1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Nuvoton NCT6694 GPIO controller driver based on USB interface.
4 *
5 * Copyright (C) 2025 Nuvoton Technology Corp.
6 */
7
8 #include <linux/bits.h>
9 #include <linux/gpio/driver.h>
10 #include <linux/idr.h>
11 #include <linux/interrupt.h>
12 #include <linux/mfd/nct6694.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15
16 /*
17 * USB command module type for NCT6694 GPIO controller.
18 * This defines the module type used for communication with the NCT6694
19 * GPIO controller over the USB interface.
20 */
21 #define NCT6694_GPIO_MOD 0xFF
22
23 #define NCT6694_GPIO_VER 0x90
24 #define NCT6694_GPIO_VALID 0x110
25 #define NCT6694_GPI_DATA 0x120
26 #define NCT6694_GPO_DIR 0x170
27 #define NCT6694_GPO_TYPE 0x180
28 #define NCT6694_GPO_DATA 0x190
29
30 #define NCT6694_GPI_STS 0x130
31 #define NCT6694_GPI_CLR 0x140
32 #define NCT6694_GPI_FALLING 0x150
33 #define NCT6694_GPI_RISING 0x160
34
35 #define NCT6694_NR_GPIO 8
36
37 struct nct6694_gpio_data {
38 struct nct6694 *nct6694;
39 struct gpio_chip gpio;
40 struct mutex lock;
41 /* Protect irq operation */
42 struct mutex irq_lock;
43
44 unsigned char reg_val;
45 unsigned char irq_trig_falling;
46 unsigned char irq_trig_rising;
47
48 /* Current gpio group */
49 unsigned char group;
50 int irq;
51 };
52
nct6694_get_direction(struct gpio_chip * gpio,unsigned int offset)53 static int nct6694_get_direction(struct gpio_chip *gpio, unsigned int offset)
54 {
55 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
56 const struct nct6694_cmd_header cmd_hd = {
57 .mod = NCT6694_GPIO_MOD,
58 .offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
59 .len = cpu_to_le16(sizeof(data->reg_val))
60 };
61 int ret;
62
63 guard(mutex)(&data->lock);
64
65 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
66 if (ret < 0)
67 return ret;
68
69 return !(BIT(offset) & data->reg_val);
70 }
71
nct6694_direction_input(struct gpio_chip * gpio,unsigned int offset)72 static int nct6694_direction_input(struct gpio_chip *gpio, unsigned int offset)
73 {
74 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
75 const struct nct6694_cmd_header cmd_hd = {
76 .mod = NCT6694_GPIO_MOD,
77 .offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
78 .len = cpu_to_le16(sizeof(data->reg_val))
79 };
80 int ret;
81
82 guard(mutex)(&data->lock);
83
84 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
85 if (ret < 0)
86 return ret;
87
88 data->reg_val &= ~BIT(offset);
89
90 return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
91 }
92
nct6694_direction_output(struct gpio_chip * gpio,unsigned int offset,int val)93 static int nct6694_direction_output(struct gpio_chip *gpio,
94 unsigned int offset, int val)
95 {
96 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
97 struct nct6694_cmd_header cmd_hd = {
98 .mod = NCT6694_GPIO_MOD,
99 .offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
100 .len = cpu_to_le16(sizeof(data->reg_val))
101 };
102 int ret;
103
104 guard(mutex)(&data->lock);
105
106 /* Set direction to output */
107 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
108 if (ret < 0)
109 return ret;
110
111 data->reg_val |= BIT(offset);
112 ret = nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
113 if (ret < 0)
114 return ret;
115
116 /* Then set output level */
117 cmd_hd.offset = cpu_to_le16(NCT6694_GPO_DATA + data->group);
118 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
119 if (ret < 0)
120 return ret;
121
122 if (val)
123 data->reg_val |= BIT(offset);
124 else
125 data->reg_val &= ~BIT(offset);
126
127 return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
128 }
129
nct6694_get_value(struct gpio_chip * gpio,unsigned int offset)130 static int nct6694_get_value(struct gpio_chip *gpio, unsigned int offset)
131 {
132 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
133 struct nct6694_cmd_header cmd_hd = {
134 .mod = NCT6694_GPIO_MOD,
135 .offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
136 .len = cpu_to_le16(sizeof(data->reg_val))
137 };
138 int ret;
139
140 guard(mutex)(&data->lock);
141
142 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
143 if (ret < 0)
144 return ret;
145
146 if (BIT(offset) & data->reg_val) {
147 cmd_hd.offset = cpu_to_le16(NCT6694_GPO_DATA + data->group);
148 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
149 if (ret < 0)
150 return ret;
151
152 return !!(BIT(offset) & data->reg_val);
153 }
154
155 cmd_hd.offset = cpu_to_le16(NCT6694_GPI_DATA + data->group);
156 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
157 if (ret < 0)
158 return ret;
159
160 return !!(BIT(offset) & data->reg_val);
161 }
162
nct6694_set_value(struct gpio_chip * gpio,unsigned int offset,int val)163 static int nct6694_set_value(struct gpio_chip *gpio, unsigned int offset,
164 int val)
165 {
166 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
167 const struct nct6694_cmd_header cmd_hd = {
168 .mod = NCT6694_GPIO_MOD,
169 .offset = cpu_to_le16(NCT6694_GPO_DATA + data->group),
170 .len = cpu_to_le16(sizeof(data->reg_val))
171 };
172 int ret;
173
174 guard(mutex)(&data->lock);
175
176 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
177 if (ret < 0)
178 return ret;
179
180 if (val)
181 data->reg_val |= BIT(offset);
182 else
183 data->reg_val &= ~BIT(offset);
184
185 return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
186 }
187
nct6694_set_config(struct gpio_chip * gpio,unsigned int offset,unsigned long config)188 static int nct6694_set_config(struct gpio_chip *gpio, unsigned int offset,
189 unsigned long config)
190 {
191 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
192 const struct nct6694_cmd_header cmd_hd = {
193 .mod = NCT6694_GPIO_MOD,
194 .offset = cpu_to_le16(NCT6694_GPO_TYPE + data->group),
195 .len = cpu_to_le16(sizeof(data->reg_val))
196 };
197 int ret;
198
199 guard(mutex)(&data->lock);
200
201 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
202 if (ret < 0)
203 return ret;
204
205 switch (pinconf_to_config_param(config)) {
206 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
207 data->reg_val |= BIT(offset);
208 break;
209 case PIN_CONFIG_DRIVE_PUSH_PULL:
210 data->reg_val &= ~BIT(offset);
211 break;
212 default:
213 return -ENOTSUPP;
214 }
215
216 return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
217 }
218
nct6694_init_valid_mask(struct gpio_chip * gpio,unsigned long * valid_mask,unsigned int ngpios)219 static int nct6694_init_valid_mask(struct gpio_chip *gpio,
220 unsigned long *valid_mask,
221 unsigned int ngpios)
222 {
223 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
224 const struct nct6694_cmd_header cmd_hd = {
225 .mod = NCT6694_GPIO_MOD,
226 .offset = cpu_to_le16(NCT6694_GPIO_VALID + data->group),
227 .len = cpu_to_le16(sizeof(data->reg_val))
228 };
229 int ret;
230
231 guard(mutex)(&data->lock);
232
233 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
234 if (ret < 0)
235 return ret;
236
237 *valid_mask = data->reg_val;
238
239 return ret;
240 }
241
nct6694_irq_handler(int irq,void * priv)242 static irqreturn_t nct6694_irq_handler(int irq, void *priv)
243 {
244 struct nct6694_gpio_data *data = priv;
245 struct nct6694_cmd_header cmd_hd = {
246 .mod = NCT6694_GPIO_MOD,
247 .offset = cpu_to_le16(NCT6694_GPI_STS + data->group),
248 .len = cpu_to_le16(sizeof(data->reg_val))
249 };
250 unsigned char status;
251 int ret;
252
253 guard(mutex)(&data->lock);
254
255 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
256 if (ret)
257 return IRQ_NONE;
258
259 status = data->reg_val;
260
261 while (status) {
262 int bit = __ffs(status);
263
264 data->reg_val = BIT(bit);
265 handle_nested_irq(irq_find_mapping(data->gpio.irq.domain, bit));
266 status &= ~BIT(bit);
267 cmd_hd.offset = cpu_to_le16(NCT6694_GPI_CLR + data->group);
268 nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
269 }
270
271 return IRQ_HANDLED;
272 }
273
nct6694_get_irq_trig(struct nct6694_gpio_data * data)274 static int nct6694_get_irq_trig(struct nct6694_gpio_data *data)
275 {
276 struct nct6694_cmd_header cmd_hd = {
277 .mod = NCT6694_GPIO_MOD,
278 .offset = cpu_to_le16(NCT6694_GPI_FALLING + data->group),
279 .len = cpu_to_le16(sizeof(data->reg_val))
280 };
281 int ret;
282
283 guard(mutex)(&data->lock);
284
285 ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->irq_trig_falling);
286 if (ret)
287 return ret;
288
289 cmd_hd.offset = cpu_to_le16(NCT6694_GPI_RISING + data->group);
290 return nct6694_read_msg(data->nct6694, &cmd_hd, &data->irq_trig_rising);
291 }
292
nct6694_irq_mask(struct irq_data * d)293 static void nct6694_irq_mask(struct irq_data *d)
294 {
295 struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
296 irq_hw_number_t hwirq = irqd_to_hwirq(d);
297
298 gpiochip_disable_irq(gpio, hwirq);
299 }
300
nct6694_irq_unmask(struct irq_data * d)301 static void nct6694_irq_unmask(struct irq_data *d)
302 {
303 struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
304 irq_hw_number_t hwirq = irqd_to_hwirq(d);
305
306 gpiochip_enable_irq(gpio, hwirq);
307 }
308
nct6694_irq_set_type(struct irq_data * d,unsigned int type)309 static int nct6694_irq_set_type(struct irq_data *d, unsigned int type)
310 {
311 struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
312 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
313 irq_hw_number_t hwirq = irqd_to_hwirq(d);
314
315 guard(mutex)(&data->lock);
316
317 switch (type) {
318 case IRQ_TYPE_EDGE_RISING:
319 data->irq_trig_rising |= BIT(hwirq);
320 break;
321
322 case IRQ_TYPE_EDGE_FALLING:
323 data->irq_trig_falling |= BIT(hwirq);
324 break;
325
326 case IRQ_TYPE_EDGE_BOTH:
327 data->irq_trig_rising |= BIT(hwirq);
328 data->irq_trig_falling |= BIT(hwirq);
329 break;
330
331 default:
332 return -ENOTSUPP;
333 }
334
335 return 0;
336 }
337
nct6694_irq_bus_lock(struct irq_data * d)338 static void nct6694_irq_bus_lock(struct irq_data *d)
339 {
340 struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
341 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
342
343 mutex_lock(&data->irq_lock);
344 }
345
nct6694_irq_bus_sync_unlock(struct irq_data * d)346 static void nct6694_irq_bus_sync_unlock(struct irq_data *d)
347 {
348 struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
349 struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
350 struct nct6694_cmd_header cmd_hd = {
351 .mod = NCT6694_GPIO_MOD,
352 .offset = cpu_to_le16(NCT6694_GPI_FALLING + data->group),
353 .len = cpu_to_le16(sizeof(data->reg_val))
354 };
355
356 scoped_guard(mutex, &data->lock) {
357 nct6694_write_msg(data->nct6694, &cmd_hd, &data->irq_trig_falling);
358
359 cmd_hd.offset = cpu_to_le16(NCT6694_GPI_RISING + data->group);
360 nct6694_write_msg(data->nct6694, &cmd_hd, &data->irq_trig_rising);
361 }
362
363 mutex_unlock(&data->irq_lock);
364 }
365
366 static const struct irq_chip nct6694_irq_chip = {
367 .name = "gpio-nct6694",
368 .irq_mask = nct6694_irq_mask,
369 .irq_unmask = nct6694_irq_unmask,
370 .irq_set_type = nct6694_irq_set_type,
371 .irq_bus_lock = nct6694_irq_bus_lock,
372 .irq_bus_sync_unlock = nct6694_irq_bus_sync_unlock,
373 .flags = IRQCHIP_IMMUTABLE,
374 GPIOCHIP_IRQ_RESOURCE_HELPERS,
375 };
376
nct6694_irq_dispose_mapping(void * d)377 static void nct6694_irq_dispose_mapping(void *d)
378 {
379 struct nct6694_gpio_data *data = d;
380
381 irq_dispose_mapping(data->irq);
382 }
383
nct6694_gpio_ida_free(void * d)384 static void nct6694_gpio_ida_free(void *d)
385 {
386 struct nct6694_gpio_data *data = d;
387 struct nct6694 *nct6694 = data->nct6694;
388
389 ida_free(&nct6694->gpio_ida, data->group);
390 }
391
nct6694_gpio_probe(struct platform_device * pdev)392 static int nct6694_gpio_probe(struct platform_device *pdev)
393 {
394 struct device *dev = &pdev->dev;
395 struct nct6694 *nct6694 = dev_get_drvdata(dev->parent);
396 struct nct6694_gpio_data *data;
397 struct gpio_irq_chip *girq;
398 int ret, i;
399 char **names;
400
401 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
402 if (!data)
403 return -ENOMEM;
404
405 data->nct6694 = nct6694;
406
407 ret = ida_alloc(&nct6694->gpio_ida, GFP_KERNEL);
408 if (ret < 0)
409 return ret;
410 data->group = ret;
411
412 ret = devm_add_action_or_reset(dev, nct6694_gpio_ida_free, data);
413 if (ret)
414 return ret;
415
416 names = devm_kcalloc(dev, NCT6694_NR_GPIO, sizeof(char *),
417 GFP_KERNEL);
418 if (!names)
419 return -ENOMEM;
420
421 for (i = 0; i < NCT6694_NR_GPIO; i++) {
422 names[i] = devm_kasprintf(dev, GFP_KERNEL, "GPIO%X%d",
423 data->group, i);
424 if (!names[i])
425 return -ENOMEM;
426 }
427
428 data->irq = irq_create_mapping(nct6694->domain,
429 NCT6694_IRQ_GPIO0 + data->group);
430 if (!data->irq)
431 return -EINVAL;
432
433 ret = devm_add_action_or_reset(dev, nct6694_irq_dispose_mapping, data);
434 if (ret)
435 return ret;
436
437 data->gpio.names = (const char * const*)names;
438 data->gpio.label = pdev->name;
439 data->gpio.direction_input = nct6694_direction_input;
440 data->gpio.get = nct6694_get_value;
441 data->gpio.direction_output = nct6694_direction_output;
442 data->gpio.set = nct6694_set_value;
443 data->gpio.get_direction = nct6694_get_direction;
444 data->gpio.set_config = nct6694_set_config;
445 data->gpio.init_valid_mask = nct6694_init_valid_mask;
446 data->gpio.base = -1;
447 data->gpio.can_sleep = false;
448 data->gpio.owner = THIS_MODULE;
449 data->gpio.ngpio = NCT6694_NR_GPIO;
450
451 platform_set_drvdata(pdev, data);
452
453 ret = devm_mutex_init(dev, &data->lock);
454 if (ret)
455 return ret;
456
457 ret = devm_mutex_init(dev, &data->irq_lock);
458 if (ret)
459 return ret;
460
461 ret = nct6694_get_irq_trig(data);
462 if (ret) {
463 dev_err_probe(dev, ret, "Failed to get irq trigger type\n");
464 return ret;
465 }
466
467 girq = &data->gpio.irq;
468 gpio_irq_chip_set_chip(girq, &nct6694_irq_chip);
469 girq->parent_handler = NULL;
470 girq->num_parents = 0;
471 girq->parents = NULL;
472 girq->default_type = IRQ_TYPE_NONE;
473 girq->handler = handle_level_irq;
474 girq->threaded = true;
475
476 ret = devm_request_threaded_irq(dev, data->irq, NULL, nct6694_irq_handler,
477 IRQF_ONESHOT | IRQF_SHARED,
478 "gpio-nct6694", data);
479 if (ret) {
480 dev_err_probe(dev, ret, "Failed to request irq\n");
481 return ret;
482 }
483
484 return devm_gpiochip_add_data(dev, &data->gpio, data);
485 }
486
487 static struct platform_driver nct6694_gpio_driver = {
488 .driver = {
489 .name = "nct6694-gpio",
490 },
491 .probe = nct6694_gpio_probe,
492 };
493
494 module_platform_driver(nct6694_gpio_driver);
495
496 MODULE_DESCRIPTION("USB-GPIO controller driver for NCT6694");
497 MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
498 MODULE_LICENSE("GPL");
499 MODULE_ALIAS("platform:nct6694-gpio");
500