Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[linux-2.6] / arch / arm / plat-s3c24xx / pwm.c
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
22 #include <asm/plat-s3c24xx/devs.h>
23 #include <asm/plat-s3c/regs-timer.h>
24
25 struct pwm_device {
26         struct list_head         list;
27         struct platform_device  *pdev;
28
29         struct clk              *clk_div;
30         struct clk              *clk;
31         const char              *label;
32
33         unsigned int             period_ns;
34         unsigned int             duty_ns;
35
36         unsigned char            tcon_base;
37         unsigned char            running;
38         unsigned char            use_count;
39         unsigned char            pwm_id;
40 };
41
42 #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
43
44 static struct clk *clk_scaler[2];
45
46 /* Standard setup for a timer block. */
47
48 #define TIMER_RESOURCE_SIZE (1)
49
50 #define TIMER_RESOURCE(_tmr, _irq)                      \
51         (struct resource [TIMER_RESOURCE_SIZE]) {       \
52                 [0] = {                                 \
53                         .start  = _irq,                 \
54                         .end    = _irq,                 \
55                         .flags  = IORESOURCE_IRQ        \
56                 }                                       \
57         }
58
59 #define DEFINE_TIMER(_tmr_no, _irq)                     \
60         .name           = "s3c24xx-pwm",                \
61         .id             = _tmr_no,                      \
62         .num_resources  = TIMER_RESOURCE_SIZE,          \
63         .resource       = TIMER_RESOURCE(_tmr_no, _irq),        \
64
65 /* since we already have an static mapping for the timer, we do not
66  * bother setting any IO resource for the base.
67  */
68
69 struct platform_device s3c_device_timer[] = {
70         [0] = { DEFINE_TIMER(0, IRQ_TIMER0) },
71         [1] = { DEFINE_TIMER(1, IRQ_TIMER1) },
72         [2] = { DEFINE_TIMER(2, IRQ_TIMER2) },
73         [3] = { DEFINE_TIMER(3, IRQ_TIMER3) },
74         [4] = { DEFINE_TIMER(4, IRQ_TIMER4) },
75 };
76
77 static inline int pwm_is_tdiv(struct pwm_device *pwm)
78 {
79         return clk_get_parent(pwm->clk) == pwm->clk_div;
80 }
81
82 static DEFINE_MUTEX(pwm_lock);
83 static LIST_HEAD(pwm_list);
84
85 struct pwm_device *pwm_request(int pwm_id, const char *label)
86 {
87         struct pwm_device *pwm;
88         int found = 0;
89
90         mutex_lock(&pwm_lock);
91
92         list_for_each_entry(pwm, &pwm_list, list) {
93                 if (pwm->pwm_id == pwm_id) {
94                         found = 1;
95                         break;
96                 }
97         }
98
99         if (found) {
100                 if (pwm->use_count == 0) {
101                         pwm->use_count = 1;
102                         pwm->label = label;
103                 } else
104                         pwm = ERR_PTR(-EBUSY);
105         } else
106                 pwm = ERR_PTR(-ENOENT);
107
108         mutex_unlock(&pwm_lock);
109         return pwm;
110 }
111
112 EXPORT_SYMBOL(pwm_request);
113
114
115 void pwm_free(struct pwm_device *pwm)
116 {
117         mutex_lock(&pwm_lock);
118
119         if (pwm->use_count) {
120                 pwm->use_count--;
121                 pwm->label = NULL;
122         } else
123                 printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id);
124
125         mutex_unlock(&pwm_lock);
126 }
127
128 EXPORT_SYMBOL(pwm_free);
129
130 #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0))
131 #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2))
132 #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3))
133 #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1))
134
135 int pwm_enable(struct pwm_device *pwm)
136 {
137         unsigned long flags;
138         unsigned long tcon;
139
140         local_irq_save(flags);
141
142         tcon = __raw_readl(S3C2410_TCON);
143         tcon |= pwm_tcon_start(pwm);
144         __raw_writel(tcon, S3C2410_TCON);
145
146         local_irq_restore(flags);
147
148         pwm->running = 1;
149         return 0;
150 }
151
152 EXPORT_SYMBOL(pwm_enable);
153
154 void pwm_disable(struct pwm_device *pwm)
155 {
156         unsigned long flags;
157         unsigned long tcon;
158
159         local_irq_save(flags);
160
161         tcon = __raw_readl(S3C2410_TCON);
162         tcon &= ~pwm_tcon_start(pwm);
163         __raw_writel(tcon, S3C2410_TCON);
164
165         local_irq_restore(flags);
166
167         pwm->running = 0;
168 }
169
170 EXPORT_SYMBOL(pwm_disable);
171
172 static unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq)
173 {
174         unsigned long tin_parent_rate;
175         unsigned int div;
176
177         tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div));
178         pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate);
179
180         for (div = 2; div <= 16; div *= 2) {
181                 if ((tin_parent_rate / (div << 16)) < freq)
182                         return tin_parent_rate / div;
183         }
184
185         return tin_parent_rate / 16;
186 }
187
188 #define NS_IN_HZ (1000000000UL)
189
190 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
191 {
192         unsigned long tin_rate;
193         unsigned long tin_ns;
194         unsigned long period;
195         unsigned long flags;
196         unsigned long tcon;
197         unsigned long tcnt;
198         long tcmp;
199
200         /* We currently avoid using 64bit arithmetic by using the
201          * fact that anything faster than 1Hz is easily representable
202          * by 32bits. */
203
204         if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ)
205                 return -ERANGE;
206
207         if (duty_ns > period_ns)
208                 return -EINVAL;
209
210         if (period_ns == pwm->period_ns &&
211             duty_ns == pwm->duty_ns)
212                 return 0;
213
214         /* The TCMP and TCNT can be read without a lock, they're not
215          * shared between the timers. */
216
217         tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id));
218         tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id));
219
220         period = NS_IN_HZ / period_ns;
221
222         pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n",
223                 duty_ns, period_ns, period);
224
225         /* Check to see if we are changing the clock rate of the PWM */
226
227         if (pwm->period_ns != period_ns) {
228                 if (pwm_is_tdiv(pwm)) {
229                         tin_rate = pwm_calc_tin(pwm, period);
230                         clk_set_rate(pwm->clk_div, tin_rate);
231                 } else
232                         tin_rate = clk_get_rate(pwm->clk);
233
234                 pwm->period_ns = period_ns;
235
236                 pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate);
237
238                 tin_ns = NS_IN_HZ / tin_rate;
239                 tcnt = period_ns / tin_ns;
240         } else
241                 tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk);
242
243         /* Note, counters count down */
244
245         tcmp = duty_ns / tin_ns;
246         tcmp = tcnt - tcmp;
247
248         pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt);
249
250         if (tcmp < 0)
251                 tcmp = 0;
252
253         /* Update the PWM register block. */
254
255         local_irq_save(flags);
256
257         __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id));
258         __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id));
259
260         tcon = __raw_readl(S3C2410_TCON);
261         tcon |= pwm_tcon_manulupdate(pwm);
262         tcon |= pwm_tcon_autoreload(pwm);
263         __raw_writel(tcon, S3C2410_TCON);
264
265         tcon &= ~pwm_tcon_manulupdate(pwm);
266         __raw_writel(tcon, S3C2410_TCON);
267
268         local_irq_restore(flags);
269
270         return 0;
271 }
272
273 EXPORT_SYMBOL(pwm_config);
274
275 static int pwm_register(struct pwm_device *pwm)
276 {
277         pwm->duty_ns = -1;
278         pwm->period_ns = -1;
279
280         mutex_lock(&pwm_lock);
281         list_add_tail(&pwm->list, &pwm_list);
282         mutex_unlock(&pwm_lock);
283
284         return 0;
285 }
286
287 static int s3c_pwm_probe(struct platform_device *pdev)
288 {
289         struct device *dev = &pdev->dev;
290         struct pwm_device *pwm;
291         unsigned long flags;
292         unsigned long tcon;
293         unsigned int id = pdev->id;
294         int ret;
295
296         if (id == 4) {
297                 dev_err(dev, "TIMER4 is currently not supported\n");
298                 return -ENXIO;
299         }
300
301         pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
302         if (pwm == NULL) {
303                 dev_err(dev, "failed to allocate pwm_device\n");
304                 return -ENOMEM;
305         }
306
307         pwm->pdev = pdev;
308         pwm->pwm_id = id;
309
310         /* calculate base of control bits in TCON */
311         pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4;
312
313         pwm->clk = clk_get(dev, "pwm-tin");
314         if (IS_ERR(pwm->clk)) {
315                 dev_err(dev, "failed to get pwm tin clk\n");
316                 ret = PTR_ERR(pwm->clk);
317                 goto err_alloc;
318         }
319
320         pwm->clk_div = clk_get(dev, "pwm-tdiv");
321         if (IS_ERR(pwm->clk_div)) {
322                 dev_err(dev, "failed to get pwm tdiv clk\n");
323                 ret = PTR_ERR(pwm->clk_div);
324                 goto err_clk_tin;
325         }
326
327         local_irq_save(flags);
328
329         tcon = __raw_readl(S3C2410_TCON);
330         tcon |= pwm_tcon_invert(pwm);
331         __raw_writel(tcon, S3C2410_TCON);
332
333         local_irq_restore(flags);
334
335
336         ret = pwm_register(pwm);
337         if (ret) {
338                 dev_err(dev, "failed to register pwm\n");
339                 goto err_clk_tdiv;
340         }
341
342         pwm_dbg(pwm, "config bits %02x\n",
343                 (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f);
344
345         dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
346                  clk_get_rate(pwm->clk),
347                  clk_get_rate(pwm->clk_div),
348                  pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base);
349
350         platform_set_drvdata(pdev, pwm);
351         return 0;
352
353  err_clk_tdiv:
354         clk_put(pwm->clk_div);
355
356  err_clk_tin:
357         clk_put(pwm->clk);
358
359  err_alloc:
360         kfree(pwm);
361         return ret;
362 }
363
364 static int s3c_pwm_remove(struct platform_device *pdev)
365 {
366         struct pwm_device *pwm = platform_get_drvdata(pdev);
367
368         clk_put(pwm->clk_div);
369         clk_put(pwm->clk);
370         kfree(pwm);
371
372         return 0;
373 }
374
375 static struct platform_driver s3c_pwm_driver = {
376         .driver         = {
377                 .name   = "s3c24xx-pwm",
378                 .owner  = THIS_MODULE,
379         },
380         .probe          = s3c_pwm_probe,
381         .remove         = __devexit_p(s3c_pwm_remove),
382 };
383
384 static int __init pwm_init(void)
385 {
386         int ret;
387
388         clk_scaler[0] = clk_get(NULL, "pwm-scaler0");
389         clk_scaler[1] = clk_get(NULL, "pwm-scaler1");
390
391         if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) {
392                 printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__);
393                 return -EINVAL;
394         }
395
396         ret = platform_driver_register(&s3c_pwm_driver);
397         if (ret)
398                 printk(KERN_ERR "%s: failed to add pwm driver\n", __func__);
399
400         return ret;
401 }
402
403 arch_initcall(pwm_init);