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