xref: /freebsd/sys/arm/ti/am335x/am335x_ehrpwm.c (revision 7cc42f6d)
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 SIMPLEBUS_PNP_INFO(compat_data);
203 
204 static void
205 am335x_ehrpwm_cfg_duty(struct am335x_ehrpwm_softc *sc, u_int chan, u_int duty)
206 {
207 	u_int tbcmp;
208 
209 	if (duty == 0)
210 		tbcmp = 0;
211 	else
212 		tbcmp = max(1, duty / sc->sc_clktick);
213 
214 	sc->sc_channels[chan].duty = tbcmp * sc->sc_clktick;
215 
216 	PWM_LOCK_ASSERT(sc);
217 	EPWM_WRITE2(sc, (chan == 0) ? EPWM_CMPA : EPWM_CMPB, tbcmp);
218 }
219 
220 static void
221 am335x_ehrpwm_cfg_enable(struct am335x_ehrpwm_softc *sc, u_int chan, bool enable)
222 {
223 	uint16_t regval;
224 
225 	sc->sc_channels[chan].enabled = enable;
226 
227 	/*
228 	 * Turn off any existing software-force of the channel, then force
229 	 * it in the right direction (high or low) if it's not being enabled.
230 	 */
231 	PWM_LOCK_ASSERT(sc);
232 	regval = EPWM_READ2(sc, EPWM_AQCSFRC);
233 	regval &= ~AQCSFRC(chan, AQCSFRC_MASK);
234 	if (!sc->sc_channels[chan].enabled) {
235 		if (sc->sc_channels[chan].inverted)
236 			regval |= AQCSFRC(chan, AQCSFRC_HI);
237 		else
238 			regval |= AQCSFRC(chan, AQCSFRC_LO);
239 	}
240 	EPWM_WRITE2(sc, EPWM_AQCSFRC, regval);
241 }
242 
243 static bool
244 am335x_ehrpwm_cfg_period(struct am335x_ehrpwm_softc *sc, u_int period)
245 {
246 	uint16_t regval;
247 	u_int clkdiv, hspclkdiv, pwmclk, pwmtick, tbprd;
248 
249 	/* Can't do a period shorter than 2 clock ticks. */
250 	if (period < 2 * NS_PER_SEC / PWM_CLOCK) {
251 		sc->sc_clkfreq = 0;
252 		sc->sc_clktick = 0;
253 		sc->sc_period  = 0;
254 		return (false);
255 	}
256 
257 	/*
258 	 * Figure out how much we have to divide down the base 100MHz clock so
259 	 * that we can express the requested period as a 16-bit tick count.
260 	 */
261 	tbprd = 0;
262 	for (clkdiv = 0; clkdiv < 8; ++clkdiv) {
263 		const u_int cd = 1 << clkdiv;
264 		for (hspclkdiv = 0; hspclkdiv < 8; ++hspclkdiv) {
265 			const u_int cdhs = max(1, hspclkdiv * 2);
266 			pwmclk = PWM_CLOCK / (cd * cdhs);
267 			pwmtick = NS_PER_SEC / pwmclk;
268 			if (period / pwmtick < 65536) {
269 				tbprd = period / pwmtick;
270 				break;
271 			}
272 		}
273 		if (tbprd != 0)
274 			break;
275 	}
276 
277 	/* Handle requested period too long for available clock divisors. */
278 	if (tbprd == 0)
279 		return (false);
280 
281 	/*
282 	 * If anything has changed from the current settings, reprogram the
283 	 * clock divisors and period register.
284 	 */
285 	if (sc->sc_clkfreq != pwmclk || sc->sc_clktick != pwmtick ||
286 	    sc->sc_period != tbprd * pwmtick) {
287 		sc->sc_clkfreq = pwmclk;
288 		sc->sc_clktick = pwmtick;
289 		sc->sc_period  = tbprd * pwmtick;
290 
291 		PWM_LOCK_ASSERT(sc);
292 		regval = EPWM_READ2(sc, EPWM_TBCTL);
293 		regval &= ~(TBCTL_CLKDIV_MASK | TBCTL_HSPCLKDIV_MASK);
294 		regval |= TBCTL_CLKDIV(clkdiv) | TBCTL_HSPCLKDIV(hspclkdiv);
295 		EPWM_WRITE2(sc, EPWM_TBCTL, regval);
296 		EPWM_WRITE2(sc, EPWM_TBPRD, tbprd - 1);
297 #if 0
298 		device_printf(sc->sc_dev, "clkdiv %u hspclkdiv %u tbprd %u "
299 		    "clkfreq %u Hz clktick %u ns period got %u requested %u\n",
300 		    clkdiv, hspclkdiv, tbprd - 1,
301 		    sc->sc_clkfreq, sc->sc_clktick, sc->sc_period, period);
302 #endif
303 		/*
304 		 * If the period changed, that invalidates the current CMP
305 		 * registers (duty values), just zero them out.
306 		 */
307 		am335x_ehrpwm_cfg_duty(sc, 0, 0);
308 		am335x_ehrpwm_cfg_duty(sc, 1, 0);
309 	}
310 
311 	return (true);
312 }
313 
314 static void
315 am335x_ehrpwm_freq(struct am335x_ehrpwm_softc *sc)
316 {
317 	int clkdiv;
318 
319 	clkdiv = am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv];
320 	sc->sc_pwm_freq = PWM_CLOCK / (1 * clkdiv) / sc->sc_pwm_period;
321 }
322 
323 static int
324 am335x_ehrpwm_sysctl_freq(SYSCTL_HANDLER_ARGS)
325 {
326 	int clkdiv, error, freq, i, period;
327 	struct am335x_ehrpwm_softc *sc;
328 	uint32_t reg;
329 
330 	sc = (struct am335x_ehrpwm_softc *)arg1;
331 
332 	PWM_LOCK(sc);
333 	freq = sc->sc_pwm_freq;
334 	PWM_UNLOCK(sc);
335 
336 	error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
337 	if (error != 0 || req->newptr == NULL)
338 		return (error);
339 
340 	if (freq > PWM_CLOCK)
341 		freq = PWM_CLOCK;
342 
343 	PWM_LOCK(sc);
344 	if (freq != sc->sc_pwm_freq) {
345 		for (i = nitems(am335x_ehrpwm_clkdiv) - 1; i >= 0; i--) {
346 			clkdiv = am335x_ehrpwm_clkdiv[i];
347 			period = PWM_CLOCK / clkdiv / freq;
348 			if (period > USHRT_MAX)
349 				break;
350 			sc->sc_pwm_clkdiv = i;
351 			sc->sc_pwm_period = period;
352 		}
353 		/* Reset the duty cycle settings. */
354 		sc->sc_pwm_dutyA = 0;
355 		sc->sc_pwm_dutyB = 0;
356 		EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
357 		EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
358 		/* Update the clkdiv settings. */
359 		reg = EPWM_READ2(sc, EPWM_TBCTL);
360 		reg &= ~TBCTL_CLKDIV_MASK;
361 		reg |= TBCTL_CLKDIV(sc->sc_pwm_clkdiv);
362 		EPWM_WRITE2(sc, EPWM_TBCTL, reg);
363 		/* Update the period settings. */
364 		EPWM_WRITE2(sc, EPWM_TBPRD, sc->sc_pwm_period - 1);
365 		am335x_ehrpwm_freq(sc);
366 	}
367 	PWM_UNLOCK(sc);
368 
369 	return (0);
370 }
371 
372 static int
373 am335x_ehrpwm_sysctl_clkdiv(SYSCTL_HANDLER_ARGS)
374 {
375 	int error, i, clkdiv;
376 	struct am335x_ehrpwm_softc *sc;
377 	uint32_t reg;
378 
379 	sc = (struct am335x_ehrpwm_softc *)arg1;
380 
381 	PWM_LOCK(sc);
382 	clkdiv = am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv];
383 	PWM_UNLOCK(sc);
384 
385 	error = sysctl_handle_int(oidp, &clkdiv, sizeof(clkdiv), req);
386 	if (error != 0 || req->newptr == NULL)
387 		return (error);
388 
389 	PWM_LOCK(sc);
390 	if (clkdiv != am335x_ehrpwm_clkdiv[sc->sc_pwm_clkdiv]) {
391 		for (i = 0; i < nitems(am335x_ehrpwm_clkdiv); i++)
392 			if (clkdiv >= am335x_ehrpwm_clkdiv[i])
393 				sc->sc_pwm_clkdiv = i;
394 
395 		reg = EPWM_READ2(sc, EPWM_TBCTL);
396 		reg &= ~TBCTL_CLKDIV_MASK;
397 		reg |= TBCTL_CLKDIV(sc->sc_pwm_clkdiv);
398 		EPWM_WRITE2(sc, EPWM_TBCTL, reg);
399 		am335x_ehrpwm_freq(sc);
400 	}
401 	PWM_UNLOCK(sc);
402 
403 	return (0);
404 }
405 
406 static int
407 am335x_ehrpwm_sysctl_duty(SYSCTL_HANDLER_ARGS)
408 {
409 	struct am335x_ehrpwm_softc *sc = (struct am335x_ehrpwm_softc*)arg1;
410 	int error;
411 	uint32_t duty;
412 
413 	if (oidp == sc->sc_chanA_oid)
414 		duty = sc->sc_pwm_dutyA;
415 	else
416 		duty = sc->sc_pwm_dutyB;
417 	error = sysctl_handle_int(oidp, &duty, 0, req);
418 
419 	if (error != 0 || req->newptr == NULL)
420 		return (error);
421 
422 	if (duty > sc->sc_pwm_period) {
423 		device_printf(sc->sc_dev, "Duty cycle can't be greater then period\n");
424 		return (EINVAL);
425 	}
426 
427 	PWM_LOCK(sc);
428 	if (oidp == sc->sc_chanA_oid) {
429 		sc->sc_pwm_dutyA = duty;
430 		EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
431 	}
432 	else {
433 		sc->sc_pwm_dutyB = duty;
434 		EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
435 	}
436 	PWM_UNLOCK(sc);
437 
438 	return (error);
439 }
440 
441 static int
442 am335x_ehrpwm_sysctl_period(SYSCTL_HANDLER_ARGS)
443 {
444 	struct am335x_ehrpwm_softc *sc = (struct am335x_ehrpwm_softc*)arg1;
445 	int error;
446 	uint32_t period;
447 
448 	period = sc->sc_pwm_period;
449 	error = sysctl_handle_int(oidp, &period, 0, req);
450 
451 	if (error != 0 || req->newptr == NULL)
452 		return (error);
453 
454 	if (period < 1)
455 		return (EINVAL);
456 
457 	if (period > USHRT_MAX)
458 		period = USHRT_MAX;
459 
460 	PWM_LOCK(sc);
461 	/* Reset the duty cycle settings. */
462 	sc->sc_pwm_dutyA = 0;
463 	sc->sc_pwm_dutyB = 0;
464 	EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
465 	EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
466 	/* Update the period settings. */
467 	sc->sc_pwm_period = period;
468 	EPWM_WRITE2(sc, EPWM_TBPRD, period - 1);
469 	am335x_ehrpwm_freq(sc);
470 	PWM_UNLOCK(sc);
471 
472 	return (error);
473 }
474 
475 static int
476 am335x_ehrpwm_channel_count(device_t dev, u_int *nchannel)
477 {
478 
479 	*nchannel = NUM_CHANNELS;
480 
481 	return (0);
482 }
483 
484 static int
485 am335x_ehrpwm_channel_config(device_t dev, u_int channel, u_int period, u_int duty)
486 {
487 	struct am335x_ehrpwm_softc *sc;
488 	bool status;
489 
490 	if (channel >= NUM_CHANNELS)
491 		return (EINVAL);
492 
493 	sc = device_get_softc(dev);
494 
495 	PWM_LOCK(sc);
496 	status = am335x_ehrpwm_cfg_period(sc, period);
497 	if (status)
498 		am335x_ehrpwm_cfg_duty(sc, channel, duty);
499 	PWM_UNLOCK(sc);
500 
501 	return (status ? 0 : EINVAL);
502 }
503 
504 static int
505 am335x_ehrpwm_channel_get_config(device_t dev, u_int channel,
506     u_int *period, u_int *duty)
507 {
508 	struct am335x_ehrpwm_softc *sc;
509 
510 	if (channel >= NUM_CHANNELS)
511 		return (EINVAL);
512 
513 	sc = device_get_softc(dev);
514 	*period = sc->sc_period;
515 	*duty = sc->sc_channels[channel].duty;
516 	return (0);
517 }
518 
519 static int
520 am335x_ehrpwm_channel_enable(device_t dev, u_int channel, bool enable)
521 {
522 	struct am335x_ehrpwm_softc *sc;
523 
524 	if (channel >= NUM_CHANNELS)
525 		return (EINVAL);
526 
527 	sc = device_get_softc(dev);
528 
529 	PWM_LOCK(sc);
530 	am335x_ehrpwm_cfg_enable(sc, channel, enable);
531 	PWM_UNLOCK(sc);
532 
533 	return (0);
534 }
535 
536 static int
537 am335x_ehrpwm_channel_is_enabled(device_t dev, u_int channel, bool *enabled)
538 {
539 	struct am335x_ehrpwm_softc *sc;
540 
541 	if (channel >= NUM_CHANNELS)
542 		return (EINVAL);
543 
544 	sc = device_get_softc(dev);
545 
546 	*enabled = sc->sc_channels[channel].enabled;
547 
548 	return (0);
549 }
550 
551 static int
552 am335x_ehrpwm_probe(device_t dev)
553 {
554 
555 	if (!ofw_bus_status_okay(dev))
556 		return (ENXIO);
557 
558 	if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
559 		return (ENXIO);
560 
561 	device_set_desc(dev, "AM335x EHRPWM");
562 
563 	return (BUS_PROBE_DEFAULT);
564 }
565 
566 static int
567 am335x_ehrpwm_attach(device_t dev)
568 {
569 	struct am335x_ehrpwm_softc *sc;
570 	uint32_t reg;
571 	struct sysctl_ctx_list *ctx;
572 	struct sysctl_oid *tree;
573 
574 	sc = device_get_softc(dev);
575 	sc->sc_dev = dev;
576 
577 	PWM_LOCK_INIT(sc);
578 
579 	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
580 	    &sc->sc_mem_rid, RF_ACTIVE);
581 	if (sc->sc_mem_res == NULL) {
582 		device_printf(dev, "cannot allocate memory resources\n");
583 		goto fail;
584 	}
585 
586 	/* Init sysctl interface */
587 	ctx = device_get_sysctl_ctx(sc->sc_dev);
588 	tree = device_get_sysctl_tree(sc->sc_dev);
589 
590 	sc->sc_clkdiv_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
591 	    "clkdiv", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
592 	    am335x_ehrpwm_sysctl_clkdiv, "I", "PWM clock prescaler");
593 
594 	sc->sc_freq_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
595 	    "freq", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
596 	    am335x_ehrpwm_sysctl_freq, "I", "PWM frequency");
597 
598 	sc->sc_period_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
599 	    "period", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
600 	    am335x_ehrpwm_sysctl_period, "I", "PWM period");
601 
602 	sc->sc_chanA_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
603 	    "dutyA", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
604 	    am335x_ehrpwm_sysctl_duty, "I", "Channel A duty cycles");
605 
606 	sc->sc_chanB_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
607 	    "dutyB", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, sc, 0,
608 	    am335x_ehrpwm_sysctl_duty, "I", "Channel B duty cycles");
609 
610 	/* CONFIGURE EPWM1 */
611 	reg = EPWM_READ2(sc, EPWM_TBCTL);
612 	reg &= ~(TBCTL_CLKDIV_MASK | TBCTL_HSPCLKDIV_MASK);
613 	EPWM_WRITE2(sc, EPWM_TBCTL, reg);
614 
615 	sc->sc_pwm_period = DEFAULT_PWM_PERIOD;
616 	sc->sc_pwm_dutyA = 0;
617 	sc->sc_pwm_dutyB = 0;
618 	am335x_ehrpwm_freq(sc);
619 
620 	EPWM_WRITE2(sc, EPWM_TBPRD, sc->sc_pwm_period - 1);
621 	EPWM_WRITE2(sc, EPWM_CMPA, sc->sc_pwm_dutyA);
622 	EPWM_WRITE2(sc, EPWM_CMPB, sc->sc_pwm_dutyB);
623 
624 	EPWM_WRITE2(sc, EPWM_AQCTLA, (AQCTL_ZRO_SET | AQCTL_CAU_CLEAR));
625 	EPWM_WRITE2(sc, EPWM_AQCTLB, (AQCTL_ZRO_SET | AQCTL_CBU_CLEAR));
626 
627 	/* START EPWM */
628 	reg &= ~TBCTL_CTRMODE_MASK;
629 	reg |= TBCTL_CTRMODE_UP | TBCTL_FREERUN;
630 	EPWM_WRITE2(sc, EPWM_TBCTL, reg);
631 
632 	EPWM_WRITE2(sc, EPWM_TZCTL, 0xf);
633 	reg = EPWM_READ2(sc, EPWM_TZFLG);
634 
635 	if ((sc->sc_busdev = device_add_child(dev, "pwmbus", -1)) == NULL) {
636 		device_printf(dev, "Cannot add child pwmbus\n");
637 		// This driver can still do things even without the bus child.
638 	}
639 
640 	bus_generic_probe(dev);
641 	return (bus_generic_attach(dev));
642 fail:
643 	PWM_LOCK_DESTROY(sc);
644 	if (sc->sc_mem_res)
645 		bus_release_resource(dev, SYS_RES_MEMORY,
646 		    sc->sc_mem_rid, sc->sc_mem_res);
647 
648 	return(ENXIO);
649 }
650 
651 static int
652 am335x_ehrpwm_detach(device_t dev)
653 {
654 	struct am335x_ehrpwm_softc *sc;
655 	int error;
656 
657 	sc = device_get_softc(dev);
658 
659 	if ((error = bus_generic_detach(sc->sc_dev)) != 0)
660 		return (error);
661 
662 	PWM_LOCK(sc);
663 
664 	if (sc->sc_busdev != NULL)
665 		device_delete_child(dev, sc->sc_busdev);
666 
667 	if (sc->sc_mem_res)
668 		bus_release_resource(dev, SYS_RES_MEMORY,
669 		    sc->sc_mem_rid, sc->sc_mem_res);
670 
671 	PWM_UNLOCK(sc);
672 
673 	PWM_LOCK_DESTROY(sc);
674 
675 	return (0);
676 }
677 
678 static phandle_t
679 am335x_ehrpwm_get_node(device_t bus, device_t dev)
680 {
681 
682 	/*
683 	 * Share our controller node with our pwmbus child; it instantiates
684 	 * devices by walking the children contained within our node.
685 	 */
686 	return ofw_bus_get_node(bus);
687 }
688 
689 static device_method_t am335x_ehrpwm_methods[] = {
690 	DEVMETHOD(device_probe,		am335x_ehrpwm_probe),
691 	DEVMETHOD(device_attach,	am335x_ehrpwm_attach),
692 	DEVMETHOD(device_detach,	am335x_ehrpwm_detach),
693 
694 	/* ofw_bus_if */
695 	DEVMETHOD(ofw_bus_get_node,	am335x_ehrpwm_get_node),
696 
697 	/* pwm interface */
698 	DEVMETHOD(pwmbus_channel_count,		am335x_ehrpwm_channel_count),
699 	DEVMETHOD(pwmbus_channel_config,	am335x_ehrpwm_channel_config),
700 	DEVMETHOD(pwmbus_channel_get_config,	am335x_ehrpwm_channel_get_config),
701 	DEVMETHOD(pwmbus_channel_enable,	am335x_ehrpwm_channel_enable),
702 	DEVMETHOD(pwmbus_channel_is_enabled,	am335x_ehrpwm_channel_is_enabled),
703 
704 	DEVMETHOD_END
705 };
706 
707 static driver_t am335x_ehrpwm_driver = {
708 	"pwm",
709 	am335x_ehrpwm_methods,
710 	sizeof(struct am335x_ehrpwm_softc),
711 };
712 
713 static devclass_t am335x_ehrpwm_devclass;
714 
715 DRIVER_MODULE(am335x_ehrpwm, am335x_pwmss, am335x_ehrpwm_driver, am335x_ehrpwm_devclass, 0, 0);
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