xref: /openbmc/linux/drivers/pwm/pwm-fsl-ftm.c (revision 45cc35e8) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Freescale FlexTimer Module (FTM) PWM Driver
4  *
5  *  Copyright 2012-2013 Freescale Semiconductor, Inc.
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/err.h>
10 #include <linux/io.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/of_address.h>
15 #include <linux/of_device.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm.h>
18 #include <linux/pwm.h>
19 #include <linux/regmap.h>
20 #include <linux/slab.h>
21 #include <linux/fsl/ftm.h>
22 
23 #define FTM_SC_CLK(c)	(((c) + 1) << FTM_SC_CLK_MASK_SHIFT)
24 
25 enum fsl_pwm_clk {
26 	FSL_PWM_CLK_SYS,
27 	FSL_PWM_CLK_FIX,
28 	FSL_PWM_CLK_EXT,
29 	FSL_PWM_CLK_CNTEN,
30 	FSL_PWM_CLK_MAX
31 };
32 
33 struct fsl_ftm_soc {
34 	bool has_enable_bits;
35 };
36 
37 struct fsl_pwm_periodcfg {
38 	enum fsl_pwm_clk clk_select;
39 	unsigned int clk_ps;
40 	unsigned int mod_period;
41 };
42 
43 struct fsl_pwm_chip {
44 	struct pwm_chip chip;
45 	struct mutex lock;
46 	struct regmap *regmap;
47 
48 	/* This value is valid iff a pwm is running */
49 	struct fsl_pwm_periodcfg period;
50 
51 	struct clk *ipg_clk;
52 	struct clk *clk[FSL_PWM_CLK_MAX];
53 
54 	const struct fsl_ftm_soc *soc;
55 };
56 
57 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
58 {
59 	return container_of(chip, struct fsl_pwm_chip, chip);
60 }
61 
62 static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
63 {
64 	u32 val;
65 
66 	regmap_read(fpc->regmap, FTM_FMS, &val);
67 	if (val & FTM_FMS_WPEN)
68 		regmap_set_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS);
69 }
70 
71 static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
72 {
73 	regmap_set_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN);
74 }
75 
76 static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
77 					const struct fsl_pwm_periodcfg *b)
78 {
79 	if (a->clk_select != b->clk_select)
80 		return false;
81 	if (a->clk_ps != b->clk_ps)
82 		return false;
83 	if (a->mod_period != b->mod_period)
84 		return false;
85 	return true;
86 }
87 
88 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
89 {
90 	int ret;
91 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
92 
93 	ret = clk_prepare_enable(fpc->ipg_clk);
94 	if (!ret && fpc->soc->has_enable_bits) {
95 		mutex_lock(&fpc->lock);
96 		regmap_set_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16));
97 		mutex_unlock(&fpc->lock);
98 	}
99 
100 	return ret;
101 }
102 
103 static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
104 {
105 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
106 
107 	if (fpc->soc->has_enable_bits) {
108 		mutex_lock(&fpc->lock);
109 		regmap_clear_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16));
110 		mutex_unlock(&fpc->lock);
111 	}
112 
113 	clk_disable_unprepare(fpc->ipg_clk);
114 }
115 
116 static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
117 					  unsigned int ticks)
118 {
119 	unsigned long rate;
120 	unsigned long long exval;
121 
122 	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
123 	exval = ticks;
124 	exval *= 1000000000UL;
125 	do_div(exval, rate >> fpc->period.clk_ps);
126 	return exval;
127 }
128 
129 static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
130 					 unsigned int period_ns,
131 					 enum fsl_pwm_clk index,
132 					 struct fsl_pwm_periodcfg *periodcfg
133 					 )
134 {
135 	unsigned long long c;
136 	unsigned int ps;
137 
138 	c = clk_get_rate(fpc->clk[index]);
139 	c = c * period_ns;
140 	do_div(c, 1000000000UL);
141 
142 	if (c == 0)
143 		return false;
144 
145 	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
146 		if (c <= 0x10000) {
147 			periodcfg->clk_select = index;
148 			periodcfg->clk_ps = ps;
149 			periodcfg->mod_period = c - 1;
150 			return true;
151 		}
152 	}
153 	return false;
154 }
155 
156 static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
157 				     unsigned int period_ns,
158 				     struct fsl_pwm_periodcfg *periodcfg)
159 {
160 	enum fsl_pwm_clk m0, m1;
161 	unsigned long fix_rate, ext_rate;
162 	bool ret;
163 
164 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
165 					   periodcfg);
166 	if (ret)
167 		return true;
168 
169 	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
170 	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
171 
172 	if (fix_rate > ext_rate) {
173 		m0 = FSL_PWM_CLK_FIX;
174 		m1 = FSL_PWM_CLK_EXT;
175 	} else {
176 		m0 = FSL_PWM_CLK_EXT;
177 		m1 = FSL_PWM_CLK_FIX;
178 	}
179 
180 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
181 	if (ret)
182 		return true;
183 
184 	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
185 }
186 
187 static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
188 					   unsigned int duty_ns)
189 {
190 	unsigned long long duty;
191 
192 	unsigned int period = fpc->period.mod_period + 1;
193 	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
194 
195 	duty = (unsigned long long)duty_ns * period;
196 	do_div(duty, period_ns);
197 
198 	return (unsigned int)duty;
199 }
200 
201 static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
202 				       struct pwm_device *pwm)
203 {
204 	u32 val;
205 
206 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
207 	if (~val & 0xFF)
208 		return true;
209 	else
210 		return false;
211 }
212 
213 static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
214 					 struct pwm_device *pwm)
215 {
216 	u32 val;
217 
218 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
219 	if (~(val | BIT(pwm->hwpwm)) & 0xFF)
220 		return true;
221 	else
222 		return false;
223 }
224 
225 static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
226 				struct pwm_device *pwm,
227 				const struct pwm_state *newstate)
228 {
229 	unsigned int duty;
230 	u32 reg_polarity;
231 
232 	struct fsl_pwm_periodcfg periodcfg;
233 	bool do_write_period = false;
234 
235 	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
236 		dev_err(fpc->chip.dev, "failed to calculate new period\n");
237 		return -EINVAL;
238 	}
239 
240 	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
241 		do_write_period = true;
242 	/*
243 	 * The Freescale FTM controller supports only a single period for
244 	 * all PWM channels, therefore verify if the newly computed period
245 	 * is different than the current period being used. In such case
246 	 * we allow to change the period only if no other pwm is running.
247 	 */
248 	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
249 		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
250 			dev_err(fpc->chip.dev,
251 				"Cannot change period for PWM %u, disable other PWMs first\n",
252 				pwm->hwpwm);
253 			return -EBUSY;
254 		}
255 		if (fpc->period.clk_select != periodcfg.clk_select) {
256 			int ret;
257 			enum fsl_pwm_clk oldclk = fpc->period.clk_select;
258 			enum fsl_pwm_clk newclk = periodcfg.clk_select;
259 
260 			ret = clk_prepare_enable(fpc->clk[newclk]);
261 			if (ret)
262 				return ret;
263 			clk_disable_unprepare(fpc->clk[oldclk]);
264 		}
265 		do_write_period = true;
266 	}
267 
268 	ftm_clear_write_protection(fpc);
269 
270 	if (do_write_period) {
271 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
272 				   FTM_SC_CLK(periodcfg.clk_select));
273 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
274 				   periodcfg.clk_ps);
275 		regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);
276 
277 		fpc->period = periodcfg;
278 	}
279 
280 	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);
281 
282 	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
283 		     FTM_CSC_MSB | FTM_CSC_ELSB);
284 	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
285 
286 	reg_polarity = 0;
287 	if (newstate->polarity == PWM_POLARITY_INVERSED)
288 		reg_polarity = BIT(pwm->hwpwm);
289 
290 	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);
291 
292 	ftm_set_write_protection(fpc);
293 
294 	return 0;
295 }
296 
297 static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
298 			 const struct pwm_state *newstate)
299 {
300 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
301 	struct pwm_state *oldstate = &pwm->state;
302 	int ret = 0;
303 
304 	/*
305 	 * oldstate to newstate : action
306 	 *
307 	 * disabled to disabled : ignore
308 	 * enabled to disabled : disable
309 	 * enabled to enabled : update settings
310 	 * disabled to enabled : update settings + enable
311 	 */
312 
313 	mutex_lock(&fpc->lock);
314 
315 	if (!newstate->enabled) {
316 		if (oldstate->enabled) {
317 			regmap_set_bits(fpc->regmap, FTM_OUTMASK,
318 					BIT(pwm->hwpwm));
319 			clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
320 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
321 		}
322 
323 		goto end_mutex;
324 	}
325 
326 	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
327 	if (ret)
328 		goto end_mutex;
329 
330 	/* check if need to enable */
331 	if (!oldstate->enabled) {
332 		ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
333 		if (ret)
334 			goto end_mutex;
335 
336 		ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
337 		if (ret) {
338 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
339 			goto end_mutex;
340 		}
341 
342 		regmap_clear_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm));
343 	}
344 
345 end_mutex:
346 	mutex_unlock(&fpc->lock);
347 	return ret;
348 }
349 
350 static const struct pwm_ops fsl_pwm_ops = {
351 	.request = fsl_pwm_request,
352 	.free = fsl_pwm_free,
353 	.apply = fsl_pwm_apply,
354 	.owner = THIS_MODULE,
355 };
356 
357 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
358 {
359 	int ret;
360 
361 	ret = clk_prepare_enable(fpc->ipg_clk);
362 	if (ret)
363 		return ret;
364 
365 	regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
366 	regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
367 	regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);
368 
369 	clk_disable_unprepare(fpc->ipg_clk);
370 
371 	return 0;
372 }
373 
374 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
375 {
376 	switch (reg) {
377 	case FTM_FMS:
378 	case FTM_MODE:
379 	case FTM_CNT:
380 		return true;
381 	}
382 	return false;
383 }
384 
385 static const struct regmap_config fsl_pwm_regmap_config = {
386 	.reg_bits = 32,
387 	.reg_stride = 4,
388 	.val_bits = 32,
389 
390 	.max_register = FTM_PWMLOAD,
391 	.volatile_reg = fsl_pwm_volatile_reg,
392 	.cache_type = REGCACHE_FLAT,
393 };
394 
395 static int fsl_pwm_probe(struct platform_device *pdev)
396 {
397 	struct fsl_pwm_chip *fpc;
398 	void __iomem *base;
399 	int ret;
400 
401 	fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
402 	if (!fpc)
403 		return -ENOMEM;
404 
405 	mutex_init(&fpc->lock);
406 
407 	fpc->soc = of_device_get_match_data(&pdev->dev);
408 	fpc->chip.dev = &pdev->dev;
409 
410 	base = devm_platform_ioremap_resource(pdev, 0);
411 	if (IS_ERR(base))
412 		return PTR_ERR(base);
413 
414 	fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
415 						&fsl_pwm_regmap_config);
416 	if (IS_ERR(fpc->regmap)) {
417 		dev_err(&pdev->dev, "regmap init failed\n");
418 		return PTR_ERR(fpc->regmap);
419 	}
420 
421 	fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
422 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
423 		dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
424 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
425 	}
426 
427 	fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
428 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
429 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
430 
431 	fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
432 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
433 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
434 
435 	fpc->clk[FSL_PWM_CLK_CNTEN] =
436 				devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
437 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
438 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
439 
440 	/*
441 	 * ipg_clk is the interface clock for the IP. If not provided, use the
442 	 * ftm_sys clock as the default.
443 	 */
444 	fpc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
445 	if (IS_ERR(fpc->ipg_clk))
446 		fpc->ipg_clk = fpc->clk[FSL_PWM_CLK_SYS];
447 
448 
449 	fpc->chip.ops = &fsl_pwm_ops;
450 	fpc->chip.npwm = 8;
451 
452 	ret = devm_pwmchip_add(&pdev->dev, &fpc->chip);
453 	if (ret < 0) {
454 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
455 		return ret;
456 	}
457 
458 	platform_set_drvdata(pdev, fpc);
459 
460 	return fsl_pwm_init(fpc);
461 }
462 
463 #ifdef CONFIG_PM_SLEEP
464 static int fsl_pwm_suspend(struct device *dev)
465 {
466 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
467 	int i;
468 
469 	regcache_cache_only(fpc->regmap, true);
470 	regcache_mark_dirty(fpc->regmap);
471 
472 	for (i = 0; i < fpc->chip.npwm; i++) {
473 		struct pwm_device *pwm = &fpc->chip.pwms[i];
474 
475 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
476 			continue;
477 
478 		clk_disable_unprepare(fpc->ipg_clk);
479 
480 		if (!pwm_is_enabled(pwm))
481 			continue;
482 
483 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
484 		clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
485 	}
486 
487 	return 0;
488 }
489 
490 static int fsl_pwm_resume(struct device *dev)
491 {
492 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
493 	int i;
494 
495 	for (i = 0; i < fpc->chip.npwm; i++) {
496 		struct pwm_device *pwm = &fpc->chip.pwms[i];
497 
498 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
499 			continue;
500 
501 		clk_prepare_enable(fpc->ipg_clk);
502 
503 		if (!pwm_is_enabled(pwm))
504 			continue;
505 
506 		clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
507 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
508 	}
509 
510 	/* restore all registers from cache */
511 	regcache_cache_only(fpc->regmap, false);
512 	regcache_sync(fpc->regmap);
513 
514 	return 0;
515 }
516 #endif
517 
518 static const struct dev_pm_ops fsl_pwm_pm_ops = {
519 	SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
520 };
521 
522 static const struct fsl_ftm_soc vf610_ftm_pwm = {
523 	.has_enable_bits = false,
524 };
525 
526 static const struct fsl_ftm_soc imx8qm_ftm_pwm = {
527 	.has_enable_bits = true,
528 };
529 
530 static const struct of_device_id fsl_pwm_dt_ids[] = {
531 	{ .compatible = "fsl,vf610-ftm-pwm", .data = &vf610_ftm_pwm },
532 	{ .compatible = "fsl,imx8qm-ftm-pwm", .data = &imx8qm_ftm_pwm },
533 	{ /* sentinel */ }
534 };
535 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
536 
537 static struct platform_driver fsl_pwm_driver = {
538 	.driver = {
539 		.name = "fsl-ftm-pwm",
540 		.of_match_table = fsl_pwm_dt_ids,
541 		.pm = &fsl_pwm_pm_ops,
542 	},
543 	.probe = fsl_pwm_probe,
544 };
545 module_platform_driver(fsl_pwm_driver);
546 
547 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
548 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
549 MODULE_ALIAS("platform:fsl-ftm-pwm");
550 MODULE_LICENSE("GPL");
551