1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011-2012 Avionic Design GmbH
4 */
5
6 #include <linux/gpio/driver.h>
7 #include <linux/i2c.h>
8 #include <linux/interrupt.h>
9 #include <linux/mod_devicetable.h>
10 #include <linux/module.h>
11 #include <linux/property.h>
12 #include <linux/seq_file.h>
13 #include <linux/slab.h>
14
15 #define GPIO_DDR(gpio) (0x00 << (gpio)->reg_shift)
16 #define GPIO_PLR(gpio) (0x01 << (gpio)->reg_shift)
17 #define GPIO_IER(gpio) (0x02 << (gpio)->reg_shift)
18 #define GPIO_ISR(gpio) (0x03 << (gpio)->reg_shift)
19 #define GPIO_PTR(gpio) (0x04 << (gpio)->reg_shift)
20
21 struct adnp {
22 struct i2c_client *client;
23 struct gpio_chip gpio;
24 unsigned int reg_shift;
25
26 struct mutex i2c_lock;
27 struct mutex irq_lock;
28
29 u8 *irq_enable;
30 u8 *irq_level;
31 u8 *irq_rise;
32 u8 *irq_fall;
33 u8 *irq_high;
34 u8 *irq_low;
35 };
36
adnp_read(struct adnp * adnp,unsigned offset,uint8_t * value)37 static int adnp_read(struct adnp *adnp, unsigned offset, uint8_t *value)
38 {
39 int err;
40
41 err = i2c_smbus_read_byte_data(adnp->client, offset);
42 if (err < 0) {
43 dev_err(adnp->gpio.parent, "%s failed: %d\n",
44 "i2c_smbus_read_byte_data()", err);
45 return err;
46 }
47
48 *value = err;
49 return 0;
50 }
51
adnp_write(struct adnp * adnp,unsigned offset,uint8_t value)52 static int adnp_write(struct adnp *adnp, unsigned offset, uint8_t value)
53 {
54 int err;
55
56 err = i2c_smbus_write_byte_data(adnp->client, offset, value);
57 if (err < 0) {
58 dev_err(adnp->gpio.parent, "%s failed: %d\n",
59 "i2c_smbus_write_byte_data()", err);
60 return err;
61 }
62
63 return 0;
64 }
65
adnp_gpio_get(struct gpio_chip * chip,unsigned offset)66 static int adnp_gpio_get(struct gpio_chip *chip, unsigned offset)
67 {
68 struct adnp *adnp = gpiochip_get_data(chip);
69 unsigned int reg = offset >> adnp->reg_shift;
70 unsigned int pos = offset & 7;
71 u8 value;
72 int err;
73
74 err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &value);
75 if (err < 0)
76 return err;
77
78 return (value & BIT(pos)) ? 1 : 0;
79 }
80
__adnp_gpio_set(struct adnp * adnp,unsigned offset,int value)81 static void __adnp_gpio_set(struct adnp *adnp, unsigned offset, int value)
82 {
83 unsigned int reg = offset >> adnp->reg_shift;
84 unsigned int pos = offset & 7;
85 int err;
86 u8 val;
87
88 err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &val);
89 if (err < 0)
90 return;
91
92 if (value)
93 val |= BIT(pos);
94 else
95 val &= ~BIT(pos);
96
97 adnp_write(adnp, GPIO_PLR(adnp) + reg, val);
98 }
99
adnp_gpio_set(struct gpio_chip * chip,unsigned offset,int value)100 static void adnp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
101 {
102 struct adnp *adnp = gpiochip_get_data(chip);
103
104 mutex_lock(&adnp->i2c_lock);
105 __adnp_gpio_set(adnp, offset, value);
106 mutex_unlock(&adnp->i2c_lock);
107 }
108
adnp_gpio_direction_input(struct gpio_chip * chip,unsigned offset)109 static int adnp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
110 {
111 struct adnp *adnp = gpiochip_get_data(chip);
112 unsigned int reg = offset >> adnp->reg_shift;
113 unsigned int pos = offset & 7;
114 u8 value;
115 int err;
116
117 mutex_lock(&adnp->i2c_lock);
118
119 err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
120 if (err < 0)
121 goto out;
122
123 value &= ~BIT(pos);
124
125 err = adnp_write(adnp, GPIO_DDR(adnp) + reg, value);
126 if (err < 0)
127 goto out;
128
129 err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
130 if (err < 0)
131 goto out;
132
133 if (value & BIT(pos)) {
134 err = -EPERM;
135 goto out;
136 }
137
138 err = 0;
139
140 out:
141 mutex_unlock(&adnp->i2c_lock);
142 return err;
143 }
144
adnp_gpio_direction_output(struct gpio_chip * chip,unsigned offset,int value)145 static int adnp_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
146 int value)
147 {
148 struct adnp *adnp = gpiochip_get_data(chip);
149 unsigned int reg = offset >> adnp->reg_shift;
150 unsigned int pos = offset & 7;
151 int err;
152 u8 val;
153
154 mutex_lock(&adnp->i2c_lock);
155
156 err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
157 if (err < 0)
158 goto out;
159
160 val |= BIT(pos);
161
162 err = adnp_write(adnp, GPIO_DDR(adnp) + reg, val);
163 if (err < 0)
164 goto out;
165
166 err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
167 if (err < 0)
168 goto out;
169
170 if (!(val & BIT(pos))) {
171 err = -EPERM;
172 goto out;
173 }
174
175 __adnp_gpio_set(adnp, offset, value);
176 err = 0;
177
178 out:
179 mutex_unlock(&adnp->i2c_lock);
180 return err;
181 }
182
adnp_gpio_dbg_show(struct seq_file * s,struct gpio_chip * chip)183 static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
184 {
185 struct adnp *adnp = gpiochip_get_data(chip);
186 unsigned int num_regs = 1 << adnp->reg_shift, i, j;
187 int err;
188
189 for (i = 0; i < num_regs; i++) {
190 u8 ddr, plr, ier, isr;
191
192 mutex_lock(&adnp->i2c_lock);
193
194 err = adnp_read(adnp, GPIO_DDR(adnp) + i, &ddr);
195 if (err < 0)
196 goto unlock;
197
198 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &plr);
199 if (err < 0)
200 goto unlock;
201
202 err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
203 if (err < 0)
204 goto unlock;
205
206 err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
207 if (err < 0)
208 goto unlock;
209
210 mutex_unlock(&adnp->i2c_lock);
211
212 for (j = 0; j < 8; j++) {
213 unsigned int bit = (i << adnp->reg_shift) + j;
214 const char *direction = "input ";
215 const char *level = "low ";
216 const char *interrupt = "disabled";
217 const char *pending = "";
218
219 if (ddr & BIT(j))
220 direction = "output";
221
222 if (plr & BIT(j))
223 level = "high";
224
225 if (ier & BIT(j))
226 interrupt = "enabled ";
227
228 if (isr & BIT(j))
229 pending = "pending";
230
231 seq_printf(s, "%2u: %s %s IRQ %s %s\n", bit,
232 direction, level, interrupt, pending);
233 }
234 }
235
236 return;
237
238 unlock:
239 mutex_unlock(&adnp->i2c_lock);
240 }
241
adnp_irq(int irq,void * data)242 static irqreturn_t adnp_irq(int irq, void *data)
243 {
244 struct adnp *adnp = data;
245 unsigned int num_regs, i;
246
247 num_regs = 1 << adnp->reg_shift;
248
249 for (i = 0; i < num_regs; i++) {
250 unsigned int base = i << adnp->reg_shift, bit;
251 u8 changed, level, isr, ier;
252 unsigned long pending;
253 int err;
254
255 mutex_lock(&adnp->i2c_lock);
256
257 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &level);
258 if (err < 0) {
259 mutex_unlock(&adnp->i2c_lock);
260 continue;
261 }
262
263 err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
264 if (err < 0) {
265 mutex_unlock(&adnp->i2c_lock);
266 continue;
267 }
268
269 err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
270 if (err < 0) {
271 mutex_unlock(&adnp->i2c_lock);
272 continue;
273 }
274
275 mutex_unlock(&adnp->i2c_lock);
276
277 /* determine pins that changed levels */
278 changed = level ^ adnp->irq_level[i];
279
280 /* compute edge-triggered interrupts */
281 pending = changed & ((adnp->irq_fall[i] & ~level) |
282 (adnp->irq_rise[i] & level));
283
284 /* add in level-triggered interrupts */
285 pending |= (adnp->irq_high[i] & level) |
286 (adnp->irq_low[i] & ~level);
287
288 /* mask out non-pending and disabled interrupts */
289 pending &= isr & ier;
290
291 for_each_set_bit(bit, &pending, 8) {
292 unsigned int child_irq;
293 child_irq = irq_find_mapping(adnp->gpio.irq.domain,
294 base + bit);
295 handle_nested_irq(child_irq);
296 }
297 }
298
299 return IRQ_HANDLED;
300 }
301
adnp_irq_mask(struct irq_data * d)302 static void adnp_irq_mask(struct irq_data *d)
303 {
304 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
305 struct adnp *adnp = gpiochip_get_data(gc);
306 unsigned int reg = d->hwirq >> adnp->reg_shift;
307 unsigned int pos = d->hwirq & 7;
308
309 adnp->irq_enable[reg] &= ~BIT(pos);
310 }
311
adnp_irq_unmask(struct irq_data * d)312 static void adnp_irq_unmask(struct irq_data *d)
313 {
314 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
315 struct adnp *adnp = gpiochip_get_data(gc);
316 unsigned int reg = d->hwirq >> adnp->reg_shift;
317 unsigned int pos = d->hwirq & 7;
318
319 adnp->irq_enable[reg] |= BIT(pos);
320 }
321
adnp_irq_set_type(struct irq_data * d,unsigned int type)322 static int adnp_irq_set_type(struct irq_data *d, unsigned int type)
323 {
324 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
325 struct adnp *adnp = gpiochip_get_data(gc);
326 unsigned int reg = d->hwirq >> adnp->reg_shift;
327 unsigned int pos = d->hwirq & 7;
328
329 if (type & IRQ_TYPE_EDGE_RISING)
330 adnp->irq_rise[reg] |= BIT(pos);
331 else
332 adnp->irq_rise[reg] &= ~BIT(pos);
333
334 if (type & IRQ_TYPE_EDGE_FALLING)
335 adnp->irq_fall[reg] |= BIT(pos);
336 else
337 adnp->irq_fall[reg] &= ~BIT(pos);
338
339 if (type & IRQ_TYPE_LEVEL_HIGH)
340 adnp->irq_high[reg] |= BIT(pos);
341 else
342 adnp->irq_high[reg] &= ~BIT(pos);
343
344 if (type & IRQ_TYPE_LEVEL_LOW)
345 adnp->irq_low[reg] |= BIT(pos);
346 else
347 adnp->irq_low[reg] &= ~BIT(pos);
348
349 return 0;
350 }
351
adnp_irq_bus_lock(struct irq_data * d)352 static void adnp_irq_bus_lock(struct irq_data *d)
353 {
354 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
355 struct adnp *adnp = gpiochip_get_data(gc);
356
357 mutex_lock(&adnp->irq_lock);
358 }
359
adnp_irq_bus_unlock(struct irq_data * d)360 static void adnp_irq_bus_unlock(struct irq_data *d)
361 {
362 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
363 struct adnp *adnp = gpiochip_get_data(gc);
364 unsigned int num_regs = 1 << adnp->reg_shift, i;
365
366 mutex_lock(&adnp->i2c_lock);
367
368 for (i = 0; i < num_regs; i++)
369 adnp_write(adnp, GPIO_IER(adnp) + i, adnp->irq_enable[i]);
370
371 mutex_unlock(&adnp->i2c_lock);
372 mutex_unlock(&adnp->irq_lock);
373 }
374
375 static struct irq_chip adnp_irq_chip = {
376 .name = "gpio-adnp",
377 .irq_mask = adnp_irq_mask,
378 .irq_unmask = adnp_irq_unmask,
379 .irq_set_type = adnp_irq_set_type,
380 .irq_bus_lock = adnp_irq_bus_lock,
381 .irq_bus_sync_unlock = adnp_irq_bus_unlock,
382 };
383
adnp_irq_setup(struct adnp * adnp)384 static int adnp_irq_setup(struct adnp *adnp)
385 {
386 unsigned int num_regs = 1 << adnp->reg_shift, i;
387 struct gpio_chip *chip = &adnp->gpio;
388 int err;
389
390 mutex_init(&adnp->irq_lock);
391
392 /*
393 * Allocate memory to keep track of the current level and trigger
394 * modes of the interrupts. To avoid multiple allocations, a single
395 * large buffer is allocated and pointers are setup to point at the
396 * corresponding offsets. For consistency, the layout of the buffer
397 * is chosen to match the register layout of the hardware in that
398 * each segment contains the corresponding bits for all interrupts.
399 */
400 adnp->irq_enable = devm_kcalloc(chip->parent, num_regs, 6,
401 GFP_KERNEL);
402 if (!adnp->irq_enable)
403 return -ENOMEM;
404
405 adnp->irq_level = adnp->irq_enable + (num_regs * 1);
406 adnp->irq_rise = adnp->irq_enable + (num_regs * 2);
407 adnp->irq_fall = adnp->irq_enable + (num_regs * 3);
408 adnp->irq_high = adnp->irq_enable + (num_regs * 4);
409 adnp->irq_low = adnp->irq_enable + (num_regs * 5);
410
411 for (i = 0; i < num_regs; i++) {
412 /*
413 * Read the initial level of all pins to allow the emulation
414 * of edge triggered interrupts.
415 */
416 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &adnp->irq_level[i]);
417 if (err < 0)
418 return err;
419
420 /* disable all interrupts */
421 err = adnp_write(adnp, GPIO_IER(adnp) + i, 0);
422 if (err < 0)
423 return err;
424
425 adnp->irq_enable[i] = 0x00;
426 }
427
428 err = devm_request_threaded_irq(chip->parent, adnp->client->irq,
429 NULL, adnp_irq,
430 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
431 dev_name(chip->parent), adnp);
432 if (err != 0) {
433 dev_err(chip->parent, "can't request IRQ#%d: %d\n",
434 adnp->client->irq, err);
435 return err;
436 }
437
438 return 0;
439 }
440
adnp_gpio_setup(struct adnp * adnp,unsigned int num_gpios,bool is_irq_controller)441 static int adnp_gpio_setup(struct adnp *adnp, unsigned int num_gpios,
442 bool is_irq_controller)
443 {
444 struct gpio_chip *chip = &adnp->gpio;
445 int err;
446
447 adnp->reg_shift = get_count_order(num_gpios) - 3;
448
449 chip->direction_input = adnp_gpio_direction_input;
450 chip->direction_output = adnp_gpio_direction_output;
451 chip->get = adnp_gpio_get;
452 chip->set = adnp_gpio_set;
453 chip->can_sleep = true;
454
455 if (IS_ENABLED(CONFIG_DEBUG_FS))
456 chip->dbg_show = adnp_gpio_dbg_show;
457
458 chip->base = -1;
459 chip->ngpio = num_gpios;
460 chip->label = adnp->client->name;
461 chip->parent = &adnp->client->dev;
462 chip->owner = THIS_MODULE;
463
464 if (is_irq_controller) {
465 struct gpio_irq_chip *girq;
466
467 err = adnp_irq_setup(adnp);
468 if (err)
469 return err;
470
471 girq = &chip->irq;
472 girq->chip = &adnp_irq_chip;
473 /* This will let us handle the parent IRQ in the driver */
474 girq->parent_handler = NULL;
475 girq->num_parents = 0;
476 girq->parents = NULL;
477 girq->default_type = IRQ_TYPE_NONE;
478 girq->handler = handle_simple_irq;
479 girq->threaded = true;
480 }
481
482 err = devm_gpiochip_add_data(&adnp->client->dev, chip, adnp);
483 if (err)
484 return err;
485
486 return 0;
487 }
488
adnp_i2c_probe(struct i2c_client * client)489 static int adnp_i2c_probe(struct i2c_client *client)
490 {
491 struct device *dev = &client->dev;
492 struct adnp *adnp;
493 u32 num_gpios;
494 int err;
495
496 err = device_property_read_u32(dev, "nr-gpios", &num_gpios);
497 if (err < 0)
498 return err;
499
500 adnp = devm_kzalloc(&client->dev, sizeof(*adnp), GFP_KERNEL);
501 if (!adnp)
502 return -ENOMEM;
503
504 mutex_init(&adnp->i2c_lock);
505 adnp->client = client;
506
507 err = adnp_gpio_setup(adnp, num_gpios, device_property_read_bool(dev, "interrupt-controller"));
508 if (err)
509 return err;
510
511 i2c_set_clientdata(client, adnp);
512
513 return 0;
514 }
515
516 static const struct i2c_device_id adnp_i2c_id[] = {
517 { "gpio-adnp" },
518 { },
519 };
520 MODULE_DEVICE_TABLE(i2c, adnp_i2c_id);
521
522 static const struct of_device_id adnp_of_match[] = {
523 { .compatible = "ad,gpio-adnp", },
524 { },
525 };
526 MODULE_DEVICE_TABLE(of, adnp_of_match);
527
528 static struct i2c_driver adnp_i2c_driver = {
529 .driver = {
530 .name = "gpio-adnp",
531 .of_match_table = adnp_of_match,
532 },
533 .probe_new = adnp_i2c_probe,
534 .id_table = adnp_i2c_id,
535 };
536 module_i2c_driver(adnp_i2c_driver);
537
538 MODULE_DESCRIPTION("Avionic Design N-bit GPIO expander");
539 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
540 MODULE_LICENSE("GPL");
541
