Merge branch 'fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6
[linux-2.6.git] / arch / arm / plat-pxa / pwm.c
1 /*
2  * linux/arch/arm/mach-pxa/pwm.c
3  *
4  * simple driver for PWM (Pulse Width Modulator) controller
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * 2008-02-13   initial version
11  *              eric miao <eric.miao@marvell.com>
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/div64.h>
23
24 #define HAS_SECONDARY_PWM       0x10
25 #define PWM_ID_BASE(d)          ((d) & 0xf)
26
27 static const struct platform_device_id pwm_id_table[] = {
28         /*   PWM    has_secondary_pwm? */
29         { "pxa25x-pwm", 0 },
30         { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM },
31         { "pxa168-pwm", 1 },
32         { "pxa910-pwm", 1 },
33         { },
34 };
35 MODULE_DEVICE_TABLE(platform, pwm_id_table);
36
37 /* PWM registers and bits definitions */
38 #define PWMCR           (0x00)
39 #define PWMDCR          (0x04)
40 #define PWMPCR          (0x08)
41
42 #define PWMCR_SD        (1 << 6)
43 #define PWMDCR_FD       (1 << 10)
44
45 struct pwm_device {
46         struct list_head        node;
47         struct pwm_device       *secondary;
48         struct platform_device  *pdev;
49
50         const char      *label;
51         struct clk      *clk;
52         int             clk_enabled;
53         void __iomem    *mmio_base;
54
55         unsigned int    use_count;
56         unsigned int    pwm_id;
57 };
58
59 /*
60  * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
61  * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
62  */
63 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
64 {
65         unsigned long long c;
66         unsigned long period_cycles, prescale, pv, dc;
67
68         if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
69                 return -EINVAL;
70
71         c = clk_get_rate(pwm->clk);
72         c = c * period_ns;
73         do_div(c, 1000000000);
74         period_cycles = c;
75
76         if (period_cycles < 1)
77                 period_cycles = 1;
78         prescale = (period_cycles - 1) / 1024;
79         pv = period_cycles / (prescale + 1) - 1;
80
81         if (prescale > 63)
82                 return -EINVAL;
83
84         if (duty_ns == period_ns)
85                 dc = PWMDCR_FD;
86         else
87                 dc = (pv + 1) * duty_ns / period_ns;
88
89         /* NOTE: the clock to PWM has to be enabled first
90          * before writing to the registers
91          */
92         clk_enable(pwm->clk);
93         __raw_writel(prescale, pwm->mmio_base + PWMCR);
94         __raw_writel(dc, pwm->mmio_base + PWMDCR);
95         __raw_writel(pv, pwm->mmio_base + PWMPCR);
96         clk_disable(pwm->clk);
97
98         return 0;
99 }
100 EXPORT_SYMBOL(pwm_config);
101
102 int pwm_enable(struct pwm_device *pwm)
103 {
104         int rc = 0;
105
106         if (!pwm->clk_enabled) {
107                 rc = clk_enable(pwm->clk);
108                 if (!rc)
109                         pwm->clk_enabled = 1;
110         }
111         return rc;
112 }
113 EXPORT_SYMBOL(pwm_enable);
114
115 void pwm_disable(struct pwm_device *pwm)
116 {
117         if (pwm->clk_enabled) {
118                 clk_disable(pwm->clk);
119                 pwm->clk_enabled = 0;
120         }
121 }
122 EXPORT_SYMBOL(pwm_disable);
123
124 static DEFINE_MUTEX(pwm_lock);
125 static LIST_HEAD(pwm_list);
126
127 struct pwm_device *pwm_request(int pwm_id, const char *label)
128 {
129         struct pwm_device *pwm;
130         int found = 0;
131
132         mutex_lock(&pwm_lock);
133
134         list_for_each_entry(pwm, &pwm_list, node) {
135                 if (pwm->pwm_id == pwm_id) {
136                         found = 1;
137                         break;
138                 }
139         }
140
141         if (found) {
142                 if (pwm->use_count == 0) {
143                         pwm->use_count++;
144                         pwm->label = label;
145                 } else
146                         pwm = ERR_PTR(-EBUSY);
147         } else
148                 pwm = ERR_PTR(-ENOENT);
149
150         mutex_unlock(&pwm_lock);
151         return pwm;
152 }
153 EXPORT_SYMBOL(pwm_request);
154
155 void pwm_free(struct pwm_device *pwm)
156 {
157         mutex_lock(&pwm_lock);
158
159         if (pwm->use_count) {
160                 pwm->use_count--;
161                 pwm->label = NULL;
162         } else
163                 pr_warning("PWM device already freed\n");
164
165         mutex_unlock(&pwm_lock);
166 }
167 EXPORT_SYMBOL(pwm_free);
168
169 static inline void __add_pwm(struct pwm_device *pwm)
170 {
171         mutex_lock(&pwm_lock);
172         list_add_tail(&pwm->node, &pwm_list);
173         mutex_unlock(&pwm_lock);
174 }
175
176 static int __devinit pwm_probe(struct platform_device *pdev)
177 {
178         struct platform_device_id *id = platform_get_device_id(pdev);
179         struct pwm_device *pwm, *secondary = NULL;
180         struct resource *r;
181         int ret = 0;
182
183         pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
184         if (pwm == NULL) {
185                 dev_err(&pdev->dev, "failed to allocate memory\n");
186                 return -ENOMEM;
187         }
188
189         pwm->clk = clk_get(&pdev->dev, NULL);
190         if (IS_ERR(pwm->clk)) {
191                 ret = PTR_ERR(pwm->clk);
192                 goto err_free;
193         }
194         pwm->clk_enabled = 0;
195
196         pwm->use_count = 0;
197         pwm->pwm_id = PWM_ID_BASE(id->driver_data) + pdev->id;
198         pwm->pdev = pdev;
199
200         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
201         if (r == NULL) {
202                 dev_err(&pdev->dev, "no memory resource defined\n");
203                 ret = -ENODEV;
204                 goto err_free_clk;
205         }
206
207         r = request_mem_region(r->start, resource_size(r), pdev->name);
208         if (r == NULL) {
209                 dev_err(&pdev->dev, "failed to request memory resource\n");
210                 ret = -EBUSY;
211                 goto err_free_clk;
212         }
213
214         pwm->mmio_base = ioremap(r->start, resource_size(r));
215         if (pwm->mmio_base == NULL) {
216                 dev_err(&pdev->dev, "failed to ioremap() registers\n");
217                 ret = -ENODEV;
218                 goto err_free_mem;
219         }
220
221         if (id->driver_data & HAS_SECONDARY_PWM) {
222                 secondary = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
223                 if (secondary == NULL) {
224                         ret = -ENOMEM;
225                         goto err_free_mem;
226                 }
227
228                 *secondary = *pwm;
229                 pwm->secondary = secondary;
230
231                 /* registers for the second PWM has offset of 0x10 */
232                 secondary->mmio_base = pwm->mmio_base + 0x10;
233                 secondary->pwm_id = pdev->id + 2;
234         }
235
236         __add_pwm(pwm);
237         if (secondary)
238                 __add_pwm(secondary);
239
240         platform_set_drvdata(pdev, pwm);
241         return 0;
242
243 err_free_mem:
244         release_mem_region(r->start, resource_size(r));
245 err_free_clk:
246         clk_put(pwm->clk);
247 err_free:
248         kfree(pwm);
249         return ret;
250 }
251
252 static int __devexit pwm_remove(struct platform_device *pdev)
253 {
254         struct pwm_device *pwm;
255         struct resource *r;
256
257         pwm = platform_get_drvdata(pdev);
258         if (pwm == NULL)
259                 return -ENODEV;
260
261         mutex_lock(&pwm_lock);
262
263         if (pwm->secondary) {
264                 list_del(&pwm->secondary->node);
265                 kfree(pwm->secondary);
266         }
267
268         list_del(&pwm->node);
269         mutex_unlock(&pwm_lock);
270
271         iounmap(pwm->mmio_base);
272
273         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
274         release_mem_region(r->start, resource_size(r));
275
276         clk_put(pwm->clk);
277         kfree(pwm);
278         return 0;
279 }
280
281 static struct platform_driver pwm_driver = {
282         .driver         = {
283                 .name   = "pxa25x-pwm",
284                 .owner  = THIS_MODULE,
285         },
286         .probe          = pwm_probe,
287         .remove         = __devexit_p(pwm_remove),
288         .id_table       = pwm_id_table,
289 };
290
291 static int __init pwm_init(void)
292 {
293         return platform_driver_register(&pwm_driver);
294 }
295 arch_initcall(pwm_init);
296
297 static void __exit pwm_exit(void)
298 {
299         platform_driver_unregister(&pwm_driver);
300 }
301 module_exit(pwm_exit);
302
303 MODULE_LICENSE("GPL v2");