xref: /openbmc/linux/drivers/mfd/ezx-pcap.c (revision 275876e2) 
1 /*
2  * Driver for Motorola PCAP2 as present in EZX phones
3  *
4  * Copyright (C) 2006 Harald Welte <laforge@openezx.org>
5  * Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  */
12 
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/platform_device.h>
16 #include <linux/interrupt.h>
17 #include <linux/irq.h>
18 #include <linux/mfd/ezx-pcap.h>
19 #include <linux/spi/spi.h>
20 #include <linux/gpio.h>
21 #include <linux/slab.h>
22 
23 #define PCAP_ADC_MAXQ		8
24 struct pcap_adc_request {
25 	u8 bank;
26 	u8 ch[2];
27 	u32 flags;
28 	void (*callback)(void *, u16[]);
29 	void *data;
30 };
31 
32 struct pcap_adc_sync_request {
33 	u16 res[2];
34 	struct completion completion;
35 };
36 
37 struct pcap_chip {
38 	struct spi_device *spi;
39 
40 	/* IO */
41 	u32 buf;
42 	struct mutex io_mutex;
43 
44 	/* IRQ */
45 	unsigned int irq_base;
46 	u32 msr;
47 	struct work_struct isr_work;
48 	struct work_struct msr_work;
49 	struct workqueue_struct *workqueue;
50 
51 	/* ADC */
52 	struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ];
53 	u8 adc_head;
54 	u8 adc_tail;
55 	struct mutex adc_mutex;
56 };
57 
58 /* IO */
59 static int ezx_pcap_putget(struct pcap_chip *pcap, u32 *data)
60 {
61 	struct spi_transfer t;
62 	struct spi_message m;
63 	int status;
64 
65 	memset(&t, 0, sizeof(t));
66 	spi_message_init(&m);
67 	t.len = sizeof(u32);
68 	spi_message_add_tail(&t, &m);
69 
70 	pcap->buf = *data;
71 	t.tx_buf = (u8 *) &pcap->buf;
72 	t.rx_buf = (u8 *) &pcap->buf;
73 	status = spi_sync(pcap->spi, &m);
74 
75 	if (status == 0)
76 		*data = pcap->buf;
77 
78 	return status;
79 }
80 
81 int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value)
82 {
83 	int ret;
84 
85 	mutex_lock(&pcap->io_mutex);
86 	value &= PCAP_REGISTER_VALUE_MASK;
87 	value |= PCAP_REGISTER_WRITE_OP_BIT
88 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
89 	ret = ezx_pcap_putget(pcap, &value);
90 	mutex_unlock(&pcap->io_mutex);
91 
92 	return ret;
93 }
94 EXPORT_SYMBOL_GPL(ezx_pcap_write);
95 
96 int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value)
97 {
98 	int ret;
99 
100 	mutex_lock(&pcap->io_mutex);
101 	*value = PCAP_REGISTER_READ_OP_BIT
102 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
103 
104 	ret = ezx_pcap_putget(pcap, value);
105 	mutex_unlock(&pcap->io_mutex);
106 
107 	return ret;
108 }
109 EXPORT_SYMBOL_GPL(ezx_pcap_read);
110 
111 int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
112 {
113 	int ret;
114 	u32 tmp = PCAP_REGISTER_READ_OP_BIT |
115 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
116 
117 	mutex_lock(&pcap->io_mutex);
118 	ret = ezx_pcap_putget(pcap, &tmp);
119 	if (ret)
120 		goto out_unlock;
121 
122 	tmp &= (PCAP_REGISTER_VALUE_MASK & ~mask);
123 	tmp |= (val & mask) | PCAP_REGISTER_WRITE_OP_BIT |
124 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
125 
126 	ret = ezx_pcap_putget(pcap, &tmp);
127 out_unlock:
128 	mutex_unlock(&pcap->io_mutex);
129 
130 	return ret;
131 }
132 EXPORT_SYMBOL_GPL(ezx_pcap_set_bits);
133 
134 /* IRQ */
135 int irq_to_pcap(struct pcap_chip *pcap, int irq)
136 {
137 	return irq - pcap->irq_base;
138 }
139 EXPORT_SYMBOL_GPL(irq_to_pcap);
140 
141 int pcap_to_irq(struct pcap_chip *pcap, int irq)
142 {
143 	return pcap->irq_base + irq;
144 }
145 EXPORT_SYMBOL_GPL(pcap_to_irq);
146 
147 static void pcap_mask_irq(struct irq_data *d)
148 {
149 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
150 
151 	pcap->msr |= 1 << irq_to_pcap(pcap, d->irq);
152 	queue_work(pcap->workqueue, &pcap->msr_work);
153 }
154 
155 static void pcap_unmask_irq(struct irq_data *d)
156 {
157 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
158 
159 	pcap->msr &= ~(1 << irq_to_pcap(pcap, d->irq));
160 	queue_work(pcap->workqueue, &pcap->msr_work);
161 }
162 
163 static struct irq_chip pcap_irq_chip = {
164 	.name		= "pcap",
165 	.irq_disable	= pcap_mask_irq,
166 	.irq_mask	= pcap_mask_irq,
167 	.irq_unmask	= pcap_unmask_irq,
168 };
169 
170 static void pcap_msr_work(struct work_struct *work)
171 {
172 	struct pcap_chip *pcap = container_of(work, struct pcap_chip, msr_work);
173 
174 	ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
175 }
176 
177 static void pcap_isr_work(struct work_struct *work)
178 {
179 	struct pcap_chip *pcap = container_of(work, struct pcap_chip, isr_work);
180 	struct pcap_platform_data *pdata = dev_get_platdata(&pcap->spi->dev);
181 	u32 msr, isr, int_sel, service;
182 	int irq;
183 
184 	do {
185 		ezx_pcap_read(pcap, PCAP_REG_MSR, &msr);
186 		ezx_pcap_read(pcap, PCAP_REG_ISR, &isr);
187 
188 		/* We can't service/ack irqs that are assigned to port 2 */
189 		if (!(pdata->config & PCAP_SECOND_PORT)) {
190 			ezx_pcap_read(pcap, PCAP_REG_INT_SEL, &int_sel);
191 			isr &= ~int_sel;
192 		}
193 
194 		ezx_pcap_write(pcap, PCAP_REG_MSR, isr | msr);
195 		ezx_pcap_write(pcap, PCAP_REG_ISR, isr);
196 
197 		local_irq_disable();
198 		service = isr & ~msr;
199 		for (irq = pcap->irq_base; service; service >>= 1, irq++) {
200 			if (service & 1)
201 				generic_handle_irq(irq);
202 		}
203 		local_irq_enable();
204 		ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
205 	} while (gpio_get_value(pdata->gpio));
206 }
207 
208 static void pcap_irq_handler(unsigned int irq, struct irq_desc *desc)
209 {
210 	struct pcap_chip *pcap = irq_get_handler_data(irq);
211 
212 	desc->irq_data.chip->irq_ack(&desc->irq_data);
213 	queue_work(pcap->workqueue, &pcap->isr_work);
214 }
215 
216 /* ADC */
217 void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
218 {
219 	u32 tmp;
220 
221 	mutex_lock(&pcap->adc_mutex);
222 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
223 	tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
224 	tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
225 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
226 	mutex_unlock(&pcap->adc_mutex);
227 }
228 EXPORT_SYMBOL_GPL(pcap_set_ts_bits);
229 
230 static void pcap_disable_adc(struct pcap_chip *pcap)
231 {
232 	u32 tmp;
233 
234 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
235 	tmp &= ~(PCAP_ADC_ADEN|PCAP_ADC_BATT_I_ADC|PCAP_ADC_BATT_I_POLARITY);
236 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
237 }
238 
239 static void pcap_adc_trigger(struct pcap_chip *pcap)
240 {
241 	u32 tmp;
242 	u8 head;
243 
244 	mutex_lock(&pcap->adc_mutex);
245 	head = pcap->adc_head;
246 	if (!pcap->adc_queue[head]) {
247 		/* queue is empty, save power */
248 		pcap_disable_adc(pcap);
249 		mutex_unlock(&pcap->adc_mutex);
250 		return;
251 	}
252 	/* start conversion on requested bank, save TS_M bits */
253 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
254 	tmp &= (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
255 	tmp |= pcap->adc_queue[head]->flags | PCAP_ADC_ADEN;
256 
257 	if (pcap->adc_queue[head]->bank == PCAP_ADC_BANK_1)
258 		tmp |= PCAP_ADC_AD_SEL1;
259 
260 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
261 	mutex_unlock(&pcap->adc_mutex);
262 	ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC);
263 }
264 
265 static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
266 {
267 	struct pcap_chip *pcap = _pcap;
268 	struct pcap_adc_request *req;
269 	u16 res[2];
270 	u32 tmp;
271 
272 	mutex_lock(&pcap->adc_mutex);
273 	req = pcap->adc_queue[pcap->adc_head];
274 
275 	if (WARN(!req, "adc irq without pending request\n")) {
276 		mutex_unlock(&pcap->adc_mutex);
277 		return IRQ_HANDLED;
278 	}
279 
280 	/* read requested channels results */
281 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
282 	tmp &= ~(PCAP_ADC_ADA1_MASK | PCAP_ADC_ADA2_MASK);
283 	tmp |= (req->ch[0] << PCAP_ADC_ADA1_SHIFT);
284 	tmp |= (req->ch[1] << PCAP_ADC_ADA2_SHIFT);
285 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
286 	ezx_pcap_read(pcap, PCAP_REG_ADR, &tmp);
287 	res[0] = (tmp & PCAP_ADR_ADD1_MASK) >> PCAP_ADR_ADD1_SHIFT;
288 	res[1] = (tmp & PCAP_ADR_ADD2_MASK) >> PCAP_ADR_ADD2_SHIFT;
289 
290 	pcap->adc_queue[pcap->adc_head] = NULL;
291 	pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1);
292 	mutex_unlock(&pcap->adc_mutex);
293 
294 	/* pass the results and release memory */
295 	req->callback(req->data, res);
296 	kfree(req);
297 
298 	/* trigger next conversion (if any) on queue */
299 	pcap_adc_trigger(pcap);
300 
301 	return IRQ_HANDLED;
302 }
303 
304 int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
305 						void *callback, void *data)
306 {
307 	struct pcap_adc_request *req;
308 
309 	/* This will be freed after we have a result */
310 	req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL);
311 	if (!req)
312 		return -ENOMEM;
313 
314 	req->bank = bank;
315 	req->flags = flags;
316 	req->ch[0] = ch[0];
317 	req->ch[1] = ch[1];
318 	req->callback = callback;
319 	req->data = data;
320 
321 	mutex_lock(&pcap->adc_mutex);
322 	if (pcap->adc_queue[pcap->adc_tail]) {
323 		mutex_unlock(&pcap->adc_mutex);
324 		kfree(req);
325 		return -EBUSY;
326 	}
327 	pcap->adc_queue[pcap->adc_tail] = req;
328 	pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
329 	mutex_unlock(&pcap->adc_mutex);
330 
331 	/* start conversion */
332 	pcap_adc_trigger(pcap);
333 
334 	return 0;
335 }
336 EXPORT_SYMBOL_GPL(pcap_adc_async);
337 
338 static void pcap_adc_sync_cb(void *param, u16 res[])
339 {
340 	struct pcap_adc_sync_request *req = param;
341 
342 	req->res[0] = res[0];
343 	req->res[1] = res[1];
344 	complete(&req->completion);
345 }
346 
347 int pcap_adc_sync(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
348 								u16 res[])
349 {
350 	struct pcap_adc_sync_request sync_data;
351 	int ret;
352 
353 	init_completion(&sync_data.completion);
354 	ret = pcap_adc_async(pcap, bank, flags, ch, pcap_adc_sync_cb,
355 								&sync_data);
356 	if (ret)
357 		return ret;
358 	wait_for_completion(&sync_data.completion);
359 	res[0] = sync_data.res[0];
360 	res[1] = sync_data.res[1];
361 
362 	return 0;
363 }
364 EXPORT_SYMBOL_GPL(pcap_adc_sync);
365 
366 /* subdevs */
367 static int pcap_remove_subdev(struct device *dev, void *unused)
368 {
369 	platform_device_unregister(to_platform_device(dev));
370 	return 0;
371 }
372 
373 static int pcap_add_subdev(struct pcap_chip *pcap,
374 						struct pcap_subdev *subdev)
375 {
376 	struct platform_device *pdev;
377 	int ret;
378 
379 	pdev = platform_device_alloc(subdev->name, subdev->id);
380 	if (!pdev)
381 		return -ENOMEM;
382 
383 	pdev->dev.parent = &pcap->spi->dev;
384 	pdev->dev.platform_data = subdev->platform_data;
385 
386 	ret = platform_device_add(pdev);
387 	if (ret)
388 		platform_device_put(pdev);
389 
390 	return ret;
391 }
392 
393 static int ezx_pcap_remove(struct spi_device *spi)
394 {
395 	struct pcap_chip *pcap = spi_get_drvdata(spi);
396 	int i;
397 
398 	/* remove all registered subdevs */
399 	device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
400 
401 	/* cleanup ADC */
402 	mutex_lock(&pcap->adc_mutex);
403 	for (i = 0; i < PCAP_ADC_MAXQ; i++)
404 		kfree(pcap->adc_queue[i]);
405 	mutex_unlock(&pcap->adc_mutex);
406 
407 	/* cleanup irqchip */
408 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
409 		irq_set_chip_and_handler(i, NULL, NULL);
410 
411 	destroy_workqueue(pcap->workqueue);
412 
413 	return 0;
414 }
415 
416 static int ezx_pcap_probe(struct spi_device *spi)
417 {
418 	struct pcap_platform_data *pdata = dev_get_platdata(&spi->dev);
419 	struct pcap_chip *pcap;
420 	int i, adc_irq;
421 	int ret = -ENODEV;
422 
423 	/* platform data is required */
424 	if (!pdata)
425 		goto ret;
426 
427 	pcap = devm_kzalloc(&spi->dev, sizeof(*pcap), GFP_KERNEL);
428 	if (!pcap) {
429 		ret = -ENOMEM;
430 		goto ret;
431 	}
432 
433 	mutex_init(&pcap->io_mutex);
434 	mutex_init(&pcap->adc_mutex);
435 	INIT_WORK(&pcap->isr_work, pcap_isr_work);
436 	INIT_WORK(&pcap->msr_work, pcap_msr_work);
437 	spi_set_drvdata(spi, pcap);
438 
439 	/* setup spi */
440 	spi->bits_per_word = 32;
441 	spi->mode = SPI_MODE_0 | (pdata->config & PCAP_CS_AH ? SPI_CS_HIGH : 0);
442 	ret = spi_setup(spi);
443 	if (ret)
444 		goto ret;
445 
446 	pcap->spi = spi;
447 
448 	/* setup irq */
449 	pcap->irq_base = pdata->irq_base;
450 	pcap->workqueue = create_singlethread_workqueue("pcapd");
451 	if (!pcap->workqueue) {
452 		ret = -ENOMEM;
453 		dev_err(&spi->dev, "can't create pcap thread\n");
454 		goto ret;
455 	}
456 
457 	/* redirect interrupts to AP, except adcdone2 */
458 	if (!(pdata->config & PCAP_SECOND_PORT))
459 		ezx_pcap_write(pcap, PCAP_REG_INT_SEL,
460 					(1 << PCAP_IRQ_ADCDONE2));
461 
462 	/* setup irq chip */
463 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++) {
464 		irq_set_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
465 		irq_set_chip_data(i, pcap);
466 #ifdef CONFIG_ARM
467 		set_irq_flags(i, IRQF_VALID);
468 #else
469 		irq_set_noprobe(i);
470 #endif
471 	}
472 
473 	/* mask/ack all PCAP interrupts */
474 	ezx_pcap_write(pcap, PCAP_REG_MSR, PCAP_MASK_ALL_INTERRUPT);
475 	ezx_pcap_write(pcap, PCAP_REG_ISR, PCAP_CLEAR_INTERRUPT_REGISTER);
476 	pcap->msr = PCAP_MASK_ALL_INTERRUPT;
477 
478 	irq_set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
479 	irq_set_handler_data(spi->irq, pcap);
480 	irq_set_chained_handler(spi->irq, pcap_irq_handler);
481 	irq_set_irq_wake(spi->irq, 1);
482 
483 	/* ADC */
484 	adc_irq = pcap_to_irq(pcap, (pdata->config & PCAP_SECOND_PORT) ?
485 					PCAP_IRQ_ADCDONE2 : PCAP_IRQ_ADCDONE);
486 
487 	ret = devm_request_irq(&spi->dev, adc_irq, pcap_adc_irq, 0, "ADC",
488 				pcap);
489 	if (ret)
490 		goto free_irqchip;
491 
492 	/* setup subdevs */
493 	for (i = 0; i < pdata->num_subdevs; i++) {
494 		ret = pcap_add_subdev(pcap, &pdata->subdevs[i]);
495 		if (ret)
496 			goto remove_subdevs;
497 	}
498 
499 	/* board specific quirks */
500 	if (pdata->init)
501 		pdata->init(pcap);
502 
503 	return 0;
504 
505 remove_subdevs:
506 	device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
507 free_irqchip:
508 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
509 		irq_set_chip_and_handler(i, NULL, NULL);
510 /* destroy_workqueue: */
511 	destroy_workqueue(pcap->workqueue);
512 ret:
513 	return ret;
514 }
515 
516 static struct spi_driver ezxpcap_driver = {
517 	.probe	= ezx_pcap_probe,
518 	.remove = ezx_pcap_remove,
519 	.driver = {
520 		.name	= "ezx-pcap",
521 		.owner	= THIS_MODULE,
522 	},
523 };
524 
525 static int __init ezx_pcap_init(void)
526 {
527 	return spi_register_driver(&ezxpcap_driver);
528 }
529 
530 static void __exit ezx_pcap_exit(void)
531 {
532 	spi_unregister_driver(&ezxpcap_driver);
533 }
534 
535 subsys_initcall(ezx_pcap_init);
536 module_exit(ezx_pcap_exit);
537 
538 MODULE_LICENSE("GPL");
539 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
540 MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");
541 MODULE_ALIAS("spi:ezx-pcap");
542