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b5ead1cd | 1 | /* arch/arm/plat-s3c/pwm.c |
6fc601e3 BD |
2 | * |
3 | * Copyright (c) 2007 Ben Dooks | |
4 | * Copyright (c) 2008 Simtec Electronics | |
5 | * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org> | |
6 | * | |
b5ead1cd | 7 | * S3C series PWM device core |
6fc601e3 BD |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License. | |
12 | */ | |
13 | ||
14 | #include <linux/module.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/platform_device.h> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
6fc601e3 BD |
18 | #include <linux/err.h> |
19 | #include <linux/clk.h> | |
20 | #include <linux/io.h> | |
21 | #include <linux/pwm.h> | |
22 | ||
b5ead1cd | 23 | #include <mach/map.h> |
80b02c17 | 24 | |
a2b7ba9c | 25 | #include <plat/regs-timer.h> |
6fc601e3 BD |
26 | |
27 | struct pwm_device { | |
28 | struct list_head list; | |
29 | struct platform_device *pdev; | |
30 | ||
31 | struct clk *clk_div; | |
32 | struct clk *clk; | |
33 | const char *label; | |
34 | ||
35 | unsigned int period_ns; | |
36 | unsigned int duty_ns; | |
37 | ||
38 | unsigned char tcon_base; | |
39 | unsigned char running; | |
40 | unsigned char use_count; | |
41 | unsigned char pwm_id; | |
42 | }; | |
43 | ||
66592eee | 44 | #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg) |
6fc601e3 BD |
45 | |
46 | static struct clk *clk_scaler[2]; | |
47 | ||
6fc601e3 BD |
48 | static inline int pwm_is_tdiv(struct pwm_device *pwm) |
49 | { | |
50 | return clk_get_parent(pwm->clk) == pwm->clk_div; | |
51 | } | |
52 | ||
53 | static DEFINE_MUTEX(pwm_lock); | |
54 | static LIST_HEAD(pwm_list); | |
55 | ||
56 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
57 | { | |
58 | struct pwm_device *pwm; | |
59 | int found = 0; | |
60 | ||
61 | mutex_lock(&pwm_lock); | |
62 | ||
63 | list_for_each_entry(pwm, &pwm_list, list) { | |
64 | if (pwm->pwm_id == pwm_id) { | |
65 | found = 1; | |
66 | break; | |
67 | } | |
68 | } | |
69 | ||
70 | if (found) { | |
71 | if (pwm->use_count == 0) { | |
72 | pwm->use_count = 1; | |
73 | pwm->label = label; | |
74 | } else | |
75 | pwm = ERR_PTR(-EBUSY); | |
76 | } else | |
77 | pwm = ERR_PTR(-ENOENT); | |
78 | ||
79 | mutex_unlock(&pwm_lock); | |
80 | return pwm; | |
81 | } | |
82 | ||
83 | EXPORT_SYMBOL(pwm_request); | |
84 | ||
85 | ||
86 | void pwm_free(struct pwm_device *pwm) | |
87 | { | |
88 | mutex_lock(&pwm_lock); | |
89 | ||
90 | if (pwm->use_count) { | |
91 | pwm->use_count--; | |
92 | pwm->label = NULL; | |
93 | } else | |
94 | printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id); | |
95 | ||
96 | mutex_unlock(&pwm_lock); | |
97 | } | |
98 | ||
99 | EXPORT_SYMBOL(pwm_free); | |
100 | ||
101 | #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) | |
102 | #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) | |
103 | #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) | |
104 | #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) | |
105 | ||
106 | int pwm_enable(struct pwm_device *pwm) | |
107 | { | |
108 | unsigned long flags; | |
109 | unsigned long tcon; | |
110 | ||
111 | local_irq_save(flags); | |
112 | ||
113 | tcon = __raw_readl(S3C2410_TCON); | |
114 | tcon |= pwm_tcon_start(pwm); | |
115 | __raw_writel(tcon, S3C2410_TCON); | |
116 | ||
117 | local_irq_restore(flags); | |
118 | ||
119 | pwm->running = 1; | |
120 | return 0; | |
121 | } | |
122 | ||
123 | EXPORT_SYMBOL(pwm_enable); | |
124 | ||
125 | void pwm_disable(struct pwm_device *pwm) | |
126 | { | |
127 | unsigned long flags; | |
128 | unsigned long tcon; | |
129 | ||
130 | local_irq_save(flags); | |
131 | ||
132 | tcon = __raw_readl(S3C2410_TCON); | |
133 | tcon &= ~pwm_tcon_start(pwm); | |
134 | __raw_writel(tcon, S3C2410_TCON); | |
135 | ||
136 | local_irq_restore(flags); | |
137 | ||
138 | pwm->running = 0; | |
139 | } | |
140 | ||
141 | EXPORT_SYMBOL(pwm_disable); | |
142 | ||
10389592 | 143 | static unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq) |
6fc601e3 BD |
144 | { |
145 | unsigned long tin_parent_rate; | |
146 | unsigned int div; | |
147 | ||
148 | tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div)); | |
149 | pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate); | |
150 | ||
151 | for (div = 2; div <= 16; div *= 2) { | |
152 | if ((tin_parent_rate / (div << 16)) < freq) | |
153 | return tin_parent_rate / div; | |
154 | } | |
155 | ||
156 | return tin_parent_rate / 16; | |
157 | } | |
158 | ||
159 | #define NS_IN_HZ (1000000000UL) | |
160 | ||
161 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
162 | { | |
163 | unsigned long tin_rate; | |
164 | unsigned long tin_ns; | |
165 | unsigned long period; | |
166 | unsigned long flags; | |
167 | unsigned long tcon; | |
168 | unsigned long tcnt; | |
169 | long tcmp; | |
170 | ||
171 | /* We currently avoid using 64bit arithmetic by using the | |
172 | * fact that anything faster than 1Hz is easily representable | |
173 | * by 32bits. */ | |
174 | ||
175 | if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) | |
176 | return -ERANGE; | |
177 | ||
178 | if (duty_ns > period_ns) | |
179 | return -EINVAL; | |
180 | ||
181 | if (period_ns == pwm->period_ns && | |
182 | duty_ns == pwm->duty_ns) | |
183 | return 0; | |
184 | ||
185 | /* The TCMP and TCNT can be read without a lock, they're not | |
186 | * shared between the timers. */ | |
187 | ||
188 | tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id)); | |
189 | tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id)); | |
190 | ||
191 | period = NS_IN_HZ / period_ns; | |
192 | ||
193 | pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n", | |
194 | duty_ns, period_ns, period); | |
195 | ||
196 | /* Check to see if we are changing the clock rate of the PWM */ | |
197 | ||
198 | if (pwm->period_ns != period_ns) { | |
199 | if (pwm_is_tdiv(pwm)) { | |
200 | tin_rate = pwm_calc_tin(pwm, period); | |
201 | clk_set_rate(pwm->clk_div, tin_rate); | |
202 | } else | |
203 | tin_rate = clk_get_rate(pwm->clk); | |
204 | ||
205 | pwm->period_ns = period_ns; | |
206 | ||
207 | pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate); | |
208 | ||
209 | tin_ns = NS_IN_HZ / tin_rate; | |
210 | tcnt = period_ns / tin_ns; | |
211 | } else | |
212 | tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk); | |
213 | ||
214 | /* Note, counters count down */ | |
215 | ||
216 | tcmp = duty_ns / tin_ns; | |
217 | tcmp = tcnt - tcmp; | |
165f5f64 PK |
218 | /* the pwm hw only checks the compare register after a decrement, |
219 | so the pin never toggles if tcmp = tcnt */ | |
220 | if (tcmp == tcnt) | |
221 | tcmp--; | |
6fc601e3 BD |
222 | |
223 | pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); | |
224 | ||
225 | if (tcmp < 0) | |
226 | tcmp = 0; | |
227 | ||
228 | /* Update the PWM register block. */ | |
229 | ||
230 | local_irq_save(flags); | |
231 | ||
232 | __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id)); | |
233 | __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id)); | |
234 | ||
235 | tcon = __raw_readl(S3C2410_TCON); | |
236 | tcon |= pwm_tcon_manulupdate(pwm); | |
237 | tcon |= pwm_tcon_autoreload(pwm); | |
238 | __raw_writel(tcon, S3C2410_TCON); | |
239 | ||
240 | tcon &= ~pwm_tcon_manulupdate(pwm); | |
241 | __raw_writel(tcon, S3C2410_TCON); | |
242 | ||
243 | local_irq_restore(flags); | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
248 | EXPORT_SYMBOL(pwm_config); | |
249 | ||
250 | static int pwm_register(struct pwm_device *pwm) | |
251 | { | |
252 | pwm->duty_ns = -1; | |
253 | pwm->period_ns = -1; | |
254 | ||
255 | mutex_lock(&pwm_lock); | |
256 | list_add_tail(&pwm->list, &pwm_list); | |
257 | mutex_unlock(&pwm_lock); | |
258 | ||
259 | return 0; | |
260 | } | |
261 | ||
262 | static int s3c_pwm_probe(struct platform_device *pdev) | |
263 | { | |
264 | struct device *dev = &pdev->dev; | |
265 | struct pwm_device *pwm; | |
266 | unsigned long flags; | |
267 | unsigned long tcon; | |
268 | unsigned int id = pdev->id; | |
269 | int ret; | |
270 | ||
271 | if (id == 4) { | |
272 | dev_err(dev, "TIMER4 is currently not supported\n"); | |
273 | return -ENXIO; | |
274 | } | |
275 | ||
276 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
277 | if (pwm == NULL) { | |
278 | dev_err(dev, "failed to allocate pwm_device\n"); | |
279 | return -ENOMEM; | |
280 | } | |
281 | ||
282 | pwm->pdev = pdev; | |
283 | pwm->pwm_id = id; | |
284 | ||
285 | /* calculate base of control bits in TCON */ | |
286 | pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4; | |
287 | ||
288 | pwm->clk = clk_get(dev, "pwm-tin"); | |
289 | if (IS_ERR(pwm->clk)) { | |
290 | dev_err(dev, "failed to get pwm tin clk\n"); | |
291 | ret = PTR_ERR(pwm->clk); | |
292 | goto err_alloc; | |
293 | } | |
294 | ||
295 | pwm->clk_div = clk_get(dev, "pwm-tdiv"); | |
296 | if (IS_ERR(pwm->clk_div)) { | |
297 | dev_err(dev, "failed to get pwm tdiv clk\n"); | |
298 | ret = PTR_ERR(pwm->clk_div); | |
299 | goto err_clk_tin; | |
300 | } | |
301 | ||
302 | local_irq_save(flags); | |
303 | ||
304 | tcon = __raw_readl(S3C2410_TCON); | |
305 | tcon |= pwm_tcon_invert(pwm); | |
306 | __raw_writel(tcon, S3C2410_TCON); | |
307 | ||
308 | local_irq_restore(flags); | |
309 | ||
310 | ||
311 | ret = pwm_register(pwm); | |
312 | if (ret) { | |
313 | dev_err(dev, "failed to register pwm\n"); | |
314 | goto err_clk_tdiv; | |
315 | } | |
316 | ||
317 | pwm_dbg(pwm, "config bits %02x\n", | |
318 | (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f); | |
319 | ||
320 | dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", | |
321 | clk_get_rate(pwm->clk), | |
322 | clk_get_rate(pwm->clk_div), | |
323 | pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base); | |
324 | ||
325 | platform_set_drvdata(pdev, pwm); | |
326 | return 0; | |
327 | ||
328 | err_clk_tdiv: | |
329 | clk_put(pwm->clk_div); | |
330 | ||
331 | err_clk_tin: | |
332 | clk_put(pwm->clk); | |
333 | ||
334 | err_alloc: | |
335 | kfree(pwm); | |
336 | return ret; | |
337 | } | |
338 | ||
93b0d8c6 | 339 | static int __devexit s3c_pwm_remove(struct platform_device *pdev) |
6fc601e3 BD |
340 | { |
341 | struct pwm_device *pwm = platform_get_drvdata(pdev); | |
342 | ||
343 | clk_put(pwm->clk_div); | |
344 | clk_put(pwm->clk); | |
345 | kfree(pwm); | |
346 | ||
347 | return 0; | |
348 | } | |
349 | ||
e79032aa VK |
350 | #ifdef CONFIG_PM |
351 | static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state) | |
352 | { | |
353 | struct pwm_device *pwm = platform_get_drvdata(pdev); | |
354 | ||
355 | /* No one preserve these values during suspend so reset them | |
356 | * Otherwise driver leaves PWM unconfigured if same values | |
357 | * passed to pwm_config | |
358 | */ | |
359 | pwm->period_ns = 0; | |
360 | pwm->duty_ns = 0; | |
361 | ||
362 | return 0; | |
363 | } | |
364 | ||
365 | static int s3c_pwm_resume(struct platform_device *pdev) | |
366 | { | |
367 | struct pwm_device *pwm = platform_get_drvdata(pdev); | |
368 | unsigned long tcon; | |
369 | ||
370 | /* Restore invertion */ | |
371 | tcon = __raw_readl(S3C2410_TCON); | |
372 | tcon |= pwm_tcon_invert(pwm); | |
373 | __raw_writel(tcon, S3C2410_TCON); | |
374 | ||
375 | return 0; | |
376 | } | |
377 | ||
378 | #else | |
379 | #define s3c_pwm_suspend NULL | |
380 | #define s3c_pwm_resume NULL | |
381 | #endif | |
382 | ||
6fc601e3 BD |
383 | static struct platform_driver s3c_pwm_driver = { |
384 | .driver = { | |
385 | .name = "s3c24xx-pwm", | |
386 | .owner = THIS_MODULE, | |
387 | }, | |
388 | .probe = s3c_pwm_probe, | |
389 | .remove = __devexit_p(s3c_pwm_remove), | |
e79032aa VK |
390 | .suspend = s3c_pwm_suspend, |
391 | .resume = s3c_pwm_resume, | |
6fc601e3 BD |
392 | }; |
393 | ||
394 | static int __init pwm_init(void) | |
395 | { | |
396 | int ret; | |
397 | ||
398 | clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); | |
399 | clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); | |
400 | ||
401 | if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { | |
402 | printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__); | |
403 | return -EINVAL; | |
404 | } | |
405 | ||
406 | ret = platform_driver_register(&s3c_pwm_driver); | |
407 | if (ret) | |
408 | printk(KERN_ERR "%s: failed to add pwm driver\n", __func__); | |
409 | ||
410 | return ret; | |
411 | } | |
412 | ||
413 | arch_initcall(pwm_init); |