xref: /freebsd/sys/arm/ti/am335x/am335x_ehrpwm.c (revision 3110d4ebd6c0848cf5e25890d01791bb407e2a9b)
1 /*-
2  * Copyright (c) 2013 Oleksandr Tymoshenko <gonzo@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/kernel.h>
34 #include <sys/limits.h>
35 #include <sys/lock.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
38 #include <sys/resource.h>
39 #include <sys/rman.h>
40 #include <sys/sysctl.h>
41 
42 #include <machine/bus.h>
43 
44 #include <dev/ofw/openfirm.h>
45 #include <dev/ofw/ofw_bus.h>
46 #include <dev/ofw/ofw_bus_subr.h>
47 
48 #include "pwmbus_if.h"
49 
50 #include "am335x_pwm.h"
51 
52 /*******************************************************************************
53  * Enhanced resolution PWM driver.  Many of the advanced featues of the hardware
54  * are not supported by this driver.  What is implemented here is simple
55  * variable-duty-cycle PWM output.
56  *
57  * Note that this driver was historically configured using a set of sysctl
58  * variables/procs, and later gained support for the PWM(9) API.  The sysctl
59  * code is still present to support existing apps, but that interface is
60  * considered deprecated.
61  *
62  * An important caveat is that the original sysctl interface and the new PWM API
63  * cannot both be used at once.  If both interfaces are used to change
64  * configuration, it's quite likely you won't get the expected results.  Also,
65  * reading the sysctl values after configuring via PWM will not return the right
66  * results.
67  ******************************************************************************/
68 
69 /* In ticks */
70 #define	DEFAULT_PWM_PERIOD	1000
71 #define	PWM_CLOCK		100000000UL
72 
73 #define	NS_PER_SEC		1000000000
74 
75 #define	PWM_LOCK(_sc)		mtx_lock(&(_sc)->sc_mtx)
76 #define	PWM_UNLOCK(_sc)		mtx_unlock(&(_sc)->sc_mtx)
77 #define	PWM_LOCK_ASSERT(_sc)    mtx_assert(&(_sc)->sc_mtx, MA_OWNED)
78 #define	PWM_LOCK_INIT(_sc)	mtx_init(&(_sc)->sc_mtx, \
79     device_get_nameunit(_sc->sc_dev), "am335x_ehrpwm softc", MTX_DEF)
80 #define	PWM_LOCK_DESTROY(_sc)	mtx_destroy(&(_sc)->sc_mtx)
81 
82 #define	EPWM_READ2(_sc, reg)	bus_read_2((_sc)->sc_mem_res, reg)
83 #define	EPWM_WRITE2(_sc, reg, value)	\
84     bus_write_2((_sc)->sc_mem_res, reg, value)
85 
86 #define	EPWM_TBCTL		0x00
87 #define		TBCTL_FREERUN		(2 << 14)
88 #define		TBCTL_PHDIR_UP		(1 << 13)
89 #define		TBCTL_PHDIR_DOWN	(0 << 13)
90 #define		TBCTL_CLKDIV(x)		((x) << 10)
91 #define		TBCTL_CLKDIV_MASK	(3 << 10)
92 #define		TBCTL_HSPCLKDIV(x)	((x) << 7)
93 #define		TBCTL_HSPCLKDIV_MASK	(3 << 7)
94 #define		TBCTL_SYNCOSEL_DISABLED	(3 << 4)
95 #define		TBCTL_PRDLD_SHADOW	(0 << 3)
96 #define		TBCTL_PRDLD_IMMEDIATE	(0 << 3)
97 #define		TBCTL_PHSEN_ENABLED	(1 << 2)
98 #define		TBCTL_PHSEN_DISABLED	(0 << 2)
99 #define		TBCTL_CTRMODE_MASK	(3)
100 #define		TBCTL_CTRMODE_UP	(0 << 0)
101 #define		TBCTL_CTRMODE_DOWN	(1 << 0)
102 #define		TBCTL_CTRMODE_UPDOWN	(2 << 0)
103 #define		TBCTL_CTRMODE_FREEZE	(3 << 0)
104 
105 #define	EPWM_TBSTS		0x02
106 #define	EPWM_TBPHSHR		0x04
107 #define	EPWM_TBPHS		0x06
108 #define	EPWM_TBCNT		0x08
109 #define	EPWM_TBPRD		0x0a
110 /* Counter-compare */
111 #define	EPWM_CMPCTL		0x0e
112 #define		CMPCTL_SHDWBMODE_SHADOW		(1 << 6)
113 #define		CMPCTL_SHDWBMODE_IMMEDIATE	(0 << 6)
114 #define		CMPCTL_SHDWAMODE_SHADOW		(1 << 4)
115 #define		CMPCTL_SHDWAMODE_IMMEDIATE	(0 << 4)
116 #define		CMPCTL_LOADBMODE_ZERO		(0 << 2)
117 #define		CMPCTL_LOADBMODE_PRD		(1 << 2)
118 #define		CMPCTL_LOADBMODE_EITHER		(2 << 2)
119 #define		CMPCTL_LOADBMODE_FREEZE		(3 << 2)
120 #define		CMPCTL_LOADAMODE_ZERO		(0 << 0)
121 #define		CMPCTL_LOADAMODE_PRD		(1 << 0)
122 #define		CMPCTL_LOADAMODE_EITHER		(2 << 0)
123 #define		CMPCTL_LOADAMODE_FREEZE		(3 << 0)
124 #define	EPWM_CMPAHR		0x10
125 #define	EPWM_CMPA		0x12
126 #define	EPWM_CMPB		0x14
127 /* CMPCTL_LOADAMODE_ZERO */
128 #define	EPWM_AQCTLA		0x16
129 #define	EPWM_AQCTLB		0x18
130 #define		AQCTL_CBU_NONE		(0 << 8)
131 #define		AQCTL_CBU_CLEAR		(1 << 8)
132 #define		AQCTL_CBU_SET		(2 << 8)
133 #define		AQCTL_CBU_TOGGLE	(3 << 8)
134 #define		AQCTL_CAU_NONE		(0 << 4)
135 #define		AQCTL_CAU_CLEAR		(1 << 4)
136 #define		AQCTL_CAU_SET		(2 << 4)
137 #define		AQCTL_CAU_TOGGLE	(3 << 4)
138 #define		AQCTL_ZRO_NONE		(0 << 0)
139 #define		AQCTL_ZRO_CLEAR		(1 << 0)
140 #define		AQCTL_ZRO_SET		(2 << 0)
141 #define		AQCTL_ZRO_TOGGLE	(3 << 0)
142 #define	EPWM_AQSFRC		0x1a
143 #define	EPWM_AQCSFRC		0x1c
144 #define		AQCSFRC_OFF		0
145 #define		AQCSFRC_LO		1
146 #define		AQCSFRC_HI		2
147 #define		AQCSFRC_MASK		3
148 #define		AQCSFRC(chan, hilo)	((hilo) << (2 * chan))
149 
150 /* Trip-Zone module */
151 #define	EPWM_TZCTL		0x28
152 #define	EPWM_TZFLG		0x2C
153 /* High-Resolution PWM */
154 #define	EPWM_HRCTL		0x40
155 #define		HRCTL_DELMODE_BOTH	3
156 #define		HRCTL_DELMODE_FALL	2
157 #define		HRCTL_DELMODE_RISE	1
158 
159 static device_probe_t am335x_ehrpwm_probe;
160 static device_attach_t am335x_ehrpwm_attach;
161 static device_detach_t am335x_ehrpwm_detach;
162 
163 static int am335x_ehrpwm_clkdiv[8] = { 1, 2, 4, 8, 16, 32, 64, 128 };
164 
165 struct ehrpwm_channel {
166 	u_int	duty;		/* on duration, in ns */
167 	bool	enabled;	/* channel enabled? */
168 	bool	inverted;	/* signal inverted? */
169 };
170 #define	NUM_CHANNELS	2
171 
172 struct am335x_ehrpwm_softc {
173 	device_t		sc_dev;
174 	device_t		sc_busdev;
175 	struct mtx		sc_mtx;
176 	struct resource		*sc_mem_res;
177 	int			sc_mem_rid;
178 
179 	/* Things used for configuration via sysctl [deprecated]. */
180 	int			sc_pwm_clkdiv;
181 	int			sc_pwm_freq;
182 	struct sysctl_oid	*sc_clkdiv_oid;
183 	struct sysctl_oid	*sc_freq_oid;
184 	struct sysctl_oid	*sc_period_oid;
185 	struct sysctl_oid	*sc_chanA_oid;
186 	struct sysctl_oid	*sc_chanB_oid;
187 	uint32_t		sc_pwm_period;
188 	uint32_t		sc_pwm_dutyA;
189 	uint32_t		sc_pwm_dutyB;
190 
191 	/* Things used for configuration via pwm(9) api. */
192 	u_int			sc_clkfreq; /* frequency in Hz */
193 	u_int			sc_clktick; /* duration in ns */
194 	u_int			sc_period;  /* duration in ns */
195 	struct ehrpwm_channel	sc_channels[NUM_CHANNELS];
196 };
197 
198 static struct ofw_compat_data compat_data[] = {
199 	{"ti,am33xx-ehrpwm",    true},
200 	{NULL,                  false},
201 };
202 
203 static void
204 am335x_ehrpwm_cfg_duty(struct am335x_ehrpwm_softc *sc, u_int chan, u_int duty)
205 {
206 	u_int tbcmp;
207 
208 	if (duty == 0)
209 		tbcmp = 0;
210 	else
211 		tbcmp = max(1, duty / sc->sc_clktick);
212 
213 	sc->sc_channels[chan].duty = tbcmp * sc->sc_clktick;
214 
215 	PWM_LOCK_ASSERT(sc);
216 	EPWM_WRITE2(sc, (chan == 0) ? EPWM_CMPA : EPWM_CMPB, tbcmp);
217 }
218 
219 static void
220 am335x_ehrpwm_cfg_enable(struct am335x_ehrpwm_softc *sc, u_int chan, bool enable)
221 {
222 	uint16_t regval;
223 
224 	sc->sc_channels[chan].enabled = enable;
225 
226 	/*
227 	 * Turn off any existing software-force of the channel, then force
228 	 * it in the right direction (high or low) if it's not being enabled.
229 	 */
230 	PWM_LOCK_ASSERT(sc);
231 	regval = EPWM_READ2(sc, EPWM_AQCSFRC);
232 	regval &= ~AQCSFRC(chan, AQCSFRC_MASK);
233 	if (!sc->sc_channels[chan].enabled) {
234 		if (sc->sc_channels[chan].inverted)
235 			regval |= AQCSFRC(chan, AQCSFRC_HI);
236 		else
237 			regval |= AQCSFRC(chan, AQCSFRC_LO);
238 	}
239 	EPWM_WRITE2(sc, EPWM_AQCSFRC, regval);
240 }
241 
242 static bool
243 am335x_ehrpwm_cfg_period(struct am335x_ehrpwm_softc *sc, u_int period)
244 {
245 	uint16_t regval;
246 	u_int clkdiv, hspclkdiv, pwmclk, pwmtick, tbprd;
247 
248 	/* Can't do a period shorter than 2 clock ticks. */
249 	if (period < 2 * NS_PER_SEC / PWM_CLOCK) {
250 		sc->sc_clkfreq = 0;
251 		sc->sc_clktick = 0;
252 		sc->sc_period  = 0;
253 		return (false);
254 	}
255 
256 	/*
257 	 * Figure out how much we have to divide down the base 100MHz clock so
258 	 * that we can express the requested period as a 16-bit tick count.
259 	 */
260 	tbprd = 0;
261 	for (clkdiv = 0; clkdiv < 8; ++clkdiv) {
262 		const u_int cd = 1 << clkdiv;
263 		for (hspclkdiv = 0; hspclkdiv < 8; ++hspclkdiv) {
264 			const u_int cdhs = max(1, hspclkdiv * 2);
265 			pwmclk = PWM_CLOCK / (cd * cdhs);
266 			pwmtick = NS_PER_SEC / pwmclk;
267 			if (period / pwmtick < 65536) {
268 				tbprd = period / pwmtick;
269 				break;
270 			}
271 		}
272 		if (tbprd != 0)
273 			break;
274 	}
275 
276 	/* Handle requested period too long for available clock divisors. */
277 	if (tbprd == 0)
278 		return (false);
279 
280 	/*
281 	 * If anything has changed from the current settings, reprogram the
282 	 * clock divisors and period register.
283 	 */
284 	if (sc->sc_clkfreq != pwmclk || sc->sc_clktick != pwmtick ||
285 	    sc->sc_period != tbprd * pwmtick) {
286 		sc->sc_clkfreq = pwmclk;
287 		sc->sc_clktick = pwmtick;
288 		sc->sc_period  = tbprd * pwmtick;
289 
290 		PWM_LOCK_ASSERT(sc);
291 		regval = EPWM_READ2(sc, EPWM_TBCTL);
292 		regval &= ~(TBCTL_CLKDIV_MASK | TBCTL_HSPCLKDIV_MASK);
293 		regval |= TBCTL_CLKDIV(clkdiv) | TBCTL_HSPCLKDIV(hspclkdiv);
294 		EPWM_WRITE2(sc, EPWM_TBCTL, regval);
295 		EPWM_WRITE2(sc, EPWM_TBPRD, tbprd - 1);
296 #if 0
297 		device_printf(sc->sc_dev, "clkdiv %u hspclkdiv %u tbprd %u "
298 		    "clkfreq %u Hz clktick %u ns period got %u requested %u\n",
299 		    clkdiv, hspclkdiv, tbprd - 1,
300 		    sc->sc_clkfreq, sc->sc_clktick, sc->sc_period, period);
301 #endif
302 		/*
303 		 * If the period changed, that invalidates the current CMP
304 		 * registers (duty values), just zero them out.
305 		 */
306 		am335x_ehrpwm_cfg_duty(sc, 0, 0);
307 		am335x_ehrpwm_cfg_duty(sc, 1, 0);
308 	}
309 
310 	return (true);
311 }
312 
313 static void
314 am335x_ehrpwm_freq(struct am335x_ehrpwm_softc *sc)
315 {
316 	int clkdiv;
317 
318 	clkdiv = am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv];
319 	sc->sc_pwm_freq = PWM_CLOCK / (1 * clkdiv) / sc->sc_pwm_period;
320 }
321 
322 static int
323 am335x_ehrpwm_sysctl_freq(SYSCTL_HANDLER_ARGS)
324 {
325 	int clkdiv, error, freq, i, period;
326 	struct am335x_ehrpwm_softc *sc;
327 	uint32_t reg;
328 
329 	sc = (struct am335x_ehrpwm_softc *)arg1;
330 
331 	PWM_LOCK(sc);
332 	freq = sc->sc_pwm_freq;
333 	PWM_UNLOCK(sc);
334 
335 	error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
336 	if (error != 0 || req->newptr == NULL)
337 		return (error);
338 
339 	if (freq > PWM_CLOCK)
340 		freq = PWM_CLOCK;
341 
342 	PWM_LOCK(sc);
343 	if (freq != sc->sc_pwm_freq) {
344 		for (i = nitems(am335x_ehrpwm_clkdiv) - 1; i >= 0; i--) {
345 			clkdiv = am335x_ehrpwm_clkdiv[i];
346 			period = PWM_CLOCK / clkdiv / freq;
347 			if (period > USHRT_MAX)
348 				break;
349 			sc->sc_pwm_clkdiv = i;
350 			sc->sc_pwm_period = period;
351 		}
352 		/* Reset the duty cycle settings. */
353 		sc->sc_pwm_dutyA = 0;
354 		sc->sc_pwm_dutyB = 0;
355 		EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
356 		EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
357 		/* Update the clkdiv settings. */
358 		reg = EPWM_READ2(sc, EPWM_TBCTL);
359 		reg &= ~TBCTL_CLKDIV_MASK;
360 		reg |= TBCTL_CLKDIV(sc->sc_pwm_clkdiv);
361 		EPWM_WRITE2(sc, EPWM_TBCTL, reg);
362 		/* Update the period settings. */
363 		EPWM_WRITE2(sc, EPWM_TBPRD, sc->sc_pwm_period - 1);
364 		am335x_ehrpwm_freq(sc);
365 	}
366 	PWM_UNLOCK(sc);
367 
368 	return (0);
369 }
370 
371 static int
372 am335x_ehrpwm_sysctl_clkdiv(SYSCTL_HANDLER_ARGS)
373 {
374 	int error, i, clkdiv;
375 	struct am335x_ehrpwm_softc *sc;
376 	uint32_t reg;
377 
378 	sc = (struct am335x_ehrpwm_softc *)arg1;
379 
380 	PWM_LOCK(sc);
381 	clkdiv = am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv];
382 	PWM_UNLOCK(sc);
383 
384 	error = sysctl_handle_int(oidp, &clkdiv, sizeof(clkdiv), req);
385 	if (error != 0 || req->newptr == NULL)
386 		return (error);
387 
388 	PWM_LOCK(sc);
389 	if (clkdiv != am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv]) {
390 		for (i = 0; i < nitems(am335x_ehrpwm_clkdiv); i++)
391 			if (clkdiv >= am335x_ehrpwm_clkdiv[i])
392 				sc->sc_pwm_clkdiv = i;
393 
394 		reg = EPWM_READ2(sc, EPWM_TBCTL);
395 		reg &= ~TBCTL_CLKDIV_MASK;
396 		reg |= TBCTL_CLKDIV(sc->sc_pwm_clkdiv);
397 		EPWM_WRITE2(sc, EPWM_TBCTL, reg);
398 		am335x_ehrpwm_freq(sc);
399 	}
400 	PWM_UNLOCK(sc);
401 
402 	return (0);
403 }
404 
405 static int
406 am335x_ehrpwm_sysctl_duty(SYSCTL_HANDLER_ARGS)
407 {
408 	struct am335x_ehrpwm_softc *sc = (struct am335x_ehrpwm_softc*)arg1;
409 	int error;
410 	uint32_t duty;
411 
412 	if (oidp == sc->sc_chanA_oid)
413 		duty = sc->sc_pwm_dutyA;
414 	else
415 		duty = sc->sc_pwm_dutyB;
416 	error = sysctl_handle_int(oidp, &duty, 0, req);
417 
418 	if (error != 0 || req->newptr == NULL)
419 		return (error);
420 
421 	if (duty > sc->sc_pwm_period) {
422 		device_printf(sc->sc_dev, "Duty cycle can't be greater then period\n");
423 		return (EINVAL);
424 	}
425 
426 	PWM_LOCK(sc);
427 	if (oidp == sc->sc_chanA_oid) {
428 		sc->sc_pwm_dutyA = duty;
429 		EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
430 	}
431 	else {
432 		sc->sc_pwm_dutyB = duty;
433 		EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
434 	}
435 	PWM_UNLOCK(sc);
436 
437 	return (error);
438 }
439 
440 static int
441 am335x_ehrpwm_sysctl_period(SYSCTL_HANDLER_ARGS)
442 {
443 	struct am335x_ehrpwm_softc *sc = (struct am335x_ehrpwm_softc*)arg1;
444 	int error;
445 	uint32_t period;
446 
447 	period = sc->sc_pwm_period;
448 	error = sysctl_handle_int(oidp, &period, 0, req);
449 
450 	if (error != 0 || req->newptr == NULL)
451 		return (error);
452 
453 	if (period < 1)
454 		return (EINVAL);
455 
456 	if (period > USHRT_MAX)
457 		period = USHRT_MAX;
458 
459 	PWM_LOCK(sc);
460 	/* Reset the duty cycle settings. */
461 	sc->sc_pwm_dutyA = 0;
462 	sc->sc_pwm_dutyB = 0;
463 	EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
464 	EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
465 	/* Update the period settings. */
466 	sc->sc_pwm_period = period;
467 	EPWM_WRITE2(sc, EPWM_TBPRD, period - 1);
468 	am335x_ehrpwm_freq(sc);
469 	PWM_UNLOCK(sc);
470 
471 	return (error);
472 }
473 
474 static int
475 am335x_ehrpwm_channel_count(device_t dev, u_int *nchannel)
476 {
477 
478 	*nchannel = NUM_CHANNELS;
479 
480 	return (0);
481 }
482 
483 static int
484 am335x_ehrpwm_channel_config(device_t dev, u_int channel, u_int period, u_int duty)
485 {
486 	struct am335x_ehrpwm_softc *sc;
487 	bool status;
488 
489 	if (channel >= NUM_CHANNELS)
490 		return (EINVAL);
491 
492 	sc = device_get_softc(dev);
493 
494 	PWM_LOCK(sc);
495 	status = am335x_ehrpwm_cfg_period(sc, period);
496 	if (status)
497 		am335x_ehrpwm_cfg_duty(sc, channel, duty);
498 	PWM_UNLOCK(sc);
499 
500 	return (status ? 0 : EINVAL);
501 }
502 
503 static int
504 am335x_ehrpwm_channel_get_config(device_t dev, u_int channel,
505     u_int *period, u_int *duty)
506 {
507 	struct am335x_ehrpwm_softc *sc;
508 
509 	if (channel >= NUM_CHANNELS)
510 		return (EINVAL);
511 
512 	sc = device_get_softc(dev);
513 	*period = sc->sc_period;
514 	*duty = sc->sc_channels[channel].duty;
515 	return (0);
516 }
517 
518 static int
519 am335x_ehrpwm_channel_enable(device_t dev, u_int channel, bool enable)
520 {
521 	struct am335x_ehrpwm_softc *sc;
522 
523 	if (channel >= NUM_CHANNELS)
524 		return (EINVAL);
525 
526 	sc = device_get_softc(dev);
527 
528 	PWM_LOCK(sc);
529 	am335x_ehrpwm_cfg_enable(sc, channel, enable);
530 	PWM_UNLOCK(sc);
531 
532 	return (0);
533 }
534 
535 static int
536 am335x_ehrpwm_channel_is_enabled(device_t dev, u_int channel, bool *enabled)
537 {
538 	struct am335x_ehrpwm_softc *sc;
539 
540 	if (channel >= NUM_CHANNELS)
541 		return (EINVAL);
542 
543 	sc = device_get_softc(dev);
544 
545 	*enabled = sc->sc_channels[channel].enabled;
546 
547 	return (0);
548 }
549 
550 static int
551 am335x_ehrpwm_probe(device_t dev)
552 {
553 
554 	if (!ofw_bus_status_okay(dev))
555 		return (ENXIO);
556 
557 	if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
558 		return (ENXIO);
559 
560 	device_set_desc(dev, "AM335x EHRPWM");
561 
562 	return (BUS_PROBE_DEFAULT);
563 }
564 
565 static int
566 am335x_ehrpwm_attach(device_t dev)
567 {
568 	struct am335x_ehrpwm_softc *sc;
569 	uint32_t reg;
570 	struct sysctl_ctx_list *ctx;
571 	struct sysctl_oid *tree;
572 
573 	sc = device_get_softc(dev);
574 	sc->sc_dev = dev;
575 
576 	PWM_LOCK_INIT(sc);
577 
578 	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
579 	    &sc->sc_mem_rid, RF_ACTIVE);
580 	if (sc->sc_mem_res == NULL) {
581 		device_printf(dev, "cannot allocate memory resources\n");
582 		goto fail;
583 	}
584 
585 	/* Init sysctl interface */
586 	ctx = device_get_sysctl_ctx(sc->sc_dev);
587 	tree = device_get_sysctl_tree(sc->sc_dev);
588 
589 	sc->sc_clkdiv_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
590 	    "clkdiv", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
591 	    am335x_ehrpwm_sysctl_clkdiv, "I", "PWM clock prescaler");
592 
593 	sc->sc_freq_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
594 	    "freq", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
595 	    am335x_ehrpwm_sysctl_freq, "I", "PWM frequency");
596 
597 	sc->sc_period_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
598 	    "period", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
599 	    am335x_ehrpwm_sysctl_period, "I", "PWM period");
600 
601 	sc->sc_chanA_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
602 	    "dutyA", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
603 	    am335x_ehrpwm_sysctl_duty, "I", "Channel A duty cycles");
604 
605 	sc->sc_chanB_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
606 	    "dutyB", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
607 	    am335x_ehrpwm_sysctl_duty, "I", "Channel B duty cycles");
608 
609 	/* CONFIGURE EPWM1 */
610 	reg = EPWM_READ2(sc, EPWM_TBCTL);
611 	reg &= ~(TBCTL_CLKDIV_MASK | TBCTL_HSPCLKDIV_MASK);
612 	EPWM_WRITE2(sc, EPWM_TBCTL, reg);
613 
614 	sc->sc_pwm_period = DEFAULT_PWM_PERIOD;
615 	sc->sc_pwm_dutyA = 0;
616 	sc->sc_pwm_dutyB = 0;
617 	am335x_ehrpwm_freq(sc);
618 
619 	EPWM_WRITE2(sc, EPWM_TBPRD, sc->sc_pwm_period - 1);
620 	EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
621 	EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
622 
623 	EPWM_WRITE2(sc, EPWM_AQCTLA, (AQCTL_ZRO_SET | AQCTL_CAU_CLEAR));
624 	EPWM_WRITE2(sc, EPWM_AQCTLB, (AQCTL_ZRO_SET | AQCTL_CBU_CLEAR));
625 
626 	/* START EPWM */
627 	reg &= ~TBCTL_CTRMODE_MASK;
628 	reg |= TBCTL_CTRMODE_UP | TBCTL_FREERUN;
629 	EPWM_WRITE2(sc, EPWM_TBCTL, reg);
630 
631 	EPWM_WRITE2(sc, EPWM_TZCTL, 0xf);
632 	reg = EPWM_READ2(sc, EPWM_TZFLG);
633 
634 	if ((sc->sc_busdev = device_add_child(dev, "pwmbus", -1)) == NULL) {
635 		device_printf(dev, "Cannot add child pwmbus\n");
636 		// This driver can still do things even without the bus child.
637 	}
638 
639 	bus_generic_probe(dev);
640 	return (bus_generic_attach(dev));
641 fail:
642 	PWM_LOCK_DESTROY(sc);
643 	if (sc->sc_mem_res)
644 		bus_release_resource(dev, SYS_RES_MEMORY,
645 		    sc->sc_mem_rid, sc->sc_mem_res);
646 
647 	return(ENXIO);
648 }
649 
650 static int
651 am335x_ehrpwm_detach(device_t dev)
652 {
653 	struct am335x_ehrpwm_softc *sc;
654 	int error;
655 
656 	sc = device_get_softc(dev);
657 
658 	if ((error = bus_generic_detach(sc->sc_dev)) != 0)
659 		return (error);
660 
661 	PWM_LOCK(sc);
662 
663 	if (sc->sc_busdev != NULL)
664 		device_delete_child(dev, sc->sc_busdev);
665 
666 	if (sc->sc_mem_res)
667 		bus_release_resource(dev, SYS_RES_MEMORY,
668 		    sc->sc_mem_rid, sc->sc_mem_res);
669 
670 	PWM_UNLOCK(sc);
671 
672 	PWM_LOCK_DESTROY(sc);
673 
674 	return (0);
675 }
676 
677 static phandle_t
678 am335x_ehrpwm_get_node(device_t bus, device_t dev)
679 {
680 
681 	/*
682 	 * Share our controller node with our pwmbus child; it instantiates
683 	 * devices by walking the children contained within our node.
684 	 */
685 	return ofw_bus_get_node(bus);
686 }
687 
688 static device_method_t am335x_ehrpwm_methods[] = {
689 	DEVMETHOD(device_probe,		am335x_ehrpwm_probe),
690 	DEVMETHOD(device_attach,	am335x_ehrpwm_attach),
691 	DEVMETHOD(device_detach,	am335x_ehrpwm_detach),
692 
693 	/* ofw_bus_if */
694 	DEVMETHOD(ofw_bus_get_node,	am335x_ehrpwm_get_node),
695 
696 	/* pwm interface */
697 	DEVMETHOD(pwmbus_channel_count,		am335x_ehrpwm_channel_count),
698 	DEVMETHOD(pwmbus_channel_config,	am335x_ehrpwm_channel_config),
699 	DEVMETHOD(pwmbus_channel_get_config,	am335x_ehrpwm_channel_get_config),
700 	DEVMETHOD(pwmbus_channel_enable,	am335x_ehrpwm_channel_enable),
701 	DEVMETHOD(pwmbus_channel_is_enabled,	am335x_ehrpwm_channel_is_enabled),
702 
703 	DEVMETHOD_END
704 };
705 
706 static driver_t am335x_ehrpwm_driver = {
707 	"pwm",
708 	am335x_ehrpwm_methods,
709 	sizeof(struct am335x_ehrpwm_softc),
710 };
711 
712 static devclass_t am335x_ehrpwm_devclass;
713 
714 DRIVER_MODULE(am335x_ehrpwm, am335x_pwmss, am335x_ehrpwm_driver, am335x_ehrpwm_devclass, 0, 0);
715 SIMPLEBUS_PNP_INFO(compat_data);
716 MODULE_VERSION(am335x_ehrpwm, 1);
717 MODULE_DEPEND(am335x_ehrpwm, am335x_pwmss, 1, 1, 1);
718 MODULE_DEPEND(am335x_ehrpwm, pwmbus, 1, 1, 1);
719