xref: /openbmc/linux/drivers/pwm/pwm-fsl-ftm.c (revision 69f03be1) 
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.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm.h>
17 #include <linux/pwm.h>
18 #include <linux/regmap.h>
19 #include <linux/slab.h>
20 #include <linux/fsl/ftm.h>
21 
22 #define FTM_SC_CLK(c)	(((c) + 1) << FTM_SC_CLK_MASK_SHIFT)
23 
24 enum fsl_pwm_clk {
25 	FSL_PWM_CLK_SYS,
26 	FSL_PWM_CLK_FIX,
27 	FSL_PWM_CLK_EXT,
28 	FSL_PWM_CLK_CNTEN,
29 	FSL_PWM_CLK_MAX
30 };
31 
32 struct fsl_ftm_soc {
33 	bool has_enable_bits;
34 };
35 
36 struct fsl_pwm_periodcfg {
37 	enum fsl_pwm_clk clk_select;
38 	unsigned int clk_ps;
39 	unsigned int mod_period;
40 };
41 
42 struct fsl_pwm_chip {
43 	struct pwm_chip chip;
44 	struct mutex lock;
45 	struct regmap *regmap;
46 
47 	/* This value is valid iff a pwm is running */
48 	struct fsl_pwm_periodcfg period;
49 
50 	struct clk *ipg_clk;
51 	struct clk *clk[FSL_PWM_CLK_MAX];
52 
53 	const struct fsl_ftm_soc *soc;
54 };
55 
56 static inline struct fsl_pwm_chip *to_fsl_chip(struct pwm_chip *chip)
57 {
58 	return container_of(chip, struct fsl_pwm_chip, chip);
59 }
60 
61 static void ftm_clear_write_protection(struct fsl_pwm_chip *fpc)
62 {
63 	u32 val;
64 
65 	regmap_read(fpc->regmap, FTM_FMS, &val);
66 	if (val & FTM_FMS_WPEN)
67 		regmap_set_bits(fpc->regmap, FTM_MODE, FTM_MODE_WPDIS);
68 }
69 
70 static void ftm_set_write_protection(struct fsl_pwm_chip *fpc)
71 {
72 	regmap_set_bits(fpc->regmap, FTM_FMS, FTM_FMS_WPEN);
73 }
74 
75 static bool fsl_pwm_periodcfg_are_equal(const struct fsl_pwm_periodcfg *a,
76 					const struct fsl_pwm_periodcfg *b)
77 {
78 	if (a->clk_select != b->clk_select)
79 		return false;
80 	if (a->clk_ps != b->clk_ps)
81 		return false;
82 	if (a->mod_period != b->mod_period)
83 		return false;
84 	return true;
85 }
86 
87 static int fsl_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
88 {
89 	int ret;
90 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
91 
92 	ret = clk_prepare_enable(fpc->ipg_clk);
93 	if (!ret && fpc->soc->has_enable_bits) {
94 		mutex_lock(&fpc->lock);
95 		regmap_set_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16));
96 		mutex_unlock(&fpc->lock);
97 	}
98 
99 	return ret;
100 }
101 
102 static void fsl_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
103 {
104 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
105 
106 	if (fpc->soc->has_enable_bits) {
107 		mutex_lock(&fpc->lock);
108 		regmap_clear_bits(fpc->regmap, FTM_SC, BIT(pwm->hwpwm + 16));
109 		mutex_unlock(&fpc->lock);
110 	}
111 
112 	clk_disable_unprepare(fpc->ipg_clk);
113 }
114 
115 static unsigned int fsl_pwm_ticks_to_ns(struct fsl_pwm_chip *fpc,
116 					  unsigned int ticks)
117 {
118 	unsigned long rate;
119 	unsigned long long exval;
120 
121 	rate = clk_get_rate(fpc->clk[fpc->period.clk_select]);
122 	exval = ticks;
123 	exval *= 1000000000UL;
124 	do_div(exval, rate >> fpc->period.clk_ps);
125 	return exval;
126 }
127 
128 static bool fsl_pwm_calculate_period_clk(struct fsl_pwm_chip *fpc,
129 					 unsigned int period_ns,
130 					 enum fsl_pwm_clk index,
131 					 struct fsl_pwm_periodcfg *periodcfg
132 					 )
133 {
134 	unsigned long long c;
135 	unsigned int ps;
136 
137 	c = clk_get_rate(fpc->clk[index]);
138 	c = c * period_ns;
139 	do_div(c, 1000000000UL);
140 
141 	if (c == 0)
142 		return false;
143 
144 	for (ps = 0; ps < 8 ; ++ps, c >>= 1) {
145 		if (c <= 0x10000) {
146 			periodcfg->clk_select = index;
147 			periodcfg->clk_ps = ps;
148 			periodcfg->mod_period = c - 1;
149 			return true;
150 		}
151 	}
152 	return false;
153 }
154 
155 static bool fsl_pwm_calculate_period(struct fsl_pwm_chip *fpc,
156 				     unsigned int period_ns,
157 				     struct fsl_pwm_periodcfg *periodcfg)
158 {
159 	enum fsl_pwm_clk m0, m1;
160 	unsigned long fix_rate, ext_rate;
161 	bool ret;
162 
163 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, FSL_PWM_CLK_SYS,
164 					   periodcfg);
165 	if (ret)
166 		return true;
167 
168 	fix_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_FIX]);
169 	ext_rate = clk_get_rate(fpc->clk[FSL_PWM_CLK_EXT]);
170 
171 	if (fix_rate > ext_rate) {
172 		m0 = FSL_PWM_CLK_FIX;
173 		m1 = FSL_PWM_CLK_EXT;
174 	} else {
175 		m0 = FSL_PWM_CLK_EXT;
176 		m1 = FSL_PWM_CLK_FIX;
177 	}
178 
179 	ret = fsl_pwm_calculate_period_clk(fpc, period_ns, m0, periodcfg);
180 	if (ret)
181 		return true;
182 
183 	return fsl_pwm_calculate_period_clk(fpc, period_ns, m1, periodcfg);
184 }
185 
186 static unsigned int fsl_pwm_calculate_duty(struct fsl_pwm_chip *fpc,
187 					   unsigned int duty_ns)
188 {
189 	unsigned long long duty;
190 
191 	unsigned int period = fpc->period.mod_period + 1;
192 	unsigned int period_ns = fsl_pwm_ticks_to_ns(fpc, period);
193 
194 	duty = (unsigned long long)duty_ns * period;
195 	do_div(duty, period_ns);
196 
197 	return (unsigned int)duty;
198 }
199 
200 static bool fsl_pwm_is_any_pwm_enabled(struct fsl_pwm_chip *fpc,
201 				       struct pwm_device *pwm)
202 {
203 	u32 val;
204 
205 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
206 	if (~val & 0xFF)
207 		return true;
208 	else
209 		return false;
210 }
211 
212 static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
213 					 struct pwm_device *pwm)
214 {
215 	u32 val;
216 
217 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
218 	if (~(val | BIT(pwm->hwpwm)) & 0xFF)
219 		return true;
220 	else
221 		return false;
222 }
223 
224 static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
225 				struct pwm_device *pwm,
226 				const struct pwm_state *newstate)
227 {
228 	unsigned int duty;
229 	u32 reg_polarity;
230 
231 	struct fsl_pwm_periodcfg periodcfg;
232 	bool do_write_period = false;
233 
234 	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
235 		dev_err(fpc->chip.dev, "failed to calculate new period\n");
236 		return -EINVAL;
237 	}
238 
239 	if (!fsl_pwm_is_any_pwm_enabled(fpc, pwm))
240 		do_write_period = true;
241 	/*
242 	 * The Freescale FTM controller supports only a single period for
243 	 * all PWM channels, therefore verify if the newly computed period
244 	 * is different than the current period being used. In such case
245 	 * we allow to change the period only if no other pwm is running.
246 	 */
247 	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
248 		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
249 			dev_err(fpc->chip.dev,
250 				"Cannot change period for PWM %u, disable other PWMs first\n",
251 				pwm->hwpwm);
252 			return -EBUSY;
253 		}
254 		if (fpc->period.clk_select != periodcfg.clk_select) {
255 			int ret;
256 			enum fsl_pwm_clk oldclk = fpc->period.clk_select;
257 			enum fsl_pwm_clk newclk = periodcfg.clk_select;
258 
259 			ret = clk_prepare_enable(fpc->clk[newclk]);
260 			if (ret)
261 				return ret;
262 			clk_disable_unprepare(fpc->clk[oldclk]);
263 		}
264 		do_write_period = true;
265 	}
266 
267 	ftm_clear_write_protection(fpc);
268 
269 	if (do_write_period) {
270 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
271 				   FTM_SC_CLK(periodcfg.clk_select));
272 		regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_PS_MASK,
273 				   periodcfg.clk_ps);
274 		regmap_write(fpc->regmap, FTM_MOD, periodcfg.mod_period);
275 
276 		fpc->period = periodcfg;
277 	}
278 
279 	duty = fsl_pwm_calculate_duty(fpc, newstate->duty_cycle);
280 
281 	regmap_write(fpc->regmap, FTM_CSC(pwm->hwpwm),
282 		     FTM_CSC_MSB | FTM_CSC_ELSB);
283 	regmap_write(fpc->regmap, FTM_CV(pwm->hwpwm), duty);
284 
285 	reg_polarity = 0;
286 	if (newstate->polarity == PWM_POLARITY_INVERSED)
287 		reg_polarity = BIT(pwm->hwpwm);
288 
289 	regmap_update_bits(fpc->regmap, FTM_POL, BIT(pwm->hwpwm), reg_polarity);
290 
291 	ftm_set_write_protection(fpc);
292 
293 	return 0;
294 }
295 
296 static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
297 			 const struct pwm_state *newstate)
298 {
299 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
300 	struct pwm_state *oldstate = &pwm->state;
301 	int ret = 0;
302 
303 	/*
304 	 * oldstate to newstate : action
305 	 *
306 	 * disabled to disabled : ignore
307 	 * enabled to disabled : disable
308 	 * enabled to enabled : update settings
309 	 * disabled to enabled : update settings + enable
310 	 */
311 
312 	mutex_lock(&fpc->lock);
313 
314 	if (!newstate->enabled) {
315 		if (oldstate->enabled) {
316 			regmap_set_bits(fpc->regmap, FTM_OUTMASK,
317 					BIT(pwm->hwpwm));
318 			clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
319 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
320 		}
321 
322 		goto end_mutex;
323 	}
324 
325 	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
326 	if (ret)
327 		goto end_mutex;
328 
329 	/* check if need to enable */
330 	if (!oldstate->enabled) {
331 		ret = clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
332 		if (ret)
333 			goto end_mutex;
334 
335 		ret = clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
336 		if (ret) {
337 			clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
338 			goto end_mutex;
339 		}
340 
341 		regmap_clear_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm));
342 	}
343 
344 end_mutex:
345 	mutex_unlock(&fpc->lock);
346 	return ret;
347 }
348 
349 static const struct pwm_ops fsl_pwm_ops = {
350 	.request = fsl_pwm_request,
351 	.free = fsl_pwm_free,
352 	.apply = fsl_pwm_apply,
353 	.owner = THIS_MODULE,
354 };
355 
356 static int fsl_pwm_init(struct fsl_pwm_chip *fpc)
357 {
358 	int ret;
359 
360 	ret = clk_prepare_enable(fpc->ipg_clk);
361 	if (ret)
362 		return ret;
363 
364 	regmap_write(fpc->regmap, FTM_CNTIN, 0x00);
365 	regmap_write(fpc->regmap, FTM_OUTINIT, 0x00);
366 	regmap_write(fpc->regmap, FTM_OUTMASK, 0xFF);
367 
368 	clk_disable_unprepare(fpc->ipg_clk);
369 
370 	return 0;
371 }
372 
373 static bool fsl_pwm_volatile_reg(struct device *dev, unsigned int reg)
374 {
375 	switch (reg) {
376 	case FTM_FMS:
377 	case FTM_MODE:
378 	case FTM_CNT:
379 		return true;
380 	}
381 	return false;
382 }
383 
384 static const struct regmap_config fsl_pwm_regmap_config = {
385 	.reg_bits = 32,
386 	.reg_stride = 4,
387 	.val_bits = 32,
388 
389 	.max_register = FTM_PWMLOAD,
390 	.volatile_reg = fsl_pwm_volatile_reg,
391 	.cache_type = REGCACHE_FLAT,
392 };
393 
394 static int fsl_pwm_probe(struct platform_device *pdev)
395 {
396 	struct fsl_pwm_chip *fpc;
397 	void __iomem *base;
398 	int ret;
399 
400 	fpc = devm_kzalloc(&pdev->dev, sizeof(*fpc), GFP_KERNEL);
401 	if (!fpc)
402 		return -ENOMEM;
403 
404 	mutex_init(&fpc->lock);
405 
406 	fpc->soc = of_device_get_match_data(&pdev->dev);
407 	fpc->chip.dev = &pdev->dev;
408 
409 	base = devm_platform_ioremap_resource(pdev, 0);
410 	if (IS_ERR(base))
411 		return PTR_ERR(base);
412 
413 	fpc->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "ftm_sys", base,
414 						&fsl_pwm_regmap_config);
415 	if (IS_ERR(fpc->regmap)) {
416 		dev_err(&pdev->dev, "regmap init failed\n");
417 		return PTR_ERR(fpc->regmap);
418 	}
419 
420 	fpc->clk[FSL_PWM_CLK_SYS] = devm_clk_get(&pdev->dev, "ftm_sys");
421 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_SYS])) {
422 		dev_err(&pdev->dev, "failed to get \"ftm_sys\" clock\n");
423 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_SYS]);
424 	}
425 
426 	fpc->clk[FSL_PWM_CLK_FIX] = devm_clk_get(fpc->chip.dev, "ftm_fix");
427 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_FIX]))
428 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_FIX]);
429 
430 	fpc->clk[FSL_PWM_CLK_EXT] = devm_clk_get(fpc->chip.dev, "ftm_ext");
431 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_EXT]))
432 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_EXT]);
433 
434 	fpc->clk[FSL_PWM_CLK_CNTEN] =
435 				devm_clk_get(fpc->chip.dev, "ftm_cnt_clk_en");
436 	if (IS_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]))
437 		return PTR_ERR(fpc->clk[FSL_PWM_CLK_CNTEN]);
438 
439 	/*
440 	 * ipg_clk is the interface clock for the IP. If not provided, use the
441 	 * ftm_sys clock as the default.
442 	 */
443 	fpc->ipg_clk = devm_clk_get(&pdev->dev, "ipg");
444 	if (IS_ERR(fpc->ipg_clk))
445 		fpc->ipg_clk = fpc->clk[FSL_PWM_CLK_SYS];
446 
447 
448 	fpc->chip.ops = &fsl_pwm_ops;
449 	fpc->chip.npwm = 8;
450 
451 	ret = devm_pwmchip_add(&pdev->dev, &fpc->chip);
452 	if (ret < 0) {
453 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
454 		return ret;
455 	}
456 
457 	platform_set_drvdata(pdev, fpc);
458 
459 	return fsl_pwm_init(fpc);
460 }
461 
462 #ifdef CONFIG_PM_SLEEP
463 static int fsl_pwm_suspend(struct device *dev)
464 {
465 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
466 	int i;
467 
468 	regcache_cache_only(fpc->regmap, true);
469 	regcache_mark_dirty(fpc->regmap);
470 
471 	for (i = 0; i < fpc->chip.npwm; i++) {
472 		struct pwm_device *pwm = &fpc->chip.pwms[i];
473 
474 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
475 			continue;
476 
477 		clk_disable_unprepare(fpc->ipg_clk);
478 
479 		if (!pwm_is_enabled(pwm))
480 			continue;
481 
482 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
483 		clk_disable_unprepare(fpc->clk[fpc->period.clk_select]);
484 	}
485 
486 	return 0;
487 }
488 
489 static int fsl_pwm_resume(struct device *dev)
490 {
491 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
492 	int i;
493 
494 	for (i = 0; i < fpc->chip.npwm; i++) {
495 		struct pwm_device *pwm = &fpc->chip.pwms[i];
496 
497 		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
498 			continue;
499 
500 		clk_prepare_enable(fpc->ipg_clk);
501 
502 		if (!pwm_is_enabled(pwm))
503 			continue;
504 
505 		clk_prepare_enable(fpc->clk[fpc->period.clk_select]);
506 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
507 	}
508 
509 	/* restore all registers from cache */
510 	regcache_cache_only(fpc->regmap, false);
511 	regcache_sync(fpc->regmap);
512 
513 	return 0;
514 }
515 #endif
516 
517 static const struct dev_pm_ops fsl_pwm_pm_ops = {
518 	SET_SYSTEM_SLEEP_PM_OPS(fsl_pwm_suspend, fsl_pwm_resume)
519 };
520 
521 static const struct fsl_ftm_soc vf610_ftm_pwm = {
522 	.has_enable_bits = false,
523 };
524 
525 static const struct fsl_ftm_soc imx8qm_ftm_pwm = {
526 	.has_enable_bits = true,
527 };
528 
529 static const struct of_device_id fsl_pwm_dt_ids[] = {
530 	{ .compatible = "fsl,vf610-ftm-pwm", .data = &vf610_ftm_pwm },
531 	{ .compatible = "fsl,imx8qm-ftm-pwm", .data = &imx8qm_ftm_pwm },
532 	{ /* sentinel */ }
533 };
534 MODULE_DEVICE_TABLE(of, fsl_pwm_dt_ids);
535 
536 static struct platform_driver fsl_pwm_driver = {
537 	.driver = {
538 		.name = "fsl-ftm-pwm",
539 		.of_match_table = fsl_pwm_dt_ids,
540 		.pm = &fsl_pwm_pm_ops,
541 	},
542 	.probe = fsl_pwm_probe,
543 };
544 module_platform_driver(fsl_pwm_driver);
545 
546 MODULE_DESCRIPTION("Freescale FlexTimer Module PWM Driver");
547 MODULE_AUTHOR("Xiubo Li <Li.Xiubo@freescale.com>");
548 MODULE_ALIAS("platform:fsl-ftm-pwm");
549 MODULE_LICENSE("GPL");
550