Root/drivers/gpio/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
30struct 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
46struct 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
61static 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
94static const struct i2c_device_id sx150x_id[] = {
95    {"sx1508q", 0},
96    {"sx1509q", 1},
97    {}
98};
99MODULE_DEVICE_TABLE(i2c, sx150x_id);
100
101static 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
112static 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
125static 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 */
149static 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
158static 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
176static 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
192static 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
199static 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
208static 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
217static 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
235static 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
251static 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
265static 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
280static 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
297static 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
312static 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
324static 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
337static 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
360static 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
392static 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
402static 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    }
432out:
433    mutex_unlock(&chip->lock);
434}
435
436static 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
472static 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
482static 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
498static 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
541static 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
577static 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
590static 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;
630probe_fail_post_gpiochip_add:
631    WARN_ON(gpiochip_remove(&chip->gpio_chip) < 0);
632probe_fail_pre_gpiochip_add:
633    kfree(chip);
634    return rc;
635}
636
637static 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
655static 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
665static int __init sx150x_init(void)
666{
667    return i2c_add_driver(&sx150x_driver);
668}
669subsys_initcall(sx150x_init);
670
671static void __exit sx150x_exit(void)
672{
673    return i2c_del_driver(&sx150x_driver);
674}
675module_exit(sx150x_exit);
676
677MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
678MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
679MODULE_LICENSE("GPL v2");
680MODULE_ALIAS("i2c:sx150x");
681

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