1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * htc-i2cpld.c
4 * Chip driver for an unknown CPLD chip found on omap850 HTC devices like
5 * the HTC Wizard and HTC Herald.
6 * The cpld is located on the i2c bus and acts as an input/output GPIO
7 * extender.
8 *
9 * Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
10 *
11 * Based on work done in the linwizard project
12 * Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/platform_device.h>
19 #include <linux/i2c.h>
20 #include <linux/irq.h>
21 #include <linux/spinlock.h>
22 #include <linux/htcpld.h>
23 #include <linux/gpio.h>
24 #include <linux/slab.h>
25
26 struct htcpld_chip {
27 spinlock_t lock;
28
29 /* chip info */
30 u8 reset;
31 u8 addr;
32 struct device *dev;
33 struct i2c_client *client;
34
35 /* Output details */
36 u8 cache_out;
37 struct gpio_chip chip_out;
38
39 /* Input details */
40 u8 cache_in;
41 struct gpio_chip chip_in;
42
43 u16 irqs_enabled;
44 uint irq_start;
45 int nirqs;
46
47 unsigned int flow_type;
48 /*
49 * Work structure to allow for setting values outside of any
50 * possible interrupt context
51 */
52 struct work_struct set_val_work;
53 };
54
55 struct htcpld_data {
56 /* irq info */
57 u16 irqs_enabled;
58 uint irq_start;
59 int nirqs;
60 uint chained_irq;
61 unsigned int int_reset_gpio_hi;
62 unsigned int int_reset_gpio_lo;
63
64 /* htcpld info */
65 struct htcpld_chip *chip;
66 unsigned int nchips;
67 };
68
69 /* There does not appear to be a way to proactively mask interrupts
70 * on the htcpld chip itself. So, we simply ignore interrupts that
71 * aren't desired. */
htcpld_mask(struct irq_data * data)72 static void htcpld_mask(struct irq_data *data)
73 {
74 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
75 chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
76 pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
77 }
htcpld_unmask(struct irq_data * data)78 static void htcpld_unmask(struct irq_data *data)
79 {
80 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
81 chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
82 pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
83 }
84
htcpld_set_type(struct irq_data * data,unsigned int flags)85 static int htcpld_set_type(struct irq_data *data, unsigned int flags)
86 {
87 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
88
89 if (flags & ~IRQ_TYPE_SENSE_MASK)
90 return -EINVAL;
91
92 /* We only allow edge triggering */
93 if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
94 return -EINVAL;
95
96 chip->flow_type = flags;
97 return 0;
98 }
99
100 static struct irq_chip htcpld_muxed_chip = {
101 .name = "htcpld",
102 .irq_mask = htcpld_mask,
103 .irq_unmask = htcpld_unmask,
104 .irq_set_type = htcpld_set_type,
105 };
106
107 /* To properly dispatch IRQ events, we need to read from the
108 * chip. This is an I2C action that could possibly sleep
109 * (which is bad in interrupt context) -- so we use a threaded
110 * interrupt handler to get around that.
111 */
htcpld_handler(int irq,void * dev)112 static irqreturn_t htcpld_handler(int irq, void *dev)
113 {
114 struct htcpld_data *htcpld = dev;
115 unsigned int i;
116 unsigned long flags;
117 int irqpin;
118
119 if (!htcpld) {
120 pr_debug("htcpld is null in ISR\n");
121 return IRQ_HANDLED;
122 }
123
124 /*
125 * For each chip, do a read of the chip and trigger any interrupts
126 * desired. The interrupts will be triggered from LSB to MSB (i.e.
127 * bit 0 first, then bit 1, etc.)
128 *
129 * For chips that have no interrupt range specified, just skip 'em.
130 */
131 for (i = 0; i < htcpld->nchips; i++) {
132 struct htcpld_chip *chip = &htcpld->chip[i];
133 struct i2c_client *client;
134 int val;
135 unsigned long uval, old_val;
136
137 if (!chip) {
138 pr_debug("chip %d is null in ISR\n", i);
139 continue;
140 }
141
142 if (chip->nirqs == 0)
143 continue;
144
145 client = chip->client;
146 if (!client) {
147 pr_debug("client %d is null in ISR\n", i);
148 continue;
149 }
150
151 /* Scan the chip */
152 val = i2c_smbus_read_byte_data(client, chip->cache_out);
153 if (val < 0) {
154 /* Throw a warning and skip this chip */
155 dev_warn(chip->dev, "Unable to read from chip: %d\n",
156 val);
157 continue;
158 }
159
160 uval = (unsigned long)val;
161
162 spin_lock_irqsave(&chip->lock, flags);
163
164 /* Save away the old value so we can compare it */
165 old_val = chip->cache_in;
166
167 /* Write the new value */
168 chip->cache_in = uval;
169
170 spin_unlock_irqrestore(&chip->lock, flags);
171
172 /*
173 * For each bit in the data (starting at bit 0), trigger
174 * associated interrupts.
175 */
176 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
177 unsigned oldb, newb, type = chip->flow_type;
178
179 irq = chip->irq_start + irqpin;
180
181 /* Run the IRQ handler, but only if the bit value
182 * changed, and the proper flags are set */
183 oldb = (old_val >> irqpin) & 1;
184 newb = (uval >> irqpin) & 1;
185
186 if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
187 (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
188 pr_debug("fire IRQ %d\n", irqpin);
189 generic_handle_irq(irq);
190 }
191 }
192 }
193
194 /*
195 * In order to continue receiving interrupts, the int_reset_gpio must
196 * be asserted.
197 */
198 if (htcpld->int_reset_gpio_hi)
199 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
200 if (htcpld->int_reset_gpio_lo)
201 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
202
203 return IRQ_HANDLED;
204 }
205
206 /*
207 * The GPIO set routines can be called from interrupt context, especially if,
208 * for example they're attached to the led-gpio framework and a trigger is
209 * enabled. As such, we declared work above in the htcpld_chip structure,
210 * and that work is scheduled in the set routine. The kernel can then run
211 * the I2C functions, which will sleep, in process context.
212 */
htcpld_chip_set(struct gpio_chip * chip,unsigned offset,int val)213 static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
214 {
215 struct i2c_client *client;
216 struct htcpld_chip *chip_data = gpiochip_get_data(chip);
217 unsigned long flags;
218
219 client = chip_data->client;
220 if (!client)
221 return;
222
223 spin_lock_irqsave(&chip_data->lock, flags);
224 if (val)
225 chip_data->cache_out |= (1 << offset);
226 else
227 chip_data->cache_out &= ~(1 << offset);
228 spin_unlock_irqrestore(&chip_data->lock, flags);
229
230 schedule_work(&(chip_data->set_val_work));
231 }
232
htcpld_chip_set_ni(struct work_struct * work)233 static void htcpld_chip_set_ni(struct work_struct *work)
234 {
235 struct htcpld_chip *chip_data;
236 struct i2c_client *client;
237
238 chip_data = container_of(work, struct htcpld_chip, set_val_work);
239 client = chip_data->client;
240 i2c_smbus_read_byte_data(client, chip_data->cache_out);
241 }
242
htcpld_chip_get(struct gpio_chip * chip,unsigned offset)243 static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
244 {
245 struct htcpld_chip *chip_data = gpiochip_get_data(chip);
246 u8 cache;
247
248 if (!strncmp(chip->label, "htcpld-out", 10)) {
249 cache = chip_data->cache_out;
250 } else if (!strncmp(chip->label, "htcpld-in", 9)) {
251 cache = chip_data->cache_in;
252 } else
253 return -EINVAL;
254
255 return (cache >> offset) & 1;
256 }
257
htcpld_direction_output(struct gpio_chip * chip,unsigned offset,int value)258 static int htcpld_direction_output(struct gpio_chip *chip,
259 unsigned offset, int value)
260 {
261 htcpld_chip_set(chip, offset, value);
262 return 0;
263 }
264
htcpld_direction_input(struct gpio_chip * chip,unsigned offset)265 static int htcpld_direction_input(struct gpio_chip *chip,
266 unsigned offset)
267 {
268 /*
269 * No-op: this function can only be called on the input chip.
270 * We do however make sure the offset is within range.
271 */
272 return (offset < chip->ngpio) ? 0 : -EINVAL;
273 }
274
htcpld_chip_to_irq(struct gpio_chip * chip,unsigned offset)275 static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
276 {
277 struct htcpld_chip *chip_data = gpiochip_get_data(chip);
278
279 if (offset < chip_data->nirqs)
280 return chip_data->irq_start + offset;
281 else
282 return -EINVAL;
283 }
284
htcpld_chip_reset(struct i2c_client * client)285 static void htcpld_chip_reset(struct i2c_client *client)
286 {
287 struct htcpld_chip *chip_data = i2c_get_clientdata(client);
288 if (!chip_data)
289 return;
290
291 i2c_smbus_read_byte_data(
292 client, (chip_data->cache_out = chip_data->reset));
293 }
294
htcpld_setup_chip_irq(struct platform_device * pdev,int chip_index)295 static int htcpld_setup_chip_irq(
296 struct platform_device *pdev,
297 int chip_index)
298 {
299 struct htcpld_data *htcpld;
300 struct htcpld_chip *chip;
301 unsigned int irq, irq_end;
302
303 /* Get the platform and driver data */
304 htcpld = platform_get_drvdata(pdev);
305 chip = &htcpld->chip[chip_index];
306
307 /* Setup irq handlers */
308 irq_end = chip->irq_start + chip->nirqs;
309 for (irq = chip->irq_start; irq < irq_end; irq++) {
310 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
311 handle_simple_irq);
312 irq_set_chip_data(irq, chip);
313 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
314 }
315
316 return 0;
317 }
318
htcpld_register_chip_i2c(struct platform_device * pdev,int chip_index)319 static int htcpld_register_chip_i2c(
320 struct platform_device *pdev,
321 int chip_index)
322 {
323 struct htcpld_data *htcpld;
324 struct device *dev = &pdev->dev;
325 struct htcpld_core_platform_data *pdata;
326 struct htcpld_chip *chip;
327 struct htcpld_chip_platform_data *plat_chip_data;
328 struct i2c_adapter *adapter;
329 struct i2c_client *client;
330 struct i2c_board_info info;
331
332 /* Get the platform and driver data */
333 pdata = dev_get_platdata(dev);
334 htcpld = platform_get_drvdata(pdev);
335 chip = &htcpld->chip[chip_index];
336 plat_chip_data = &pdata->chip[chip_index];
337
338 adapter = i2c_get_adapter(pdata->i2c_adapter_id);
339 if (!adapter) {
340 /* Eek, no such I2C adapter! Bail out. */
341 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
342 plat_chip_data->addr, pdata->i2c_adapter_id);
343 return -ENODEV;
344 }
345
346 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
347 dev_warn(dev, "i2c adapter %d non-functional\n",
348 pdata->i2c_adapter_id);
349 i2c_put_adapter(adapter);
350 return -EINVAL;
351 }
352
353 memset(&info, 0, sizeof(struct i2c_board_info));
354 info.addr = plat_chip_data->addr;
355 strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
356 info.platform_data = chip;
357
358 /* Add the I2C device. This calls the probe() function. */
359 client = i2c_new_client_device(adapter, &info);
360 if (IS_ERR(client)) {
361 /* I2C device registration failed, contineu with the next */
362 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
363 plat_chip_data->addr);
364 i2c_put_adapter(adapter);
365 return PTR_ERR(client);
366 }
367
368 i2c_set_clientdata(client, chip);
369 snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
370 chip->client = client;
371
372 /* Reset the chip */
373 htcpld_chip_reset(client);
374 chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
375
376 return 0;
377 }
378
htcpld_unregister_chip_i2c(struct platform_device * pdev,int chip_index)379 static void htcpld_unregister_chip_i2c(
380 struct platform_device *pdev,
381 int chip_index)
382 {
383 struct htcpld_data *htcpld;
384 struct htcpld_chip *chip;
385
386 /* Get the platform and driver data */
387 htcpld = platform_get_drvdata(pdev);
388 chip = &htcpld->chip[chip_index];
389
390 i2c_unregister_device(chip->client);
391 }
392
htcpld_register_chip_gpio(struct platform_device * pdev,int chip_index)393 static int htcpld_register_chip_gpio(
394 struct platform_device *pdev,
395 int chip_index)
396 {
397 struct htcpld_data *htcpld;
398 struct device *dev = &pdev->dev;
399 struct htcpld_core_platform_data *pdata;
400 struct htcpld_chip *chip;
401 struct htcpld_chip_platform_data *plat_chip_data;
402 struct gpio_chip *gpio_chip;
403 int ret = 0;
404
405 /* Get the platform and driver data */
406 pdata = dev_get_platdata(dev);
407 htcpld = platform_get_drvdata(pdev);
408 chip = &htcpld->chip[chip_index];
409 plat_chip_data = &pdata->chip[chip_index];
410
411 /* Setup the GPIO chips */
412 gpio_chip = &(chip->chip_out);
413 gpio_chip->label = "htcpld-out";
414 gpio_chip->parent = dev;
415 gpio_chip->owner = THIS_MODULE;
416 gpio_chip->get = htcpld_chip_get;
417 gpio_chip->set = htcpld_chip_set;
418 gpio_chip->direction_input = NULL;
419 gpio_chip->direction_output = htcpld_direction_output;
420 gpio_chip->base = plat_chip_data->gpio_out_base;
421 gpio_chip->ngpio = plat_chip_data->num_gpios;
422
423 gpio_chip = &(chip->chip_in);
424 gpio_chip->label = "htcpld-in";
425 gpio_chip->parent = dev;
426 gpio_chip->owner = THIS_MODULE;
427 gpio_chip->get = htcpld_chip_get;
428 gpio_chip->set = NULL;
429 gpio_chip->direction_input = htcpld_direction_input;
430 gpio_chip->direction_output = NULL;
431 gpio_chip->to_irq = htcpld_chip_to_irq;
432 gpio_chip->base = plat_chip_data->gpio_in_base;
433 gpio_chip->ngpio = plat_chip_data->num_gpios;
434
435 /* Add the GPIO chips */
436 ret = gpiochip_add_data(&(chip->chip_out), chip);
437 if (ret) {
438 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
439 plat_chip_data->addr, ret);
440 return ret;
441 }
442
443 ret = gpiochip_add_data(&(chip->chip_in), chip);
444 if (ret) {
445 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
446 plat_chip_data->addr, ret);
447 gpiochip_remove(&(chip->chip_out));
448 return ret;
449 }
450
451 return 0;
452 }
453
htcpld_setup_chips(struct platform_device * pdev)454 static int htcpld_setup_chips(struct platform_device *pdev)
455 {
456 struct htcpld_data *htcpld;
457 struct device *dev = &pdev->dev;
458 struct htcpld_core_platform_data *pdata;
459 int i;
460
461 /* Get the platform and driver data */
462 pdata = dev_get_platdata(dev);
463 htcpld = platform_get_drvdata(pdev);
464
465 /* Setup each chip's output GPIOs */
466 htcpld->nchips = pdata->num_chip;
467 htcpld->chip = devm_kcalloc(dev,
468 htcpld->nchips,
469 sizeof(struct htcpld_chip),
470 GFP_KERNEL);
471 if (!htcpld->chip)
472 return -ENOMEM;
473
474 /* Add the chips as best we can */
475 for (i = 0; i < htcpld->nchips; i++) {
476 int ret;
477
478 /* Setup the HTCPLD chips */
479 htcpld->chip[i].reset = pdata->chip[i].reset;
480 htcpld->chip[i].cache_out = pdata->chip[i].reset;
481 htcpld->chip[i].cache_in = 0;
482 htcpld->chip[i].dev = dev;
483 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
484 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
485
486 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
487 spin_lock_init(&(htcpld->chip[i].lock));
488
489 /* Setup the interrupts for the chip */
490 if (htcpld->chained_irq) {
491 ret = htcpld_setup_chip_irq(pdev, i);
492 if (ret)
493 continue;
494 }
495
496 /* Register the chip with I2C */
497 ret = htcpld_register_chip_i2c(pdev, i);
498 if (ret)
499 continue;
500
501
502 /* Register the chips with the GPIO subsystem */
503 ret = htcpld_register_chip_gpio(pdev, i);
504 if (ret) {
505 /* Unregister the chip from i2c and continue */
506 htcpld_unregister_chip_i2c(pdev, i);
507 continue;
508 }
509
510 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
511 }
512
513 return 0;
514 }
515
htcpld_core_probe(struct platform_device * pdev)516 static int htcpld_core_probe(struct platform_device *pdev)
517 {
518 struct htcpld_data *htcpld;
519 struct device *dev = &pdev->dev;
520 struct htcpld_core_platform_data *pdata;
521 struct resource *res;
522 int ret = 0;
523
524 if (!dev)
525 return -ENODEV;
526
527 pdata = dev_get_platdata(dev);
528 if (!pdata) {
529 dev_warn(dev, "Platform data not found for htcpld core!\n");
530 return -ENXIO;
531 }
532
533 htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
534 if (!htcpld)
535 return -ENOMEM;
536
537 /* Find chained irq */
538 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
539 if (res) {
540 int flags;
541 htcpld->chained_irq = res->start;
542
543 /* Setup the chained interrupt handler */
544 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
545 IRQF_ONESHOT;
546 ret = request_threaded_irq(htcpld->chained_irq,
547 NULL, htcpld_handler,
548 flags, pdev->name, htcpld);
549 if (ret) {
550 dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
551 return ret;
552 } else
553 device_init_wakeup(dev, 0);
554 }
555
556 /* Set the driver data */
557 platform_set_drvdata(pdev, htcpld);
558
559 /* Setup the htcpld chips */
560 ret = htcpld_setup_chips(pdev);
561 if (ret)
562 return ret;
563
564 /* Request the GPIO(s) for the int reset and set them up */
565 if (pdata->int_reset_gpio_hi) {
566 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
567 if (ret) {
568 /*
569 * If it failed, that sucks, but we can probably
570 * continue on without it.
571 */
572 dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
573 htcpld->int_reset_gpio_hi = 0;
574 } else {
575 htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
576 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
577 }
578 }
579
580 if (pdata->int_reset_gpio_lo) {
581 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
582 if (ret) {
583 /*
584 * If it failed, that sucks, but we can probably
585 * continue on without it.
586 */
587 dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
588 htcpld->int_reset_gpio_lo = 0;
589 } else {
590 htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
591 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
592 }
593 }
594
595 dev_info(dev, "Initialized successfully\n");
596 return 0;
597 }
598
599 /* The I2C Driver -- used internally */
600 static const struct i2c_device_id htcpld_chip_id[] = {
601 { "htcpld-chip", 0 },
602 { }
603 };
604
605 static struct i2c_driver htcpld_chip_driver = {
606 .driver = {
607 .name = "htcpld-chip",
608 },
609 .id_table = htcpld_chip_id,
610 };
611
612 /* The Core Driver */
613 static struct platform_driver htcpld_core_driver = {
614 .driver = {
615 .name = "i2c-htcpld",
616 },
617 };
618
htcpld_core_init(void)619 static int __init htcpld_core_init(void)
620 {
621 int ret;
622
623 /* Register the I2C Chip driver */
624 ret = i2c_add_driver(&htcpld_chip_driver);
625 if (ret)
626 return ret;
627
628 /* Probe for our chips */
629 return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
630 }
631 device_initcall(htcpld_core_init);
632
