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
40 struct 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
69 struct 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. */
htcpld_mask(struct irq_data * data)86 static 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 }
htcpld_unmask(struct irq_data * data)92 static 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
htcpld_set_type(struct irq_data * data,unsigned int flags)99 static 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
114 static 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 */
htcpld_handler(int irq,void * dev)126 static 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 */
htcpld_chip_set(struct gpio_chip * chip,unsigned offset,int val)227 static 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 container_of(chip, struct htcpld_chip, chip_out);
232 unsigned long flags;
233
234 client = chip_data->client;
235 if (!client)
236 return;
237
238 spin_lock_irqsave(&chip_data->lock, flags);
239 if (val)
240 chip_data->cache_out |= (1 << offset);
241 else
242 chip_data->cache_out &= ~(1 << offset);
243 spin_unlock_irqrestore(&chip_data->lock, flags);
244
245 schedule_work(&(chip_data->set_val_work));
246 }
247
htcpld_chip_set_ni(struct work_struct * work)248 static void htcpld_chip_set_ni(struct work_struct *work)
249 {
250 struct htcpld_chip *chip_data;
251 struct i2c_client *client;
252
253 chip_data = container_of(work, struct htcpld_chip, set_val_work);
254 client = chip_data->client;
255 i2c_smbus_read_byte_data(client, chip_data->cache_out);
256 }
257
htcpld_chip_get(struct gpio_chip * chip,unsigned offset)258 static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
259 {
260 struct htcpld_chip *chip_data;
261 u8 cache;
262
263 if (!strncmp(chip->label, "htcpld-out", 10)) {
264 chip_data = container_of(chip, struct htcpld_chip, chip_out);
265 cache = chip_data->cache_out;
266 } else if (!strncmp(chip->label, "htcpld-in", 9)) {
267 chip_data = container_of(chip, struct htcpld_chip, chip_in);
268 cache = chip_data->cache_in;
269 } else
270 return -EINVAL;
271
272 return (cache >> offset) & 1;
273 }
274
htcpld_direction_output(struct gpio_chip * chip,unsigned offset,int value)275 static int htcpld_direction_output(struct gpio_chip *chip,
276 unsigned offset, int value)
277 {
278 htcpld_chip_set(chip, offset, value);
279 return 0;
280 }
281
htcpld_direction_input(struct gpio_chip * chip,unsigned offset)282 static int htcpld_direction_input(struct gpio_chip *chip,
283 unsigned offset)
284 {
285 /*
286 * No-op: this function can only be called on the input chip.
287 * We do however make sure the offset is within range.
288 */
289 return (offset < chip->ngpio) ? 0 : -EINVAL;
290 }
291
htcpld_chip_to_irq(struct gpio_chip * chip,unsigned offset)292 static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
293 {
294 struct htcpld_chip *chip_data;
295
296 chip_data = container_of(chip, struct htcpld_chip, chip_in);
297
298 if (offset < chip_data->nirqs)
299 return chip_data->irq_start + offset;
300 else
301 return -EINVAL;
302 }
303
htcpld_chip_reset(struct i2c_client * client)304 static void htcpld_chip_reset(struct i2c_client *client)
305 {
306 struct htcpld_chip *chip_data = i2c_get_clientdata(client);
307 if (!chip_data)
308 return;
309
310 i2c_smbus_read_byte_data(
311 client, (chip_data->cache_out = chip_data->reset));
312 }
313
htcpld_setup_chip_irq(struct platform_device * pdev,int chip_index)314 static int htcpld_setup_chip_irq(
315 struct platform_device *pdev,
316 int chip_index)
317 {
318 struct htcpld_data *htcpld;
319 struct htcpld_chip *chip;
320 unsigned int irq, irq_end;
321
322 /* Get the platform and driver data */
323 htcpld = platform_get_drvdata(pdev);
324 chip = &htcpld->chip[chip_index];
325
326 /* Setup irq handlers */
327 irq_end = chip->irq_start + chip->nirqs;
328 for (irq = chip->irq_start; irq < irq_end; irq++) {
329 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
330 handle_simple_irq);
331 irq_set_chip_data(irq, chip);
332 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
333 }
334
335 return 0;
336 }
337
htcpld_register_chip_i2c(struct platform_device * pdev,int chip_index)338 static int htcpld_register_chip_i2c(
339 struct platform_device *pdev,
340 int chip_index)
341 {
342 struct htcpld_data *htcpld;
343 struct device *dev = &pdev->dev;
344 struct htcpld_core_platform_data *pdata;
345 struct htcpld_chip *chip;
346 struct htcpld_chip_platform_data *plat_chip_data;
347 struct i2c_adapter *adapter;
348 struct i2c_client *client;
349 struct i2c_board_info info;
350
351 /* Get the platform and driver data */
352 pdata = dev_get_platdata(dev);
353 htcpld = platform_get_drvdata(pdev);
354 chip = &htcpld->chip[chip_index];
355 plat_chip_data = &pdata->chip[chip_index];
356
357 adapter = i2c_get_adapter(pdata->i2c_adapter_id);
358 if (!adapter) {
359 /* Eek, no such I2C adapter! Bail out. */
360 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
361 plat_chip_data->addr, pdata->i2c_adapter_id);
362 return -ENODEV;
363 }
364
365 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
366 dev_warn(dev, "i2c adapter %d non-functional\n",
367 pdata->i2c_adapter_id);
368 return -EINVAL;
369 }
370
371 memset(&info, 0, sizeof(struct i2c_board_info));
372 info.addr = plat_chip_data->addr;
373 strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
374 info.platform_data = chip;
375
376 /* Add the I2C device. This calls the probe() function. */
377 client = i2c_new_device(adapter, &info);
378 if (!client) {
379 /* I2C device registration failed, contineu with the next */
380 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
381 plat_chip_data->addr);
382 return -ENODEV;
383 }
384
385 i2c_set_clientdata(client, chip);
386 snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
387 chip->client = client;
388
389 /* Reset the chip */
390 htcpld_chip_reset(client);
391 chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
392
393 return 0;
394 }
395
htcpld_unregister_chip_i2c(struct platform_device * pdev,int chip_index)396 static void htcpld_unregister_chip_i2c(
397 struct platform_device *pdev,
398 int chip_index)
399 {
400 struct htcpld_data *htcpld;
401 struct htcpld_chip *chip;
402
403 /* Get the platform and driver data */
404 htcpld = platform_get_drvdata(pdev);
405 chip = &htcpld->chip[chip_index];
406
407 if (chip->client)
408 i2c_unregister_device(chip->client);
409 }
410
htcpld_register_chip_gpio(struct platform_device * pdev,int chip_index)411 static int htcpld_register_chip_gpio(
412 struct platform_device *pdev,
413 int chip_index)
414 {
415 struct htcpld_data *htcpld;
416 struct device *dev = &pdev->dev;
417 struct htcpld_core_platform_data *pdata;
418 struct htcpld_chip *chip;
419 struct htcpld_chip_platform_data *plat_chip_data;
420 struct gpio_chip *gpio_chip;
421 int ret = 0;
422
423 /* Get the platform and driver data */
424 pdata = dev_get_platdata(dev);
425 htcpld = platform_get_drvdata(pdev);
426 chip = &htcpld->chip[chip_index];
427 plat_chip_data = &pdata->chip[chip_index];
428
429 /* Setup the GPIO chips */
430 gpio_chip = &(chip->chip_out);
431 gpio_chip->label = "htcpld-out";
432 gpio_chip->dev = dev;
433 gpio_chip->owner = THIS_MODULE;
434 gpio_chip->get = htcpld_chip_get;
435 gpio_chip->set = htcpld_chip_set;
436 gpio_chip->direction_input = NULL;
437 gpio_chip->direction_output = htcpld_direction_output;
438 gpio_chip->base = plat_chip_data->gpio_out_base;
439 gpio_chip->ngpio = plat_chip_data->num_gpios;
440
441 gpio_chip = &(chip->chip_in);
442 gpio_chip->label = "htcpld-in";
443 gpio_chip->dev = dev;
444 gpio_chip->owner = THIS_MODULE;
445 gpio_chip->get = htcpld_chip_get;
446 gpio_chip->set = NULL;
447 gpio_chip->direction_input = htcpld_direction_input;
448 gpio_chip->direction_output = NULL;
449 gpio_chip->to_irq = htcpld_chip_to_irq;
450 gpio_chip->base = plat_chip_data->gpio_in_base;
451 gpio_chip->ngpio = plat_chip_data->num_gpios;
452
453 /* Add the GPIO chips */
454 ret = gpiochip_add(&(chip->chip_out));
455 if (ret) {
456 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
457 plat_chip_data->addr, ret);
458 return ret;
459 }
460
461 ret = gpiochip_add(&(chip->chip_in));
462 if (ret) {
463 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
464 plat_chip_data->addr, ret);
465 gpiochip_remove(&(chip->chip_out));
466 return ret;
467 }
468
469 return 0;
470 }
471
htcpld_setup_chips(struct platform_device * pdev)472 static int htcpld_setup_chips(struct platform_device *pdev)
473 {
474 struct htcpld_data *htcpld;
475 struct device *dev = &pdev->dev;
476 struct htcpld_core_platform_data *pdata;
477 int i;
478
479 /* Get the platform and driver data */
480 pdata = dev_get_platdata(dev);
481 htcpld = platform_get_drvdata(pdev);
482
483 /* Setup each chip's output GPIOs */
484 htcpld->nchips = pdata->num_chip;
485 htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips,
486 GFP_KERNEL);
487 if (!htcpld->chip) {
488 dev_warn(dev, "Unable to allocate memory for chips\n");
489 return -ENOMEM;
490 }
491
492 /* Add the chips as best we can */
493 for (i = 0; i < htcpld->nchips; i++) {
494 int ret;
495
496 /* Setup the HTCPLD chips */
497 htcpld->chip[i].reset = pdata->chip[i].reset;
498 htcpld->chip[i].cache_out = pdata->chip[i].reset;
499 htcpld->chip[i].cache_in = 0;
500 htcpld->chip[i].dev = dev;
501 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
502 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
503
504 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
505 spin_lock_init(&(htcpld->chip[i].lock));
506
507 /* Setup the interrupts for the chip */
508 if (htcpld->chained_irq) {
509 ret = htcpld_setup_chip_irq(pdev, i);
510 if (ret)
511 continue;
512 }
513
514 /* Register the chip with I2C */
515 ret = htcpld_register_chip_i2c(pdev, i);
516 if (ret)
517 continue;
518
519
520 /* Register the chips with the GPIO subsystem */
521 ret = htcpld_register_chip_gpio(pdev, i);
522 if (ret) {
523 /* Unregister the chip from i2c and continue */
524 htcpld_unregister_chip_i2c(pdev, i);
525 continue;
526 }
527
528 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
529 }
530
531 return 0;
532 }
533
htcpld_core_probe(struct platform_device * pdev)534 static int htcpld_core_probe(struct platform_device *pdev)
535 {
536 struct htcpld_data *htcpld;
537 struct device *dev = &pdev->dev;
538 struct htcpld_core_platform_data *pdata;
539 struct resource *res;
540 int ret = 0;
541
542 if (!dev)
543 return -ENODEV;
544
545 pdata = dev_get_platdata(dev);
546 if (!pdata) {
547 dev_warn(dev, "Platform data not found for htcpld core!\n");
548 return -ENXIO;
549 }
550
551 htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
552 if (!htcpld)
553 return -ENOMEM;
554
555 /* Find chained irq */
556 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
557 if (res) {
558 int flags;
559 htcpld->chained_irq = res->start;
560
561 /* Setup the chained interrupt handler */
562 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
563 IRQF_ONESHOT;
564 ret = request_threaded_irq(htcpld->chained_irq,
565 NULL, htcpld_handler,
566 flags, pdev->name, htcpld);
567 if (ret) {
568 dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
569 return ret;
570 } else
571 device_init_wakeup(dev, 0);
572 }
573
574 /* Set the driver data */
575 platform_set_drvdata(pdev, htcpld);
576
577 /* Setup the htcpld chips */
578 ret = htcpld_setup_chips(pdev);
579 if (ret)
580 return ret;
581
582 /* Request the GPIO(s) for the int reset and set them up */
583 if (pdata->int_reset_gpio_hi) {
584 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
585 if (ret) {
586 /*
587 * If it failed, that sucks, but we can probably
588 * continue on without it.
589 */
590 dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
591 htcpld->int_reset_gpio_hi = 0;
592 } else {
593 htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
594 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
595 }
596 }
597
598 if (pdata->int_reset_gpio_lo) {
599 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
600 if (ret) {
601 /*
602 * If it failed, that sucks, but we can probably
603 * continue on without it.
604 */
605 dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
606 htcpld->int_reset_gpio_lo = 0;
607 } else {
608 htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
609 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
610 }
611 }
612
613 dev_info(dev, "Initialized successfully\n");
614 return 0;
615 }
616
617 /* The I2C Driver -- used internally */
618 static const struct i2c_device_id htcpld_chip_id[] = {
619 { "htcpld-chip", 0 },
620 { }
621 };
622 MODULE_DEVICE_TABLE(i2c, htcpld_chip_id);
623
624
625 static struct i2c_driver htcpld_chip_driver = {
626 .driver = {
627 .name = "htcpld-chip",
628 },
629 .id_table = htcpld_chip_id,
630 };
631
632 /* The Core Driver */
633 static struct platform_driver htcpld_core_driver = {
634 .driver = {
635 .name = "i2c-htcpld",
636 },
637 };
638
htcpld_core_init(void)639 static int __init htcpld_core_init(void)
640 {
641 int ret;
642
643 /* Register the I2C Chip driver */
644 ret = i2c_add_driver(&htcpld_chip_driver);
645 if (ret)
646 return ret;
647
648 /* Probe for our chips */
649 return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
650 }
651
htcpld_core_exit(void)652 static void __exit htcpld_core_exit(void)
653 {
654 i2c_del_driver(&htcpld_chip_driver);
655 platform_driver_unregister(&htcpld_core_driver);
656 }
657
658 module_init(htcpld_core_init);
659 module_exit(htcpld_core_exit);
660
661 MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>");
662 MODULE_DESCRIPTION("I2C HTC PLD Driver");
663 MODULE_LICENSE("GPL");
664
665