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ef12379f HS |
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/clk.h> | |
23 | #include <linux/err.h> | |
24 | #include <linux/io.h> | |
25 | ||
26 | #include <mach/platform.h> | |
27 | ||
28 | #define EP93XX_PWMx_TERM_COUNT 0x00 | |
29 | #define EP93XX_PWMx_DUTY_CYCLE 0x04 | |
30 | #define EP93XX_PWMx_ENABLE 0x08 | |
31 | #define EP93XX_PWMx_INVERT 0x0C | |
32 | ||
33 | #define EP93XX_PWM_MAX_COUNT 0xFFFF | |
34 | ||
35 | struct ep93xx_pwm { | |
36 | void __iomem *mmio_base; | |
37 | struct clk *clk; | |
38 | u32 duty_percent; | |
39 | }; | |
40 | ||
41 | static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm, | |
42 | unsigned int val, unsigned int off) | |
43 | { | |
44 | __raw_writel(val, pwm->mmio_base + off); | |
45 | } | |
46 | ||
47 | static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm, | |
48 | unsigned int off) | |
49 | { | |
50 | return __raw_readl(pwm->mmio_base + off); | |
51 | } | |
52 | ||
53 | static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value) | |
54 | { | |
55 | ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT); | |
56 | } | |
57 | ||
58 | static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm) | |
59 | { | |
60 | return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT); | |
61 | } | |
62 | ||
63 | static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value) | |
64 | { | |
65 | ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE); | |
66 | } | |
67 | ||
68 | static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm) | |
69 | { | |
70 | ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE); | |
71 | } | |
72 | ||
73 | static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm) | |
74 | { | |
75 | ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE); | |
76 | } | |
77 | ||
78 | static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm) | |
79 | { | |
80 | return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1; | |
81 | } | |
82 | ||
83 | static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm) | |
84 | { | |
85 | ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT); | |
86 | } | |
87 | ||
88 | static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm) | |
89 | { | |
90 | ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT); | |
91 | } | |
92 | ||
93 | static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm) | |
94 | { | |
95 | return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1; | |
96 | } | |
97 | ||
98 | /* | |
99 | * /sys/devices/platform/ep93xx-pwm.N | |
100 | * /min_freq read-only minimum pwm output frequency | |
101 | * /max_req read-only maximum pwm output frequency | |
102 | * /freq read-write pwm output frequency (0 = disable output) | |
103 | * /duty_percent read-write pwm duty cycle percent (1..99) | |
104 | * /invert read-write invert pwm output | |
105 | */ | |
106 | ||
107 | static ssize_t ep93xx_pwm_get_min_freq(struct device *dev, | |
108 | struct device_attribute *attr, char *buf) | |
109 | { | |
110 | struct platform_device *pdev = to_platform_device(dev); | |
111 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
112 | unsigned long rate = clk_get_rate(pwm->clk); | |
113 | ||
114 | return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1)); | |
115 | } | |
116 | ||
117 | static ssize_t ep93xx_pwm_get_max_freq(struct device *dev, | |
118 | struct device_attribute *attr, char *buf) | |
119 | { | |
120 | struct platform_device *pdev = to_platform_device(dev); | |
121 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
122 | unsigned long rate = clk_get_rate(pwm->clk); | |
123 | ||
124 | return sprintf(buf, "%ld\n", rate / 2); | |
125 | } | |
126 | ||
127 | static ssize_t ep93xx_pwm_get_freq(struct device *dev, | |
128 | struct device_attribute *attr, char *buf) | |
129 | { | |
130 | struct platform_device *pdev = to_platform_device(dev); | |
131 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
132 | ||
133 | if (ep93xx_pwm_is_enabled(pwm)) { | |
134 | unsigned long rate = clk_get_rate(pwm->clk); | |
135 | u16 term = ep93xx_pwm_read_tc(pwm); | |
136 | ||
137 | return sprintf(buf, "%ld\n", rate / (term + 1)); | |
138 | } else { | |
139 | return sprintf(buf, "disabled\n"); | |
140 | } | |
141 | } | |
142 | ||
143 | static ssize_t ep93xx_pwm_set_freq(struct device *dev, | |
144 | struct device_attribute *attr, const char *buf, size_t count) | |
145 | { | |
146 | struct platform_device *pdev = to_platform_device(dev); | |
147 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
148 | long val; | |
149 | int err; | |
150 | ||
151 | err = strict_strtol(buf, 10, &val); | |
152 | if (err) | |
153 | return -EINVAL; | |
154 | ||
155 | if (val == 0) { | |
156 | ep93xx_pwm_disable(pwm); | |
157 | } else if (val <= (clk_get_rate(pwm->clk) / 2)) { | |
158 | u32 term, duty; | |
159 | ||
160 | val = (clk_get_rate(pwm->clk) / val) - 1; | |
161 | if (val > EP93XX_PWM_MAX_COUNT) | |
162 | val = EP93XX_PWM_MAX_COUNT; | |
163 | if (val < 1) | |
164 | val = 1; | |
165 | ||
166 | term = ep93xx_pwm_read_tc(pwm); | |
167 | duty = ((val + 1) * pwm->duty_percent / 100) - 1; | |
168 | ||
169 | /* If pwm is running, order is important */ | |
170 | if (val > term) { | |
171 | ep93xx_pwm_write_tc(pwm, val); | |
172 | ep93xx_pwm_write_dc(pwm, duty); | |
173 | } else { | |
174 | ep93xx_pwm_write_dc(pwm, duty); | |
175 | ep93xx_pwm_write_tc(pwm, val); | |
176 | } | |
177 | ||
178 | if (!ep93xx_pwm_is_enabled(pwm)) | |
179 | ep93xx_pwm_enable(pwm); | |
180 | } else { | |
181 | return -EINVAL; | |
182 | } | |
183 | ||
184 | return count; | |
185 | } | |
186 | ||
187 | static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev, | |
188 | struct device_attribute *attr, char *buf) | |
189 | { | |
190 | struct platform_device *pdev = to_platform_device(dev); | |
191 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
192 | ||
193 | return sprintf(buf, "%d\n", pwm->duty_percent); | |
194 | } | |
195 | ||
196 | static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev, | |
197 | struct device_attribute *attr, const char *buf, size_t count) | |
198 | { | |
199 | struct platform_device *pdev = to_platform_device(dev); | |
200 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
201 | long val; | |
202 | int err; | |
203 | ||
204 | err = strict_strtol(buf, 10, &val); | |
205 | if (err) | |
206 | return -EINVAL; | |
207 | ||
208 | if (val > 0 && val < 100) { | |
209 | u32 term = ep93xx_pwm_read_tc(pwm); | |
210 | ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1); | |
211 | pwm->duty_percent = val; | |
212 | return count; | |
213 | } | |
214 | ||
215 | return -EINVAL; | |
216 | } | |
217 | ||
218 | static ssize_t ep93xx_pwm_get_invert(struct device *dev, | |
219 | struct device_attribute *attr, char *buf) | |
220 | { | |
221 | struct platform_device *pdev = to_platform_device(dev); | |
222 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
223 | ||
224 | return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm)); | |
225 | } | |
226 | ||
227 | static ssize_t ep93xx_pwm_set_invert(struct device *dev, | |
228 | struct device_attribute *attr, const char *buf, size_t count) | |
229 | { | |
230 | struct platform_device *pdev = to_platform_device(dev); | |
231 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
232 | long val; | |
233 | int err; | |
234 | ||
235 | err = strict_strtol(buf, 10, &val); | |
236 | if (err) | |
237 | return -EINVAL; | |
238 | ||
239 | if (val == 0) | |
240 | ep93xx_pwm_normal(pwm); | |
241 | else if (val == 1) | |
242 | ep93xx_pwm_invert(pwm); | |
243 | else | |
244 | return -EINVAL; | |
245 | ||
246 | return count; | |
247 | } | |
248 | ||
249 | static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL); | |
250 | static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL); | |
251 | static DEVICE_ATTR(freq, S_IWUGO | S_IRUGO, | |
252 | ep93xx_pwm_get_freq, ep93xx_pwm_set_freq); | |
253 | static DEVICE_ATTR(duty_percent, S_IWUGO | S_IRUGO, | |
254 | ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent); | |
255 | static DEVICE_ATTR(invert, S_IWUGO | S_IRUGO, | |
256 | ep93xx_pwm_get_invert, ep93xx_pwm_set_invert); | |
257 | ||
258 | static struct attribute *ep93xx_pwm_attrs[] = { | |
259 | &dev_attr_min_freq.attr, | |
260 | &dev_attr_max_freq.attr, | |
261 | &dev_attr_freq.attr, | |
262 | &dev_attr_duty_percent.attr, | |
263 | &dev_attr_invert.attr, | |
264 | NULL | |
265 | }; | |
266 | ||
267 | static const struct attribute_group ep93xx_pwm_sysfs_files = { | |
268 | .attrs = ep93xx_pwm_attrs, | |
269 | }; | |
270 | ||
271 | static int __init ep93xx_pwm_probe(struct platform_device *pdev) | |
272 | { | |
273 | struct ep93xx_pwm *pwm; | |
274 | struct resource *res; | |
275 | int err; | |
276 | ||
277 | err = ep93xx_pwm_acquire_gpio(pdev); | |
278 | if (err) | |
279 | return err; | |
280 | ||
281 | pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL); | |
282 | if (!pwm) { | |
283 | err = -ENOMEM; | |
284 | goto fail_no_mem; | |
285 | } | |
286 | ||
287 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
288 | if (res == NULL) { | |
289 | err = -ENXIO; | |
290 | goto fail_no_mem_resource; | |
291 | } | |
292 | ||
293 | res = request_mem_region(res->start, resource_size(res), pdev->name); | |
294 | if (res == NULL) { | |
295 | err = -EBUSY; | |
296 | goto fail_no_mem_resource; | |
297 | } | |
298 | ||
299 | pwm->mmio_base = ioremap(res->start, resource_size(res)); | |
300 | if (pwm->mmio_base == NULL) { | |
301 | err = -ENXIO; | |
302 | goto fail_no_ioremap; | |
303 | } | |
304 | ||
305 | err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); | |
306 | if (err) | |
307 | goto fail_no_sysfs; | |
308 | ||
309 | pwm->clk = clk_get(&pdev->dev, "pwm_clk"); | |
310 | if (IS_ERR(pwm->clk)) { | |
311 | err = PTR_ERR(pwm->clk); | |
312 | goto fail_no_clk; | |
313 | } | |
314 | ||
315 | pwm->duty_percent = 50; | |
316 | ||
317 | platform_set_drvdata(pdev, pwm); | |
318 | ||
319 | /* disable pwm at startup. Avoids zero value. */ | |
320 | ep93xx_pwm_disable(pwm); | |
321 | ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT); | |
322 | ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2); | |
323 | ||
324 | clk_enable(pwm->clk); | |
325 | ||
326 | return 0; | |
327 | ||
328 | fail_no_clk: | |
329 | sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); | |
330 | fail_no_sysfs: | |
331 | iounmap(pwm->mmio_base); | |
332 | fail_no_ioremap: | |
333 | release_mem_region(res->start, resource_size(res)); | |
334 | fail_no_mem_resource: | |
335 | kfree(pwm); | |
336 | fail_no_mem: | |
337 | ep93xx_pwm_release_gpio(pdev); | |
338 | return err; | |
339 | } | |
340 | ||
341 | static int __exit ep93xx_pwm_remove(struct platform_device *pdev) | |
342 | { | |
343 | struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); | |
344 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
345 | ||
346 | ep93xx_pwm_disable(pwm); | |
347 | clk_disable(pwm->clk); | |
348 | clk_put(pwm->clk); | |
349 | platform_set_drvdata(pdev, NULL); | |
350 | sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); | |
351 | iounmap(pwm->mmio_base); | |
352 | release_mem_region(res->start, resource_size(res)); | |
353 | kfree(pwm); | |
354 | ep93xx_pwm_release_gpio(pdev); | |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
359 | static struct platform_driver ep93xx_pwm_driver = { | |
360 | .driver = { | |
361 | .name = "ep93xx-pwm", | |
362 | .owner = THIS_MODULE, | |
363 | }, | |
364 | .remove = __exit_p(ep93xx_pwm_remove), | |
365 | }; | |
366 | ||
367 | static int __init ep93xx_pwm_init(void) | |
368 | { | |
369 | return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe); | |
370 | } | |
371 | ||
372 | static void __exit ep93xx_pwm_exit(void) | |
373 | { | |
374 | platform_driver_unregister(&ep93xx_pwm_driver); | |
375 | } | |
376 | ||
377 | module_init(ep93xx_pwm_init); | |
378 | module_exit(ep93xx_pwm_exit); | |
379 | ||
380 | MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, " | |
381 | "H Hartley Sweeten <hsweeten@visionengravers.com>"); | |
382 | MODULE_DESCRIPTION("EP93xx PWM driver"); | |
383 | MODULE_LICENSE("GPL"); | |
384 | MODULE_ALIAS("platform:ep93xx-pwm"); |