xref: /openbmc/linux/drivers/mfd/ezx-pcap.c (revision a20eefae) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Motorola PCAP2 as present in EZX phones
4  *
5  * Copyright (C) 2006 Harald Welte <laforge@openezx.org>
6  * Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/kernel.h>
11 #include <linux/platform_device.h>
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
14 #include <linux/mfd/ezx-pcap.h>
15 #include <linux/spi/spi.h>
16 #include <linux/gpio.h>
17 #include <linux/slab.h>
18 
19 #define PCAP_ADC_MAXQ		8
20 struct pcap_adc_request {
21 	u8 bank;
22 	u8 ch[2];
23 	u32 flags;
24 	void (*callback)(void *, u16[]);
25 	void *data;
26 };
27 
28 struct pcap_adc_sync_request {
29 	u16 res[2];
30 	struct completion completion;
31 };
32 
33 struct pcap_chip {
34 	struct spi_device *spi;
35 
36 	/* IO */
37 	u32 buf;
38 	struct mutex io_mutex;
39 
40 	/* IRQ */
41 	unsigned int irq_base;
42 	u32 msr;
43 	struct work_struct isr_work;
44 	struct work_struct msr_work;
45 	struct workqueue_struct *workqueue;
46 
47 	/* ADC */
48 	struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ];
49 	u8 adc_head;
50 	u8 adc_tail;
51 	struct mutex adc_mutex;
52 };
53 
54 /* IO */
55 static int ezx_pcap_putget(struct pcap_chip *pcap, u32 *data)
56 {
57 	struct spi_transfer t;
58 	struct spi_message m;
59 	int status;
60 
61 	memset(&t, 0, sizeof(t));
62 	spi_message_init(&m);
63 	t.len = sizeof(u32);
64 	spi_message_add_tail(&t, &m);
65 
66 	pcap->buf = *data;
67 	t.tx_buf = (u8 *) &pcap->buf;
68 	t.rx_buf = (u8 *) &pcap->buf;
69 	status = spi_sync(pcap->spi, &m);
70 
71 	if (status == 0)
72 		*data = pcap->buf;
73 
74 	return status;
75 }
76 
77 int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value)
78 {
79 	int ret;
80 
81 	mutex_lock(&pcap->io_mutex);
82 	value &= PCAP_REGISTER_VALUE_MASK;
83 	value |= PCAP_REGISTER_WRITE_OP_BIT
84 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
85 	ret = ezx_pcap_putget(pcap, &value);
86 	mutex_unlock(&pcap->io_mutex);
87 
88 	return ret;
89 }
90 EXPORT_SYMBOL_GPL(ezx_pcap_write);
91 
92 int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value)
93 {
94 	int ret;
95 
96 	mutex_lock(&pcap->io_mutex);
97 	*value = PCAP_REGISTER_READ_OP_BIT
98 		| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
99 
100 	ret = ezx_pcap_putget(pcap, value);
101 	mutex_unlock(&pcap->io_mutex);
102 
103 	return ret;
104 }
105 EXPORT_SYMBOL_GPL(ezx_pcap_read);
106 
107 int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
108 {
109 	int ret;
110 	u32 tmp = PCAP_REGISTER_READ_OP_BIT |
111 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
112 
113 	mutex_lock(&pcap->io_mutex);
114 	ret = ezx_pcap_putget(pcap, &tmp);
115 	if (ret)
116 		goto out_unlock;
117 
118 	tmp &= (PCAP_REGISTER_VALUE_MASK & ~mask);
119 	tmp |= (val & mask) | PCAP_REGISTER_WRITE_OP_BIT |
120 		(reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
121 
122 	ret = ezx_pcap_putget(pcap, &tmp);
123 out_unlock:
124 	mutex_unlock(&pcap->io_mutex);
125 
126 	return ret;
127 }
128 EXPORT_SYMBOL_GPL(ezx_pcap_set_bits);
129 
130 /* IRQ */
131 int irq_to_pcap(struct pcap_chip *pcap, int irq)
132 {
133 	return irq - pcap->irq_base;
134 }
135 EXPORT_SYMBOL_GPL(irq_to_pcap);
136 
137 int pcap_to_irq(struct pcap_chip *pcap, int irq)
138 {
139 	return pcap->irq_base + irq;
140 }
141 EXPORT_SYMBOL_GPL(pcap_to_irq);
142 
143 static void pcap_mask_irq(struct irq_data *d)
144 {
145 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
146 
147 	pcap->msr |= 1 << irq_to_pcap(pcap, d->irq);
148 	queue_work(pcap->workqueue, &pcap->msr_work);
149 }
150 
151 static void pcap_unmask_irq(struct irq_data *d)
152 {
153 	struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
154 
155 	pcap->msr &= ~(1 << irq_to_pcap(pcap, d->irq));
156 	queue_work(pcap->workqueue, &pcap->msr_work);
157 }
158 
159 static struct irq_chip pcap_irq_chip = {
160 	.name		= "pcap",
161 	.irq_disable	= pcap_mask_irq,
162 	.irq_mask	= pcap_mask_irq,
163 	.irq_unmask	= pcap_unmask_irq,
164 };
165 
166 static void pcap_msr_work(struct work_struct *work)
167 {
168 	struct pcap_chip *pcap = container_of(work, struct pcap_chip, msr_work);
169 
170 	ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
171 }
172 
173 static void pcap_isr_work(struct work_struct *work)
174 {
175 	struct pcap_chip *pcap = container_of(work, struct pcap_chip, isr_work);
176 	struct pcap_platform_data *pdata = dev_get_platdata(&pcap->spi->dev);
177 	u32 msr, isr, int_sel, service;
178 	int irq;
179 
180 	do {
181 		ezx_pcap_read(pcap, PCAP_REG_MSR, &msr);
182 		ezx_pcap_read(pcap, PCAP_REG_ISR, &isr);
183 
184 		/* We can't service/ack irqs that are assigned to port 2 */
185 		if (!(pdata->config & PCAP_SECOND_PORT)) {
186 			ezx_pcap_read(pcap, PCAP_REG_INT_SEL, &int_sel);
187 			isr &= ~int_sel;
188 		}
189 
190 		ezx_pcap_write(pcap, PCAP_REG_MSR, isr | msr);
191 		ezx_pcap_write(pcap, PCAP_REG_ISR, isr);
192 
193 		local_irq_disable();
194 		service = isr & ~msr;
195 		for (irq = pcap->irq_base; service; service >>= 1, irq++) {
196 			if (service & 1)
197 				generic_handle_irq(irq);
198 		}
199 		local_irq_enable();
200 		ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
201 	} while (gpio_get_value(pdata->gpio));
202 }
203 
204 static void pcap_irq_handler(struct irq_desc *desc)
205 {
206 	struct pcap_chip *pcap = irq_desc_get_handler_data(desc);
207 
208 	desc->irq_data.chip->irq_ack(&desc->irq_data);
209 	queue_work(pcap->workqueue, &pcap->isr_work);
210 }
211 
212 /* ADC */
213 void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
214 {
215 	u32 tmp;
216 
217 	mutex_lock(&pcap->adc_mutex);
218 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
219 	tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
220 	tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
221 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
222 	mutex_unlock(&pcap->adc_mutex);
223 }
224 EXPORT_SYMBOL_GPL(pcap_set_ts_bits);
225 
226 static void pcap_disable_adc(struct pcap_chip *pcap)
227 {
228 	u32 tmp;
229 
230 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
231 	tmp &= ~(PCAP_ADC_ADEN|PCAP_ADC_BATT_I_ADC|PCAP_ADC_BATT_I_POLARITY);
232 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
233 }
234 
235 static void pcap_adc_trigger(struct pcap_chip *pcap)
236 {
237 	u32 tmp;
238 	u8 head;
239 
240 	mutex_lock(&pcap->adc_mutex);
241 	head = pcap->adc_head;
242 	if (!pcap->adc_queue[head]) {
243 		/* queue is empty, save power */
244 		pcap_disable_adc(pcap);
245 		mutex_unlock(&pcap->adc_mutex);
246 		return;
247 	}
248 	/* start conversion on requested bank, save TS_M bits */
249 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
250 	tmp &= (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
251 	tmp |= pcap->adc_queue[head]->flags | PCAP_ADC_ADEN;
252 
253 	if (pcap->adc_queue[head]->bank == PCAP_ADC_BANK_1)
254 		tmp |= PCAP_ADC_AD_SEL1;
255 
256 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
257 	mutex_unlock(&pcap->adc_mutex);
258 	ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC);
259 }
260 
261 static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
262 {
263 	struct pcap_chip *pcap = _pcap;
264 	struct pcap_adc_request *req;
265 	u16 res[2];
266 	u32 tmp;
267 
268 	mutex_lock(&pcap->adc_mutex);
269 	req = pcap->adc_queue[pcap->adc_head];
270 
271 	if (WARN(!req, "adc irq without pending request\n")) {
272 		mutex_unlock(&pcap->adc_mutex);
273 		return IRQ_HANDLED;
274 	}
275 
276 	/* read requested channels results */
277 	ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
278 	tmp &= ~(PCAP_ADC_ADA1_MASK | PCAP_ADC_ADA2_MASK);
279 	tmp |= (req->ch[0] << PCAP_ADC_ADA1_SHIFT);
280 	tmp |= (req->ch[1] << PCAP_ADC_ADA2_SHIFT);
281 	ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
282 	ezx_pcap_read(pcap, PCAP_REG_ADR, &tmp);
283 	res[0] = (tmp & PCAP_ADR_ADD1_MASK) >> PCAP_ADR_ADD1_SHIFT;
284 	res[1] = (tmp & PCAP_ADR_ADD2_MASK) >> PCAP_ADR_ADD2_SHIFT;
285 
286 	pcap->adc_queue[pcap->adc_head] = NULL;
287 	pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1);
288 	mutex_unlock(&pcap->adc_mutex);
289 
290 	/* pass the results and release memory */
291 	req->callback(req->data, res);
292 	kfree(req);
293 
294 	/* trigger next conversion (if any) on queue */
295 	pcap_adc_trigger(pcap);
296 
297 	return IRQ_HANDLED;
298 }
299 
300 int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
301 						void *callback, void *data)
302 {
303 	struct pcap_adc_request *req;
304 
305 	/* This will be freed after we have a result */
306 	req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL);
307 	if (!req)
308 		return -ENOMEM;
309 
310 	req->bank = bank;
311 	req->flags = flags;
312 	req->ch[0] = ch[0];
313 	req->ch[1] = ch[1];
314 	req->callback = callback;
315 	req->data = data;
316 
317 	mutex_lock(&pcap->adc_mutex);
318 	if (pcap->adc_queue[pcap->adc_tail]) {
319 		mutex_unlock(&pcap->adc_mutex);
320 		kfree(req);
321 		return -EBUSY;
322 	}
323 	pcap->adc_queue[pcap->adc_tail] = req;
324 	pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
325 	mutex_unlock(&pcap->adc_mutex);
326 
327 	/* start conversion */
328 	pcap_adc_trigger(pcap);
329 
330 	return 0;
331 }
332 EXPORT_SYMBOL_GPL(pcap_adc_async);
333 
334 static void pcap_adc_sync_cb(void *param, u16 res[])
335 {
336 	struct pcap_adc_sync_request *req = param;
337 
338 	req->res[0] = res[0];
339 	req->res[1] = res[1];
340 	complete(&req->completion);
341 }
342 
343 int pcap_adc_sync(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
344 								u16 res[])
345 {
346 	struct pcap_adc_sync_request sync_data;
347 	int ret;
348 
349 	init_completion(&sync_data.completion);
350 	ret = pcap_adc_async(pcap, bank, flags, ch, pcap_adc_sync_cb,
351 								&sync_data);
352 	if (ret)
353 		return ret;
354 	wait_for_completion(&sync_data.completion);
355 	res[0] = sync_data.res[0];
356 	res[1] = sync_data.res[1];
357 
358 	return 0;
359 }
360 EXPORT_SYMBOL_GPL(pcap_adc_sync);
361 
362 /* subdevs */
363 static int pcap_remove_subdev(struct device *dev, void *unused)
364 {
365 	platform_device_unregister(to_platform_device(dev));
366 	return 0;
367 }
368 
369 static int pcap_add_subdev(struct pcap_chip *pcap,
370 						struct pcap_subdev *subdev)
371 {
372 	struct platform_device *pdev;
373 	int ret;
374 
375 	pdev = platform_device_alloc(subdev->name, subdev->id);
376 	if (!pdev)
377 		return -ENOMEM;
378 
379 	pdev->dev.parent = &pcap->spi->dev;
380 	pdev->dev.platform_data = subdev->platform_data;
381 
382 	ret = platform_device_add(pdev);
383 	if (ret)
384 		platform_device_put(pdev);
385 
386 	return ret;
387 }
388 
389 static int ezx_pcap_remove(struct spi_device *spi)
390 {
391 	struct pcap_chip *pcap = spi_get_drvdata(spi);
392 	int i;
393 
394 	/* remove all registered subdevs */
395 	device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
396 
397 	/* cleanup ADC */
398 	mutex_lock(&pcap->adc_mutex);
399 	for (i = 0; i < PCAP_ADC_MAXQ; i++)
400 		kfree(pcap->adc_queue[i]);
401 	mutex_unlock(&pcap->adc_mutex);
402 
403 	/* cleanup irqchip */
404 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
405 		irq_set_chip_and_handler(i, NULL, NULL);
406 
407 	destroy_workqueue(pcap->workqueue);
408 
409 	return 0;
410 }
411 
412 static int ezx_pcap_probe(struct spi_device *spi)
413 {
414 	struct pcap_platform_data *pdata = dev_get_platdata(&spi->dev);
415 	struct pcap_chip *pcap;
416 	int i, adc_irq;
417 	int ret = -ENODEV;
418 
419 	/* platform data is required */
420 	if (!pdata)
421 		goto ret;
422 
423 	pcap = devm_kzalloc(&spi->dev, sizeof(*pcap), GFP_KERNEL);
424 	if (!pcap) {
425 		ret = -ENOMEM;
426 		goto ret;
427 	}
428 
429 	mutex_init(&pcap->io_mutex);
430 	mutex_init(&pcap->adc_mutex);
431 	INIT_WORK(&pcap->isr_work, pcap_isr_work);
432 	INIT_WORK(&pcap->msr_work, pcap_msr_work);
433 	spi_set_drvdata(spi, pcap);
434 
435 	/* setup spi */
436 	spi->bits_per_word = 32;
437 	spi->mode = SPI_MODE_0 | (pdata->config & PCAP_CS_AH ? SPI_CS_HIGH : 0);
438 	ret = spi_setup(spi);
439 	if (ret)
440 		goto ret;
441 
442 	pcap->spi = spi;
443 
444 	/* setup irq */
445 	pcap->irq_base = pdata->irq_base;
446 	pcap->workqueue = create_singlethread_workqueue("pcapd");
447 	if (!pcap->workqueue) {
448 		ret = -ENOMEM;
449 		dev_err(&spi->dev, "can't create pcap thread\n");
450 		goto ret;
451 	}
452 
453 	/* redirect interrupts to AP, except adcdone2 */
454 	if (!(pdata->config & PCAP_SECOND_PORT))
455 		ezx_pcap_write(pcap, PCAP_REG_INT_SEL,
456 					(1 << PCAP_IRQ_ADCDONE2));
457 
458 	/* setup irq chip */
459 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++) {
460 		irq_set_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
461 		irq_set_chip_data(i, pcap);
462 		irq_clear_status_flags(i, IRQ_NOREQUEST | IRQ_NOPROBE);
463 	}
464 
465 	/* mask/ack all PCAP interrupts */
466 	ezx_pcap_write(pcap, PCAP_REG_MSR, PCAP_MASK_ALL_INTERRUPT);
467 	ezx_pcap_write(pcap, PCAP_REG_ISR, PCAP_CLEAR_INTERRUPT_REGISTER);
468 	pcap->msr = PCAP_MASK_ALL_INTERRUPT;
469 
470 	irq_set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
471 	irq_set_chained_handler_and_data(spi->irq, pcap_irq_handler, pcap);
472 	irq_set_irq_wake(spi->irq, 1);
473 
474 	/* ADC */
475 	adc_irq = pcap_to_irq(pcap, (pdata->config & PCAP_SECOND_PORT) ?
476 					PCAP_IRQ_ADCDONE2 : PCAP_IRQ_ADCDONE);
477 
478 	ret = devm_request_irq(&spi->dev, adc_irq, pcap_adc_irq, 0, "ADC",
479 				pcap);
480 	if (ret)
481 		goto free_irqchip;
482 
483 	/* setup subdevs */
484 	for (i = 0; i < pdata->num_subdevs; i++) {
485 		ret = pcap_add_subdev(pcap, &pdata->subdevs[i]);
486 		if (ret)
487 			goto remove_subdevs;
488 	}
489 
490 	/* board specific quirks */
491 	if (pdata->init)
492 		pdata->init(pcap);
493 
494 	return 0;
495 
496 remove_subdevs:
497 	device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
498 free_irqchip:
499 	for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
500 		irq_set_chip_and_handler(i, NULL, NULL);
501 /* destroy_workqueue: */
502 	destroy_workqueue(pcap->workqueue);
503 ret:
504 	return ret;
505 }
506 
507 static struct spi_driver ezxpcap_driver = {
508 	.probe	= ezx_pcap_probe,
509 	.remove = ezx_pcap_remove,
510 	.driver = {
511 		.name	= "ezx-pcap",
512 	},
513 };
514 
515 static int __init ezx_pcap_init(void)
516 {
517 	return spi_register_driver(&ezxpcap_driver);
518 }
519 
520 static void __exit ezx_pcap_exit(void)
521 {
522 	spi_unregister_driver(&ezxpcap_driver);
523 }
524 
525 subsys_initcall(ezx_pcap_init);
526 module_exit(ezx_pcap_exit);
527 
528 MODULE_LICENSE("GPL");
529 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
530 MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");
531 MODULE_ALIAS("spi:ezx-pcap");
532