rcu: Fix wrong check in list_splice_init_rcu()
[linux-2.6.git] / drivers / gpio / sx150x.c
1 /* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
2  *
3  * This program is free software; you can redistribute it and/or modify
4  * it under the terms of the GNU General Public License version 2 and
5  * only version 2 as published by the Free Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 #include <linux/gpio.h>
18 #include <linux/i2c.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/workqueue.h>
26 #include <linux/i2c/sx150x.h>
27
28 #define NO_UPDATE_PENDING       -1
29
30 struct sx150x_device_data {
31         u8 reg_pullup;
32         u8 reg_pulldn;
33         u8 reg_drain;
34         u8 reg_polarity;
35         u8 reg_dir;
36         u8 reg_data;
37         u8 reg_irq_mask;
38         u8 reg_irq_src;
39         u8 reg_sense;
40         u8 reg_clock;
41         u8 reg_misc;
42         u8 reg_reset;
43         u8 ngpios;
44 };
45
46 struct sx150x_chip {
47         struct gpio_chip                 gpio_chip;
48         struct i2c_client               *client;
49         const struct sx150x_device_data *dev_cfg;
50         int                              irq_summary;
51         int                              irq_base;
52         int                              irq_update;
53         u32                              irq_sense;
54         u32                              irq_masked;
55         u32                              dev_sense;
56         u32                              dev_masked;
57         struct irq_chip                  irq_chip;
58         struct mutex                     lock;
59 };
60
61 static const struct sx150x_device_data sx150x_devices[] = {
62         [0] = { /* sx1508q */
63                 .reg_pullup   = 0x03,
64                 .reg_pulldn   = 0x04,
65                 .reg_drain    = 0x05,
66                 .reg_polarity = 0x06,
67                 .reg_dir      = 0x07,
68                 .reg_data     = 0x08,
69                 .reg_irq_mask = 0x09,
70                 .reg_irq_src  = 0x0c,
71                 .reg_sense    = 0x0b,
72                 .reg_clock    = 0x0f,
73                 .reg_misc     = 0x10,
74                 .reg_reset    = 0x7d,
75                 .ngpios       = 8
76         },
77         [1] = { /* sx1509q */
78                 .reg_pullup   = 0x07,
79                 .reg_pulldn   = 0x09,
80                 .reg_drain    = 0x0b,
81                 .reg_polarity = 0x0d,
82                 .reg_dir      = 0x0f,
83                 .reg_data     = 0x11,
84                 .reg_irq_mask = 0x13,
85                 .reg_irq_src  = 0x19,
86                 .reg_sense    = 0x17,
87                 .reg_clock    = 0x1e,
88                 .reg_misc     = 0x1f,
89                 .reg_reset    = 0x7d,
90                 .ngpios       = 16
91         },
92 };
93
94 static const struct i2c_device_id sx150x_id[] = {
95         {"sx1508q", 0},
96         {"sx1509q", 1},
97         {}
98 };
99 MODULE_DEVICE_TABLE(i2c, sx150x_id);
100
101 static s32 sx150x_i2c_write(struct i2c_client *client, u8 reg, u8 val)
102 {
103         s32 err = i2c_smbus_write_byte_data(client, reg, val);
104
105         if (err < 0)
106                 dev_warn(&client->dev,
107                         "i2c write fail: can't write %02x to %02x: %d\n",
108                         val, reg, err);
109         return err;
110 }
111
112 static s32 sx150x_i2c_read(struct i2c_client *client, u8 reg, u8 *val)
113 {
114         s32 err = i2c_smbus_read_byte_data(client, reg);
115
116         if (err >= 0)
117                 *val = err;
118         else
119                 dev_warn(&client->dev,
120                         "i2c read fail: can't read from %02x: %d\n",
121                         reg, err);
122         return err;
123 }
124
125 static inline bool offset_is_oscio(struct sx150x_chip *chip, unsigned offset)
126 {
127         return (chip->dev_cfg->ngpios == offset);
128 }
129
130 /*
131  * These utility functions solve the common problem of locating and setting
132  * configuration bits.  Configuration bits are grouped into registers
133  * whose indexes increase downwards.  For example, with eight-bit registers,
134  * sixteen gpios would have their config bits grouped in the following order:
135  * REGISTER N-1 [ f e d c b a 9 8 ]
136  *          N   [ 7 6 5 4 3 2 1 0 ]
137  *
138  * For multi-bit configurations, the pattern gets wider:
139  * REGISTER N-3 [ f f e e d d c c ]
140  *          N-2 [ b b a a 9 9 8 8 ]
141  *          N-1 [ 7 7 6 6 5 5 4 4 ]
142  *          N   [ 3 3 2 2 1 1 0 0 ]
143  *
144  * Given the address of the starting register 'N', the index of the gpio
145  * whose configuration we seek to change, and the width in bits of that
146  * configuration, these functions allow us to locate the correct
147  * register and mask the correct bits.
148  */
149 static inline void sx150x_find_cfg(u8 offset, u8 width,
150                                 u8 *reg, u8 *mask, u8 *shift)
151 {
152         *reg   -= offset * width / 8;
153         *mask   = (1 << width) - 1;
154         *shift  = (offset * width) % 8;
155         *mask <<= *shift;
156 }
157
158 static s32 sx150x_write_cfg(struct sx150x_chip *chip,
159                         u8 offset, u8 width, u8 reg, u8 val)
160 {
161         u8  mask;
162         u8  data;
163         u8  shift;
164         s32 err;
165
166         sx150x_find_cfg(offset, width, &reg, &mask, &shift);
167         err = sx150x_i2c_read(chip->client, reg, &data);
168         if (err < 0)
169                 return err;
170
171         data &= ~mask;
172         data |= (val << shift) & mask;
173         return sx150x_i2c_write(chip->client, reg, data);
174 }
175
176 static int sx150x_get_io(struct sx150x_chip *chip, unsigned offset)
177 {
178         u8  reg = chip->dev_cfg->reg_data;
179         u8  mask;
180         u8  data;
181         u8  shift;
182         s32 err;
183
184         sx150x_find_cfg(offset, 1, &reg, &mask, &shift);
185         err = sx150x_i2c_read(chip->client, reg, &data);
186         if (err >= 0)
187                 err = (data & mask) != 0 ? 1 : 0;
188
189         return err;
190 }
191
192 static void sx150x_set_oscio(struct sx150x_chip *chip, int val)
193 {
194         sx150x_i2c_write(chip->client,
195                         chip->dev_cfg->reg_clock,
196                         (val ? 0x1f : 0x10));
197 }
198
199 static void sx150x_set_io(struct sx150x_chip *chip, unsigned offset, int val)
200 {
201         sx150x_write_cfg(chip,
202                         offset,
203                         1,
204                         chip->dev_cfg->reg_data,
205                         (val ? 1 : 0));
206 }
207
208 static int sx150x_io_input(struct sx150x_chip *chip, unsigned offset)
209 {
210         return sx150x_write_cfg(chip,
211                                 offset,
212                                 1,
213                                 chip->dev_cfg->reg_dir,
214                                 1);
215 }
216
217 static int sx150x_io_output(struct sx150x_chip *chip, unsigned offset, int val)
218 {
219         int err;
220
221         err = sx150x_write_cfg(chip,
222                         offset,
223                         1,
224                         chip->dev_cfg->reg_data,
225                         (val ? 1 : 0));
226         if (err >= 0)
227                 err = sx150x_write_cfg(chip,
228                                 offset,
229                                 1,
230                                 chip->dev_cfg->reg_dir,
231                                 0);
232         return err;
233 }
234
235 static int sx150x_gpio_get(struct gpio_chip *gc, unsigned offset)
236 {
237         struct sx150x_chip *chip;
238         int status = -EINVAL;
239
240         chip = container_of(gc, struct sx150x_chip, gpio_chip);
241
242         if (!offset_is_oscio(chip, offset)) {
243                 mutex_lock(&chip->lock);
244                 status = sx150x_get_io(chip, offset);
245                 mutex_unlock(&chip->lock);
246         }
247
248         return status;
249 }
250
251 static void sx150x_gpio_set(struct gpio_chip *gc, unsigned offset, int val)
252 {
253         struct sx150x_chip *chip;
254
255         chip = container_of(gc, struct sx150x_chip, gpio_chip);
256
257         mutex_lock(&chip->lock);
258         if (offset_is_oscio(chip, offset))
259                 sx150x_set_oscio(chip, val);
260         else
261                 sx150x_set_io(chip, offset, val);
262         mutex_unlock(&chip->lock);
263 }
264
265 static int sx150x_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
266 {
267         struct sx150x_chip *chip;
268         int status = -EINVAL;
269
270         chip = container_of(gc, struct sx150x_chip, gpio_chip);
271
272         if (!offset_is_oscio(chip, offset)) {
273                 mutex_lock(&chip->lock);
274                 status = sx150x_io_input(chip, offset);
275                 mutex_unlock(&chip->lock);
276         }
277         return status;
278 }
279
280 static int sx150x_gpio_direction_output(struct gpio_chip *gc,
281                                         unsigned offset,
282                                         int val)
283 {
284         struct sx150x_chip *chip;
285         int status = 0;
286
287         chip = container_of(gc, struct sx150x_chip, gpio_chip);
288
289         if (!offset_is_oscio(chip, offset)) {
290                 mutex_lock(&chip->lock);
291                 status = sx150x_io_output(chip, offset, val);
292                 mutex_unlock(&chip->lock);
293         }
294         return status;
295 }
296
297 static int sx150x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
298 {
299         struct sx150x_chip *chip;
300
301         chip = container_of(gc, struct sx150x_chip, gpio_chip);
302
303         if (offset >= chip->dev_cfg->ngpios)
304                 return -EINVAL;
305
306         if (chip->irq_base < 0)
307                 return -EINVAL;
308
309         return chip->irq_base + offset;
310 }
311
312 static void sx150x_irq_mask(struct irq_data *d)
313 {
314         struct irq_chip *ic = irq_data_get_irq_chip(d);
315         struct sx150x_chip *chip;
316         unsigned n;
317
318         chip = container_of(ic, struct sx150x_chip, irq_chip);
319         n = d->irq - chip->irq_base;
320         chip->irq_masked |= (1 << n);
321         chip->irq_update = n;
322 }
323
324 static void sx150x_irq_unmask(struct irq_data *d)
325 {
326         struct irq_chip *ic = irq_data_get_irq_chip(d);
327         struct sx150x_chip *chip;
328         unsigned n;
329
330         chip = container_of(ic, struct sx150x_chip, irq_chip);
331         n = d->irq - chip->irq_base;
332
333         chip->irq_masked &= ~(1 << n);
334         chip->irq_update = n;
335 }
336
337 static int sx150x_irq_set_type(struct irq_data *d, unsigned int flow_type)
338 {
339         struct irq_chip *ic = irq_data_get_irq_chip(d);
340         struct sx150x_chip *chip;
341         unsigned n, val = 0;
342
343         if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
344                 return -EINVAL;
345
346         chip = container_of(ic, struct sx150x_chip, irq_chip);
347         n = d->irq - chip->irq_base;
348
349         if (flow_type & IRQ_TYPE_EDGE_RISING)
350                 val |= 0x1;
351         if (flow_type & IRQ_TYPE_EDGE_FALLING)
352                 val |= 0x2;
353
354         chip->irq_sense &= ~(3UL << (n * 2));
355         chip->irq_sense |= val << (n * 2);
356         chip->irq_update = n;
357         return 0;
358 }
359
360 static irqreturn_t sx150x_irq_thread_fn(int irq, void *dev_id)
361 {
362         struct sx150x_chip *chip = (struct sx150x_chip *)dev_id;
363         unsigned nhandled = 0;
364         unsigned sub_irq;
365         unsigned n;
366         s32 err;
367         u8 val;
368         int i;
369
370         for (i = (chip->dev_cfg->ngpios / 8) - 1; i >= 0; --i) {
371                 err = sx150x_i2c_read(chip->client,
372                                       chip->dev_cfg->reg_irq_src - i,
373                                       &val);
374                 if (err < 0)
375                         continue;
376
377                 sx150x_i2c_write(chip->client,
378                                 chip->dev_cfg->reg_irq_src - i,
379                                 val);
380                 for (n = 0; n < 8; ++n) {
381                         if (val & (1 << n)) {
382                                 sub_irq = chip->irq_base + (i * 8) + n;
383                                 handle_nested_irq(sub_irq);
384                                 ++nhandled;
385                         }
386                 }
387         }
388
389         return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
390 }
391
392 static void sx150x_irq_bus_lock(struct irq_data *d)
393 {
394         struct irq_chip *ic = irq_data_get_irq_chip(d);
395         struct sx150x_chip *chip;
396
397         chip = container_of(ic, struct sx150x_chip, irq_chip);
398
399         mutex_lock(&chip->lock);
400 }
401
402 static void sx150x_irq_bus_sync_unlock(struct irq_data *d)
403 {
404         struct irq_chip *ic = irq_data_get_irq_chip(d);
405         struct sx150x_chip *chip;
406         unsigned n;
407
408         chip = container_of(ic, struct sx150x_chip, irq_chip);
409
410         if (chip->irq_update == NO_UPDATE_PENDING)
411                 goto out;
412
413         n = chip->irq_update;
414         chip->irq_update = NO_UPDATE_PENDING;
415
416         /* Avoid updates if nothing changed */
417         if (chip->dev_sense == chip->irq_sense &&
418             chip->dev_sense == chip->irq_masked)
419                 goto out;
420
421         chip->dev_sense = chip->irq_sense;
422         chip->dev_masked = chip->irq_masked;
423
424         if (chip->irq_masked & (1 << n)) {
425                 sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
426                 sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
427         } else {
428                 sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
429                 sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
430                                  chip->irq_sense >> (n * 2));
431         }
432 out:
433         mutex_unlock(&chip->lock);
434 }
435
436 static void sx150x_init_chip(struct sx150x_chip *chip,
437                         struct i2c_client *client,
438                         kernel_ulong_t driver_data,
439                         struct sx150x_platform_data *pdata)
440 {
441         mutex_init(&chip->lock);
442
443         chip->client                     = client;
444         chip->dev_cfg                    = &sx150x_devices[driver_data];
445         chip->gpio_chip.label            = client->name;
446         chip->gpio_chip.direction_input  = sx150x_gpio_direction_input;
447         chip->gpio_chip.direction_output = sx150x_gpio_direction_output;
448         chip->gpio_chip.get              = sx150x_gpio_get;
449         chip->gpio_chip.set              = sx150x_gpio_set;
450         chip->gpio_chip.to_irq           = sx150x_gpio_to_irq;
451         chip->gpio_chip.base             = pdata->gpio_base;
452         chip->gpio_chip.can_sleep        = 1;
453         chip->gpio_chip.ngpio            = chip->dev_cfg->ngpios;
454         if (pdata->oscio_is_gpo)
455                 ++chip->gpio_chip.ngpio;
456
457         chip->irq_chip.name                = client->name;
458         chip->irq_chip.irq_mask            = sx150x_irq_mask;
459         chip->irq_chip.irq_unmask          = sx150x_irq_unmask;
460         chip->irq_chip.irq_set_type        = sx150x_irq_set_type;
461         chip->irq_chip.irq_bus_lock        = sx150x_irq_bus_lock;
462         chip->irq_chip.irq_bus_sync_unlock = sx150x_irq_bus_sync_unlock;
463         chip->irq_summary                  = -1;
464         chip->irq_base                     = -1;
465         chip->irq_masked                   = ~0;
466         chip->irq_sense                    = 0;
467         chip->dev_masked                   = ~0;
468         chip->dev_sense                    = 0;
469         chip->irq_update                   = NO_UPDATE_PENDING;
470 }
471
472 static int sx150x_init_io(struct sx150x_chip *chip, u8 base, u16 cfg)
473 {
474         int err = 0;
475         unsigned n;
476
477         for (n = 0; err >= 0 && n < (chip->dev_cfg->ngpios / 8); ++n)
478                 err = sx150x_i2c_write(chip->client, base - n, cfg >> (n * 8));
479         return err;
480 }
481
482 static int sx150x_reset(struct sx150x_chip *chip)
483 {
484         int err;
485
486         err = i2c_smbus_write_byte_data(chip->client,
487                                         chip->dev_cfg->reg_reset,
488                                         0x12);
489         if (err < 0)
490                 return err;
491
492         err = i2c_smbus_write_byte_data(chip->client,
493                                         chip->dev_cfg->reg_reset,
494                                         0x34);
495         return err;
496 }
497
498 static int sx150x_init_hw(struct sx150x_chip *chip,
499                         struct sx150x_platform_data *pdata)
500 {
501         int err = 0;
502
503         if (pdata->reset_during_probe) {
504                 err = sx150x_reset(chip);
505                 if (err < 0)
506                         return err;
507         }
508
509         err = sx150x_i2c_write(chip->client,
510                         chip->dev_cfg->reg_misc,
511                         0x01);
512         if (err < 0)
513                 return err;
514
515         err = sx150x_init_io(chip, chip->dev_cfg->reg_pullup,
516                         pdata->io_pullup_ena);
517         if (err < 0)
518                 return err;
519
520         err = sx150x_init_io(chip, chip->dev_cfg->reg_pulldn,
521                         pdata->io_pulldn_ena);
522         if (err < 0)
523                 return err;
524
525         err = sx150x_init_io(chip, chip->dev_cfg->reg_drain,
526                         pdata->io_open_drain_ena);
527         if (err < 0)
528                 return err;
529
530         err = sx150x_init_io(chip, chip->dev_cfg->reg_polarity,
531                         pdata->io_polarity);
532         if (err < 0)
533                 return err;
534
535         if (pdata->oscio_is_gpo)
536                 sx150x_set_oscio(chip, 0);
537
538         return err;
539 }
540
541 static int sx150x_install_irq_chip(struct sx150x_chip *chip,
542                                 int irq_summary,
543                                 int irq_base)
544 {
545         int err;
546         unsigned n;
547         unsigned irq;
548
549         chip->irq_summary = irq_summary;
550         chip->irq_base    = irq_base;
551
552         for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
553                 irq = irq_base + n;
554                 irq_set_chip_and_handler(irq, &chip->irq_chip, handle_edge_irq);
555                 irq_set_nested_thread(irq, 1);
556 #ifdef CONFIG_ARM
557                 set_irq_flags(irq, IRQF_VALID);
558 #else
559                 irq_set_noprobe(irq);
560 #endif
561         }
562
563         err = request_threaded_irq(irq_summary,
564                                 NULL,
565                                 sx150x_irq_thread_fn,
566                                 IRQF_SHARED | IRQF_TRIGGER_FALLING,
567                                 chip->irq_chip.name,
568                                 chip);
569         if (err < 0) {
570                 chip->irq_summary = -1;
571                 chip->irq_base    = -1;
572         }
573
574         return err;
575 }
576
577 static void sx150x_remove_irq_chip(struct sx150x_chip *chip)
578 {
579         unsigned n;
580         unsigned irq;
581
582         free_irq(chip->irq_summary, chip);
583
584         for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
585                 irq = chip->irq_base + n;
586                 irq_set_chip_and_handler(irq, NULL, NULL);
587         }
588 }
589
590 static int __devinit sx150x_probe(struct i2c_client *client,
591                                 const struct i2c_device_id *id)
592 {
593         static const u32 i2c_funcs = I2C_FUNC_SMBUS_BYTE_DATA |
594                                      I2C_FUNC_SMBUS_WRITE_WORD_DATA;
595         struct sx150x_platform_data *pdata;
596         struct sx150x_chip *chip;
597         int rc;
598
599         pdata = client->dev.platform_data;
600         if (!pdata)
601                 return -EINVAL;
602
603         if (!i2c_check_functionality(client->adapter, i2c_funcs))
604                 return -ENOSYS;
605
606         chip = kzalloc(sizeof(struct sx150x_chip), GFP_KERNEL);
607         if (!chip)
608                 return -ENOMEM;
609
610         sx150x_init_chip(chip, client, id->driver_data, pdata);
611         rc = sx150x_init_hw(chip, pdata);
612         if (rc < 0)
613                 goto probe_fail_pre_gpiochip_add;
614
615         rc = gpiochip_add(&chip->gpio_chip);
616         if (rc < 0)
617                 goto probe_fail_pre_gpiochip_add;
618
619         if (pdata->irq_summary >= 0) {
620                 rc = sx150x_install_irq_chip(chip,
621                                         pdata->irq_summary,
622                                         pdata->irq_base);
623                 if (rc < 0)
624                         goto probe_fail_post_gpiochip_add;
625         }
626
627         i2c_set_clientdata(client, chip);
628
629         return 0;
630 probe_fail_post_gpiochip_add:
631         WARN_ON(gpiochip_remove(&chip->gpio_chip) < 0);
632 probe_fail_pre_gpiochip_add:
633         kfree(chip);
634         return rc;
635 }
636
637 static int __devexit sx150x_remove(struct i2c_client *client)
638 {
639         struct sx150x_chip *chip;
640         int rc;
641
642         chip = i2c_get_clientdata(client);
643         rc = gpiochip_remove(&chip->gpio_chip);
644         if (rc < 0)
645                 return rc;
646
647         if (chip->irq_summary >= 0)
648                 sx150x_remove_irq_chip(chip);
649
650         kfree(chip);
651
652         return 0;
653 }
654
655 static struct i2c_driver sx150x_driver = {
656         .driver = {
657                 .name = "sx150x",
658                 .owner = THIS_MODULE
659         },
660         .probe    = sx150x_probe,
661         .remove   = __devexit_p(sx150x_remove),
662         .id_table = sx150x_id,
663 };
664
665 static int __init sx150x_init(void)
666 {
667         return i2c_add_driver(&sx150x_driver);
668 }
669 subsys_initcall(sx150x_init);
670
671 static void __exit sx150x_exit(void)
672 {
673         return i2c_del_driver(&sx150x_driver);
674 }
675 module_exit(sx150x_exit);
676
677 MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
678 MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
679 MODULE_LICENSE("GPL v2");
680 MODULE_ALIAS("i2c:sx150x");