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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * R-Mobile TPU PWM driver
4 *
5 * Copyright (C) 2012 Renesas Solutions Corp.
6 */
7
8#include <linux/clk.h>
9#include <linux/err.h>
10#include <linux/io.h>
11#include <linux/init.h>
12#include <linux/ioport.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17#include <linux/pm_runtime.h>
18#include <linux/pwm.h>
19#include <linux/slab.h>
20#include <linux/spinlock.h>
21
22#define TPU_CHANNEL_MAX 4
23
24#define TPU_TSTR 0x00 /* Timer start register (shared) */
25
26#define TPU_TCRn 0x00 /* Timer control register */
27#define TPU_TCR_CCLR_NONE (0 << 5)
28#define TPU_TCR_CCLR_TGRA (1 << 5)
29#define TPU_TCR_CCLR_TGRB (2 << 5)
30#define TPU_TCR_CCLR_TGRC (5 << 5)
31#define TPU_TCR_CCLR_TGRD (6 << 5)
32#define TPU_TCR_CKEG_RISING (0 << 3)
33#define TPU_TCR_CKEG_FALLING (1 << 3)
34#define TPU_TCR_CKEG_BOTH (2 << 3)
35#define TPU_TMDRn 0x04 /* Timer mode register */
36#define TPU_TMDR_BFWT (1 << 6)
37#define TPU_TMDR_BFB (1 << 5)
38#define TPU_TMDR_BFA (1 << 4)
39#define TPU_TMDR_MD_NORMAL (0 << 0)
40#define TPU_TMDR_MD_PWM (2 << 0)
41#define TPU_TIORn 0x08 /* Timer I/O control register */
42#define TPU_TIOR_IOA_0 (0 << 0)
43#define TPU_TIOR_IOA_0_CLR (1 << 0)
44#define TPU_TIOR_IOA_0_SET (2 << 0)
45#define TPU_TIOR_IOA_0_TOGGLE (3 << 0)
46#define TPU_TIOR_IOA_1 (4 << 0)
47#define TPU_TIOR_IOA_1_CLR (5 << 0)
48#define TPU_TIOR_IOA_1_SET (6 << 0)
49#define TPU_TIOR_IOA_1_TOGGLE (7 << 0)
50#define TPU_TIERn 0x0c /* Timer interrupt enable register */
51#define TPU_TSRn 0x10 /* Timer status register */
52#define TPU_TCNTn 0x14 /* Timer counter */
53#define TPU_TGRAn 0x18 /* Timer general register A */
54#define TPU_TGRBn 0x1c /* Timer general register B */
55#define TPU_TGRCn 0x20 /* Timer general register C */
56#define TPU_TGRDn 0x24 /* Timer general register D */
57
58#define TPU_CHANNEL_OFFSET 0x10
59#define TPU_CHANNEL_SIZE 0x40
60
61enum tpu_pin_state {
62 TPU_PIN_INACTIVE, /* Pin is driven inactive */
63 TPU_PIN_PWM, /* Pin is driven by PWM */
64 TPU_PIN_ACTIVE, /* Pin is driven active */
65};
66
67struct tpu_device;
68
69struct tpu_pwm_device {
70 bool timer_on; /* Whether the timer is running */
71
72 struct tpu_device *tpu;
73 unsigned int channel; /* Channel number in the TPU */
74
75 enum pwm_polarity polarity;
76 unsigned int prescaler;
77 u16 period;
78 u16 duty;
79};
80
81struct tpu_device {
82 struct platform_device *pdev;
83 struct pwm_chip chip;
84 spinlock_t lock;
85
86 void __iomem *base;
87 struct clk *clk;
88};
89
90#define to_tpu_device(c) container_of(c, struct tpu_device, chip)
91
92static void tpu_pwm_write(struct tpu_pwm_device *pwm, int reg_nr, u16 value)
93{
94 void __iomem *base = pwm->tpu->base + TPU_CHANNEL_OFFSET
95 + pwm->channel * TPU_CHANNEL_SIZE;
96
97 iowrite16(value, base + reg_nr);
98}
99
100static void tpu_pwm_set_pin(struct tpu_pwm_device *pwm,
101 enum tpu_pin_state state)
102{
103 static const char * const states[] = { "inactive", "PWM", "active" };
104
105 dev_dbg(&pwm->tpu->pdev->dev, "%u: configuring pin as %s\n",
106 pwm->channel, states[state]);
107
108 switch (state) {
109 case TPU_PIN_INACTIVE:
110 tpu_pwm_write(pwm, TPU_TIORn,
111 pwm->polarity == PWM_POLARITY_INVERSED ?
112 TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0);
113 break;
114 case TPU_PIN_PWM:
115 tpu_pwm_write(pwm, TPU_TIORn,
116 pwm->polarity == PWM_POLARITY_INVERSED ?
117 TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR);
118 break;
119 case TPU_PIN_ACTIVE:
120 tpu_pwm_write(pwm, TPU_TIORn,
121 pwm->polarity == PWM_POLARITY_INVERSED ?
122 TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1);
123 break;
124 }
125}
126
127static void tpu_pwm_start_stop(struct tpu_pwm_device *pwm, int start)
128{
129 unsigned long flags;
130 u16 value;
131
132 spin_lock_irqsave(&pwm->tpu->lock, flags);
133 value = ioread16(pwm->tpu->base + TPU_TSTR);
134
135 if (start)
136 value |= 1 << pwm->channel;
137 else
138 value &= ~(1 << pwm->channel);
139
140 iowrite16(value, pwm->tpu->base + TPU_TSTR);
141 spin_unlock_irqrestore(&pwm->tpu->lock, flags);
142}
143
144static int tpu_pwm_timer_start(struct tpu_pwm_device *pwm)
145{
146 int ret;
147
148 if (!pwm->timer_on) {
149 /* Wake up device and enable clock. */
150 pm_runtime_get_sync(&pwm->tpu->pdev->dev);
151 ret = clk_prepare_enable(pwm->tpu->clk);
152 if (ret) {
153 dev_err(&pwm->tpu->pdev->dev, "cannot enable clock\n");
154 return ret;
155 }
156 pwm->timer_on = true;
157 }
158
159 /*
160 * Make sure the channel is stopped, as we need to reconfigure it
161 * completely. First drive the pin to the inactive state to avoid
162 * glitches.
163 */
164 tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
165 tpu_pwm_start_stop(pwm, false);
166
167 /*
168 * - Clear TCNT on TGRB match
169 * - Count on rising edge
170 * - Set prescaler
171 * - Output 0 until TGRA, output 1 until TGRB (active low polarity)
172 * - Output 1 until TGRA, output 0 until TGRB (active high polarity
173 * - PWM mode
174 */
175 tpu_pwm_write(pwm, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING |
176 pwm->prescaler);
177 tpu_pwm_write(pwm, TPU_TMDRn, TPU_TMDR_MD_PWM);
178 tpu_pwm_set_pin(pwm, TPU_PIN_PWM);
179 tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
180 tpu_pwm_write(pwm, TPU_TGRBn, pwm->period);
181
182 dev_dbg(&pwm->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n",
183 pwm->channel, pwm->duty, pwm->period);
184
185 /* Start the channel. */
186 tpu_pwm_start_stop(pwm, true);
187
188 return 0;
189}
190
191static void tpu_pwm_timer_stop(struct tpu_pwm_device *pwm)
192{
193 if (!pwm->timer_on)
194 return;
195
196 /* Disable channel. */
197 tpu_pwm_start_stop(pwm, false);
198
199 /* Stop clock and mark device as idle. */
200 clk_disable_unprepare(pwm->tpu->clk);
201 pm_runtime_put(&pwm->tpu->pdev->dev);
202
203 pwm->timer_on = false;
204}
205
206/* -----------------------------------------------------------------------------
207 * PWM API
208 */
209
210static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm)
211{
212 struct tpu_device *tpu = to_tpu_device(chip);
213 struct tpu_pwm_device *pwm;
214
215 if (_pwm->hwpwm >= TPU_CHANNEL_MAX)
216 return -EINVAL;
217
218 pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
219 if (pwm == NULL)
220 return -ENOMEM;
221
222 pwm->tpu = tpu;
223 pwm->channel = _pwm->hwpwm;
224 pwm->polarity = PWM_POLARITY_NORMAL;
225 pwm->prescaler = 0;
226 pwm->period = 0;
227 pwm->duty = 0;
228
229 pwm->timer_on = false;
230
231 pwm_set_chip_data(_pwm, pwm);
232
233 return 0;
234}
235
236static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *_pwm)
237{
238 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
239
240 tpu_pwm_timer_stop(pwm);
241 kfree(pwm);
242}
243
244static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
245 int duty_ns, int period_ns)
246{
247 static const unsigned int prescalers[] = { 1, 4, 16, 64 };
248 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
249 struct tpu_device *tpu = to_tpu_device(chip);
250 unsigned int prescaler;
251 bool duty_only = false;
252 u32 clk_rate;
253 u32 period;
254 u32 duty;
255 int ret;
256
257 /*
258 * Pick a prescaler to avoid overflowing the counter.
259 * TODO: Pick the highest acceptable prescaler.
260 */
261 clk_rate = clk_get_rate(tpu->clk);
262
263 for (prescaler = 0; prescaler < ARRAY_SIZE(prescalers); ++prescaler) {
264 period = clk_rate / prescalers[prescaler]
265 / (NSEC_PER_SEC / period_ns);
266 if (period <= 0xffff)
267 break;
268 }
269
270 if (prescaler == ARRAY_SIZE(prescalers) || period == 0) {
271 dev_err(&tpu->pdev->dev, "clock rate mismatch\n");
272 return -ENOTSUPP;
273 }
274
275 if (duty_ns) {
276 duty = clk_rate / prescalers[prescaler]
277 / (NSEC_PER_SEC / duty_ns);
278 if (duty > period)
279 return -EINVAL;
280 } else {
281 duty = 0;
282 }
283
284 dev_dbg(&tpu->pdev->dev,
285 "rate %u, prescaler %u, period %u, duty %u\n",
286 clk_rate, prescalers[prescaler], period, duty);
287
288 if (pwm->prescaler == prescaler && pwm->period == period)
289 duty_only = true;
290
291 pwm->prescaler = prescaler;
292 pwm->period = period;
293 pwm->duty = duty;
294
295 /* If the channel is disabled we're done. */
296 if (!pwm_is_enabled(_pwm))
297 return 0;
298
299 if (duty_only && pwm->timer_on) {
300 /*
301 * If only the duty cycle changed and the timer is already
302 * running, there's no need to reconfigure it completely, Just
303 * modify the duty cycle.
304 */
305 tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
306 dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", pwm->channel,
307 pwm->duty);
308 } else {
309 /* Otherwise perform a full reconfiguration. */
310 ret = tpu_pwm_timer_start(pwm);
311 if (ret < 0)
312 return ret;
313 }
314
315 if (duty == 0 || duty == period) {
316 /*
317 * To avoid running the timer when not strictly required, handle
318 * 0% and 100% duty cycles as fixed levels and stop the timer.
319 */
320 tpu_pwm_set_pin(pwm, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
321 tpu_pwm_timer_stop(pwm);
322 }
323
324 return 0;
325}
326
327static int tpu_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *_pwm,
328 enum pwm_polarity polarity)
329{
330 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
331
332 pwm->polarity = polarity;
333
334 return 0;
335}
336
337static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *_pwm)
338{
339 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
340 int ret;
341
342 ret = tpu_pwm_timer_start(pwm);
343 if (ret < 0)
344 return ret;
345
346 /*
347 * To avoid running the timer when not strictly required, handle 0% and
348 * 100% duty cycles as fixed levels and stop the timer.
349 */
350 if (pwm->duty == 0 || pwm->duty == pwm->period) {
351 tpu_pwm_set_pin(pwm, pwm->duty ?
352 TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
353 tpu_pwm_timer_stop(pwm);
354 }
355
356 return 0;
357}
358
359static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
360{
361 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
362
363 /* The timer must be running to modify the pin output configuration. */
364 tpu_pwm_timer_start(pwm);
365 tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
366 tpu_pwm_timer_stop(pwm);
367}
368
369static const struct pwm_ops tpu_pwm_ops = {
370 .request = tpu_pwm_request,
371 .free = tpu_pwm_free,
372 .config = tpu_pwm_config,
373 .set_polarity = tpu_pwm_set_polarity,
374 .enable = tpu_pwm_enable,
375 .disable = tpu_pwm_disable,
376 .owner = THIS_MODULE,
377};
378
379/* -----------------------------------------------------------------------------
380 * Probe and remove
381 */
382
383static int tpu_probe(struct platform_device *pdev)
384{
385 struct tpu_device *tpu;
386 struct resource *res;
387 int ret;
388
389 tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
390 if (tpu == NULL)
391 return -ENOMEM;
392
393 spin_lock_init(&tpu->lock);
394 tpu->pdev = pdev;
395
396 /* Map memory, get clock and pin control. */
397 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
398 tpu->base = devm_ioremap_resource(&pdev->dev, res);
399 if (IS_ERR(tpu->base))
400 return PTR_ERR(tpu->base);
401
402 tpu->clk = devm_clk_get(&pdev->dev, NULL);
403 if (IS_ERR(tpu->clk)) {
404 dev_err(&pdev->dev, "cannot get clock\n");
405 return PTR_ERR(tpu->clk);
406 }
407
408 /* Initialize and register the device. */
409 platform_set_drvdata(pdev, tpu);
410
411 tpu->chip.dev = &pdev->dev;
412 tpu->chip.ops = &tpu_pwm_ops;
413 tpu->chip.of_xlate = of_pwm_xlate_with_flags;
414 tpu->chip.of_pwm_n_cells = 3;
415 tpu->chip.base = -1;
416 tpu->chip.npwm = TPU_CHANNEL_MAX;
417
418 ret = pwmchip_add(&tpu->chip);
419 if (ret < 0) {
420 dev_err(&pdev->dev, "failed to register PWM chip\n");
421 return ret;
422 }
423
424 dev_info(&pdev->dev, "TPU PWM %d registered\n", tpu->pdev->id);
425
426 pm_runtime_enable(&pdev->dev);
427
428 return 0;
429}
430
431static int tpu_remove(struct platform_device *pdev)
432{
433 struct tpu_device *tpu = platform_get_drvdata(pdev);
434 int ret;
435
436 ret = pwmchip_remove(&tpu->chip);
437 if (ret)
438 return ret;
439
440 pm_runtime_disable(&pdev->dev);
441
442 return 0;
443}
444
445#ifdef CONFIG_OF
446static const struct of_device_id tpu_of_table[] = {
447 { .compatible = "renesas,tpu-r8a73a4", },
448 { .compatible = "renesas,tpu-r8a7740", },
449 { .compatible = "renesas,tpu-r8a7790", },
450 { .compatible = "renesas,tpu", },
451 { },
452};
453
454MODULE_DEVICE_TABLE(of, tpu_of_table);
455#endif
456
457static struct platform_driver tpu_driver = {
458 .probe = tpu_probe,
459 .remove = tpu_remove,
460 .driver = {
461 .name = "renesas-tpu-pwm",
462 .of_match_table = of_match_ptr(tpu_of_table),
463 }
464};
465
466module_platform_driver(tpu_driver);
467
468MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
469MODULE_DESCRIPTION("Renesas TPU PWM Driver");
470MODULE_LICENSE("GPL v2");
471MODULE_ALIAS("platform:renesas-tpu-pwm");