel. */
#define GPIO_MOCKUP_MAX_PROP	4

#define gpio_mockup_err(...)	pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)

enum {
	GPIO_MOCKUP_DIR_IN = 0,
	GPIO_MOCKUP_DIR_OUT = 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;
};

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_chip *chip;
	struct gpio_chip *gc;
	struct device *dev;
	const char *name;
	int rv, base;
	u16 ngpio;

	dev = &pdev->dev;

	rv = device_property_read_u32(dev, "gpio-base", &base);
	if (rv)
		base = -1;

	rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
	if (rv)
		return rv;

	rv = device_property_read_string(dev, "chip-name", &name);
	if (rv)
		name = NULL;

	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	if (!name) {
		name = devm_kasprintf(dev, GFP_KERNEL,
				      "%s-%c", pdev->name, pdev->id + 'A');
		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 (device_property_read_bool(dev, "named-gpio-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)
{
	struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
	int i, prop, num_chips, err = 0, base;
	struct platform_device_info pdevinfo;
	struct platform_device *pdev;
	u16 ngpio;

	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++) {
		memset(properties, 0, sizeof(properties));
		memset(&pdevinfo, 0, sizeof(pdevinfo));
		prop = 0;

		base = gpio_mockup_range_base(i);
		if (base >= 0)
			properties[prop++] = PROPERTY_ENTRY_U32("gpio-base",
								base);

		ngpio = base < 0 ? gpio_mockup_range_ngpio(i)
				 : gpio_mockup_range_ngpio(i) - base;
		properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);

		if (gpio_mockup_named_lines)
			properties[prop++] = PROPERTY_ENTRY_BOOL(
						"named-gpio-lines");

		pdevinfo.name = GPIO_MOCKUP_NAME;
		pdevinfo.id = i;
		pdevinfo.properties = properties;

		pdev = platform_device_register_full(&pdevinfo);
		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");