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1/*
2 * htc-i2cpld.c
3 * Chip driver for an unknown CPLD chip found on omap850 HTC devices like
4 * the HTC Wizard and HTC Herald.
5 * The cpld is located on the i2c bus and acts as an input/output GPIO
6 * extender.
7 *
8 * Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
9 *
10 * Based on work done in the linwizard project
11 * Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28#include <linux/kernel.h>
29#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/interrupt.h>
32#include <linux/platform_device.h>
33#include <linux/i2c.h>
34#include <linux/irq.h>
35#include <linux/spinlock.h>
36#include <linux/htcpld.h>
37#include <linux/gpio.h>
38#include <linux/slab.h>
39
40struct htcpld_chip {
41 spinlock_t lock;
42
43 /* chip info */
44 u8 reset;
45 u8 addr;
46 struct device *dev;
47 struct i2c_client *client;
48
49 /* Output details */
50 u8 cache_out;
51 struct gpio_chip chip_out;
52
53 /* Input details */
54 u8 cache_in;
55 struct gpio_chip chip_in;
56
57 u16 irqs_enabled;
58 uint irq_start;
59 int nirqs;
60
61 unsigned int flow_type;
62 /*
63 * Work structure to allow for setting values outside of any
64 * possible interrupt context
65 */
66 struct work_struct set_val_work;
67};
68
69struct htcpld_data {
70 /* irq info */
71 u16 irqs_enabled;
72 uint irq_start;
73 int nirqs;
74 uint chained_irq;
75 unsigned int int_reset_gpio_hi;
76 unsigned int int_reset_gpio_lo;
77
78 /* htcpld info */
79 struct htcpld_chip *chip;
80 unsigned int nchips;
81};
82
83/* There does not appear to be a way to proactively mask interrupts
84 * on the htcpld chip itself. So, we simply ignore interrupts that
85 * aren't desired. */
86static void htcpld_mask(struct irq_data *data)
87{
88 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
89 chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
90 pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
91}
92static void htcpld_unmask(struct irq_data *data)
93{
94 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
95 chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
96 pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
97}
98
99static int htcpld_set_type(struct irq_data *data, unsigned int flags)
100{
101 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
102
103 if (flags & ~IRQ_TYPE_SENSE_MASK)
104 return -EINVAL;
105
106 /* We only allow edge triggering */
107 if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
108 return -EINVAL;
109
110 chip->flow_type = flags;
111 return 0;
112}
113
114static struct irq_chip htcpld_muxed_chip = {
115 .name = "htcpld",
116 .irq_mask = htcpld_mask,
117 .irq_unmask = htcpld_unmask,
118 .irq_set_type = htcpld_set_type,
119};
120
121/* To properly dispatch IRQ events, we need to read from the
122 * chip. This is an I2C action that could possibly sleep
123 * (which is bad in interrupt context) -- so we use a threaded
124 * interrupt handler to get around that.
125 */
126static irqreturn_t htcpld_handler(int irq, void *dev)
127{
128 struct htcpld_data *htcpld = dev;
129 unsigned int i;
130 unsigned long flags;
131 int irqpin;
132
133 if (!htcpld) {
134 pr_debug("htcpld is null in ISR\n");
135 return IRQ_HANDLED;
136 }
137
138 /*
139 * For each chip, do a read of the chip and trigger any interrupts
140 * desired. The interrupts will be triggered from LSB to MSB (i.e.
141 * bit 0 first, then bit 1, etc.)
142 *
143 * For chips that have no interrupt range specified, just skip 'em.
144 */
145 for (i = 0; i < htcpld->nchips; i++) {
146 struct htcpld_chip *chip = &htcpld->chip[i];
147 struct i2c_client *client;
148 int val;
149 unsigned long uval, old_val;
150
151 if (!chip) {
152 pr_debug("chip %d is null in ISR\n", i);
153 continue;
154 }
155
156 if (chip->nirqs == 0)
157 continue;
158
159 client = chip->client;
160 if (!client) {
161 pr_debug("client %d is null in ISR\n", i);
162 continue;
163 }
164
165 /* Scan the chip */
166 val = i2c_smbus_read_byte_data(client, chip->cache_out);
167 if (val < 0) {
168 /* Throw a warning and skip this chip */
169 dev_warn(chip->dev, "Unable to read from chip: %d\n",
170 val);
171 continue;
172 }
173
174 uval = (unsigned long)val;
175
176 spin_lock_irqsave(&chip->lock, flags);
177
178 /* Save away the old value so we can compare it */
179 old_val = chip->cache_in;
180
181 /* Write the new value */
182 chip->cache_in = uval;
183
184 spin_unlock_irqrestore(&chip->lock, flags);
185
186 /*
187 * For each bit in the data (starting at bit 0), trigger
188 * associated interrupts.
189 */
190 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
191 unsigned oldb, newb, type = chip->flow_type;
192
193 irq = chip->irq_start + irqpin;
194
195 /* Run the IRQ handler, but only if the bit value
196 * changed, and the proper flags are set */
197 oldb = (old_val >> irqpin) & 1;
198 newb = (uval >> irqpin) & 1;
199
200 if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
201 (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
202 pr_debug("fire IRQ %d\n", irqpin);
203 generic_handle_irq(irq);
204 }
205 }
206 }
207
208 /*
209 * In order to continue receiving interrupts, the int_reset_gpio must
210 * be asserted.
211 */
212 if (htcpld->int_reset_gpio_hi)
213 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
214 if (htcpld->int_reset_gpio_lo)
215 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
216
217 return IRQ_HANDLED;
218}
219
220/*
221 * The GPIO set routines can be called from interrupt context, especially if,
222 * for example they're attached to the led-gpio framework and a trigger is
223 * enabled. As such, we declared work above in the htcpld_chip structure,
224 * and that work is scheduled in the set routine. The kernel can then run
225 * the I2C functions, which will sleep, in process context.
226 */
227static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
228{
229 struct i2c_client *client;
230 struct htcpld_chip *chip_data;
231 unsigned long flags;
232
233 chip_data = container_of(chip, struct htcpld_chip, chip_out);
234 if (!chip_data)
235 return;
236
237 client = chip_data->client;
238 if (client == NULL)
239 return;
240
241 spin_lock_irqsave(&chip_data->lock, flags);
242 if (val)
243 chip_data->cache_out |= (1 << offset);
244 else
245 chip_data->cache_out &= ~(1 << offset);
246 spin_unlock_irqrestore(&chip_data->lock, flags);
247
248 schedule_work(&(chip_data->set_val_work));
249}
250
251static void htcpld_chip_set_ni(struct work_struct *work)
252{
253 struct htcpld_chip *chip_data;
254 struct i2c_client *client;
255
256 chip_data = container_of(work, struct htcpld_chip, set_val_work);
257 client = chip_data->client;
258 i2c_smbus_read_byte_data(client, chip_data->cache_out);
259}
260
261static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
262{
263 struct htcpld_chip *chip_data;
264 int val = 0;
265 int is_input = 0;
266
267 /* Try out first */
268 chip_data = container_of(chip, struct htcpld_chip, chip_out);
269 if (!chip_data) {
270 /* Try in */
271 is_input = 1;
272 chip_data = container_of(chip, struct htcpld_chip, chip_in);
273 if (!chip_data)
274 return -EINVAL;
275 }
276
277 /* Determine if this is an input or output GPIO */
278 if (!is_input)
279 /* Use the output cache */
280 val = (chip_data->cache_out >> offset) & 1;
281 else
282 /* Use the input cache */
283 val = (chip_data->cache_in >> offset) & 1;
284
285 if (val)
286 return 1;
287 else
288 return 0;
289}
290
291static int htcpld_direction_output(struct gpio_chip *chip,
292 unsigned offset, int value)
293{
294 htcpld_chip_set(chip, offset, value);
295 return 0;
296}
297
298static int htcpld_direction_input(struct gpio_chip *chip,
299 unsigned offset)
300{
301 /*
302 * No-op: this function can only be called on the input chip.
303 * We do however make sure the offset is within range.
304 */
305 return (offset < chip->ngpio) ? 0 : -EINVAL;
306}
307
308static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
309{
310 struct htcpld_chip *chip_data;
311
312 chip_data = container_of(chip, struct htcpld_chip, chip_in);
313
314 if (offset < chip_data->nirqs)
315 return chip_data->irq_start + offset;
316 else
317 return -EINVAL;
318}
319
320static void htcpld_chip_reset(struct i2c_client *client)
321{
322 struct htcpld_chip *chip_data = i2c_get_clientdata(client);
323 if (!chip_data)
324 return;
325
326 i2c_smbus_read_byte_data(
327 client, (chip_data->cache_out = chip_data->reset));
328}
329
330static int htcpld_setup_chip_irq(
331 struct platform_device *pdev,
332 int chip_index)
333{
334 struct htcpld_data *htcpld;
335 struct device *dev = &pdev->dev;
336 struct htcpld_core_platform_data *pdata;
337 struct htcpld_chip *chip;
338 struct htcpld_chip_platform_data *plat_chip_data;
339 unsigned int irq, irq_end;
340 int ret = 0;
341
342 /* Get the platform and driver data */
343 pdata = dev_get_platdata(dev);
344 htcpld = platform_get_drvdata(pdev);
345 chip = &htcpld->chip[chip_index];
346 plat_chip_data = &pdata->chip[chip_index];
347
348 /* Setup irq handlers */
349 irq_end = chip->irq_start + chip->nirqs;
350 for (irq = chip->irq_start; irq < irq_end; irq++) {
351 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
352 handle_simple_irq);
353 irq_set_chip_data(irq, chip);
354#ifdef CONFIG_ARM
355 set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
356#else
357 irq_set_probe(irq);
358#endif
359 }
360
361 return ret;
362}
363
364static int htcpld_register_chip_i2c(
365 struct platform_device *pdev,
366 int chip_index)
367{
368 struct htcpld_data *htcpld;
369 struct device *dev = &pdev->dev;
370 struct htcpld_core_platform_data *pdata;
371 struct htcpld_chip *chip;
372 struct htcpld_chip_platform_data *plat_chip_data;
373 struct i2c_adapter *adapter;
374 struct i2c_client *client;
375 struct i2c_board_info info;
376
377 /* Get the platform and driver data */
378 pdata = dev_get_platdata(dev);
379 htcpld = platform_get_drvdata(pdev);
380 chip = &htcpld->chip[chip_index];
381 plat_chip_data = &pdata->chip[chip_index];
382
383 adapter = i2c_get_adapter(pdata->i2c_adapter_id);
384 if (adapter == NULL) {
385 /* Eek, no such I2C adapter! Bail out. */
386 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
387 plat_chip_data->addr, pdata->i2c_adapter_id);
388 return -ENODEV;
389 }
390
391 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
392 dev_warn(dev, "i2c adapter %d non-functional\n",
393 pdata->i2c_adapter_id);
394 return -EINVAL;
395 }
396
397 memset(&info, 0, sizeof(struct i2c_board_info));
398 info.addr = plat_chip_data->addr;
399 strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
400 info.platform_data = chip;
401
402 /* Add the I2C device. This calls the probe() function. */
403 client = i2c_new_device(adapter, &info);
404 if (!client) {
405 /* I2C device registration failed, contineu with the next */
406 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
407 plat_chip_data->addr);
408 return -ENODEV;
409 }
410
411 i2c_set_clientdata(client, chip);
412 snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%d", client->addr);
413 chip->client = client;
414
415 /* Reset the chip */
416 htcpld_chip_reset(client);
417 chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
418
419 return 0;
420}
421
422static void htcpld_unregister_chip_i2c(
423 struct platform_device *pdev,
424 int chip_index)
425{
426 struct htcpld_data *htcpld;
427 struct htcpld_chip *chip;
428
429 /* Get the platform and driver data */
430 htcpld = platform_get_drvdata(pdev);
431 chip = &htcpld->chip[chip_index];
432
433 if (chip->client)
434 i2c_unregister_device(chip->client);
435}
436
437static int htcpld_register_chip_gpio(
438 struct platform_device *pdev,
439 int chip_index)
440{
441 struct htcpld_data *htcpld;
442 struct device *dev = &pdev->dev;
443 struct htcpld_core_platform_data *pdata;
444 struct htcpld_chip *chip;
445 struct htcpld_chip_platform_data *plat_chip_data;
446 struct gpio_chip *gpio_chip;
447 int ret = 0;
448
449 /* Get the platform and driver data */
450 pdata = dev_get_platdata(dev);
451 htcpld = platform_get_drvdata(pdev);
452 chip = &htcpld->chip[chip_index];
453 plat_chip_data = &pdata->chip[chip_index];
454
455 /* Setup the GPIO chips */
456 gpio_chip = &(chip->chip_out);
457 gpio_chip->label = "htcpld-out";
458 gpio_chip->dev = dev;
459 gpio_chip->owner = THIS_MODULE;
460 gpio_chip->get = htcpld_chip_get;
461 gpio_chip->set = htcpld_chip_set;
462 gpio_chip->direction_input = NULL;
463 gpio_chip->direction_output = htcpld_direction_output;
464 gpio_chip->base = plat_chip_data->gpio_out_base;
465 gpio_chip->ngpio = plat_chip_data->num_gpios;
466
467 gpio_chip = &(chip->chip_in);
468 gpio_chip->label = "htcpld-in";
469 gpio_chip->dev = dev;
470 gpio_chip->owner = THIS_MODULE;
471 gpio_chip->get = htcpld_chip_get;
472 gpio_chip->set = NULL;
473 gpio_chip->direction_input = htcpld_direction_input;
474 gpio_chip->direction_output = NULL;
475 gpio_chip->to_irq = htcpld_chip_to_irq;
476 gpio_chip->base = plat_chip_data->gpio_in_base;
477 gpio_chip->ngpio = plat_chip_data->num_gpios;
478
479 /* Add the GPIO chips */
480 ret = gpiochip_add(&(chip->chip_out));
481 if (ret) {
482 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
483 plat_chip_data->addr, ret);
484 return ret;
485 }
486
487 ret = gpiochip_add(&(chip->chip_in));
488 if (ret) {
489 int error;
490
491 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
492 plat_chip_data->addr, ret);
493
494 error = gpiochip_remove(&(chip->chip_out));
495 if (error)
496 dev_warn(dev, "Error while trying to unregister gpio chip: %d\n", error);
497
498 return ret;
499 }
500
501 return 0;
502}
503
504static int htcpld_setup_chips(struct platform_device *pdev)
505{
506 struct htcpld_data *htcpld;
507 struct device *dev = &pdev->dev;
508 struct htcpld_core_platform_data *pdata;
509 int i;
510
511 /* Get the platform and driver data */
512 pdata = dev_get_platdata(dev);
513 htcpld = platform_get_drvdata(pdev);
514
515 /* Setup each chip's output GPIOs */
516 htcpld->nchips = pdata->num_chip;
517 htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips,
518 GFP_KERNEL);
519 if (!htcpld->chip) {
520 dev_warn(dev, "Unable to allocate memory for chips\n");
521 return -ENOMEM;
522 }
523
524 /* Add the chips as best we can */
525 for (i = 0; i < htcpld->nchips; i++) {
526 int ret;
527
528 /* Setup the HTCPLD chips */
529 htcpld->chip[i].reset = pdata->chip[i].reset;
530 htcpld->chip[i].cache_out = pdata->chip[i].reset;
531 htcpld->chip[i].cache_in = 0;
532 htcpld->chip[i].dev = dev;
533 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
534 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
535
536 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
537 spin_lock_init(&(htcpld->chip[i].lock));
538
539 /* Setup the interrupts for the chip */
540 if (htcpld->chained_irq) {
541 ret = htcpld_setup_chip_irq(pdev, i);
542 if (ret)
543 continue;
544 }
545
546 /* Register the chip with I2C */
547 ret = htcpld_register_chip_i2c(pdev, i);
548 if (ret)
549 continue;
550
551
552 /* Register the chips with the GPIO subsystem */
553 ret = htcpld_register_chip_gpio(pdev, i);
554 if (ret) {
555 /* Unregister the chip from i2c and continue */
556 htcpld_unregister_chip_i2c(pdev, i);
557 continue;
558 }
559
560 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
561 }
562
563 return 0;
564}
565
566static int htcpld_core_probe(struct platform_device *pdev)
567{
568 struct htcpld_data *htcpld;
569 struct device *dev = &pdev->dev;
570 struct htcpld_core_platform_data *pdata;
571 struct resource *res;
572 int ret = 0;
573
574 if (!dev)
575 return -ENODEV;
576
577 pdata = dev_get_platdata(dev);
578 if (!pdata) {
579 dev_warn(dev, "Platform data not found for htcpld core!\n");
580 return -ENXIO;
581 }
582
583 htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
584 if (!htcpld)
585 return -ENOMEM;
586
587 /* Find chained irq */
588 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
589 if (res) {
590 int flags;
591 htcpld->chained_irq = res->start;
592
593 /* Setup the chained interrupt handler */
594 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
595 ret = request_threaded_irq(htcpld->chained_irq,
596 NULL, htcpld_handler,
597 flags, pdev->name, htcpld);
598 if (ret) {
599 dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
600 return ret;
601 } else
602 device_init_wakeup(dev, 0);
603 }
604
605 /* Set the driver data */
606 platform_set_drvdata(pdev, htcpld);
607
608 /* Setup the htcpld chips */
609 ret = htcpld_setup_chips(pdev);
610 if (ret)
611 return ret;
612
613 /* Request the GPIO(s) for the int reset and set them up */
614 if (pdata->int_reset_gpio_hi) {
615 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
616 if (ret) {
617 /*
618 * If it failed, that sucks, but we can probably
619 * continue on without it.
620 */
621 dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
622 htcpld->int_reset_gpio_hi = 0;
623 } else {
624 htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
625 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
626 }
627 }
628
629 if (pdata->int_reset_gpio_lo) {
630 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
631 if (ret) {
632 /*
633 * If it failed, that sucks, but we can probably
634 * continue on without it.
635 */
636 dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
637 htcpld->int_reset_gpio_lo = 0;
638 } else {
639 htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
640 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
641 }
642 }
643
644 dev_info(dev, "Initialized successfully\n");
645 return 0;
646}
647
648/* The I2C Driver -- used internally */
649static const struct i2c_device_id htcpld_chip_id[] = {
650 { "htcpld-chip", 0 },
651 { }
652};
653MODULE_DEVICE_TABLE(i2c, htcpld_chip_id);
654
655
656static struct i2c_driver htcpld_chip_driver = {
657 .driver = {
658 .name = "htcpld-chip",
659 },
660 .id_table = htcpld_chip_id,
661};
662
663/* The Core Driver */
664static struct platform_driver htcpld_core_driver = {
665 .driver = {
666 .name = "i2c-htcpld",
667 },
668};
669
670static int __init htcpld_core_init(void)
671{
672 int ret;
673
674 /* Register the I2C Chip driver */
675 ret = i2c_add_driver(&htcpld_chip_driver);
676 if (ret)
677 return ret;
678
679 /* Probe for our chips */
680 return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
681}
682
683static void __exit htcpld_core_exit(void)
684{
685 i2c_del_driver(&htcpld_chip_driver);
686 platform_driver_unregister(&htcpld_core_driver);
687}
688
689module_init(htcpld_core_init);
690module_exit(htcpld_core_exit);
691
692MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>");
693MODULE_DESCRIPTION("I2C HTC PLD Driver");
694MODULE_LICENSE("GPL");
695