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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 <bamvor.zhangjian@linaro.org>
6 *
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.
11 *
12 */
13
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/gpio/driver.h>
9202ba23 17#include <linux/gpio/consumer.h>
0f98dd1b 18#include <linux/platform_device.h>
8a68ea00 19#include <linux/slab.h>
e2ff7408
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20#include <linux/interrupt.h>
21#include <linux/irq.h>
22#include <linux/irq_work.h>
9202ba23
BG
23#include <linux/debugfs.h>
24#include <linux/uaccess.h>
25
26#include "gpiolib.h"
0f98dd1b 27
ca409160
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28#define GPIO_MOCKUP_NAME "gpio-mockup"
29#define GPIO_MOCKUP_MAX_GC 10
0f98dd1b 30
ca409160
BG
31enum {
32 DIR_IN = 0,
33 DIR_OUT,
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34};
35
36/*
37 * struct gpio_pin_status - structure describing a GPIO status
38 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
39 * @value: Configures status of the gpio as 0(low) or 1(high)
40 */
ca409160
BG
41struct gpio_mockup_line_status {
42 int dir;
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43 bool value;
44};
45
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46struct gpio_mockup_irq_context {
47 struct irq_work work;
48 int irq;
49};
50
ca409160 51struct gpio_mockup_chip {
0f98dd1b 52 struct gpio_chip gc;
ca409160 53 struct gpio_mockup_line_status *lines;
e2ff7408 54 struct gpio_mockup_irq_context irq_ctx;
9202ba23
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55 struct dentry *dbg_dir;
56};
57
58struct gpio_mockup_dbgfs_private {
59 struct gpio_mockup_chip *chip;
60 struct gpio_desc *desc;
61 int offset;
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62};
63
ca409160 64static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_GC << 1];
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65static int gpio_mockup_params_nr;
66module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);
67
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68static bool gpio_mockup_named_lines;
69module_param_named(gpio_mockup_named_lines,
70 gpio_mockup_named_lines, bool, 0400);
71
ca409160 72static const char gpio_mockup_name_start = 'A';
9202ba23 73static struct dentry *gpio_mockup_dbg_dir;
0f98dd1b 74
ca409160 75static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
0f98dd1b 76{
ca409160 77 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
0f98dd1b 78
ca409160 79 return chip->lines[offset].value;
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80}
81
ca409160 82static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
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83 int value)
84{
ca409160 85 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
0f98dd1b 86
ca409160 87 chip->lines[offset].value = !!value;
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88}
89
ca409160 90static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
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91 int value)
92{
ca409160
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93 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
94
95 gpio_mockup_set(gc, offset, value);
96 chip->lines[offset].dir = DIR_OUT;
0f98dd1b 97
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98 return 0;
99}
100
ca409160 101static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
0f98dd1b 102{
ca409160
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103 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
104
105 chip->lines[offset].dir = DIR_IN;
0f98dd1b 106
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107 return 0;
108}
109
ca409160 110static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
0f98dd1b 111{
ca409160 112 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
0f98dd1b 113
ca409160 114 return chip->lines[offset].dir;
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115}
116
8a68ea00
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117static int gpio_mockup_name_lines(struct device *dev,
118 struct gpio_mockup_chip *chip)
119{
120 struct gpio_chip *gc = &chip->gc;
121 char **names;
122 int i;
123
124 names = devm_kzalloc(dev, sizeof(char *) * gc->ngpio, GFP_KERNEL);
125 if (!names)
126 return -ENOMEM;
127
128 for (i = 0; i < gc->ngpio; i++) {
129 names[i] = devm_kasprintf(dev, GFP_KERNEL,
130 "%s-%d", gc->label, i);
131 if (!names[i])
132 return -ENOMEM;
133 }
134
135 gc->names = (const char *const *)names;
136
137 return 0;
138}
139
e2ff7408
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140static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
141{
142 return chip->irq_base + offset;
143}
144
145/*
146 * While we should generally support irqmask and irqunmask, this driver is
147 * for testing purposes only so we don't care.
148 */
149static void gpio_mockup_irqmask(struct irq_data *d) { }
150static void gpio_mockup_irqunmask(struct irq_data *d) { }
151
152static struct irq_chip gpio_mockup_irqchip = {
153 .name = GPIO_MOCKUP_NAME,
154 .irq_mask = gpio_mockup_irqmask,
155 .irq_unmask = gpio_mockup_irqunmask,
156};
157
158static void gpio_mockup_handle_irq(struct irq_work *work)
159{
160 struct gpio_mockup_irq_context *irq_ctx;
161
162 irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
163 handle_simple_irq(irq_to_desc(irq_ctx->irq));
164}
165
166static int gpio_mockup_irqchip_setup(struct device *dev,
167 struct gpio_mockup_chip *chip)
168{
169 struct gpio_chip *gc = &chip->gc;
170 int irq_base, i;
171
172 irq_base = irq_alloc_descs(-1, 0, gc->ngpio, 0);
173 if (irq_base < 0)
174 return irq_base;
175
176 gc->irq_base = irq_base;
177 gc->irqchip = &gpio_mockup_irqchip;
178
179 for (i = 0; i < gc->ngpio; i++) {
180 irq_set_chip(irq_base + i, gc->irqchip);
181 irq_set_handler(irq_base + i, &handle_simple_irq);
182 irq_modify_status(irq_base + i,
183 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
184 }
185
186 init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
187
188 return 0;
189}
190
9202ba23
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191static ssize_t gpio_mockup_event_write(struct file *file,
192 const char __user *usr_buf,
193 size_t size, loff_t *ppos)
194{
195 struct gpio_mockup_dbgfs_private *priv;
196 struct gpio_mockup_chip *chip;
197 struct seq_file *sfile;
198 struct gpio_desc *desc;
199 struct gpio_chip *gc;
fa6256db 200 int val;
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201 char buf;
202
203 sfile = file->private_data;
204 priv = sfile->private;
205 desc = priv->desc;
206 chip = priv->chip;
207 gc = &chip->gc;
208
fa6256db
DC
209 if (copy_from_user(&buf, usr_buf, 1))
210 return -EFAULT;
9202ba23
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211
212 if (buf == '0')
213 val = 0;
214 else if (buf == '1')
215 val = 1;
216 else
217 return -EINVAL;
218
219 gpiod_set_value_cansleep(desc, val);
220 priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
221 irq_work_queue(&priv->chip->irq_ctx.work);
222
223 return size;
224}
225
226static int gpio_mockup_event_open(struct inode *inode, struct file *file)
227{
228 return single_open(file, NULL, inode->i_private);
229}
230
231static const struct file_operations gpio_mockup_event_ops = {
232 .owner = THIS_MODULE,
233 .open = gpio_mockup_event_open,
234 .write = gpio_mockup_event_write,
235 .llseek = no_llseek,
236};
237
238static void gpio_mockup_debugfs_setup(struct device *dev,
239 struct gpio_mockup_chip *chip)
240{
241 struct gpio_mockup_dbgfs_private *priv;
242 struct dentry *evfile;
243 struct gpio_chip *gc;
244 char *name;
245 int i;
246
247 gc = &chip->gc;
248
249 chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
250 if (!chip->dbg_dir)
251 goto err;
252
253 for (i = 0; i < gc->ngpio; i++) {
254 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
255 if (!name)
256 goto err;
257
258 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
259 if (!priv)
260 goto err;
261
262 priv->chip = chip;
263 priv->offset = i;
264 priv->desc = &gc->gpiodev->descs[i];
265
266 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
267 &gpio_mockup_event_ops);
268 if (!evfile)
269 goto err;
270 }
271
272 return;
273
274err:
275 dev_err(dev, "error creating debugfs directory\n");
276}
277
ca409160
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278static int gpio_mockup_add(struct device *dev,
279 struct gpio_mockup_chip *chip,
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280 const char *name, int base, int ngpio)
281{
ca409160 282 struct gpio_chip *gc = &chip->gc;
8a68ea00 283 int ret;
0f98dd1b 284
ca409160
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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->direction_output = gpio_mockup_dirout;
293 gc->direction_input = gpio_mockup_dirin;
294 gc->get_direction = gpio_mockup_get_direction;
e2ff7408 295 gc->to_irq = gpio_mockup_to_irq;
ca409160
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296
297 chip->lines = devm_kzalloc(dev, sizeof(*chip->lines) * gc->ngpio,
0f98dd1b 298 GFP_KERNEL);
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299 if (!chip->lines)
300 return -ENOMEM;
ca409160 301
8a68ea00
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302 if (gpio_mockup_named_lines) {
303 ret = gpio_mockup_name_lines(dev, chip);
304 if (ret)
305 return ret;
306 }
307
e2ff7408
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308 ret = gpio_mockup_irqchip_setup(dev, chip);
309 if (ret)
310 return ret;
311
9202ba23
BG
312 ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
313 if (ret)
314 return ret;
315
316 if (gpio_mockup_dbg_dir)
317 gpio_mockup_debugfs_setup(dev, chip);
318
319 return 0;
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320}
321
ca409160 322static int gpio_mockup_probe(struct platform_device *pdev)
0f98dd1b 323{
ca409160 324 struct gpio_mockup_chip *chips;
364ac456
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325 struct device *dev = &pdev->dev;
326 int ret, i, base, ngpio;
ad6d8004 327 char *chip_name;
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328
329 if (gpio_mockup_params_nr < 2)
330 return -EINVAL;
331
ca409160
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332 chips = devm_kzalloc(dev,
333 sizeof(*chips) * (gpio_mockup_params_nr >> 1),
334 GFP_KERNEL);
335 if (!chips)
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336 return -ENOMEM;
337
ca409160 338 platform_set_drvdata(pdev, chips);
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339
340 for (i = 0; i < gpio_mockup_params_nr >> 1; i++) {
341 base = gpio_mockup_ranges[i * 2];
ca409160 342
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343 if (base == -1)
344 ngpio = gpio_mockup_ranges[i * 2 + 1];
345 else
346 ngpio = gpio_mockup_ranges[i * 2 + 1] - base;
347
348 if (ngpio >= 0) {
ad6d8004 349 chip_name = devm_kasprintf(dev, GFP_KERNEL,
ca409160
BG
350 "%s-%c", GPIO_MOCKUP_NAME,
351 gpio_mockup_name_start + i);
ad6d8004
BG
352 if (!chip_name)
353 return -ENOMEM;
354
ca409160 355 ret = gpio_mockup_add(dev, &chips[i],
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356 chip_name, base, ngpio);
357 } else {
358 ret = -1;
359 }
ca409160 360
0f98dd1b 361 if (ret) {
e4ba07bf
BG
362 dev_err(dev, "gpio<%d..%d> add failed\n",
363 base, base < 0 ? ngpio : base + ngpio);
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364
365 return ret;
366 }
e4ba07bf
BG
367
368 dev_info(dev, "gpio<%d..%d> add successful!",
369 base, base + ngpio);
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370 }
371
372 return 0;
373}
374
e2ff7408
BG
375static int gpio_mockup_remove(struct platform_device *pdev)
376{
377 struct gpio_mockup_chip *chips;
378 int i;
379
380 chips = platform_get_drvdata(pdev);
381
382 for (i = 0; i < gpio_mockup_params_nr >> 1; i++)
383 irq_free_descs(chips[i].gc.irq_base, chips[i].gc.ngpio);
384
385 return 0;
386}
387
ca409160 388static struct platform_driver gpio_mockup_driver = {
0f98dd1b 389 .driver = {
ca409160 390 .name = GPIO_MOCKUP_NAME,
364ac456 391 },
ca409160 392 .probe = gpio_mockup_probe,
e2ff7408 393 .remove = gpio_mockup_remove,
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394};
395
396static struct platform_device *pdev;
397static int __init mock_device_init(void)
398{
399 int err;
400
9202ba23
BG
401 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
402 if (!gpio_mockup_dbg_dir)
403 pr_err("%s: error creating debugfs directory\n",
404 GPIO_MOCKUP_NAME);
405
ca409160 406 pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
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407 if (!pdev)
408 return -ENOMEM;
409
410 err = platform_device_add(pdev);
411 if (err) {
412 platform_device_put(pdev);
413 return err;
414 }
415
ca409160 416 err = platform_driver_register(&gpio_mockup_driver);
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417 if (err) {
418 platform_device_unregister(pdev);
419 return err;
420 }
421
422 return 0;
423}
424
425static void __exit mock_device_exit(void)
426{
9202ba23 427 debugfs_remove_recursive(gpio_mockup_dbg_dir);
ca409160 428 platform_driver_unregister(&gpio_mockup_driver);
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429 platform_device_unregister(pdev);
430}
431
432module_init(mock_device_init);
433module_exit(mock_device_exit);
434
435MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
436MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
437MODULE_DESCRIPTION("GPIO Testing driver");
438MODULE_LICENSE("GPL v2");