diff options
author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
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committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
commit | c50e86ce7c2961a41f2f7aa6e4fd6c99229ba205 (patch) | |
tree | 4ea36009719bd8fc523239fe1bdccb90f0dce3ae /drivers/pwm/pwm-samsung.c | |
parent | 14d33d384693eb6083396199de516fdef320f7af (diff) | |
parent | 4cbe5a555fa58a79b6ecbb6c531b8bab0650778d (diff) |
Merge tag 'v3.6-rc4'
Merge 3.6-rc4 to get latest OMAP and device tree fixes.
Diffstat (limited to 'drivers/pwm/pwm-samsung.c')
-rw-r--r-- | drivers/pwm/pwm-samsung.c | 357 |
1 files changed, 357 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c new file mode 100644 index 000000000000..e5187c0ade9f --- /dev/null +++ b/drivers/pwm/pwm-samsung.c | |||
@@ -0,0 +1,357 @@ | |||
1 | /* drivers/pwm/pwm-samsung.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 | * S3C series 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 | #define pr_fmt(fmt) "pwm-samsung: " fmt | ||
15 | |||
16 | #include <linux/export.h> | ||
17 | #include <linux/kernel.h> | ||
18 | #include <linux/platform_device.h> | ||
19 | #include <linux/slab.h> | ||
20 | #include <linux/err.h> | ||
21 | #include <linux/clk.h> | ||
22 | #include <linux/io.h> | ||
23 | #include <linux/pwm.h> | ||
24 | |||
25 | #include <mach/map.h> | ||
26 | |||
27 | #include <plat/regs-timer.h> | ||
28 | |||
29 | struct s3c_chip { | ||
30 | struct platform_device *pdev; | ||
31 | |||
32 | struct clk *clk_div; | ||
33 | struct clk *clk; | ||
34 | const char *label; | ||
35 | |||
36 | unsigned int period_ns; | ||
37 | unsigned int duty_ns; | ||
38 | |||
39 | unsigned char tcon_base; | ||
40 | unsigned char pwm_id; | ||
41 | struct pwm_chip chip; | ||
42 | }; | ||
43 | |||
44 | #define to_s3c_chip(chip) container_of(chip, struct s3c_chip, chip) | ||
45 | |||
46 | #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg) | ||
47 | |||
48 | static struct clk *clk_scaler[2]; | ||
49 | |||
50 | static inline int pwm_is_tdiv(struct s3c_chip *chip) | ||
51 | { | ||
52 | return clk_get_parent(chip->clk) == chip->clk_div; | ||
53 | } | ||
54 | |||
55 | #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) | ||
56 | #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) | ||
57 | #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) | ||
58 | #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) | ||
59 | |||
60 | static int s3c_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
61 | { | ||
62 | struct s3c_chip *s3c = to_s3c_chip(chip); | ||
63 | unsigned long flags; | ||
64 | unsigned long tcon; | ||
65 | |||
66 | local_irq_save(flags); | ||
67 | |||
68 | tcon = __raw_readl(S3C2410_TCON); | ||
69 | tcon |= pwm_tcon_start(s3c); | ||
70 | __raw_writel(tcon, S3C2410_TCON); | ||
71 | |||
72 | local_irq_restore(flags); | ||
73 | |||
74 | return 0; | ||
75 | } | ||
76 | |||
77 | static void s3c_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
78 | { | ||
79 | struct s3c_chip *s3c = to_s3c_chip(chip); | ||
80 | unsigned long flags; | ||
81 | unsigned long tcon; | ||
82 | |||
83 | local_irq_save(flags); | ||
84 | |||
85 | tcon = __raw_readl(S3C2410_TCON); | ||
86 | tcon &= ~pwm_tcon_start(s3c); | ||
87 | __raw_writel(tcon, S3C2410_TCON); | ||
88 | |||
89 | local_irq_restore(flags); | ||
90 | } | ||
91 | |||
92 | static unsigned long pwm_calc_tin(struct s3c_chip *s3c, unsigned long freq) | ||
93 | { | ||
94 | unsigned long tin_parent_rate; | ||
95 | unsigned int div; | ||
96 | |||
97 | tin_parent_rate = clk_get_rate(clk_get_parent(s3c->clk_div)); | ||
98 | pwm_dbg(s3c, "tin parent at %lu\n", tin_parent_rate); | ||
99 | |||
100 | for (div = 2; div <= 16; div *= 2) { | ||
101 | if ((tin_parent_rate / (div << 16)) < freq) | ||
102 | return tin_parent_rate / div; | ||
103 | } | ||
104 | |||
105 | return tin_parent_rate / 16; | ||
106 | } | ||
107 | |||
108 | #define NS_IN_HZ (1000000000UL) | ||
109 | |||
110 | static int s3c_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | ||
111 | int duty_ns, int period_ns) | ||
112 | { | ||
113 | struct s3c_chip *s3c = to_s3c_chip(chip); | ||
114 | unsigned long tin_rate; | ||
115 | unsigned long tin_ns; | ||
116 | unsigned long period; | ||
117 | unsigned long flags; | ||
118 | unsigned long tcon; | ||
119 | unsigned long tcnt; | ||
120 | long tcmp; | ||
121 | |||
122 | /* We currently avoid using 64bit arithmetic by using the | ||
123 | * fact that anything faster than 1Hz is easily representable | ||
124 | * by 32bits. */ | ||
125 | |||
126 | if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) | ||
127 | return -ERANGE; | ||
128 | |||
129 | if (duty_ns > period_ns) | ||
130 | return -EINVAL; | ||
131 | |||
132 | if (period_ns == s3c->period_ns && | ||
133 | duty_ns == s3c->duty_ns) | ||
134 | return 0; | ||
135 | |||
136 | /* The TCMP and TCNT can be read without a lock, they're not | ||
137 | * shared between the timers. */ | ||
138 | |||
139 | tcmp = __raw_readl(S3C2410_TCMPB(s3c->pwm_id)); | ||
140 | tcnt = __raw_readl(S3C2410_TCNTB(s3c->pwm_id)); | ||
141 | |||
142 | period = NS_IN_HZ / period_ns; | ||
143 | |||
144 | pwm_dbg(s3c, "duty_ns=%d, period_ns=%d (%lu)\n", | ||
145 | duty_ns, period_ns, period); | ||
146 | |||
147 | /* Check to see if we are changing the clock rate of the PWM */ | ||
148 | |||
149 | if (s3c->period_ns != period_ns) { | ||
150 | if (pwm_is_tdiv(s3c)) { | ||
151 | tin_rate = pwm_calc_tin(s3c, period); | ||
152 | clk_set_rate(s3c->clk_div, tin_rate); | ||
153 | } else | ||
154 | tin_rate = clk_get_rate(s3c->clk); | ||
155 | |||
156 | s3c->period_ns = period_ns; | ||
157 | |||
158 | pwm_dbg(s3c, "tin_rate=%lu\n", tin_rate); | ||
159 | |||
160 | tin_ns = NS_IN_HZ / tin_rate; | ||
161 | tcnt = period_ns / tin_ns; | ||
162 | } else | ||
163 | tin_ns = NS_IN_HZ / clk_get_rate(s3c->clk); | ||
164 | |||
165 | /* Note, counters count down */ | ||
166 | |||
167 | tcmp = duty_ns / tin_ns; | ||
168 | tcmp = tcnt - tcmp; | ||
169 | /* the pwm hw only checks the compare register after a decrement, | ||
170 | so the pin never toggles if tcmp = tcnt */ | ||
171 | if (tcmp == tcnt) | ||
172 | tcmp--; | ||
173 | |||
174 | pwm_dbg(s3c, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); | ||
175 | |||
176 | if (tcmp < 0) | ||
177 | tcmp = 0; | ||
178 | |||
179 | /* Update the PWM register block. */ | ||
180 | |||
181 | local_irq_save(flags); | ||
182 | |||
183 | __raw_writel(tcmp, S3C2410_TCMPB(s3c->pwm_id)); | ||
184 | __raw_writel(tcnt, S3C2410_TCNTB(s3c->pwm_id)); | ||
185 | |||
186 | tcon = __raw_readl(S3C2410_TCON); | ||
187 | tcon |= pwm_tcon_manulupdate(s3c); | ||
188 | tcon |= pwm_tcon_autoreload(s3c); | ||
189 | __raw_writel(tcon, S3C2410_TCON); | ||
190 | |||
191 | tcon &= ~pwm_tcon_manulupdate(s3c); | ||
192 | __raw_writel(tcon, S3C2410_TCON); | ||
193 | |||
194 | local_irq_restore(flags); | ||
195 | |||
196 | return 0; | ||
197 | } | ||
198 | |||
199 | static struct pwm_ops s3c_pwm_ops = { | ||
200 | .enable = s3c_pwm_enable, | ||
201 | .disable = s3c_pwm_disable, | ||
202 | .config = s3c_pwm_config, | ||
203 | .owner = THIS_MODULE, | ||
204 | }; | ||
205 | |||
206 | static int s3c_pwm_probe(struct platform_device *pdev) | ||
207 | { | ||
208 | struct device *dev = &pdev->dev; | ||
209 | struct s3c_chip *s3c; | ||
210 | unsigned long flags; | ||
211 | unsigned long tcon; | ||
212 | unsigned int id = pdev->id; | ||
213 | int ret; | ||
214 | |||
215 | if (id == 4) { | ||
216 | dev_err(dev, "TIMER4 is currently not supported\n"); | ||
217 | return -ENXIO; | ||
218 | } | ||
219 | |||
220 | s3c = devm_kzalloc(&pdev->dev, sizeof(*s3c), GFP_KERNEL); | ||
221 | if (s3c == NULL) { | ||
222 | dev_err(dev, "failed to allocate pwm_device\n"); | ||
223 | return -ENOMEM; | ||
224 | } | ||
225 | |||
226 | /* calculate base of control bits in TCON */ | ||
227 | s3c->tcon_base = id == 0 ? 0 : (id * 4) + 4; | ||
228 | s3c->chip.dev = &pdev->dev; | ||
229 | s3c->chip.ops = &s3c_pwm_ops; | ||
230 | s3c->chip.base = -1; | ||
231 | s3c->chip.npwm = 1; | ||
232 | |||
233 | s3c->clk = devm_clk_get(dev, "pwm-tin"); | ||
234 | if (IS_ERR(s3c->clk)) { | ||
235 | dev_err(dev, "failed to get pwm tin clk\n"); | ||
236 | return PTR_ERR(s3c->clk); | ||
237 | } | ||
238 | |||
239 | s3c->clk_div = devm_clk_get(dev, "pwm-tdiv"); | ||
240 | if (IS_ERR(s3c->clk_div)) { | ||
241 | dev_err(dev, "failed to get pwm tdiv clk\n"); | ||
242 | return PTR_ERR(s3c->clk_div); | ||
243 | } | ||
244 | |||
245 | clk_enable(s3c->clk); | ||
246 | clk_enable(s3c->clk_div); | ||
247 | |||
248 | local_irq_save(flags); | ||
249 | |||
250 | tcon = __raw_readl(S3C2410_TCON); | ||
251 | tcon |= pwm_tcon_invert(s3c); | ||
252 | __raw_writel(tcon, S3C2410_TCON); | ||
253 | |||
254 | local_irq_restore(flags); | ||
255 | |||
256 | ret = pwmchip_add(&s3c->chip); | ||
257 | if (ret < 0) { | ||
258 | dev_err(dev, "failed to register pwm\n"); | ||
259 | goto err_clk_tdiv; | ||
260 | } | ||
261 | |||
262 | pwm_dbg(s3c, "config bits %02x\n", | ||
263 | (__raw_readl(S3C2410_TCON) >> s3c->tcon_base) & 0x0f); | ||
264 | |||
265 | dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", | ||
266 | clk_get_rate(s3c->clk), | ||
267 | clk_get_rate(s3c->clk_div), | ||
268 | pwm_is_tdiv(s3c) ? "div" : "ext", s3c->tcon_base); | ||
269 | |||
270 | platform_set_drvdata(pdev, s3c); | ||
271 | return 0; | ||
272 | |||
273 | err_clk_tdiv: | ||
274 | clk_disable(s3c->clk_div); | ||
275 | clk_disable(s3c->clk); | ||
276 | return ret; | ||
277 | } | ||
278 | |||
279 | static int __devexit s3c_pwm_remove(struct platform_device *pdev) | ||
280 | { | ||
281 | struct s3c_chip *s3c = platform_get_drvdata(pdev); | ||
282 | int err; | ||
283 | |||
284 | err = pwmchip_remove(&s3c->chip); | ||
285 | if (err < 0) | ||
286 | return err; | ||
287 | |||
288 | clk_disable(s3c->clk_div); | ||
289 | clk_disable(s3c->clk); | ||
290 | |||
291 | return 0; | ||
292 | } | ||
293 | |||
294 | #ifdef CONFIG_PM | ||
295 | static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state) | ||
296 | { | ||
297 | struct s3c_chip *s3c = platform_get_drvdata(pdev); | ||
298 | |||
299 | /* No one preserve these values during suspend so reset them | ||
300 | * Otherwise driver leaves PWM unconfigured if same values | ||
301 | * passed to pwm_config | ||
302 | */ | ||
303 | s3c->period_ns = 0; | ||
304 | s3c->duty_ns = 0; | ||
305 | |||
306 | return 0; | ||
307 | } | ||
308 | |||
309 | static int s3c_pwm_resume(struct platform_device *pdev) | ||
310 | { | ||
311 | struct s3c_chip *s3c = platform_get_drvdata(pdev); | ||
312 | unsigned long tcon; | ||
313 | |||
314 | /* Restore invertion */ | ||
315 | tcon = __raw_readl(S3C2410_TCON); | ||
316 | tcon |= pwm_tcon_invert(s3c); | ||
317 | __raw_writel(tcon, S3C2410_TCON); | ||
318 | |||
319 | return 0; | ||
320 | } | ||
321 | |||
322 | #else | ||
323 | #define s3c_pwm_suspend NULL | ||
324 | #define s3c_pwm_resume NULL | ||
325 | #endif | ||
326 | |||
327 | static struct platform_driver s3c_pwm_driver = { | ||
328 | .driver = { | ||
329 | .name = "s3c24xx-pwm", | ||
330 | .owner = THIS_MODULE, | ||
331 | }, | ||
332 | .probe = s3c_pwm_probe, | ||
333 | .remove = __devexit_p(s3c_pwm_remove), | ||
334 | .suspend = s3c_pwm_suspend, | ||
335 | .resume = s3c_pwm_resume, | ||
336 | }; | ||
337 | |||
338 | static int __init pwm_init(void) | ||
339 | { | ||
340 | int ret; | ||
341 | |||
342 | clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); | ||
343 | clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); | ||
344 | |||
345 | if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { | ||
346 | pr_err("failed to get scaler clocks\n"); | ||
347 | return -EINVAL; | ||
348 | } | ||
349 | |||
350 | ret = platform_driver_register(&s3c_pwm_driver); | ||
351 | if (ret) | ||
352 | pr_err("failed to add pwm driver\n"); | ||
353 | |||
354 | return ret; | ||
355 | } | ||
356 | |||
357 | arch_initcall(pwm_init); | ||