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6fc601e3 BD |
1 | /* arch/arm/plat-s3c24xx/pwm.c |
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 | * | |
7 | * S3C24XX PWM device core | |
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> | |
17 | #include <linux/err.h> | |
18 | #include <linux/clk.h> | |
19 | #include <linux/io.h> | |
20 | #include <linux/pwm.h> | |
21 | ||
80b02c17 RK |
22 | #include <mach/irqs.h> |
23 | ||
a2b7ba9c BD |
24 | #include <plat/devs.h> |
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 | ||
48 | /* Standard setup for a timer block. */ | |
49 | ||
50 | #define TIMER_RESOURCE_SIZE (1) | |
51 | ||
52 | #define TIMER_RESOURCE(_tmr, _irq) \ | |
53 | (struct resource [TIMER_RESOURCE_SIZE]) { \ | |
54 | [0] = { \ | |
55 | .start = _irq, \ | |
56 | .end = _irq, \ | |
57 | .flags = IORESOURCE_IRQ \ | |
58 | } \ | |
59 | } | |
60 | ||
55b404fd | 61 | #define DEFINE_S3C_TIMER(_tmr_no, _irq) \ |
6fc601e3 BD |
62 | .name = "s3c24xx-pwm", \ |
63 | .id = _tmr_no, \ | |
64 | .num_resources = TIMER_RESOURCE_SIZE, \ | |
65 | .resource = TIMER_RESOURCE(_tmr_no, _irq), \ | |
66 | ||
67 | /* since we already have an static mapping for the timer, we do not | |
68 | * bother setting any IO resource for the base. | |
69 | */ | |
70 | ||
71 | struct platform_device s3c_device_timer[] = { | |
55b404fd NC |
72 | [0] = { DEFINE_S3C_TIMER(0, IRQ_TIMER0) }, |
73 | [1] = { DEFINE_S3C_TIMER(1, IRQ_TIMER1) }, | |
74 | [2] = { DEFINE_S3C_TIMER(2, IRQ_TIMER2) }, | |
75 | [3] = { DEFINE_S3C_TIMER(3, IRQ_TIMER3) }, | |
76 | [4] = { DEFINE_S3C_TIMER(4, IRQ_TIMER4) }, | |
6fc601e3 BD |
77 | }; |
78 | ||
79 | static inline int pwm_is_tdiv(struct pwm_device *pwm) | |
80 | { | |
81 | return clk_get_parent(pwm->clk) == pwm->clk_div; | |
82 | } | |
83 | ||
84 | static DEFINE_MUTEX(pwm_lock); | |
85 | static LIST_HEAD(pwm_list); | |
86 | ||
87 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
88 | { | |
89 | struct pwm_device *pwm; | |
90 | int found = 0; | |
91 | ||
92 | mutex_lock(&pwm_lock); | |
93 | ||
94 | list_for_each_entry(pwm, &pwm_list, list) { | |
95 | if (pwm->pwm_id == pwm_id) { | |
96 | found = 1; | |
97 | break; | |
98 | } | |
99 | } | |
100 | ||
101 | if (found) { | |
102 | if (pwm->use_count == 0) { | |
103 | pwm->use_count = 1; | |
104 | pwm->label = label; | |
105 | } else | |
106 | pwm = ERR_PTR(-EBUSY); | |
107 | } else | |
108 | pwm = ERR_PTR(-ENOENT); | |
109 | ||
110 | mutex_unlock(&pwm_lock); | |
111 | return pwm; | |
112 | } | |
113 | ||
114 | EXPORT_SYMBOL(pwm_request); | |
115 | ||
116 | ||
117 | void pwm_free(struct pwm_device *pwm) | |
118 | { | |
119 | mutex_lock(&pwm_lock); | |
120 | ||
121 | if (pwm->use_count) { | |
122 | pwm->use_count--; | |
123 | pwm->label = NULL; | |
124 | } else | |
125 | printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id); | |
126 | ||
127 | mutex_unlock(&pwm_lock); | |
128 | } | |
129 | ||
130 | EXPORT_SYMBOL(pwm_free); | |
131 | ||
132 | #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) | |
133 | #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) | |
134 | #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) | |
135 | #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) | |
136 | ||
137 | int pwm_enable(struct pwm_device *pwm) | |
138 | { | |
139 | unsigned long flags; | |
140 | unsigned long tcon; | |
141 | ||
142 | local_irq_save(flags); | |
143 | ||
144 | tcon = __raw_readl(S3C2410_TCON); | |
145 | tcon |= pwm_tcon_start(pwm); | |
146 | __raw_writel(tcon, S3C2410_TCON); | |
147 | ||
148 | local_irq_restore(flags); | |
149 | ||
150 | pwm->running = 1; | |
151 | return 0; | |
152 | } | |
153 | ||
154 | EXPORT_SYMBOL(pwm_enable); | |
155 | ||
156 | void pwm_disable(struct pwm_device *pwm) | |
157 | { | |
158 | unsigned long flags; | |
159 | unsigned long tcon; | |
160 | ||
161 | local_irq_save(flags); | |
162 | ||
163 | tcon = __raw_readl(S3C2410_TCON); | |
164 | tcon &= ~pwm_tcon_start(pwm); | |
165 | __raw_writel(tcon, S3C2410_TCON); | |
166 | ||
167 | local_irq_restore(flags); | |
168 | ||
169 | pwm->running = 0; | |
170 | } | |
171 | ||
172 | EXPORT_SYMBOL(pwm_disable); | |
173 | ||
10389592 | 174 | static unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq) |
6fc601e3 BD |
175 | { |
176 | unsigned long tin_parent_rate; | |
177 | unsigned int div; | |
178 | ||
179 | tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div)); | |
180 | pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate); | |
181 | ||
182 | for (div = 2; div <= 16; div *= 2) { | |
183 | if ((tin_parent_rate / (div << 16)) < freq) | |
184 | return tin_parent_rate / div; | |
185 | } | |
186 | ||
187 | return tin_parent_rate / 16; | |
188 | } | |
189 | ||
190 | #define NS_IN_HZ (1000000000UL) | |
191 | ||
192 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
193 | { | |
194 | unsigned long tin_rate; | |
195 | unsigned long tin_ns; | |
196 | unsigned long period; | |
197 | unsigned long flags; | |
198 | unsigned long tcon; | |
199 | unsigned long tcnt; | |
200 | long tcmp; | |
201 | ||
202 | /* We currently avoid using 64bit arithmetic by using the | |
203 | * fact that anything faster than 1Hz is easily representable | |
204 | * by 32bits. */ | |
205 | ||
206 | if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) | |
207 | return -ERANGE; | |
208 | ||
209 | if (duty_ns > period_ns) | |
210 | return -EINVAL; | |
211 | ||
212 | if (period_ns == pwm->period_ns && | |
213 | duty_ns == pwm->duty_ns) | |
214 | return 0; | |
215 | ||
216 | /* The TCMP and TCNT can be read without a lock, they're not | |
217 | * shared between the timers. */ | |
218 | ||
219 | tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id)); | |
220 | tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id)); | |
221 | ||
222 | period = NS_IN_HZ / period_ns; | |
223 | ||
224 | pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n", | |
225 | duty_ns, period_ns, period); | |
226 | ||
227 | /* Check to see if we are changing the clock rate of the PWM */ | |
228 | ||
229 | if (pwm->period_ns != period_ns) { | |
230 | if (pwm_is_tdiv(pwm)) { | |
231 | tin_rate = pwm_calc_tin(pwm, period); | |
232 | clk_set_rate(pwm->clk_div, tin_rate); | |
233 | } else | |
234 | tin_rate = clk_get_rate(pwm->clk); | |
235 | ||
236 | pwm->period_ns = period_ns; | |
237 | ||
238 | pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate); | |
239 | ||
240 | tin_ns = NS_IN_HZ / tin_rate; | |
241 | tcnt = period_ns / tin_ns; | |
242 | } else | |
243 | tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk); | |
244 | ||
245 | /* Note, counters count down */ | |
246 | ||
247 | tcmp = duty_ns / tin_ns; | |
248 | tcmp = tcnt - tcmp; | |
249 | ||
250 | pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); | |
251 | ||
252 | if (tcmp < 0) | |
253 | tcmp = 0; | |
254 | ||
255 | /* Update the PWM register block. */ | |
256 | ||
257 | local_irq_save(flags); | |
258 | ||
259 | __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id)); | |
260 | __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id)); | |
261 | ||
262 | tcon = __raw_readl(S3C2410_TCON); | |
263 | tcon |= pwm_tcon_manulupdate(pwm); | |
264 | tcon |= pwm_tcon_autoreload(pwm); | |
265 | __raw_writel(tcon, S3C2410_TCON); | |
266 | ||
267 | tcon &= ~pwm_tcon_manulupdate(pwm); | |
268 | __raw_writel(tcon, S3C2410_TCON); | |
269 | ||
270 | local_irq_restore(flags); | |
271 | ||
272 | return 0; | |
273 | } | |
274 | ||
275 | EXPORT_SYMBOL(pwm_config); | |
276 | ||
277 | static int pwm_register(struct pwm_device *pwm) | |
278 | { | |
279 | pwm->duty_ns = -1; | |
280 | pwm->period_ns = -1; | |
281 | ||
282 | mutex_lock(&pwm_lock); | |
283 | list_add_tail(&pwm->list, &pwm_list); | |
284 | mutex_unlock(&pwm_lock); | |
285 | ||
286 | return 0; | |
287 | } | |
288 | ||
289 | static int s3c_pwm_probe(struct platform_device *pdev) | |
290 | { | |
291 | struct device *dev = &pdev->dev; | |
292 | struct pwm_device *pwm; | |
293 | unsigned long flags; | |
294 | unsigned long tcon; | |
295 | unsigned int id = pdev->id; | |
296 | int ret; | |
297 | ||
298 | if (id == 4) { | |
299 | dev_err(dev, "TIMER4 is currently not supported\n"); | |
300 | return -ENXIO; | |
301 | } | |
302 | ||
303 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
304 | if (pwm == NULL) { | |
305 | dev_err(dev, "failed to allocate pwm_device\n"); | |
306 | return -ENOMEM; | |
307 | } | |
308 | ||
309 | pwm->pdev = pdev; | |
310 | pwm->pwm_id = id; | |
311 | ||
312 | /* calculate base of control bits in TCON */ | |
313 | pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4; | |
314 | ||
315 | pwm->clk = clk_get(dev, "pwm-tin"); | |
316 | if (IS_ERR(pwm->clk)) { | |
317 | dev_err(dev, "failed to get pwm tin clk\n"); | |
318 | ret = PTR_ERR(pwm->clk); | |
319 | goto err_alloc; | |
320 | } | |
321 | ||
322 | pwm->clk_div = clk_get(dev, "pwm-tdiv"); | |
323 | if (IS_ERR(pwm->clk_div)) { | |
324 | dev_err(dev, "failed to get pwm tdiv clk\n"); | |
325 | ret = PTR_ERR(pwm->clk_div); | |
326 | goto err_clk_tin; | |
327 | } | |
328 | ||
329 | local_irq_save(flags); | |
330 | ||
331 | tcon = __raw_readl(S3C2410_TCON); | |
332 | tcon |= pwm_tcon_invert(pwm); | |
333 | __raw_writel(tcon, S3C2410_TCON); | |
334 | ||
335 | local_irq_restore(flags); | |
336 | ||
337 | ||
338 | ret = pwm_register(pwm); | |
339 | if (ret) { | |
340 | dev_err(dev, "failed to register pwm\n"); | |
341 | goto err_clk_tdiv; | |
342 | } | |
343 | ||
344 | pwm_dbg(pwm, "config bits %02x\n", | |
345 | (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f); | |
346 | ||
347 | dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", | |
348 | clk_get_rate(pwm->clk), | |
349 | clk_get_rate(pwm->clk_div), | |
350 | pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base); | |
351 | ||
352 | platform_set_drvdata(pdev, pwm); | |
353 | return 0; | |
354 | ||
355 | err_clk_tdiv: | |
356 | clk_put(pwm->clk_div); | |
357 | ||
358 | err_clk_tin: | |
359 | clk_put(pwm->clk); | |
360 | ||
361 | err_alloc: | |
362 | kfree(pwm); | |
363 | return ret; | |
364 | } | |
365 | ||
366 | static int s3c_pwm_remove(struct platform_device *pdev) | |
367 | { | |
368 | struct pwm_device *pwm = platform_get_drvdata(pdev); | |
369 | ||
370 | clk_put(pwm->clk_div); | |
371 | clk_put(pwm->clk); | |
372 | kfree(pwm); | |
373 | ||
374 | return 0; | |
375 | } | |
376 | ||
377 | static struct platform_driver s3c_pwm_driver = { | |
378 | .driver = { | |
379 | .name = "s3c24xx-pwm", | |
380 | .owner = THIS_MODULE, | |
381 | }, | |
382 | .probe = s3c_pwm_probe, | |
383 | .remove = __devexit_p(s3c_pwm_remove), | |
384 | }; | |
385 | ||
386 | static int __init pwm_init(void) | |
387 | { | |
388 | int ret; | |
389 | ||
390 | clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); | |
391 | clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); | |
392 | ||
393 | if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { | |
394 | printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__); | |
395 | return -EINVAL; | |
396 | } | |
397 | ||
398 | ret = platform_driver_register(&s3c_pwm_driver); | |
399 | if (ret) | |
400 | printk(KERN_ERR "%s: failed to add pwm driver\n", __func__); | |
401 | ||
402 | return ret; | |
403 | } | |
404 | ||
405 | arch_initcall(pwm_init); |