1 /*
2 * Simple PWM driver for EP93XX
3 *
4 * (c) Copyright 2009 Matthieu Crapet <mcrapet@gmail.com>
5 * (c) Copyright 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * EP9307 has only one channel:
13 * - PWMOUT
14 *
15 * EP9301/02/12/15 have two channels:
16 * - PWMOUT
17 * - PWMOUT1 (alternate function for EGPIO14)
18 */
19
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/slab.h>
23 #include <linux/clk.h>
24 #include <linux/err.h>
25 #include <linux/io.h>
26
27 #include <mach/platform.h>
28
29 #define EP93XX_PWMx_TERM_COUNT 0x00
30 #define EP93XX_PWMx_DUTY_CYCLE 0x04
31 #define EP93XX_PWMx_ENABLE 0x08
32 #define EP93XX_PWMx_INVERT 0x0C
33
34 #define EP93XX_PWM_MAX_COUNT 0xFFFF
35
36 struct ep93xx_pwm {
37 void __iomem *mmio_base;
38 struct clk *clk;
39 u32 duty_percent;
40 };
41
ep93xx_pwm_writel(struct ep93xx_pwm * pwm,unsigned int val,unsigned int off)42 static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm,
43 unsigned int val, unsigned int off)
44 {
45 __raw_writel(val, pwm->mmio_base + off);
46 }
47
ep93xx_pwm_readl(struct ep93xx_pwm * pwm,unsigned int off)48 static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm,
49 unsigned int off)
50 {
51 return __raw_readl(pwm->mmio_base + off);
52 }
53
ep93xx_pwm_write_tc(struct ep93xx_pwm * pwm,u16 value)54 static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value)
55 {
56 ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT);
57 }
58
ep93xx_pwm_read_tc(struct ep93xx_pwm * pwm)59 static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm)
60 {
61 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT);
62 }
63
ep93xx_pwm_write_dc(struct ep93xx_pwm * pwm,u16 value)64 static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value)
65 {
66 ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE);
67 }
68
ep93xx_pwm_enable(struct ep93xx_pwm * pwm)69 static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm)
70 {
71 ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE);
72 }
73
ep93xx_pwm_disable(struct ep93xx_pwm * pwm)74 static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm)
75 {
76 ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE);
77 }
78
ep93xx_pwm_is_enabled(struct ep93xx_pwm * pwm)79 static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm)
80 {
81 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1;
82 }
83
ep93xx_pwm_invert(struct ep93xx_pwm * pwm)84 static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm)
85 {
86 ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT);
87 }
88
ep93xx_pwm_normal(struct ep93xx_pwm * pwm)89 static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm)
90 {
91 ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT);
92 }
93
ep93xx_pwm_is_inverted(struct ep93xx_pwm * pwm)94 static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm)
95 {
96 return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1;
97 }
98
99 /*
100 * /sys/devices/platform/ep93xx-pwm.N
101 * /min_freq read-only minimum pwm output frequency
102 * /max_req read-only maximum pwm output frequency
103 * /freq read-write pwm output frequency (0 = disable output)
104 * /duty_percent read-write pwm duty cycle percent (1..99)
105 * /invert read-write invert pwm output
106 */
107
ep93xx_pwm_get_min_freq(struct device * dev,struct device_attribute * attr,char * buf)108 static ssize_t ep93xx_pwm_get_min_freq(struct device *dev,
109 struct device_attribute *attr, char *buf)
110 {
111 struct platform_device *pdev = to_platform_device(dev);
112 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
113 unsigned long rate = clk_get_rate(pwm->clk);
114
115 return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1));
116 }
117
ep93xx_pwm_get_max_freq(struct device * dev,struct device_attribute * attr,char * buf)118 static ssize_t ep93xx_pwm_get_max_freq(struct device *dev,
119 struct device_attribute *attr, char *buf)
120 {
121 struct platform_device *pdev = to_platform_device(dev);
122 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
123 unsigned long rate = clk_get_rate(pwm->clk);
124
125 return sprintf(buf, "%ld\n", rate / 2);
126 }
127
ep93xx_pwm_get_freq(struct device * dev,struct device_attribute * attr,char * buf)128 static ssize_t ep93xx_pwm_get_freq(struct device *dev,
129 struct device_attribute *attr, char *buf)
130 {
131 struct platform_device *pdev = to_platform_device(dev);
132 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
133
134 if (ep93xx_pwm_is_enabled(pwm)) {
135 unsigned long rate = clk_get_rate(pwm->clk);
136 u16 term = ep93xx_pwm_read_tc(pwm);
137
138 return sprintf(buf, "%ld\n", rate / (term + 1));
139 } else {
140 return sprintf(buf, "disabled\n");
141 }
142 }
143
ep93xx_pwm_set_freq(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)144 static ssize_t ep93xx_pwm_set_freq(struct device *dev,
145 struct device_attribute *attr, const char *buf, size_t count)
146 {
147 struct platform_device *pdev = to_platform_device(dev);
148 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
149 long val;
150 int err;
151
152 err = strict_strtol(buf, 10, &val);
153 if (err)
154 return -EINVAL;
155
156 if (val == 0) {
157 ep93xx_pwm_disable(pwm);
158 } else if (val <= (clk_get_rate(pwm->clk) / 2)) {
159 u32 term, duty;
160
161 val = (clk_get_rate(pwm->clk) / val) - 1;
162 if (val > EP93XX_PWM_MAX_COUNT)
163 val = EP93XX_PWM_MAX_COUNT;
164 if (val < 1)
165 val = 1;
166
167 term = ep93xx_pwm_read_tc(pwm);
168 duty = ((val + 1) * pwm->duty_percent / 100) - 1;
169
170 /* If pwm is running, order is important */
171 if (val > term) {
172 ep93xx_pwm_write_tc(pwm, val);
173 ep93xx_pwm_write_dc(pwm, duty);
174 } else {
175 ep93xx_pwm_write_dc(pwm, duty);
176 ep93xx_pwm_write_tc(pwm, val);
177 }
178
179 if (!ep93xx_pwm_is_enabled(pwm))
180 ep93xx_pwm_enable(pwm);
181 } else {
182 return -EINVAL;
183 }
184
185 return count;
186 }
187
ep93xx_pwm_get_duty_percent(struct device * dev,struct device_attribute * attr,char * buf)188 static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev,
189 struct device_attribute *attr, char *buf)
190 {
191 struct platform_device *pdev = to_platform_device(dev);
192 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
193
194 return sprintf(buf, "%d\n", pwm->duty_percent);
195 }
196
ep93xx_pwm_set_duty_percent(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)197 static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev,
198 struct device_attribute *attr, const char *buf, size_t count)
199 {
200 struct platform_device *pdev = to_platform_device(dev);
201 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
202 long val;
203 int err;
204
205 err = strict_strtol(buf, 10, &val);
206 if (err)
207 return -EINVAL;
208
209 if (val > 0 && val < 100) {
210 u32 term = ep93xx_pwm_read_tc(pwm);
211 ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1);
212 pwm->duty_percent = val;
213 return count;
214 }
215
216 return -EINVAL;
217 }
218
ep93xx_pwm_get_invert(struct device * dev,struct device_attribute * attr,char * buf)219 static ssize_t ep93xx_pwm_get_invert(struct device *dev,
220 struct device_attribute *attr, char *buf)
221 {
222 struct platform_device *pdev = to_platform_device(dev);
223 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
224
225 return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm));
226 }
227
ep93xx_pwm_set_invert(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)228 static ssize_t ep93xx_pwm_set_invert(struct device *dev,
229 struct device_attribute *attr, const char *buf, size_t count)
230 {
231 struct platform_device *pdev = to_platform_device(dev);
232 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
233 long val;
234 int err;
235
236 err = strict_strtol(buf, 10, &val);
237 if (err)
238 return -EINVAL;
239
240 if (val == 0)
241 ep93xx_pwm_normal(pwm);
242 else if (val == 1)
243 ep93xx_pwm_invert(pwm);
244 else
245 return -EINVAL;
246
247 return count;
248 }
249
250 static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL);
251 static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL);
252 static DEVICE_ATTR(freq, S_IWUSR | S_IRUGO,
253 ep93xx_pwm_get_freq, ep93xx_pwm_set_freq);
254 static DEVICE_ATTR(duty_percent, S_IWUSR | S_IRUGO,
255 ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent);
256 static DEVICE_ATTR(invert, S_IWUSR | S_IRUGO,
257 ep93xx_pwm_get_invert, ep93xx_pwm_set_invert);
258
259 static struct attribute *ep93xx_pwm_attrs[] = {
260 &dev_attr_min_freq.attr,
261 &dev_attr_max_freq.attr,
262 &dev_attr_freq.attr,
263 &dev_attr_duty_percent.attr,
264 &dev_attr_invert.attr,
265 NULL
266 };
267
268 static const struct attribute_group ep93xx_pwm_sysfs_files = {
269 .attrs = ep93xx_pwm_attrs,
270 };
271
ep93xx_pwm_probe(struct platform_device * pdev)272 static int __init ep93xx_pwm_probe(struct platform_device *pdev)
273 {
274 struct ep93xx_pwm *pwm;
275 struct resource *res;
276 int err;
277
278 err = ep93xx_pwm_acquire_gpio(pdev);
279 if (err)
280 return err;
281
282 pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL);
283 if (!pwm) {
284 err = -ENOMEM;
285 goto fail_no_mem;
286 }
287
288 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
289 if (res == NULL) {
290 err = -ENXIO;
291 goto fail_no_mem_resource;
292 }
293
294 res = request_mem_region(res->start, resource_size(res), pdev->name);
295 if (res == NULL) {
296 err = -EBUSY;
297 goto fail_no_mem_resource;
298 }
299
300 pwm->mmio_base = ioremap(res->start, resource_size(res));
301 if (pwm->mmio_base == NULL) {
302 err = -ENXIO;
303 goto fail_no_ioremap;
304 }
305
306 err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
307 if (err)
308 goto fail_no_sysfs;
309
310 pwm->clk = clk_get(&pdev->dev, "pwm_clk");
311 if (IS_ERR(pwm->clk)) {
312 err = PTR_ERR(pwm->clk);
313 goto fail_no_clk;
314 }
315
316 pwm->duty_percent = 50;
317
318 platform_set_drvdata(pdev, pwm);
319
320 /* disable pwm at startup. Avoids zero value. */
321 ep93xx_pwm_disable(pwm);
322 ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT);
323 ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2);
324
325 clk_enable(pwm->clk);
326
327 return 0;
328
329 fail_no_clk:
330 sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
331 fail_no_sysfs:
332 iounmap(pwm->mmio_base);
333 fail_no_ioremap:
334 release_mem_region(res->start, resource_size(res));
335 fail_no_mem_resource:
336 kfree(pwm);
337 fail_no_mem:
338 ep93xx_pwm_release_gpio(pdev);
339 return err;
340 }
341
ep93xx_pwm_remove(struct platform_device * pdev)342 static int __exit ep93xx_pwm_remove(struct platform_device *pdev)
343 {
344 struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
345 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
346
347 ep93xx_pwm_disable(pwm);
348 clk_disable(pwm->clk);
349 clk_put(pwm->clk);
350 platform_set_drvdata(pdev, NULL);
351 sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
352 iounmap(pwm->mmio_base);
353 release_mem_region(res->start, resource_size(res));
354 kfree(pwm);
355 ep93xx_pwm_release_gpio(pdev);
356
357 return 0;
358 }
359
360 static struct platform_driver ep93xx_pwm_driver = {
361 .driver = {
362 .name = "ep93xx-pwm",
363 .owner = THIS_MODULE,
364 },
365 .remove = __exit_p(ep93xx_pwm_remove),
366 };
367
ep93xx_pwm_init(void)368 static int __init ep93xx_pwm_init(void)
369 {
370 return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe);
371 }
372
ep93xx_pwm_exit(void)373 static void __exit ep93xx_pwm_exit(void)
374 {
375 platform_driver_unregister(&ep93xx_pwm_driver);
376 }
377
378 module_init(ep93xx_pwm_init);
379 module_exit(ep93xx_pwm_exit);
380
381 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
382 "H Hartley Sweeten <hsweeten@visionengravers.com>");
383 MODULE_DESCRIPTION("EP93xx PWM driver");
384 MODULE_LICENSE("GPL");
385 MODULE_ALIAS("platform:ep93xx-pwm");
386