?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
hwmon: (adt7475) fan stall prevention
[linux/fpc-iii.git] / drivers / rtc / rtc-jz4740.c
blob64989afffa3daada4b062321c527f18bca142bbb
1 /*
2 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
3 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
4 * JZ4740 SoC RTC driver
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 *
11 * You should have received a copy of the GNU General Public License along
12 * with this program; if not, write to the Free Software Foundation, Inc.,
13 * 675 Mass Ave, Cambridge, MA 02139, USA.
14 *
15 */
16
17 #include <linux/clk.h>
18 #include <linux/io.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/of_device.h>
22 #include <linux/platform_device.h>
23 #include <linux/reboot.h>
24 #include <linux/rtc.h>
25 #include <linux/slab.h>
26 #include <linux/spinlock.h>
27
28 #define JZ_REG_RTC_CTRL 0x00
29 #define JZ_REG_RTC_SEC 0x04
30 #define JZ_REG_RTC_SEC_ALARM 0x08
31 #define JZ_REG_RTC_REGULATOR 0x0C
32 #define JZ_REG_RTC_HIBERNATE 0x20
33 #define JZ_REG_RTC_WAKEUP_FILTER 0x24
34 #define JZ_REG_RTC_RESET_COUNTER 0x28
35 #define JZ_REG_RTC_SCRATCHPAD 0x34
36
37 /* The following are present on the jz4780 */
38 #define JZ_REG_RTC_WENR 0x3C
39 #define JZ_RTC_WENR_WEN BIT(31)
40
41 #define JZ_RTC_CTRL_WRDY BIT(7)
42 #define JZ_RTC_CTRL_1HZ BIT(6)
43 #define JZ_RTC_CTRL_1HZ_IRQ BIT(5)
44 #define JZ_RTC_CTRL_AF BIT(4)
45 #define JZ_RTC_CTRL_AF_IRQ BIT(3)
46 #define JZ_RTC_CTRL_AE BIT(2)
47 #define JZ_RTC_CTRL_ENABLE BIT(0)
48
49 /* Magic value to enable writes on jz4780 */
50 #define JZ_RTC_WENR_MAGIC 0xA55A
51
52 #define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
53 #define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
54
55 enum jz4740_rtc_type {
56 ID_JZ4740,
57 ID_JZ4780,
58 };
59
60 struct jz4740_rtc {
61 void __iomem *base;
62 enum jz4740_rtc_type type;
63
64 struct rtc_device *rtc;
65 struct clk *clk;
66
67 int irq;
68
69 spinlock_t lock;
70
71 unsigned int min_wakeup_pin_assert_time;
72 unsigned int reset_pin_assert_time;
73 };
74
75 static struct device *dev_for_power_off;
76
77 static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
78 {
79 return readl(rtc->base + reg);
80 }
81
82 static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
83 {
84 uint32_t ctrl;
85 int timeout = 1000;
86
87 do {
88 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
89 } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
90
91 return timeout ? 0 : -EIO;
92 }
93
94 static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
95 {
96 uint32_t ctrl;
97 int ret, timeout = 1000;
98
99 ret = jz4740_rtc_wait_write_ready(rtc);
100 if (ret != 0)
101 return ret;
102
103 writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
104
105 do {
106 ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
107 } while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
108
109 return timeout ? 0 : -EIO;
110 }
111
112 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
113 uint32_t val)
114 {
115 int ret = 0;
116
117 if (rtc->type >= ID_JZ4780)
118 ret = jz4780_rtc_enable_write(rtc);
119 if (ret == 0)
120 ret = jz4740_rtc_wait_write_ready(rtc);
121 if (ret == 0)
122 writel(val, rtc->base + reg);
123
124 return ret;
125 }
126
127 static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
128 bool set)
129 {
130 int ret;
131 unsigned long flags;
132 uint32_t ctrl;
133
134 spin_lock_irqsave(&rtc->lock, flags);
135
136 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
137
138 /* Don't clear interrupt flags by accident */
139 ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
140
141 if (set)
142 ctrl |= mask;
143 else
144 ctrl &= ~mask;
145
146 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
147
148 spin_unlock_irqrestore(&rtc->lock, flags);
149
150 return ret;
151 }
152
153 static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
154 {
155 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
156 uint32_t secs, secs2;
157 int timeout = 5;
158
159 /* If the seconds register is read while it is updated, it can contain a
160 * bogus value. This can be avoided by making sure that two consecutive
161 * reads have the same value.
162 */
163 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
164 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
165
166 while (secs != secs2 && --timeout) {
167 secs = secs2;
168 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
169 }
170
171 if (timeout == 0)
172 return -EIO;
173
174 rtc_time_to_tm(secs, time);
175
176 return rtc_valid_tm(time);
177 }
178
179 static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
180 {
181 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
182
183 return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
184 }
185
186 static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
187 {
188 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
189 uint32_t secs;
190 uint32_t ctrl;
191
192 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
193
194 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
195
196 alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
197 alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
198
199 rtc_time_to_tm(secs, &alrm->time);
200
201 return rtc_valid_tm(&alrm->time);
202 }
203
204 static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
205 {
206 int ret;
207 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
208 unsigned long secs;
209
210 rtc_tm_to_time(&alrm->time, &secs);
211
212 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
213 if (!ret)
214 ret = jz4740_rtc_ctrl_set_bits(rtc,
215 JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
216
217 return ret;
218 }
219
220 static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
221 {
222 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
223 return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
224 }
225
226 static const struct rtc_class_ops jz4740_rtc_ops = {
227 .read_time = jz4740_rtc_read_time,
228 .set_mmss = jz4740_rtc_set_mmss,
229 .read_alarm = jz4740_rtc_read_alarm,
230 .set_alarm = jz4740_rtc_set_alarm,
231 .alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
232 };
233
234 static irqreturn_t jz4740_rtc_irq(int irq, void *data)
235 {
236 struct jz4740_rtc *rtc = data;
237 uint32_t ctrl;
238 unsigned long events = 0;
239
240 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
241
242 if (ctrl & JZ_RTC_CTRL_1HZ)
243 events |= (RTC_UF | RTC_IRQF);
244
245 if (ctrl & JZ_RTC_CTRL_AF)
246 events |= (RTC_AF | RTC_IRQF);
247
248 rtc_update_irq(rtc->rtc, 1, events);
249
250 jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
251
252 return IRQ_HANDLED;
253 }
254
255 static void jz4740_rtc_poweroff(struct device *dev)
256 {
257 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
258 jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
259 }
260
261 static void jz4740_rtc_power_off(void)
262 {
263 struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off);
264 unsigned long rtc_rate;
265 unsigned long wakeup_filter_ticks;
266 unsigned long reset_counter_ticks;
267
268 clk_prepare_enable(rtc->clk);
269
270 rtc_rate = clk_get_rate(rtc->clk);
271
272 /*
273 * Set minimum wakeup pin assertion time: 100 ms.
274 * Range is 0 to 2 sec if RTC is clocked at 32 kHz.
275 */
276 wakeup_filter_ticks =
277 (rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000;
278 if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
279 wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
280 else
281 wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
282 jz4740_rtc_reg_write(rtc,
283 JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks);
284
285 /*
286 * Set reset pin low-level assertion time after wakeup: 60 ms.
287 * Range is 0 to 125 ms if RTC is clocked at 32 kHz.
288 */
289 reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000;
290 if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK)
291 reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
292 else
293 reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
294 jz4740_rtc_reg_write(rtc,
295 JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks);
296
297 jz4740_rtc_poweroff(dev_for_power_off);
298 kernel_halt();
299 }
300
301 static const struct of_device_id jz4740_rtc_of_match[] = {
302 { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
303 { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
304 {},
305 };
306 MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
307
308 static int jz4740_rtc_probe(struct platform_device *pdev)
309 {
310 int ret;
311 struct jz4740_rtc *rtc;
312 uint32_t scratchpad;
313 struct resource *mem;
314 const struct platform_device_id *id = platform_get_device_id(pdev);
315 const struct of_device_id *of_id = of_match_device(
316 jz4740_rtc_of_match, &pdev->dev);
317 struct device_node *np = pdev->dev.of_node;
318
319 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
320 if (!rtc)
321 return -ENOMEM;
322
323 if (of_id)
324 rtc->type = (enum jz4740_rtc_type)of_id->data;
325 else
326 rtc->type = id->driver_data;
327
328 rtc->irq = platform_get_irq(pdev, 0);
329 if (rtc->irq < 0) {
330 dev_err(&pdev->dev, "Failed to get platform irq\n");
331 return -ENOENT;
332 }
333
334 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
335 rtc->base = devm_ioremap_resource(&pdev->dev, mem);
336 if (IS_ERR(rtc->base))
337 return PTR_ERR(rtc->base);
338
339 rtc->clk = devm_clk_get(&pdev->dev, "rtc");
340 if (IS_ERR(rtc->clk)) {
341 dev_err(&pdev->dev, "Failed to get RTC clock\n");
342 return PTR_ERR(rtc->clk);
343 }
344
345 spin_lock_init(&rtc->lock);
346
347 platform_set_drvdata(pdev, rtc);
348
349 device_init_wakeup(&pdev->dev, 1);
350
351 rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
352 &jz4740_rtc_ops, THIS_MODULE);
353 if (IS_ERR(rtc->rtc)) {
354 ret = PTR_ERR(rtc->rtc);
355 dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
356 return ret;
357 }
358
359 ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0,
360 pdev->name, rtc);
361 if (ret) {
362 dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
363 return ret;
364 }
365
366 scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
367 if (scratchpad != 0x12345678) {
368 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
369 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
370 if (ret) {
371 dev_err(&pdev->dev, "Could not write write to RTC registers\n");
372 return ret;
373 }
374 }
375
376 if (np && of_device_is_system_power_controller(np)) {
377 if (!pm_power_off) {
378 /* Default: 60ms */
379 rtc->reset_pin_assert_time = 60;
380 of_property_read_u32(np, "reset-pin-assert-time-ms",
381 &rtc->reset_pin_assert_time);
382
383 /* Default: 100ms */
384 rtc->min_wakeup_pin_assert_time = 100;
385 of_property_read_u32(np,
386 "min-wakeup-pin-assert-time-ms",
387 &rtc->min_wakeup_pin_assert_time);
388
389 dev_for_power_off = &pdev->dev;
390 pm_power_off = jz4740_rtc_power_off;
391 } else {
392 dev_warn(&pdev->dev,
393 "Poweroff handler already present!\n");
394 }
395 }
396
397 return 0;
398 }
399
400 #ifdef CONFIG_PM
401 static int jz4740_rtc_suspend(struct device *dev)
402 {
403 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
404
405 if (device_may_wakeup(dev))
406 enable_irq_wake(rtc->irq);
407 return 0;
408 }
409
410 static int jz4740_rtc_resume(struct device *dev)
411 {
412 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
413
414 if (device_may_wakeup(dev))
415 disable_irq_wake(rtc->irq);
416 return 0;
417 }
418
419 static const struct dev_pm_ops jz4740_pm_ops = {
420 .suspend = jz4740_rtc_suspend,
421 .resume = jz4740_rtc_resume,
422 };
423 #define JZ4740_RTC_PM_OPS (&jz4740_pm_ops)
424
425 #else
426 #define JZ4740_RTC_PM_OPS NULL
427 #endif /* CONFIG_PM */
428
429 static const struct platform_device_id jz4740_rtc_ids[] = {
430 { "jz4740-rtc", ID_JZ4740 },
431 { "jz4780-rtc", ID_JZ4780 },
432 {}
433 };
434 MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids);
435
436 static struct platform_driver jz4740_rtc_driver = {
437 .probe = jz4740_rtc_probe,
438 .driver = {
439 .name = "jz4740-rtc",
440 .pm = JZ4740_RTC_PM_OPS,
441 .of_match_table = of_match_ptr(jz4740_rtc_of_match),
442 },
443 .id_table = jz4740_rtc_ids,
444 };
445
446 module_platform_driver(jz4740_rtc_driver);
447
448 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
449 MODULE_LICENSE("GPL");
450 MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
451 MODULE_ALIAS("platform:jz4740-rtc");
Linux with added FPC-III support