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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * EHRPWM PWM driver
4 *
5 * Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
6 */
7
8#include <linux/module.h>
9#include <linux/platform_device.h>
10#include <linux/pwm.h>
11#include <linux/io.h>
12#include <linux/err.h>
13#include <linux/clk.h>
14#include <linux/pm_runtime.h>
15#include <linux/of_device.h>
16
17/* EHRPWM registers and bits definitions */
18
19/* Time base module registers */
20#define TBCTL 0x00
21#define TBPRD 0x0A
22
23#define TBCTL_PRDLD_MASK BIT(3)
24#define TBCTL_PRDLD_SHDW 0
25#define TBCTL_PRDLD_IMDT BIT(3)
26#define TBCTL_CLKDIV_MASK (BIT(12) | BIT(11) | BIT(10) | BIT(9) | \
27 BIT(8) | BIT(7))
28#define TBCTL_CTRMODE_MASK (BIT(1) | BIT(0))
29#define TBCTL_CTRMODE_UP 0
30#define TBCTL_CTRMODE_DOWN BIT(0)
31#define TBCTL_CTRMODE_UPDOWN BIT(1)
32#define TBCTL_CTRMODE_FREEZE (BIT(1) | BIT(0))
33
34#define TBCTL_HSPCLKDIV_SHIFT 7
35#define TBCTL_CLKDIV_SHIFT 10
36
37#define CLKDIV_MAX 7
38#define HSPCLKDIV_MAX 7
39#define PERIOD_MAX 0xFFFF
40
41/* compare module registers */
42#define CMPA 0x12
43#define CMPB 0x14
44
45/* Action qualifier module registers */
46#define AQCTLA 0x16
47#define AQCTLB 0x18
48#define AQSFRC 0x1A
49#define AQCSFRC 0x1C
50
51#define AQCTL_CBU_MASK (BIT(9) | BIT(8))
52#define AQCTL_CBU_FRCLOW BIT(8)
53#define AQCTL_CBU_FRCHIGH BIT(9)
54#define AQCTL_CBU_FRCTOGGLE (BIT(9) | BIT(8))
55#define AQCTL_CAU_MASK (BIT(5) | BIT(4))
56#define AQCTL_CAU_FRCLOW BIT(4)
57#define AQCTL_CAU_FRCHIGH BIT(5)
58#define AQCTL_CAU_FRCTOGGLE (BIT(5) | BIT(4))
59#define AQCTL_PRD_MASK (BIT(3) | BIT(2))
60#define AQCTL_PRD_FRCLOW BIT(2)
61#define AQCTL_PRD_FRCHIGH BIT(3)
62#define AQCTL_PRD_FRCTOGGLE (BIT(3) | BIT(2))
63#define AQCTL_ZRO_MASK (BIT(1) | BIT(0))
64#define AQCTL_ZRO_FRCLOW BIT(0)
65#define AQCTL_ZRO_FRCHIGH BIT(1)
66#define AQCTL_ZRO_FRCTOGGLE (BIT(1) | BIT(0))
67
68#define AQCTL_CHANA_POLNORMAL (AQCTL_CAU_FRCLOW | AQCTL_PRD_FRCHIGH | \
69 AQCTL_ZRO_FRCHIGH)
70#define AQCTL_CHANA_POLINVERSED (AQCTL_CAU_FRCHIGH | AQCTL_PRD_FRCLOW | \
71 AQCTL_ZRO_FRCLOW)
72#define AQCTL_CHANB_POLNORMAL (AQCTL_CBU_FRCLOW | AQCTL_PRD_FRCHIGH | \
73 AQCTL_ZRO_FRCHIGH)
74#define AQCTL_CHANB_POLINVERSED (AQCTL_CBU_FRCHIGH | AQCTL_PRD_FRCLOW | \
75 AQCTL_ZRO_FRCLOW)
76
77#define AQSFRC_RLDCSF_MASK (BIT(7) | BIT(6))
78#define AQSFRC_RLDCSF_ZRO 0
79#define AQSFRC_RLDCSF_PRD BIT(6)
80#define AQSFRC_RLDCSF_ZROPRD BIT(7)
81#define AQSFRC_RLDCSF_IMDT (BIT(7) | BIT(6))
82
83#define AQCSFRC_CSFB_MASK (BIT(3) | BIT(2))
84#define AQCSFRC_CSFB_FRCDIS 0
85#define AQCSFRC_CSFB_FRCLOW BIT(2)
86#define AQCSFRC_CSFB_FRCHIGH BIT(3)
87#define AQCSFRC_CSFB_DISSWFRC (BIT(3) | BIT(2))
88#define AQCSFRC_CSFA_MASK (BIT(1) | BIT(0))
89#define AQCSFRC_CSFA_FRCDIS 0
90#define AQCSFRC_CSFA_FRCLOW BIT(0)
91#define AQCSFRC_CSFA_FRCHIGH BIT(1)
92#define AQCSFRC_CSFA_DISSWFRC (BIT(1) | BIT(0))
93
94#define NUM_PWM_CHANNEL 2 /* EHRPWM channels */
95
96struct ehrpwm_context {
97 u16 tbctl;
98 u16 tbprd;
99 u16 cmpa;
100 u16 cmpb;
101 u16 aqctla;
102 u16 aqctlb;
103 u16 aqsfrc;
104 u16 aqcsfrc;
105};
106
107struct ehrpwm_pwm_chip {
108 struct pwm_chip chip;
109 unsigned long clk_rate;
110 void __iomem *mmio_base;
111 unsigned long period_cycles[NUM_PWM_CHANNEL];
112 enum pwm_polarity polarity[NUM_PWM_CHANNEL];
113 struct clk *tbclk;
114 struct ehrpwm_context ctx;
115};
116
117static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
118{
119 return container_of(chip, struct ehrpwm_pwm_chip, chip);
120}
121
122static inline u16 ehrpwm_read(void __iomem *base, unsigned int offset)
123{
124 return readw(base + offset);
125}
126
127static inline void ehrpwm_write(void __iomem *base, unsigned int offset,
128 u16 value)
129{
130 writew(value, base + offset);
131}
132
133static void ehrpwm_modify(void __iomem *base, unsigned int offset, u16 mask,
134 u16 value)
135{
136 unsigned short val;
137
138 val = readw(base + offset);
139 val &= ~mask;
140 val |= value & mask;
141 writew(val, base + offset);
142}
143
144/**
145 * set_prescale_div - Set up the prescaler divider function
146 * @rqst_prescaler: prescaler value min
147 * @prescale_div: prescaler value set
148 * @tb_clk_div: Time Base Control prescaler bits
149 */
150static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div,
151 u16 *tb_clk_div)
152{
153 unsigned int clkdiv, hspclkdiv;
154
155 for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
156 for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) {
157 /*
158 * calculations for prescaler value :
159 * prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
160 * HSPCLKDIVIDER = 2 ** hspclkdiv
161 * CLKDIVIDER = (1), if clkdiv == 0 *OR*
162 * (2 * clkdiv), if clkdiv != 0
163 *
164 * Configure prescale_div value such that period
165 * register value is less than 65535.
166 */
167
168 *prescale_div = (1 << clkdiv) *
169 (hspclkdiv ? (hspclkdiv * 2) : 1);
170 if (*prescale_div > rqst_prescaler) {
171 *tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) |
172 (hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
173 return 0;
174 }
175 }
176 }
177
178 return 1;
179}
180
181static void configure_polarity(struct ehrpwm_pwm_chip *pc, int chan)
182{
183 u16 aqctl_val, aqctl_mask;
184 unsigned int aqctl_reg;
185
186 /*
187 * Configure PWM output to HIGH/LOW level on counter
188 * reaches compare register value and LOW/HIGH level
189 * on counter value reaches period register value and
190 * zero value on counter
191 */
192 if (chan == 1) {
193 aqctl_reg = AQCTLB;
194 aqctl_mask = AQCTL_CBU_MASK;
195
196 if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
197 aqctl_val = AQCTL_CHANB_POLINVERSED;
198 else
199 aqctl_val = AQCTL_CHANB_POLNORMAL;
200 } else {
201 aqctl_reg = AQCTLA;
202 aqctl_mask = AQCTL_CAU_MASK;
203
204 if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
205 aqctl_val = AQCTL_CHANA_POLINVERSED;
206 else
207 aqctl_val = AQCTL_CHANA_POLNORMAL;
208 }
209
210 aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
211 ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);
212}
213
214/*
215 * period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
216 * duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
217 */
218static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
219 int duty_ns, int period_ns)
220{
221 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
222 u32 period_cycles, duty_cycles;
223 u16 ps_divval, tb_divval;
224 unsigned int i, cmp_reg;
225 unsigned long long c;
226
227 if (period_ns > NSEC_PER_SEC)
228 return -ERANGE;
229
230 c = pc->clk_rate;
231 c = c * period_ns;
232 do_div(c, NSEC_PER_SEC);
233 period_cycles = (unsigned long)c;
234
235 if (period_cycles < 1) {
236 period_cycles = 1;
237 duty_cycles = 1;
238 } else {
239 c = pc->clk_rate;
240 c = c * duty_ns;
241 do_div(c, NSEC_PER_SEC);
242 duty_cycles = (unsigned long)c;
243 }
244
245 /*
246 * Period values should be same for multiple PWM channels as IP uses
247 * same period register for multiple channels.
248 */
249 for (i = 0; i < NUM_PWM_CHANNEL; i++) {
250 if (pc->period_cycles[i] &&
251 (pc->period_cycles[i] != period_cycles)) {
252 /*
253 * Allow channel to reconfigure period if no other
254 * channels being configured.
255 */
256 if (i == pwm->hwpwm)
257 continue;
258
259 dev_err(chip->dev,
260 "period value conflicts with channel %u\n",
261 i);
262 return -EINVAL;
263 }
264 }
265
266 pc->period_cycles[pwm->hwpwm] = period_cycles;
267
268 /* Configure clock prescaler to support Low frequency PWM wave */
269 if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
270 &tb_divval)) {
271 dev_err(chip->dev, "Unsupported values\n");
272 return -EINVAL;
273 }
274
275 pm_runtime_get_sync(chip->dev);
276
277 /* Update clock prescaler values */
278 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);
279
280 /* Update period & duty cycle with presacler division */
281 period_cycles = period_cycles / ps_divval;
282 duty_cycles = duty_cycles / ps_divval;
283
284 /* Configure shadow loading on Period register */
285 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);
286
287 ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);
288
289 /* Configure ehrpwm counter for up-count mode */
290 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
291 TBCTL_CTRMODE_UP);
292
293 if (pwm->hwpwm == 1)
294 /* Channel 1 configured with compare B register */
295 cmp_reg = CMPB;
296 else
297 /* Channel 0 configured with compare A register */
298 cmp_reg = CMPA;
299
300 ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
301
302 pm_runtime_put_sync(chip->dev);
303
304 return 0;
305}
306
307static int ehrpwm_pwm_set_polarity(struct pwm_chip *chip,
308 struct pwm_device *pwm,
309 enum pwm_polarity polarity)
310{
311 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
312
313 /* Configuration of polarity in hardware delayed, do at enable */
314 pc->polarity[pwm->hwpwm] = polarity;
315
316 return 0;
317}
318
319static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
320{
321 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
322 u16 aqcsfrc_val, aqcsfrc_mask;
323 int ret;
324
325 /* Leave clock enabled on enabling PWM */
326 pm_runtime_get_sync(chip->dev);
327
328 /* Disabling Action Qualifier on PWM output */
329 if (pwm->hwpwm) {
330 aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
331 aqcsfrc_mask = AQCSFRC_CSFB_MASK;
332 } else {
333 aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
334 aqcsfrc_mask = AQCSFRC_CSFA_MASK;
335 }
336
337 /* Changes to shadow mode */
338 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
339 AQSFRC_RLDCSF_ZRO);
340
341 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
342
343 /* Channels polarity can be configured from action qualifier module */
344 configure_polarity(pc, pwm->hwpwm);
345
346 /* Enable TBCLK */
347 ret = clk_enable(pc->tbclk);
348 if (ret) {
349 dev_err(chip->dev, "Failed to enable TBCLK for %s: %d\n",
350 dev_name(pc->chip.dev), ret);
351 return ret;
352 }
353
354 return 0;
355}
356
357static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
358{
359 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
360 u16 aqcsfrc_val, aqcsfrc_mask;
361
362 /* Action Qualifier puts PWM output low forcefully */
363 if (pwm->hwpwm) {
364 aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
365 aqcsfrc_mask = AQCSFRC_CSFB_MASK;
366 } else {
367 aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
368 aqcsfrc_mask = AQCSFRC_CSFA_MASK;
369 }
370
371 /* Update shadow register first before modifying active register */
372 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
373 AQSFRC_RLDCSF_ZRO);
374 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
375 /*
376 * Changes to immediate action on Action Qualifier. This puts
377 * Action Qualifier control on PWM output from next TBCLK
378 */
379 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
380 AQSFRC_RLDCSF_IMDT);
381
382 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
383
384 /* Disabling TBCLK on PWM disable */
385 clk_disable(pc->tbclk);
386
387 /* Disable clock on PWM disable */
388 pm_runtime_put_sync(chip->dev);
389}
390
391static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
392{
393 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
394
395 if (pwm_is_enabled(pwm)) {
396 dev_warn(chip->dev, "Removing PWM device without disabling\n");
397 pm_runtime_put_sync(chip->dev);
398 }
399
400 /* set period value to zero on free */
401 pc->period_cycles[pwm->hwpwm] = 0;
402}
403
404static const struct pwm_ops ehrpwm_pwm_ops = {
405 .free = ehrpwm_pwm_free,
406 .config = ehrpwm_pwm_config,
407 .set_polarity = ehrpwm_pwm_set_polarity,
408 .enable = ehrpwm_pwm_enable,
409 .disable = ehrpwm_pwm_disable,
410 .owner = THIS_MODULE,
411};
412
413static const struct of_device_id ehrpwm_of_match[] = {
414 { .compatible = "ti,am3352-ehrpwm" },
415 { .compatible = "ti,am33xx-ehrpwm" },
416 {},
417};
418MODULE_DEVICE_TABLE(of, ehrpwm_of_match);
419
420static int ehrpwm_pwm_probe(struct platform_device *pdev)
421{
422 struct device_node *np = pdev->dev.of_node;
423 struct ehrpwm_pwm_chip *pc;
424 struct clk *clk;
425 int ret;
426
427 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
428 if (!pc)
429 return -ENOMEM;
430
431 clk = devm_clk_get(&pdev->dev, "fck");
432 if (IS_ERR(clk)) {
433 if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
434 dev_warn(&pdev->dev, "Binding is obsolete.\n");
435 clk = devm_clk_get(pdev->dev.parent, "fck");
436 }
437 }
438
439 if (IS_ERR(clk))
440 return dev_err_probe(&pdev->dev, PTR_ERR(clk), "Failed to get fck\n");
441
442 pc->clk_rate = clk_get_rate(clk);
443 if (!pc->clk_rate) {
444 dev_err(&pdev->dev, "failed to get clock rate\n");
445 return -EINVAL;
446 }
447
448 pc->chip.dev = &pdev->dev;
449 pc->chip.ops = &ehrpwm_pwm_ops;
450 pc->chip.npwm = NUM_PWM_CHANNEL;
451
452 pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
453 if (IS_ERR(pc->mmio_base))
454 return PTR_ERR(pc->mmio_base);
455
456 /* Acquire tbclk for Time Base EHRPWM submodule */
457 pc->tbclk = devm_clk_get(&pdev->dev, "tbclk");
458 if (IS_ERR(pc->tbclk))
459 return dev_err_probe(&pdev->dev, PTR_ERR(pc->tbclk), "Failed to get tbclk\n");
460
461 ret = clk_prepare(pc->tbclk);
462 if (ret < 0) {
463 dev_err(&pdev->dev, "clk_prepare() failed: %d\n", ret);
464 return ret;
465 }
466
467 ret = pwmchip_add(&pc->chip);
468 if (ret < 0) {
469 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
470 goto err_clk_unprepare;
471 }
472
473 platform_set_drvdata(pdev, pc);
474 pm_runtime_enable(&pdev->dev);
475
476 return 0;
477
478err_clk_unprepare:
479 clk_unprepare(pc->tbclk);
480
481 return ret;
482}
483
484static int ehrpwm_pwm_remove(struct platform_device *pdev)
485{
486 struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev);
487
488 clk_unprepare(pc->tbclk);
489
490 pm_runtime_disable(&pdev->dev);
491
492 return pwmchip_remove(&pc->chip);
493}
494
495#ifdef CONFIG_PM_SLEEP
496static void ehrpwm_pwm_save_context(struct ehrpwm_pwm_chip *pc)
497{
498 pm_runtime_get_sync(pc->chip.dev);
499
500 pc->ctx.tbctl = ehrpwm_read(pc->mmio_base, TBCTL);
501 pc->ctx.tbprd = ehrpwm_read(pc->mmio_base, TBPRD);
502 pc->ctx.cmpa = ehrpwm_read(pc->mmio_base, CMPA);
503 pc->ctx.cmpb = ehrpwm_read(pc->mmio_base, CMPB);
504 pc->ctx.aqctla = ehrpwm_read(pc->mmio_base, AQCTLA);
505 pc->ctx.aqctlb = ehrpwm_read(pc->mmio_base, AQCTLB);
506 pc->ctx.aqsfrc = ehrpwm_read(pc->mmio_base, AQSFRC);
507 pc->ctx.aqcsfrc = ehrpwm_read(pc->mmio_base, AQCSFRC);
508
509 pm_runtime_put_sync(pc->chip.dev);
510}
511
512static void ehrpwm_pwm_restore_context(struct ehrpwm_pwm_chip *pc)
513{
514 ehrpwm_write(pc->mmio_base, TBPRD, pc->ctx.tbprd);
515 ehrpwm_write(pc->mmio_base, CMPA, pc->ctx.cmpa);
516 ehrpwm_write(pc->mmio_base, CMPB, pc->ctx.cmpb);
517 ehrpwm_write(pc->mmio_base, AQCTLA, pc->ctx.aqctla);
518 ehrpwm_write(pc->mmio_base, AQCTLB, pc->ctx.aqctlb);
519 ehrpwm_write(pc->mmio_base, AQSFRC, pc->ctx.aqsfrc);
520 ehrpwm_write(pc->mmio_base, AQCSFRC, pc->ctx.aqcsfrc);
521 ehrpwm_write(pc->mmio_base, TBCTL, pc->ctx.tbctl);
522}
523
524static int ehrpwm_pwm_suspend(struct device *dev)
525{
526 struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
527 unsigned int i;
528
529 ehrpwm_pwm_save_context(pc);
530
531 for (i = 0; i < pc->chip.npwm; i++) {
532 struct pwm_device *pwm = &pc->chip.pwms[i];
533
534 if (!pwm_is_enabled(pwm))
535 continue;
536
537 /* Disable explicitly if PWM is running */
538 pm_runtime_put_sync(dev);
539 }
540
541 return 0;
542}
543
544static int ehrpwm_pwm_resume(struct device *dev)
545{
546 struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
547 unsigned int i;
548
549 for (i = 0; i < pc->chip.npwm; i++) {
550 struct pwm_device *pwm = &pc->chip.pwms[i];
551
552 if (!pwm_is_enabled(pwm))
553 continue;
554
555 /* Enable explicitly if PWM was running */
556 pm_runtime_get_sync(dev);
557 }
558
559 ehrpwm_pwm_restore_context(pc);
560
561 return 0;
562}
563#endif
564
565static SIMPLE_DEV_PM_OPS(ehrpwm_pwm_pm_ops, ehrpwm_pwm_suspend,
566 ehrpwm_pwm_resume);
567
568static struct platform_driver ehrpwm_pwm_driver = {
569 .driver = {
570 .name = "ehrpwm",
571 .of_match_table = ehrpwm_of_match,
572 .pm = &ehrpwm_pwm_pm_ops,
573 },
574 .probe = ehrpwm_pwm_probe,
575 .remove = ehrpwm_pwm_remove,
576};
577module_platform_driver(ehrpwm_pwm_driver);
578
579MODULE_DESCRIPTION("EHRPWM PWM driver");
580MODULE_AUTHOR("Texas Instruments");
581MODULE_LICENSE("GPL");