xref: /linux/drivers/w1/masters/omap_hdq.c (revision 8e07e0e3964ca4e23ce7b68e2096fe660a888942)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2007,2012 Texas Instruments, Inc.
4  */
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/platform_device.h>
8 #include <linux/interrupt.h>
9 #include <linux/slab.h>
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/sched.h>
13 #include <linux/pm_runtime.h>
14 #include <linux/of.h>
15 
16 #include <linux/w1.h>
17 
18 #define	MOD_NAME	"OMAP_HDQ:"
19 
20 #define OMAP_HDQ_REVISION			0x00
21 #define OMAP_HDQ_TX_DATA			0x04
22 #define OMAP_HDQ_RX_DATA			0x08
23 #define OMAP_HDQ_CTRL_STATUS			0x0c
24 #define OMAP_HDQ_CTRL_STATUS_SINGLE		BIT(7)
25 #define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK	BIT(6)
26 #define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE	BIT(5)
27 #define OMAP_HDQ_CTRL_STATUS_GO                 BIT(4)
28 #define OMAP_HDQ_CTRL_STATUS_PRESENCE		BIT(3)
29 #define OMAP_HDQ_CTRL_STATUS_INITIALIZATION	BIT(2)
30 #define OMAP_HDQ_CTRL_STATUS_DIR		BIT(1)
31 #define OMAP_HDQ_INT_STATUS			0x10
32 #define OMAP_HDQ_INT_STATUS_TXCOMPLETE		BIT(2)
33 #define OMAP_HDQ_INT_STATUS_RXCOMPLETE		BIT(1)
34 #define OMAP_HDQ_INT_STATUS_TIMEOUT		BIT(0)
35 
36 #define OMAP_HDQ_FLAG_CLEAR			0
37 #define OMAP_HDQ_FLAG_SET			1
38 #define OMAP_HDQ_TIMEOUT			(HZ/5)
39 
40 #define OMAP_HDQ_MAX_USER			4
41 
42 static DECLARE_WAIT_QUEUE_HEAD(hdq_wait_queue);
43 
44 static int w1_id;
45 module_param(w1_id, int, 0400);
46 MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection in HDQ mode");
47 
48 struct hdq_data {
49 	struct device		*dev;
50 	void __iomem		*hdq_base;
51 	/* lock read/write/break operations */
52 	struct  mutex		hdq_mutex;
53 	/* interrupt status and a lock for it */
54 	u8			hdq_irqstatus;
55 	spinlock_t		hdq_spinlock;
56 	/* mode: 0-HDQ 1-W1 */
57 	int                     mode;
58 
59 };
60 
61 /* HDQ register I/O routines */
62 static inline u8 hdq_reg_in(struct hdq_data *hdq_data, u32 offset)
63 {
64 	return __raw_readl(hdq_data->hdq_base + offset);
65 }
66 
67 static inline void hdq_reg_out(struct hdq_data *hdq_data, u32 offset, u8 val)
68 {
69 	__raw_writel(val, hdq_data->hdq_base + offset);
70 }
71 
72 static inline u8 hdq_reg_merge(struct hdq_data *hdq_data, u32 offset,
73 			u8 val, u8 mask)
74 {
75 	u8 new_val = (__raw_readl(hdq_data->hdq_base + offset) & ~mask)
76 			| (val & mask);
77 	__raw_writel(new_val, hdq_data->hdq_base + offset);
78 
79 	return new_val;
80 }
81 
82 /*
83  * Wait for one or more bits in flag change.
84  * HDQ_FLAG_SET: wait until any bit in the flag is set.
85  * HDQ_FLAG_CLEAR: wait until all bits in the flag are cleared.
86  * return 0 on success and -ETIMEDOUT in the case of timeout.
87  */
88 static int hdq_wait_for_flag(struct hdq_data *hdq_data, u32 offset,
89 		u8 flag, u8 flag_set, u8 *status)
90 {
91 	int ret = 0;
92 	unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
93 
94 	if (flag_set == OMAP_HDQ_FLAG_CLEAR) {
95 		/* wait for the flag clear */
96 		while (((*status = hdq_reg_in(hdq_data, offset)) & flag)
97 			&& time_before(jiffies, timeout)) {
98 			schedule_timeout_uninterruptible(1);
99 		}
100 		if (*status & flag)
101 			ret = -ETIMEDOUT;
102 	} else if (flag_set == OMAP_HDQ_FLAG_SET) {
103 		/* wait for the flag set */
104 		while (!((*status = hdq_reg_in(hdq_data, offset)) & flag)
105 			&& time_before(jiffies, timeout)) {
106 			schedule_timeout_uninterruptible(1);
107 		}
108 		if (!(*status & flag))
109 			ret = -ETIMEDOUT;
110 	} else
111 		return -EINVAL;
112 
113 	return ret;
114 }
115 
116 /* Clear saved irqstatus after using an interrupt */
117 static u8 hdq_reset_irqstatus(struct hdq_data *hdq_data, u8 bits)
118 {
119 	unsigned long irqflags;
120 	u8 status;
121 
122 	spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
123 	status = hdq_data->hdq_irqstatus;
124 	/* this is a read-modify-write */
125 	hdq_data->hdq_irqstatus &= ~bits;
126 	spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
127 
128 	return status;
129 }
130 
131 /* write out a byte and fill *status with HDQ_INT_STATUS */
132 static int hdq_write_byte(struct hdq_data *hdq_data, u8 val, u8 *status)
133 {
134 	int ret;
135 	u8 tmp_status;
136 
137 	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
138 	if (ret < 0) {
139 		ret = -EINTR;
140 		goto rtn;
141 	}
142 
143 	if (hdq_data->hdq_irqstatus)
144 		dev_err(hdq_data->dev, "TX irqstatus not cleared (%02x)\n",
145 			hdq_data->hdq_irqstatus);
146 
147 	*status = 0;
148 
149 	hdq_reg_out(hdq_data, OMAP_HDQ_TX_DATA, val);
150 
151 	/* set the GO bit */
152 	hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, OMAP_HDQ_CTRL_STATUS_GO,
153 		OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
154 	/* wait for the TXCOMPLETE bit */
155 	ret = wait_event_timeout(hdq_wait_queue,
156 		(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
157 		OMAP_HDQ_TIMEOUT);
158 	*status = hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TXCOMPLETE);
159 	if (ret == 0) {
160 		dev_dbg(hdq_data->dev, "TX wait elapsed\n");
161 		ret = -ETIMEDOUT;
162 		goto out;
163 	}
164 
165 	/* check irqstatus */
166 	if (!(*status & OMAP_HDQ_INT_STATUS_TXCOMPLETE)) {
167 		dev_dbg(hdq_data->dev, "timeout waiting for"
168 			" TXCOMPLETE/RXCOMPLETE, %x\n", *status);
169 		ret = -ETIMEDOUT;
170 		goto out;
171 	}
172 
173 	/* wait for the GO bit return to zero */
174 	ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
175 			OMAP_HDQ_CTRL_STATUS_GO,
176 			OMAP_HDQ_FLAG_CLEAR, &tmp_status);
177 	if (ret) {
178 		dev_dbg(hdq_data->dev, "timeout waiting GO bit"
179 			" return to zero, %x\n", tmp_status);
180 	}
181 
182 out:
183 	mutex_unlock(&hdq_data->hdq_mutex);
184 rtn:
185 	return ret;
186 }
187 
188 /* HDQ Interrupt service routine */
189 static irqreturn_t hdq_isr(int irq, void *_hdq)
190 {
191 	struct hdq_data *hdq_data = _hdq;
192 	unsigned long irqflags;
193 
194 	spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
195 	hdq_data->hdq_irqstatus |= hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
196 	spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
197 	dev_dbg(hdq_data->dev, "hdq_isr: %x\n", hdq_data->hdq_irqstatus);
198 
199 	if (hdq_data->hdq_irqstatus &
200 		(OMAP_HDQ_INT_STATUS_TXCOMPLETE | OMAP_HDQ_INT_STATUS_RXCOMPLETE
201 		| OMAP_HDQ_INT_STATUS_TIMEOUT)) {
202 		/* wake up sleeping process */
203 		wake_up(&hdq_wait_queue);
204 	}
205 
206 	return IRQ_HANDLED;
207 }
208 
209 /* W1 search callback function  in HDQ mode */
210 static void omap_w1_search_bus(void *_hdq, struct w1_master *master_dev,
211 		u8 search_type, w1_slave_found_callback slave_found)
212 {
213 	u64 module_id, rn_le, cs, id;
214 
215 	if (w1_id)
216 		module_id = w1_id;
217 	else
218 		module_id = 0x1;
219 
220 	rn_le = cpu_to_le64(module_id);
221 	/*
222 	 * HDQ might not obey truly the 1-wire spec.
223 	 * So calculate CRC based on module parameter.
224 	 */
225 	cs = w1_calc_crc8((u8 *)&rn_le, 7);
226 	id = (cs << 56) | module_id;
227 
228 	slave_found(master_dev, id);
229 }
230 
231 /* Issue break pulse to the device */
232 static int omap_hdq_break(struct hdq_data *hdq_data)
233 {
234 	int ret = 0;
235 	u8 tmp_status;
236 
237 	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
238 	if (ret < 0) {
239 		dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
240 		ret = -EINTR;
241 		goto rtn;
242 	}
243 
244 	if (hdq_data->hdq_irqstatus)
245 		dev_err(hdq_data->dev, "break irqstatus not cleared (%02x)\n",
246 			hdq_data->hdq_irqstatus);
247 
248 	/* set the INIT and GO bit */
249 	hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
250 		OMAP_HDQ_CTRL_STATUS_INITIALIZATION | OMAP_HDQ_CTRL_STATUS_GO,
251 		OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
252 		OMAP_HDQ_CTRL_STATUS_GO);
253 
254 	/* wait for the TIMEOUT bit */
255 	ret = wait_event_timeout(hdq_wait_queue,
256 		(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_TIMEOUT),
257 		OMAP_HDQ_TIMEOUT);
258 	tmp_status = hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TIMEOUT);
259 	if (ret == 0) {
260 		dev_dbg(hdq_data->dev, "break wait elapsed\n");
261 		ret = -EINTR;
262 		goto out;
263 	}
264 
265 	/* check irqstatus */
266 	if (!(tmp_status & OMAP_HDQ_INT_STATUS_TIMEOUT)) {
267 		dev_dbg(hdq_data->dev, "timeout waiting for TIMEOUT, %x\n",
268 			tmp_status);
269 		ret = -ETIMEDOUT;
270 		goto out;
271 	}
272 
273 	/*
274 	 * check for the presence detect bit to get
275 	 * set to show that the slave is responding
276 	 */
277 	if (!(hdq_reg_in(hdq_data, OMAP_HDQ_CTRL_STATUS) &
278 			OMAP_HDQ_CTRL_STATUS_PRESENCE)) {
279 		dev_dbg(hdq_data->dev, "Presence bit not set\n");
280 		ret = -ETIMEDOUT;
281 		goto out;
282 	}
283 
284 	/*
285 	 * wait for both INIT and GO bits rerurn to zero.
286 	 * zero wait time expected for interrupt mode.
287 	 */
288 	ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
289 			OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
290 			OMAP_HDQ_CTRL_STATUS_GO, OMAP_HDQ_FLAG_CLEAR,
291 			&tmp_status);
292 	if (ret)
293 		dev_dbg(hdq_data->dev, "timeout waiting INIT&GO bits"
294 			" return to zero, %x\n", tmp_status);
295 
296 out:
297 	mutex_unlock(&hdq_data->hdq_mutex);
298 rtn:
299 	return ret;
300 }
301 
302 static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
303 {
304 	int ret = 0;
305 	u8 status;
306 
307 	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
308 	if (ret < 0) {
309 		ret = -EINTR;
310 		goto rtn;
311 	}
312 
313 	if (pm_runtime_suspended(hdq_data->dev)) {
314 		ret = -EINVAL;
315 		goto out;
316 	}
317 
318 	if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
319 		hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
320 			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
321 			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
322 		/*
323 		 * The RX comes immediately after TX.
324 		 */
325 		wait_event_timeout(hdq_wait_queue,
326 				   (hdq_data->hdq_irqstatus
327 				    & (OMAP_HDQ_INT_STATUS_RXCOMPLETE |
328 				       OMAP_HDQ_INT_STATUS_TIMEOUT)),
329 				   OMAP_HDQ_TIMEOUT);
330 		status = hdq_reset_irqstatus(hdq_data,
331 					     OMAP_HDQ_INT_STATUS_RXCOMPLETE |
332 					     OMAP_HDQ_INT_STATUS_TIMEOUT);
333 		hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, 0,
334 			OMAP_HDQ_CTRL_STATUS_DIR);
335 
336 		/* check irqstatus */
337 		if (!(status & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
338 			dev_dbg(hdq_data->dev, "timeout waiting for"
339 				" RXCOMPLETE, %x", status);
340 			ret = -ETIMEDOUT;
341 			goto out;
342 		}
343 	} else { /* interrupt had occurred before hdq_read_byte was called */
344 		hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
345 	}
346 	/* the data is ready. Read it in! */
347 	*val = hdq_reg_in(hdq_data, OMAP_HDQ_RX_DATA);
348 out:
349 	mutex_unlock(&hdq_data->hdq_mutex);
350 rtn:
351 	return ret;
352 
353 }
354 
355 /*
356  * W1 triplet callback function - used for searching ROM addresses.
357  * Registered only when controller is in 1-wire mode.
358  */
359 static u8 omap_w1_triplet(void *_hdq, u8 bdir)
360 {
361 	u8 id_bit, comp_bit;
362 	int err;
363 	u8 ret = 0x3; /* no slaves responded */
364 	struct hdq_data *hdq_data = _hdq;
365 	u8 ctrl = OMAP_HDQ_CTRL_STATUS_SINGLE | OMAP_HDQ_CTRL_STATUS_GO |
366 		  OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK;
367 	u8 mask = ctrl | OMAP_HDQ_CTRL_STATUS_DIR;
368 
369 	err = pm_runtime_get_sync(hdq_data->dev);
370 	if (err < 0) {
371 		pm_runtime_put_noidle(hdq_data->dev);
372 
373 		return err;
374 	}
375 
376 	err = mutex_lock_interruptible(&hdq_data->hdq_mutex);
377 	if (err < 0) {
378 		dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
379 		goto rtn;
380 	}
381 
382 	/* read id_bit */
383 	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
384 		      ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
385 	err = wait_event_timeout(hdq_wait_queue,
386 				 (hdq_data->hdq_irqstatus
387 				  & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
388 				 OMAP_HDQ_TIMEOUT);
389 	/* Must clear irqstatus for another RXCOMPLETE interrupt */
390 	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
391 
392 	if (err == 0) {
393 		dev_dbg(hdq_data->dev, "RX wait elapsed\n");
394 		goto out;
395 	}
396 	id_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
397 
398 	/* read comp_bit */
399 	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
400 		      ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
401 	err = wait_event_timeout(hdq_wait_queue,
402 				 (hdq_data->hdq_irqstatus
403 				  & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
404 				 OMAP_HDQ_TIMEOUT);
405 	/* Must clear irqstatus for another RXCOMPLETE interrupt */
406 	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
407 
408 	if (err == 0) {
409 		dev_dbg(hdq_data->dev, "RX wait elapsed\n");
410 		goto out;
411 	}
412 	comp_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
413 
414 	if (id_bit && comp_bit) {
415 		ret = 0x03;  /* no slaves responded */
416 		goto out;
417 	}
418 	if (!id_bit && !comp_bit) {
419 		/* Both bits are valid, take the direction given */
420 		ret = bdir ? 0x04 : 0;
421 	} else {
422 		/* Only one bit is valid, take that direction */
423 		bdir = id_bit;
424 		ret = id_bit ? 0x05 : 0x02;
425 	}
426 
427 	/* write bdir bit */
428 	hdq_reg_out(_hdq, OMAP_HDQ_TX_DATA, bdir);
429 	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, ctrl, mask);
430 	err = wait_event_timeout(hdq_wait_queue,
431 				 (hdq_data->hdq_irqstatus
432 				  & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
433 				 OMAP_HDQ_TIMEOUT);
434 	/* Must clear irqstatus for another TXCOMPLETE interrupt */
435 	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TXCOMPLETE);
436 
437 	if (err == 0) {
438 		dev_dbg(hdq_data->dev, "TX wait elapsed\n");
439 		goto out;
440 	}
441 
442 	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, 0,
443 		      OMAP_HDQ_CTRL_STATUS_SINGLE);
444 
445 out:
446 	mutex_unlock(&hdq_data->hdq_mutex);
447 rtn:
448 	pm_runtime_mark_last_busy(hdq_data->dev);
449 	pm_runtime_put_autosuspend(hdq_data->dev);
450 
451 	return ret;
452 }
453 
454 /* reset callback */
455 static u8 omap_w1_reset_bus(void *_hdq)
456 {
457 	struct hdq_data *hdq_data = _hdq;
458 	int err;
459 
460 	err = pm_runtime_get_sync(hdq_data->dev);
461 	if (err < 0) {
462 		pm_runtime_put_noidle(hdq_data->dev);
463 
464 		return err;
465 	}
466 
467 	omap_hdq_break(hdq_data);
468 
469 	pm_runtime_mark_last_busy(hdq_data->dev);
470 	pm_runtime_put_autosuspend(hdq_data->dev);
471 
472 	return 0;
473 }
474 
475 /* Read a byte of data from the device */
476 static u8 omap_w1_read_byte(void *_hdq)
477 {
478 	struct hdq_data *hdq_data = _hdq;
479 	u8 val = 0;
480 	int ret;
481 
482 	ret = pm_runtime_get_sync(hdq_data->dev);
483 	if (ret < 0) {
484 		pm_runtime_put_noidle(hdq_data->dev);
485 
486 		return -1;
487 	}
488 
489 	ret = hdq_read_byte(hdq_data, &val);
490 	if (ret)
491 		val = -1;
492 
493 	pm_runtime_mark_last_busy(hdq_data->dev);
494 	pm_runtime_put_autosuspend(hdq_data->dev);
495 
496 	return val;
497 }
498 
499 /* Write a byte of data to the device */
500 static void omap_w1_write_byte(void *_hdq, u8 byte)
501 {
502 	struct hdq_data *hdq_data = _hdq;
503 	int ret;
504 	u8 status;
505 
506 	ret = pm_runtime_get_sync(hdq_data->dev);
507 	if (ret < 0) {
508 		pm_runtime_put_noidle(hdq_data->dev);
509 
510 		return;
511 	}
512 
513 	/*
514 	 * We need to reset the slave before
515 	 * issuing the SKIP ROM command, else
516 	 * the slave will not work.
517 	 */
518 	if (byte == W1_SKIP_ROM)
519 		omap_hdq_break(hdq_data);
520 
521 	ret = hdq_write_byte(hdq_data, byte, &status);
522 	if (ret < 0) {
523 		dev_dbg(hdq_data->dev, "TX failure:Ctrl status %x\n", status);
524 		goto out_err;
525 	}
526 
527 out_err:
528 	pm_runtime_mark_last_busy(hdq_data->dev);
529 	pm_runtime_put_autosuspend(hdq_data->dev);
530 }
531 
532 static struct w1_bus_master omap_w1_master = {
533 	.read_byte	= omap_w1_read_byte,
534 	.write_byte	= omap_w1_write_byte,
535 	.reset_bus	= omap_w1_reset_bus,
536 };
537 
538 static int __maybe_unused omap_hdq_runtime_suspend(struct device *dev)
539 {
540 	struct hdq_data *hdq_data = dev_get_drvdata(dev);
541 
542 	hdq_reg_out(hdq_data, 0, hdq_data->mode);
543 	hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
544 
545 	return 0;
546 }
547 
548 static int __maybe_unused omap_hdq_runtime_resume(struct device *dev)
549 {
550 	struct hdq_data *hdq_data = dev_get_drvdata(dev);
551 
552 	/* select HDQ/1W mode & enable clocks */
553 	hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
554 		    OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
555 		    OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
556 		    hdq_data->mode);
557 	hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
558 
559 	return 0;
560 }
561 
562 static const struct dev_pm_ops omap_hdq_pm_ops = {
563 	SET_RUNTIME_PM_OPS(omap_hdq_runtime_suspend,
564 			   omap_hdq_runtime_resume, NULL)
565 };
566 
567 static int omap_hdq_probe(struct platform_device *pdev)
568 {
569 	struct device *dev = &pdev->dev;
570 	struct hdq_data *hdq_data;
571 	int ret, irq;
572 	u8 rev;
573 	const char *mode;
574 
575 	hdq_data = devm_kzalloc(dev, sizeof(*hdq_data), GFP_KERNEL);
576 	if (!hdq_data)
577 		return -ENOMEM;
578 
579 	hdq_data->dev = dev;
580 	platform_set_drvdata(pdev, hdq_data);
581 
582 	hdq_data->hdq_base = devm_platform_ioremap_resource(pdev, 0);
583 	if (IS_ERR(hdq_data->hdq_base))
584 		return PTR_ERR(hdq_data->hdq_base);
585 
586 	mutex_init(&hdq_data->hdq_mutex);
587 
588 	ret = of_property_read_string(pdev->dev.of_node, "ti,mode", &mode);
589 	if (ret < 0 || !strcmp(mode, "hdq")) {
590 		hdq_data->mode = 0;
591 		omap_w1_master.search = omap_w1_search_bus;
592 	} else {
593 		hdq_data->mode = 1;
594 		omap_w1_master.triplet = omap_w1_triplet;
595 	}
596 
597 	pm_runtime_enable(&pdev->dev);
598 	pm_runtime_use_autosuspend(&pdev->dev);
599 	pm_runtime_set_autosuspend_delay(&pdev->dev, 300);
600 	ret = pm_runtime_get_sync(&pdev->dev);
601 	if (ret < 0) {
602 		pm_runtime_put_noidle(&pdev->dev);
603 		dev_dbg(&pdev->dev, "pm_runtime_get_sync failed\n");
604 		goto err_w1;
605 	}
606 
607 	rev = hdq_reg_in(hdq_data, OMAP_HDQ_REVISION);
608 	dev_info(&pdev->dev, "OMAP HDQ Hardware Rev %c.%c. Driver in %s mode\n",
609 		(rev >> 4) + '0', (rev & 0x0f) + '0', "Interrupt");
610 
611 	spin_lock_init(&hdq_data->hdq_spinlock);
612 
613 	irq = platform_get_irq(pdev, 0);
614 	if (irq	< 0) {
615 		dev_dbg(&pdev->dev, "Failed to get IRQ: %d\n", irq);
616 		ret = irq;
617 		goto err_irq;
618 	}
619 
620 	ret = devm_request_irq(dev, irq, hdq_isr, 0, "omap_hdq", hdq_data);
621 	if (ret < 0) {
622 		dev_dbg(&pdev->dev, "could not request irq\n");
623 		goto err_irq;
624 	}
625 
626 	omap_hdq_break(hdq_data);
627 
628 	pm_runtime_mark_last_busy(&pdev->dev);
629 	pm_runtime_put_autosuspend(&pdev->dev);
630 
631 	omap_w1_master.data = hdq_data;
632 
633 	ret = w1_add_master_device(&omap_w1_master);
634 	if (ret) {
635 		dev_dbg(&pdev->dev, "Failure in registering w1 master\n");
636 		goto err_w1;
637 	}
638 
639 	return 0;
640 
641 err_irq:
642 	pm_runtime_put_sync(&pdev->dev);
643 err_w1:
644 	pm_runtime_dont_use_autosuspend(&pdev->dev);
645 	pm_runtime_disable(&pdev->dev);
646 
647 	return ret;
648 }
649 
650 static int omap_hdq_remove(struct platform_device *pdev)
651 {
652 	int active;
653 
654 	active = pm_runtime_get_sync(&pdev->dev);
655 	if (active < 0)
656 		pm_runtime_put_noidle(&pdev->dev);
657 
658 	w1_remove_master_device(&omap_w1_master);
659 
660 	pm_runtime_dont_use_autosuspend(&pdev->dev);
661 	if (active >= 0)
662 		pm_runtime_put_sync(&pdev->dev);
663 	pm_runtime_disable(&pdev->dev);
664 
665 	return 0;
666 }
667 
668 static const struct of_device_id omap_hdq_dt_ids[] = {
669 	{ .compatible = "ti,omap3-1w" },
670 	{ .compatible = "ti,am4372-hdq" },
671 	{}
672 };
673 MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids);
674 
675 static struct platform_driver omap_hdq_driver = {
676 	.probe = omap_hdq_probe,
677 	.remove = omap_hdq_remove,
678 	.driver = {
679 		.name =	"omap_hdq",
680 		.of_match_table = omap_hdq_dt_ids,
681 		.pm = &omap_hdq_pm_ops,
682 	},
683 };
684 module_platform_driver(omap_hdq_driver);
685 
686 MODULE_AUTHOR("Texas Instruments");
687 MODULE_DESCRIPTION("HDQ-1W driver Library");
688 MODULE_LICENSE("GPL");
689