atmel_pwm: Rename the "mck" clock to "pwm_clk"
[linux-2.6.git] / drivers / misc / atmel_pwm.c
1 #include <linux/module.h>
2 #include <linux/clk.h>
3 #include <linux/err.h>
4 #include <linux/io.h>
5 #include <linux/interrupt.h>
6 #include <linux/platform_device.h>
7 #include <linux/atmel_pwm.h>
8
9
10 /*
11  * This is a simple driver for the PWM controller found in various newer
12  * Atmel SOCs, including the AVR32 series and the AT91sam9263.
13  *
14  * Chips with current Linux ports have only 4 PWM channels, out of max 32.
15  * AT32UC3A and AT32UC3B chips have 7 channels (but currently no Linux).
16  * Docs are inconsistent about the width of the channel counter registers;
17  * it's at least 16 bits, but several places say 20 bits.
18  */
19 #define PWM_NCHAN       4               /* max 32 */
20
21 struct pwm {
22         spinlock_t              lock;
23         struct platform_device  *pdev;
24         u32                     mask;
25         int                     irq;
26         void __iomem            *base;
27         struct clk              *clk;
28         struct pwm_channel      *channel[PWM_NCHAN];
29         void                    (*handler[PWM_NCHAN])(struct pwm_channel *);
30 };
31
32
33 /* global PWM controller registers */
34 #define PWM_MR          0x00
35 #define PWM_ENA         0x04
36 #define PWM_DIS         0x08
37 #define PWM_SR          0x0c
38 #define PWM_IER         0x10
39 #define PWM_IDR         0x14
40 #define PWM_IMR         0x18
41 #define PWM_ISR         0x1c
42
43 static inline void pwm_writel(const struct pwm *p, unsigned offset, u32 val)
44 {
45         __raw_writel(val, p->base + offset);
46 }
47
48 static inline u32 pwm_readl(const struct pwm *p, unsigned offset)
49 {
50         return __raw_readl(p->base + offset);
51 }
52
53 static inline void __iomem *pwmc_regs(const struct pwm *p, int index)
54 {
55         return p->base + 0x200 + index * 0x20;
56 }
57
58 static struct pwm *pwm;
59
60 static void pwm_dumpregs(struct pwm_channel *ch, char *tag)
61 {
62         struct device   *dev = &pwm->pdev->dev;
63
64         dev_dbg(dev, "%s: mr %08x, sr %08x, imr %08x\n",
65                 tag,
66                 pwm_readl(pwm, PWM_MR),
67                 pwm_readl(pwm, PWM_SR),
68                 pwm_readl(pwm, PWM_IMR));
69         dev_dbg(dev,
70                 "pwm ch%d - mr %08x, dty %u, prd %u, cnt %u\n",
71                 ch->index,
72                 pwm_channel_readl(ch, PWM_CMR),
73                 pwm_channel_readl(ch, PWM_CDTY),
74                 pwm_channel_readl(ch, PWM_CPRD),
75                 pwm_channel_readl(ch, PWM_CCNT));
76 }
77
78
79 /**
80  * pwm_channel_alloc - allocate an unused PWM channel
81  * @index: identifies the channel
82  * @ch: structure to be initialized
83  *
84  * Drivers allocate PWM channels according to the board's wiring, and
85  * matching board-specific setup code.  Returns zero or negative errno.
86  */
87 int pwm_channel_alloc(int index, struct pwm_channel *ch)
88 {
89         unsigned long   flags;
90         int             status = 0;
91
92         /* insist on PWM init, with this signal pinned out */
93         if (!pwm || !(pwm->mask & 1 << index))
94                 return -ENODEV;
95
96         if (index < 0 || index >= PWM_NCHAN || !ch)
97                 return -EINVAL;
98         memset(ch, 0, sizeof *ch);
99
100         spin_lock_irqsave(&pwm->lock, flags);
101         if (pwm->channel[index])
102                 status = -EBUSY;
103         else {
104                 clk_enable(pwm->clk);
105
106                 ch->regs = pwmc_regs(pwm, index);
107                 ch->index = index;
108
109                 /* REVISIT: ap7000 seems to go 2x as fast as we expect!! */
110                 ch->mck = clk_get_rate(pwm->clk);
111
112                 pwm->channel[index] = ch;
113                 pwm->handler[index] = NULL;
114
115                 /* channel and irq are always disabled when we return */
116                 pwm_writel(pwm, PWM_DIS, 1 << index);
117                 pwm_writel(pwm, PWM_IDR, 1 << index);
118         }
119         spin_unlock_irqrestore(&pwm->lock, flags);
120         return status;
121 }
122 EXPORT_SYMBOL(pwm_channel_alloc);
123
124 static int pwmcheck(struct pwm_channel *ch)
125 {
126         int             index;
127
128         if (!pwm)
129                 return -ENODEV;
130         if (!ch)
131                 return -EINVAL;
132         index = ch->index;
133         if (index < 0 || index >= PWM_NCHAN || pwm->channel[index] != ch)
134                 return -EINVAL;
135
136         return index;
137 }
138
139 /**
140  * pwm_channel_free - release a previously allocated channel
141  * @ch: the channel being released
142  *
143  * The channel is completely shut down (counter and IRQ disabled),
144  * and made available for re-use.  Returns zero, or negative errno.
145  */
146 int pwm_channel_free(struct pwm_channel *ch)
147 {
148         unsigned long   flags;
149         int             t;
150
151         spin_lock_irqsave(&pwm->lock, flags);
152         t = pwmcheck(ch);
153         if (t >= 0) {
154                 pwm->channel[t] = NULL;
155                 pwm->handler[t] = NULL;
156
157                 /* channel and irq are always disabled when we return */
158                 pwm_writel(pwm, PWM_DIS, 1 << t);
159                 pwm_writel(pwm, PWM_IDR, 1 << t);
160
161                 clk_disable(pwm->clk);
162                 t = 0;
163         }
164         spin_unlock_irqrestore(&pwm->lock, flags);
165         return t;
166 }
167 EXPORT_SYMBOL(pwm_channel_free);
168
169 int __pwm_channel_onoff(struct pwm_channel *ch, int enabled)
170 {
171         unsigned long   flags;
172         int             t;
173
174         /* OMITTED FUNCTIONALITY:  starting several channels in synch */
175
176         spin_lock_irqsave(&pwm->lock, flags);
177         t = pwmcheck(ch);
178         if (t >= 0) {
179                 pwm_writel(pwm, enabled ? PWM_ENA : PWM_DIS, 1 << t);
180                 t = 0;
181                 pwm_dumpregs(ch, enabled ? "enable" : "disable");
182         }
183         spin_unlock_irqrestore(&pwm->lock, flags);
184
185         return t;
186 }
187 EXPORT_SYMBOL(__pwm_channel_onoff);
188
189 /**
190  * pwm_clk_alloc - allocate and configure CLKA or CLKB
191  * @prescale: from 0..10, the power of two used to divide MCK
192  * @div: from 1..255, the linear divisor to use
193  *
194  * Returns PWM_CPR_CLKA, PWM_CPR_CLKB, or negative errno.  The allocated
195  * clock will run with a period of (2^prescale * div) / MCK, or twice as
196  * long if center aligned PWM output is used.  The clock must later be
197  * deconfigured using pwm_clk_free().
198  */
199 int pwm_clk_alloc(unsigned prescale, unsigned div)
200 {
201         unsigned long   flags;
202         u32             mr;
203         u32             val = (prescale << 8) | div;
204         int             ret = -EBUSY;
205
206         if (prescale >= 10 || div == 0 || div > 255)
207                 return -EINVAL;
208
209         spin_lock_irqsave(&pwm->lock, flags);
210         mr = pwm_readl(pwm, PWM_MR);
211         if ((mr & 0xffff) == 0) {
212                 mr |= val;
213                 ret = PWM_CPR_CLKA;
214         }
215         if ((mr & (0xffff << 16)) == 0) {
216                 mr |= val << 16;
217                 ret = PWM_CPR_CLKB;
218         }
219         if (ret > 0)
220                 pwm_writel(pwm, PWM_MR, mr);
221         spin_unlock_irqrestore(&pwm->lock, flags);
222         return ret;
223 }
224 EXPORT_SYMBOL(pwm_clk_alloc);
225
226 /**
227  * pwm_clk_free - deconfigure and release CLKA or CLKB
228  *
229  * Reverses the effect of pwm_clk_alloc().
230  */
231 void pwm_clk_free(unsigned clk)
232 {
233         unsigned long   flags;
234         u32             mr;
235
236         spin_lock_irqsave(&pwm->lock, flags);
237         mr = pwm_readl(pwm, PWM_MR);
238         if (clk == PWM_CPR_CLKA)
239                 pwm_writel(pwm, PWM_MR, mr & ~(0xffff << 0));
240         if (clk == PWM_CPR_CLKB)
241                 pwm_writel(pwm, PWM_MR, mr & ~(0xffff << 16));
242         spin_unlock_irqrestore(&pwm->lock, flags);
243 }
244 EXPORT_SYMBOL(pwm_clk_free);
245
246 /**
247  * pwm_channel_handler - manage channel's IRQ handler
248  * @ch: the channel
249  * @handler: the handler to use, possibly NULL
250  *
251  * If the handler is non-null, the handler will be called after every
252  * period of this PWM channel.  If the handler is null, this channel
253  * won't generate an IRQ.
254  */
255 int pwm_channel_handler(struct pwm_channel *ch,
256                 void (*handler)(struct pwm_channel *ch))
257 {
258         unsigned long   flags;
259         int             t;
260
261         spin_lock_irqsave(&pwm->lock, flags);
262         t = pwmcheck(ch);
263         if (t >= 0) {
264                 pwm->handler[t] = handler;
265                 pwm_writel(pwm, handler ? PWM_IER : PWM_IDR, 1 << t);
266                 t = 0;
267         }
268         spin_unlock_irqrestore(&pwm->lock, flags);
269
270         return t;
271 }
272 EXPORT_SYMBOL(pwm_channel_handler);
273
274 static irqreturn_t pwm_irq(int id, void *_pwm)
275 {
276         struct pwm      *p = _pwm;
277         irqreturn_t     handled = IRQ_NONE;
278         u32             irqstat;
279         int             index;
280
281         spin_lock(&p->lock);
282
283         /* ack irqs, then handle them */
284         irqstat = pwm_readl(pwm, PWM_ISR);
285
286         while (irqstat) {
287                 struct pwm_channel *ch;
288                 void (*handler)(struct pwm_channel *ch);
289
290                 index = ffs(irqstat) - 1;
291                 irqstat &= ~(1 << index);
292                 ch = pwm->channel[index];
293                 handler = pwm->handler[index];
294                 if (handler && ch) {
295                         spin_unlock(&p->lock);
296                         handler(ch);
297                         spin_lock(&p->lock);
298                         handled = IRQ_HANDLED;
299                 }
300         }
301
302         spin_unlock(&p->lock);
303         return handled;
304 }
305
306 static int __init pwm_probe(struct platform_device *pdev)
307 {
308         struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
309         int irq = platform_get_irq(pdev, 0);
310         u32 *mp = pdev->dev.platform_data;
311         struct pwm *p;
312         int status = -EIO;
313
314         if (pwm)
315                 return -EBUSY;
316         if (!r || irq < 0 || !mp || !*mp)
317                 return -ENODEV;
318         if (*mp & ~((1<<PWM_NCHAN)-1)) {
319                 dev_warn(&pdev->dev, "mask 0x%x ... more than %d channels\n",
320                         *mp, PWM_NCHAN);
321                 return -EINVAL;
322         }
323
324         p = kzalloc(sizeof(*p), GFP_KERNEL);
325         if (!p)
326                 return -ENOMEM;
327
328         spin_lock_init(&p->lock);
329         p->pdev = pdev;
330         p->mask = *mp;
331         p->irq = irq;
332         p->base = ioremap(r->start, r->end - r->start + 1);
333         if (!p->base)
334                 goto fail;
335         p->clk = clk_get(&pdev->dev, "pwm_clk");
336         if (IS_ERR(p->clk)) {
337                 status = PTR_ERR(p->clk);
338                 p->clk = NULL;
339                 goto fail;
340         }
341
342         status = request_irq(irq, pwm_irq, 0, pdev->name, p);
343         if (status < 0)
344                 goto fail;
345
346         pwm = p;
347         platform_set_drvdata(pdev, p);
348
349         return 0;
350
351 fail:
352         if (p->clk)
353                 clk_put(p->clk);
354         if (p->base)
355                 iounmap(p->base);
356
357         kfree(p);
358         return status;
359 }
360
361 static int __exit pwm_remove(struct platform_device *pdev)
362 {
363         struct pwm *p = platform_get_drvdata(pdev);
364
365         if (p != pwm)
366                 return -EINVAL;
367
368         clk_enable(pwm->clk);
369         pwm_writel(pwm, PWM_DIS, (1 << PWM_NCHAN) - 1);
370         pwm_writel(pwm, PWM_IDR, (1 << PWM_NCHAN) - 1);
371         clk_disable(pwm->clk);
372
373         pwm = NULL;
374
375         free_irq(p->irq, p);
376         clk_put(p->clk);
377         iounmap(p->base);
378         kfree(p);
379
380         return 0;
381 }
382
383 static struct platform_driver atmel_pwm_driver = {
384         .driver = {
385                 .name = "atmel_pwm",
386                 .owner = THIS_MODULE,
387         },
388         .remove = __exit_p(pwm_remove),
389
390         /* NOTE: PWM can keep running in AVR32 "idle" and "frozen" states;
391          * and all AT91sam9263 states, albeit at reduced clock rate if
392          * MCK becomes the slow clock (i.e. what Linux labels STR).
393          */
394 };
395
396 static int __init pwm_init(void)
397 {
398         return platform_driver_probe(&atmel_pwm_driver, pwm_probe);
399 }
400 module_init(pwm_init);
401
402 static void __exit pwm_exit(void)
403 {
404         platform_driver_unregister(&atmel_pwm_driver);
405 }
406 module_exit(pwm_exit);
407
408 MODULE_DESCRIPTION("Driver for AT32/AT91 PWM module");
409 MODULE_LICENSE("GPL");
410 MODULE_ALIAS("platform:atmel_pwm");