leds: pca9532: fix a potential NULL pointer dereference
[muen/linux.git] / drivers / leds / leds-pca9532.c
1 /*
2  * pca9532.c - 16-bit Led dimmer
3  *
4  * Copyright (C) 2011 Jan Weitzel
5  * Copyright (C) 2008 Riku Voipio
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; version 2 of the License.
10  *
11  * Datasheet: http://www.nxp.com/documents/data_sheet/PCA9532.pdf
12  *
13  */
14
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/slab.h>
18 #include <linux/leds.h>
19 #include <linux/input.h>
20 #include <linux/mutex.h>
21 #include <linux/workqueue.h>
22 #include <linux/leds-pca9532.h>
23 #include <linux/gpio.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26
27 /* m =  num_leds*/
28 #define PCA9532_REG_INPUT(i)    ((i) >> 3)
29 #define PCA9532_REG_OFFSET(m)   ((m) >> 4)
30 #define PCA9532_REG_PSC(m, i)   (PCA9532_REG_OFFSET(m) + 0x1 + (i) * 2)
31 #define PCA9532_REG_PWM(m, i)   (PCA9532_REG_OFFSET(m) + 0x2 + (i) * 2)
32 #define LED_REG(m, led)         (PCA9532_REG_OFFSET(m) + 0x5 + (led >> 2))
33 #define LED_NUM(led)            (led & 0x3)
34
35 #define ldev_to_led(c)       container_of(c, struct pca9532_led, ldev)
36
37 struct pca9532_chip_info {
38         u8      num_leds;
39 };
40
41 struct pca9532_data {
42         struct i2c_client *client;
43         struct pca9532_led leds[16];
44         struct mutex update_lock;
45         struct input_dev *idev;
46         struct work_struct work;
47 #ifdef CONFIG_LEDS_PCA9532_GPIO
48         struct gpio_chip gpio;
49 #endif
50         const struct pca9532_chip_info *chip_info;
51         u8 pwm[2];
52         u8 psc[2];
53 };
54
55 static int pca9532_probe(struct i2c_client *client,
56         const struct i2c_device_id *id);
57 static int pca9532_remove(struct i2c_client *client);
58
59 enum {
60         pca9530,
61         pca9531,
62         pca9532,
63         pca9533,
64 };
65
66 static const struct i2c_device_id pca9532_id[] = {
67         { "pca9530", pca9530 },
68         { "pca9531", pca9531 },
69         { "pca9532", pca9532 },
70         { "pca9533", pca9533 },
71         { }
72 };
73
74 MODULE_DEVICE_TABLE(i2c, pca9532_id);
75
76 static const struct pca9532_chip_info pca9532_chip_info_tbl[] = {
77         [pca9530] = {
78                 .num_leds = 2,
79         },
80         [pca9531] = {
81                 .num_leds = 8,
82         },
83         [pca9532] = {
84                 .num_leds = 16,
85         },
86         [pca9533] = {
87                 .num_leds = 4,
88         },
89 };
90
91 #ifdef CONFIG_OF
92 static const struct of_device_id of_pca9532_leds_match[] = {
93         { .compatible = "nxp,pca9530", .data = (void *)pca9530 },
94         { .compatible = "nxp,pca9531", .data = (void *)pca9531 },
95         { .compatible = "nxp,pca9532", .data = (void *)pca9532 },
96         { .compatible = "nxp,pca9533", .data = (void *)pca9533 },
97         {},
98 };
99
100 MODULE_DEVICE_TABLE(of, of_pca9532_leds_match);
101 #endif
102
103 static struct i2c_driver pca9532_driver = {
104         .driver = {
105                 .name = "leds-pca953x",
106                 .of_match_table = of_match_ptr(of_pca9532_leds_match),
107         },
108         .probe = pca9532_probe,
109         .remove = pca9532_remove,
110         .id_table = pca9532_id,
111 };
112
113 /* We have two pwm/blinkers, but 16 possible leds to drive. Additionally,
114  * the clever Thecus people are using one pwm to drive the beeper. So,
115  * as a compromise we average one pwm to the values requested by all
116  * leds that are not ON/OFF.
117  * */
118 static int pca9532_calcpwm(struct i2c_client *client, int pwm, int blink,
119         enum led_brightness value)
120 {
121         int a = 0, b = 0, i = 0;
122         struct pca9532_data *data = i2c_get_clientdata(client);
123         for (i = 0; i < data->chip_info->num_leds; i++) {
124                 if (data->leds[i].type == PCA9532_TYPE_LED &&
125                         data->leds[i].state == PCA9532_PWM0+pwm) {
126                                 a++;
127                                 b += data->leds[i].ldev.brightness;
128                 }
129         }
130         if (a == 0) {
131                 dev_err(&client->dev,
132                 "fear of division by zero %d/%d, wanted %d\n",
133                         b, a, value);
134                 return -EINVAL;
135         }
136         b = b/a;
137         if (b > 0xFF)
138                 return -EINVAL;
139         data->pwm[pwm] = b;
140         data->psc[pwm] = blink;
141         return 0;
142 }
143
144 static int pca9532_setpwm(struct i2c_client *client, int pwm)
145 {
146         struct pca9532_data *data = i2c_get_clientdata(client);
147         u8 maxleds = data->chip_info->num_leds;
148
149         mutex_lock(&data->update_lock);
150         i2c_smbus_write_byte_data(client, PCA9532_REG_PWM(maxleds, pwm),
151                 data->pwm[pwm]);
152         i2c_smbus_write_byte_data(client, PCA9532_REG_PSC(maxleds, pwm),
153                 data->psc[pwm]);
154         mutex_unlock(&data->update_lock);
155         return 0;
156 }
157
158 /* Set LED routing */
159 static void pca9532_setled(struct pca9532_led *led)
160 {
161         struct i2c_client *client = led->client;
162         struct pca9532_data *data = i2c_get_clientdata(client);
163         u8 maxleds = data->chip_info->num_leds;
164         char reg;
165
166         mutex_lock(&data->update_lock);
167         reg = i2c_smbus_read_byte_data(client, LED_REG(maxleds, led->id));
168         /* zero led bits */
169         reg = reg & ~(0x3<<LED_NUM(led->id)*2);
170         /* set the new value */
171         reg = reg | (led->state << LED_NUM(led->id)*2);
172         i2c_smbus_write_byte_data(client, LED_REG(maxleds, led->id), reg);
173         mutex_unlock(&data->update_lock);
174 }
175
176 static int pca9532_set_brightness(struct led_classdev *led_cdev,
177         enum led_brightness value)
178 {
179         int err = 0;
180         struct pca9532_led *led = ldev_to_led(led_cdev);
181
182         if (value == LED_OFF)
183                 led->state = PCA9532_OFF;
184         else if (value == LED_FULL)
185                 led->state = PCA9532_ON;
186         else {
187                 led->state = PCA9532_PWM0; /* Thecus: hardcode one pwm */
188                 err = pca9532_calcpwm(led->client, 0, 0, value);
189                 if (err)
190                         return err;
191         }
192         if (led->state == PCA9532_PWM0)
193                 pca9532_setpwm(led->client, 0);
194         pca9532_setled(led);
195         return err;
196 }
197
198 static int pca9532_set_blink(struct led_classdev *led_cdev,
199         unsigned long *delay_on, unsigned long *delay_off)
200 {
201         struct pca9532_led *led = ldev_to_led(led_cdev);
202         struct i2c_client *client = led->client;
203         int psc;
204         int err = 0;
205
206         if (*delay_on == 0 && *delay_off == 0) {
207                 /* led subsystem ask us for a blink rate */
208                 *delay_on = 1000;
209                 *delay_off = 1000;
210         }
211         if (*delay_on != *delay_off || *delay_on > 1690 || *delay_on < 6)
212                 return -EINVAL;
213
214         /* Thecus specific: only use PSC/PWM 0 */
215         psc = (*delay_on * 152-1)/1000;
216         err = pca9532_calcpwm(client, 0, psc, led_cdev->brightness);
217         if (err)
218                 return err;
219         if (led->state == PCA9532_PWM0)
220                 pca9532_setpwm(led->client, 0);
221         pca9532_setled(led);
222
223         return 0;
224 }
225
226 static int pca9532_event(struct input_dev *dev, unsigned int type,
227         unsigned int code, int value)
228 {
229         struct pca9532_data *data = input_get_drvdata(dev);
230
231         if (!(type == EV_SND && (code == SND_BELL || code == SND_TONE)))
232                 return -1;
233
234         /* XXX: allow different kind of beeps with psc/pwm modifications */
235         if (value > 1 && value < 32767)
236                 data->pwm[1] = 127;
237         else
238                 data->pwm[1] = 0;
239
240         schedule_work(&data->work);
241
242         return 0;
243 }
244
245 static void pca9532_input_work(struct work_struct *work)
246 {
247         struct pca9532_data *data =
248                 container_of(work, struct pca9532_data, work);
249         u8 maxleds = data->chip_info->num_leds;
250
251         mutex_lock(&data->update_lock);
252         i2c_smbus_write_byte_data(data->client, PCA9532_REG_PWM(maxleds, 1),
253                 data->pwm[1]);
254         mutex_unlock(&data->update_lock);
255 }
256
257 static enum pca9532_state pca9532_getled(struct pca9532_led *led)
258 {
259         struct i2c_client *client = led->client;
260         struct pca9532_data *data = i2c_get_clientdata(client);
261         u8 maxleds = data->chip_info->num_leds;
262         char reg;
263         enum pca9532_state ret;
264
265         mutex_lock(&data->update_lock);
266         reg = i2c_smbus_read_byte_data(client, LED_REG(maxleds, led->id));
267         ret = reg >> LED_NUM(led->id)/2;
268         mutex_unlock(&data->update_lock);
269         return ret;
270 }
271
272 #ifdef CONFIG_LEDS_PCA9532_GPIO
273 static int pca9532_gpio_request_pin(struct gpio_chip *gc, unsigned offset)
274 {
275         struct pca9532_data *data = gpiochip_get_data(gc);
276         struct pca9532_led *led = &data->leds[offset];
277
278         if (led->type == PCA9532_TYPE_GPIO)
279                 return 0;
280
281         return -EBUSY;
282 }
283
284 static void pca9532_gpio_set_value(struct gpio_chip *gc, unsigned offset, int val)
285 {
286         struct pca9532_data *data = gpiochip_get_data(gc);
287         struct pca9532_led *led = &data->leds[offset];
288
289         if (val)
290                 led->state = PCA9532_ON;
291         else
292                 led->state = PCA9532_OFF;
293
294         pca9532_setled(led);
295 }
296
297 static int pca9532_gpio_get_value(struct gpio_chip *gc, unsigned offset)
298 {
299         struct pca9532_data *data = gpiochip_get_data(gc);
300         unsigned char reg;
301
302         reg = i2c_smbus_read_byte_data(data->client, PCA9532_REG_INPUT(offset));
303
304         return !!(reg & (1 << (offset % 8)));
305 }
306
307 static int pca9532_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
308 {
309         /* To use as input ensure pin is not driven */
310         pca9532_gpio_set_value(gc, offset, 0);
311
312         return 0;
313 }
314
315 static int pca9532_gpio_direction_output(struct gpio_chip *gc, unsigned offset, int val)
316 {
317         pca9532_gpio_set_value(gc, offset, val);
318
319         return 0;
320 }
321 #endif /* CONFIG_LEDS_PCA9532_GPIO */
322
323 static int pca9532_destroy_devices(struct pca9532_data *data, int n_devs)
324 {
325         int i = n_devs;
326
327         if (!data)
328                 return -EINVAL;
329
330         while (--i >= 0) {
331                 switch (data->leds[i].type) {
332                 case PCA9532_TYPE_NONE:
333                 case PCA9532_TYPE_GPIO:
334                         break;
335                 case PCA9532_TYPE_LED:
336                         led_classdev_unregister(&data->leds[i].ldev);
337                         break;
338                 case PCA9532_TYPE_N2100_BEEP:
339                         if (data->idev != NULL) {
340                                 cancel_work_sync(&data->work);
341                                 data->idev = NULL;
342                         }
343                         break;
344                 }
345         }
346
347 #ifdef CONFIG_LEDS_PCA9532_GPIO
348         if (data->gpio.parent)
349                 gpiochip_remove(&data->gpio);
350 #endif
351
352         return 0;
353 }
354
355 static int pca9532_configure(struct i2c_client *client,
356         struct pca9532_data *data, struct pca9532_platform_data *pdata)
357 {
358         int i, err = 0;
359         int gpios = 0;
360         u8 maxleds = data->chip_info->num_leds;
361
362         for (i = 0; i < 2; i++) {
363                 data->pwm[i] = pdata->pwm[i];
364                 data->psc[i] = pdata->psc[i];
365                 i2c_smbus_write_byte_data(client, PCA9532_REG_PWM(maxleds, i),
366                         data->pwm[i]);
367                 i2c_smbus_write_byte_data(client, PCA9532_REG_PSC(maxleds, i),
368                         data->psc[i]);
369         }
370
371         for (i = 0; i < data->chip_info->num_leds; i++) {
372                 struct pca9532_led *led = &data->leds[i];
373                 struct pca9532_led *pled = &pdata->leds[i];
374                 led->client = client;
375                 led->id = i;
376                 led->type = pled->type;
377                 switch (led->type) {
378                 case PCA9532_TYPE_NONE:
379                         break;
380                 case PCA9532_TYPE_GPIO:
381                         gpios++;
382                         break;
383                 case PCA9532_TYPE_LED:
384                         if (pled->state == PCA9532_KEEP)
385                                 led->state = pca9532_getled(led);
386                         else
387                                 led->state = pled->state;
388                         led->name = pled->name;
389                         led->ldev.name = led->name;
390                         led->ldev.default_trigger = pled->default_trigger;
391                         led->ldev.brightness = LED_OFF;
392                         led->ldev.brightness_set_blocking =
393                                                 pca9532_set_brightness;
394                         led->ldev.blink_set = pca9532_set_blink;
395                         err = led_classdev_register(&client->dev, &led->ldev);
396                         if (err < 0) {
397                                 dev_err(&client->dev,
398                                         "couldn't register LED %s\n",
399                                         led->name);
400                                 goto exit;
401                         }
402                         pca9532_setled(led);
403                         break;
404                 case PCA9532_TYPE_N2100_BEEP:
405                         BUG_ON(data->idev);
406                         led->state = PCA9532_PWM1;
407                         pca9532_setled(led);
408                         data->idev = devm_input_allocate_device(&client->dev);
409                         if (data->idev == NULL) {
410                                 err = -ENOMEM;
411                                 goto exit;
412                         }
413                         data->idev->name = pled->name;
414                         data->idev->phys = "i2c/pca9532";
415                         data->idev->id.bustype = BUS_HOST;
416                         data->idev->id.vendor = 0x001f;
417                         data->idev->id.product = 0x0001;
418                         data->idev->id.version = 0x0100;
419                         data->idev->evbit[0] = BIT_MASK(EV_SND);
420                         data->idev->sndbit[0] = BIT_MASK(SND_BELL) |
421                                                 BIT_MASK(SND_TONE);
422                         data->idev->event = pca9532_event;
423                         input_set_drvdata(data->idev, data);
424                         INIT_WORK(&data->work, pca9532_input_work);
425                         err = input_register_device(data->idev);
426                         if (err) {
427                                 cancel_work_sync(&data->work);
428                                 data->idev = NULL;
429                                 goto exit;
430                         }
431                         break;
432                 }
433         }
434
435 #ifdef CONFIG_LEDS_PCA9532_GPIO
436         if (gpios) {
437                 data->gpio.label = "gpio-pca9532";
438                 data->gpio.direction_input = pca9532_gpio_direction_input;
439                 data->gpio.direction_output = pca9532_gpio_direction_output;
440                 data->gpio.set = pca9532_gpio_set_value;
441                 data->gpio.get = pca9532_gpio_get_value;
442                 data->gpio.request = pca9532_gpio_request_pin;
443                 data->gpio.can_sleep = 1;
444                 data->gpio.base = pdata->gpio_base;
445                 data->gpio.ngpio = data->chip_info->num_leds;
446                 data->gpio.parent = &client->dev;
447                 data->gpio.owner = THIS_MODULE;
448
449                 err = gpiochip_add_data(&data->gpio, data);
450                 if (err) {
451                         /* Use data->gpio.dev as a flag for freeing gpiochip */
452                         data->gpio.parent = NULL;
453                         dev_warn(&client->dev, "could not add gpiochip\n");
454                 } else {
455                         dev_info(&client->dev, "gpios %i...%i\n",
456                                 data->gpio.base, data->gpio.base +
457                                 data->gpio.ngpio - 1);
458                 }
459         }
460 #endif
461
462         return 0;
463
464 exit:
465         pca9532_destroy_devices(data, i);
466         return err;
467 }
468
469 static struct pca9532_platform_data *
470 pca9532_of_populate_pdata(struct device *dev, struct device_node *np)
471 {
472         struct pca9532_platform_data *pdata;
473         struct device_node *child;
474         const struct of_device_id *match;
475         int devid, maxleds;
476         int i = 0;
477         const char *state;
478
479         match = of_match_device(of_pca9532_leds_match, dev);
480         if (!match)
481                 return ERR_PTR(-ENODEV);
482
483         devid = (int)(uintptr_t)match->data;
484         maxleds = pca9532_chip_info_tbl[devid].num_leds;
485
486         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
487         if (!pdata)
488                 return ERR_PTR(-ENOMEM);
489
490         for_each_child_of_node(np, child) {
491                 if (of_property_read_string(child, "label",
492                                             &pdata->leds[i].name))
493                         pdata->leds[i].name = child->name;
494                 of_property_read_u32(child, "type", &pdata->leds[i].type);
495                 of_property_read_string(child, "linux,default-trigger",
496                                         &pdata->leds[i].default_trigger);
497                 if (!of_property_read_string(child, "default-state", &state)) {
498                         if (!strcmp(state, "on"))
499                                 pdata->leds[i].state = PCA9532_ON;
500                         else if (!strcmp(state, "keep"))
501                                 pdata->leds[i].state = PCA9532_KEEP;
502                 }
503                 if (++i >= maxleds) {
504                         of_node_put(child);
505                         break;
506                 }
507         }
508
509         return pdata;
510 }
511
512 static int pca9532_probe(struct i2c_client *client,
513         const struct i2c_device_id *id)
514 {
515         int devid;
516         const struct of_device_id *of_id;
517         struct pca9532_data *data = i2c_get_clientdata(client);
518         struct pca9532_platform_data *pca9532_pdata =
519                         dev_get_platdata(&client->dev);
520         struct device_node *np = client->dev.of_node;
521
522         if (!pca9532_pdata) {
523                 if (np) {
524                         pca9532_pdata =
525                                 pca9532_of_populate_pdata(&client->dev, np);
526                         if (IS_ERR(pca9532_pdata))
527                                 return PTR_ERR(pca9532_pdata);
528                 } else {
529                         dev_err(&client->dev, "no platform data\n");
530                         return -EINVAL;
531                 }
532                 of_id = of_match_device(of_pca9532_leds_match,
533                                 &client->dev);
534                 if (unlikely(!of_id))
535                         return -EINVAL;
536                 devid = (int)(uintptr_t) of_id->data;
537         } else {
538                 devid = id->driver_data;
539         }
540
541         if (!i2c_check_functionality(client->adapter,
542                 I2C_FUNC_SMBUS_BYTE_DATA))
543                 return -EIO;
544
545         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
546         if (!data)
547                 return -ENOMEM;
548
549         data->chip_info = &pca9532_chip_info_tbl[devid];
550
551         dev_info(&client->dev, "setting platform data\n");
552         i2c_set_clientdata(client, data);
553         data->client = client;
554         mutex_init(&data->update_lock);
555
556         return pca9532_configure(client, data, pca9532_pdata);
557 }
558
559 static int pca9532_remove(struct i2c_client *client)
560 {
561         struct pca9532_data *data = i2c_get_clientdata(client);
562         int err;
563
564         err = pca9532_destroy_devices(data, data->chip_info->num_leds);
565         if (err)
566                 return err;
567
568         return 0;
569 }
570
571 module_i2c_driver(pca9532_driver);
572
573 MODULE_AUTHOR("Riku Voipio");
574 MODULE_LICENSE("GPL");
575 MODULE_DESCRIPTION("PCA 9532 LED dimmer");