Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/drivers/pwm/pwm-atmel-tcb.c

  1 /*
  2  * Copyright (C) Overkiz SAS 2012
  3  *
  4  * Author: Boris BREZILLON <b.brezillon@overkiz.com>
  5  * License terms: GNU General Public License (GPL) version 2
  6  */
  7 
  8 #include <linux/module.h>
  9 #include <linux/init.h>
 10 #include <linux/clocksource.h>
 11 #include <linux/clockchips.h>
 12 #include <linux/interrupt.h>
 13 #include <linux/irq.h>
 14 
 15 #include <linux/clk.h>
 16 #include <linux/err.h>
 17 #include <linux/ioport.h>
 18 #include <linux/io.h>
 19 #include <linux/platform_device.h>
 20 #include <linux/atmel_tc.h>
 21 #include <linux/pwm.h>
 22 #include <linux/of_device.h>
 23 #include <linux/slab.h>
 24 
 25 #define NPWM    6
 26 
 27 #define ATMEL_TC_ACMR_MASK      (ATMEL_TC_ACPA | ATMEL_TC_ACPC |        \
 28                                  ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)
 29 
 30 #define ATMEL_TC_BCMR_MASK      (ATMEL_TC_BCPB | ATMEL_TC_BCPC |        \
 31                                  ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG)
 32 
 33 struct atmel_tcb_pwm_device {
 34         enum pwm_polarity polarity;     /* PWM polarity */
 35         unsigned div;                   /* PWM clock divider */
 36         unsigned duty;                  /* PWM duty expressed in clk cycles */
 37         unsigned period;                /* PWM period expressed in clk cycles */
 38 };
 39 
 40 struct atmel_tcb_pwm_chip {
 41         struct pwm_chip chip;
 42         spinlock_t lock;
 43         struct atmel_tc *tc;
 44         struct atmel_tcb_pwm_device *pwms[NPWM];
 45 };
 46 
 47 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
 48 {
 49         return container_of(chip, struct atmel_tcb_pwm_chip, chip);
 50 }
 51 
 52 static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip,
 53                                       struct pwm_device *pwm,
 54                                       enum pwm_polarity polarity)
 55 {
 56         struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
 57 
 58         tcbpwm->polarity = polarity;
 59 
 60         return 0;
 61 }
 62 
 63 static int atmel_tcb_pwm_request(struct pwm_chip *chip,
 64                                  struct pwm_device *pwm)
 65 {
 66         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
 67         struct atmel_tcb_pwm_device *tcbpwm;
 68         struct atmel_tc *tc = tcbpwmc->tc;
 69         void __iomem *regs = tc->regs;
 70         unsigned group = pwm->hwpwm / 2;
 71         unsigned index = pwm->hwpwm % 2;
 72         unsigned cmr;
 73         int ret;
 74 
 75         tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL);
 76         if (!tcbpwm)
 77                 return -ENOMEM;
 78 
 79         ret = clk_prepare_enable(tc->clk[group]);
 80         if (ret) {
 81                 devm_kfree(chip->dev, tcbpwm);
 82                 return ret;
 83         }
 84 
 85         pwm_set_chip_data(pwm, tcbpwm);
 86         tcbpwm->polarity = PWM_POLARITY_NORMAL;
 87         tcbpwm->duty = 0;
 88         tcbpwm->period = 0;
 89         tcbpwm->div = 0;
 90 
 91         spin_lock(&tcbpwmc->lock);
 92         cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
 93         /*
 94          * Get init config from Timer Counter registers if
 95          * Timer Counter is already configured as a PWM generator.
 96          */
 97         if (cmr & ATMEL_TC_WAVE) {
 98                 if (index == 0)
 99                         tcbpwm->duty =
100                                 __raw_readl(regs + ATMEL_TC_REG(group, RA));
101                 else
102                         tcbpwm->duty =
103                                 __raw_readl(regs + ATMEL_TC_REG(group, RB));
104 
105                 tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
106                 tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC));
107                 cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK |
108                         ATMEL_TC_BCMR_MASK);
109         } else
110                 cmr = 0;
111 
112         cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
113         __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
114         spin_unlock(&tcbpwmc->lock);
115 
116         tcbpwmc->pwms[pwm->hwpwm] = tcbpwm;
117 
118         return 0;
119 }
120 
121 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
122 {
123         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
124         struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
125         struct atmel_tc *tc = tcbpwmc->tc;
126 
127         clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]);
128         tcbpwmc->pwms[pwm->hwpwm] = NULL;
129         devm_kfree(chip->dev, tcbpwm);
130 }
131 
132 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
133 {
134         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
135         struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
136         struct atmel_tc *tc = tcbpwmc->tc;
137         void __iomem *regs = tc->regs;
138         unsigned group = pwm->hwpwm / 2;
139         unsigned index = pwm->hwpwm % 2;
140         unsigned cmr;
141         enum pwm_polarity polarity = tcbpwm->polarity;
142 
143         /*
144          * If duty is 0 the timer will be stopped and we have to
145          * configure the output correctly on software trigger:
146          *  - set output to high if PWM_POLARITY_INVERSED
147          *  - set output to low if PWM_POLARITY_NORMAL
148          *
149          * This is why we're reverting polarity in this case.
150          */
151         if (tcbpwm->duty == 0)
152                 polarity = !polarity;
153 
154         spin_lock(&tcbpwmc->lock);
155         cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
156 
157         /* flush old setting and set the new one */
158         if (index == 0) {
159                 cmr &= ~ATMEL_TC_ACMR_MASK;
160                 if (polarity == PWM_POLARITY_INVERSED)
161                         cmr |= ATMEL_TC_ASWTRG_CLEAR;
162                 else
163                         cmr |= ATMEL_TC_ASWTRG_SET;
164         } else {
165                 cmr &= ~ATMEL_TC_BCMR_MASK;
166                 if (polarity == PWM_POLARITY_INVERSED)
167                         cmr |= ATMEL_TC_BSWTRG_CLEAR;
168                 else
169                         cmr |= ATMEL_TC_BSWTRG_SET;
170         }
171 
172         __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
173 
174         /*
175          * Use software trigger to apply the new setting.
176          * If both PWM devices in this group are disabled we stop the clock.
177          */
178         if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC)))
179                 __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS,
180                              regs + ATMEL_TC_REG(group, CCR));
181         else
182                 __raw_writel(ATMEL_TC_SWTRG, regs +
183                              ATMEL_TC_REG(group, CCR));
184 
185         spin_unlock(&tcbpwmc->lock);
186 }
187 
188 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
189 {
190         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
191         struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
192         struct atmel_tc *tc = tcbpwmc->tc;
193         void __iomem *regs = tc->regs;
194         unsigned group = pwm->hwpwm / 2;
195         unsigned index = pwm->hwpwm % 2;
196         u32 cmr;
197         enum pwm_polarity polarity = tcbpwm->polarity;
198 
199         /*
200          * If duty is 0 the timer will be stopped and we have to
201          * configure the output correctly on software trigger:
202          *  - set output to high if PWM_POLARITY_INVERSED
203          *  - set output to low if PWM_POLARITY_NORMAL
204          *
205          * This is why we're reverting polarity in this case.
206          */
207         if (tcbpwm->duty == 0)
208                 polarity = !polarity;
209 
210         spin_lock(&tcbpwmc->lock);
211         cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
212 
213         /* flush old setting and set the new one */
214         cmr &= ~ATMEL_TC_TCCLKS;
215 
216         if (index == 0) {
217                 cmr &= ~ATMEL_TC_ACMR_MASK;
218 
219                 /* Set CMR flags according to given polarity */
220                 if (polarity == PWM_POLARITY_INVERSED)
221                         cmr |= ATMEL_TC_ASWTRG_CLEAR;
222                 else
223                         cmr |= ATMEL_TC_ASWTRG_SET;
224         } else {
225                 cmr &= ~ATMEL_TC_BCMR_MASK;
226                 if (polarity == PWM_POLARITY_INVERSED)
227                         cmr |= ATMEL_TC_BSWTRG_CLEAR;
228                 else
229                         cmr |= ATMEL_TC_BSWTRG_SET;
230         }
231 
232         /*
233          * If duty is 0 or equal to period there's no need to register
234          * a specific action on RA/RB and RC compare.
235          * The output will be configured on software trigger and keep
236          * this config till next config call.
237          */
238         if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
239                 if (index == 0) {
240                         if (polarity == PWM_POLARITY_INVERSED)
241                                 cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
242                         else
243                                 cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET;
244                 } else {
245                         if (polarity == PWM_POLARITY_INVERSED)
246                                 cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR;
247                         else
248                                 cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET;
249                 }
250         }
251 
252         cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS);
253 
254         __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
255 
256         if (index == 0)
257                 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA));
258         else
259                 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB));
260 
261         __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC));
262 
263         /* Use software trigger to apply the new setting */
264         __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
265                      regs + ATMEL_TC_REG(group, CCR));
266         spin_unlock(&tcbpwmc->lock);
267         return 0;
268 }
269 
270 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
271                                 int duty_ns, int period_ns)
272 {
273         struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
274         struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
275         unsigned group = pwm->hwpwm / 2;
276         unsigned index = pwm->hwpwm % 2;
277         struct atmel_tcb_pwm_device *atcbpwm = NULL;
278         struct atmel_tc *tc = tcbpwmc->tc;
279         int i;
280         int slowclk = 0;
281         unsigned period;
282         unsigned duty;
283         unsigned rate = clk_get_rate(tc->clk[group]);
284         unsigned long long min;
285         unsigned long long max;
286 
287         /*
288          * Find best clk divisor:
289          * the smallest divisor which can fulfill the period_ns requirements.
290          */
291         for (i = 0; i < 5; ++i) {
292                 if (atmel_tc_divisors[i] == 0) {
293                         slowclk = i;
294                         continue;
295                 }
296                 min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate);
297                 max = min << tc->tcb_config->counter_width;
298                 if (max >= period_ns)
299                         break;
300         }
301 
302         /*
303          * If none of the divisor are small enough to represent period_ns
304          * take slow clock (32KHz).
305          */
306         if (i == 5) {
307                 i = slowclk;
308                 rate = 32768;
309                 min = div_u64(NSEC_PER_SEC, rate);
310                 max = min << tc->tcb_config->counter_width;
311 
312                 /* If period is too big return ERANGE error */
313                 if (max < period_ns)
314                         return -ERANGE;
315         }
316 
317         duty = div_u64(duty_ns, min);
318         period = div_u64(period_ns, min);
319 
320         if (index == 0)
321                 atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1];
322         else
323                 atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1];
324 
325         /*
326          * PWM devices provided by TCB driver are grouped by 2:
327          * - group 0: PWM 0 & 1
328          * - group 1: PWM 2 & 3
329          * - group 2: PWM 4 & 5
330          *
331          * PWM devices in a given group must be configured with the
332          * same period_ns.
333          *
334          * We're checking the period value of the second PWM device
335          * in this group before applying the new config.
336          */
337         if ((atcbpwm && atcbpwm->duty > 0 &&
338                         atcbpwm->duty != atcbpwm->period) &&
339                 (atcbpwm->div != i || atcbpwm->period != period)) {
340                 dev_err(chip->dev,
341                         "failed to configure period_ns: PWM group already configured with a different value\n");
342                 return -EINVAL;
343         }
344 
345         tcbpwm->period = period;
346         tcbpwm->div = i;
347         tcbpwm->duty = duty;
348 
349         /* If the PWM is enabled, call enable to apply the new conf */
350         if (test_bit(PWMF_ENABLED, &pwm->flags))
351                 atmel_tcb_pwm_enable(chip, pwm);
352 
353         return 0;
354 }
355 
356 static const struct pwm_ops atmel_tcb_pwm_ops = {
357         .request = atmel_tcb_pwm_request,
358         .free = atmel_tcb_pwm_free,
359         .config = atmel_tcb_pwm_config,
360         .set_polarity = atmel_tcb_pwm_set_polarity,
361         .enable = atmel_tcb_pwm_enable,
362         .disable = atmel_tcb_pwm_disable,
363         .owner = THIS_MODULE,
364 };
365 
366 static int atmel_tcb_pwm_probe(struct platform_device *pdev)
367 {
368         struct atmel_tcb_pwm_chip *tcbpwm;
369         struct device_node *np = pdev->dev.of_node;
370         struct atmel_tc *tc;
371         int err;
372         int tcblock;
373 
374         err = of_property_read_u32(np, "tc-block", &tcblock);
375         if (err < 0) {
376                 dev_err(&pdev->dev,
377                         "failed to get Timer Counter Block number from device tree (error: %d)\n",
378                         err);
379                 return err;
380         }
381 
382         tc = atmel_tc_alloc(tcblock, "tcb-pwm");
383         if (tc == NULL) {
384                 dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n");
385                 return -ENOMEM;
386         }
387 
388         tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
389         if (tcbpwm == NULL) {
390                 atmel_tc_free(tc);
391                 dev_err(&pdev->dev, "failed to allocate memory\n");
392                 return -ENOMEM;
393         }
394 
395         tcbpwm->chip.dev = &pdev->dev;
396         tcbpwm->chip.ops = &atmel_tcb_pwm_ops;
397         tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags;
398         tcbpwm->chip.of_pwm_n_cells = 3;
399         tcbpwm->chip.base = -1;
400         tcbpwm->chip.npwm = NPWM;
401         tcbpwm->tc = tc;
402 
403         spin_lock_init(&tcbpwm->lock);
404 
405         err = pwmchip_add(&tcbpwm->chip);
406         if (err < 0) {
407                 atmel_tc_free(tc);
408                 return err;
409         }
410 
411         platform_set_drvdata(pdev, tcbpwm);
412 
413         return 0;
414 }
415 
416 static int atmel_tcb_pwm_remove(struct platform_device *pdev)
417 {
418         struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
419         int err;
420 
421         err = pwmchip_remove(&tcbpwm->chip);
422         if (err < 0)
423                 return err;
424 
425         atmel_tc_free(tcbpwm->tc);
426 
427         return 0;
428 }
429 
430 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = {
431         { .compatible = "atmel,tcb-pwm", },
432         { /* sentinel */ }
433 };
434 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);
435 
436 static struct platform_driver atmel_tcb_pwm_driver = {
437         .driver = {
438                 .name = "atmel-tcb-pwm",
439                 .owner = THIS_MODULE,
440                 .of_match_table = atmel_tcb_pwm_dt_ids,
441         },
442         .probe = atmel_tcb_pwm_probe,
443         .remove = atmel_tcb_pwm_remove,
444 };
445 module_platform_driver(atmel_tcb_pwm_driver);
446 
447 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>");
448 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver");
449 MODULE_LICENSE("GPL v2");
450 

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