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
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.
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.
17 #include <linux/clk.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>
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
37 /* The following are present on the jz4780 */
38 #define JZ_REG_RTC_WENR 0x3C
39 #define JZ_RTC_WENR_WEN BIT(31)
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)
49 /* Magic value to enable writes on jz4780 */
50 #define JZ_RTC_WENR_MAGIC 0xA55A
52 #define JZ_RTC_WAKEUP_FILTER_MASK 0x0000FFE0
53 #define JZ_RTC_RESET_COUNTER_MASK 0x00000FE0
55 enum jz4740_rtc_type {
62 enum jz4740_rtc_type type;
64 struct rtc_device *rtc;
71 unsigned int min_wakeup_pin_assert_time;
72 unsigned int reset_pin_assert_time;
75 static struct device *dev_for_power_off;
77 static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
79 return readl(rtc->base + reg);
82 static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
88 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
89 } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);
91 return timeout ? 0 : -EIO;
94 static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
97 int ret, timeout = 10000;
99 ret = jz4740_rtc_wait_write_ready(rtc);
103 writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
106 ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
107 } while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
109 return timeout ? 0 : -EIO;
112 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
117 if (rtc->type >= ID_JZ4780)
118 ret = jz4780_rtc_enable_write(rtc);
120 ret = jz4740_rtc_wait_write_ready(rtc);
122 writel(val, rtc->base + reg);
127 static int jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
134 spin_lock_irqsave(&rtc->lock, flags);
136 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
138 /* Don't clear interrupt flags by accident */
139 ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
146 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
148 spin_unlock_irqrestore(&rtc->lock, flags);
153 static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
155 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
156 uint32_t secs, secs2;
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.
163 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
164 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
166 while (secs != secs2 && --timeout) {
168 secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
174 rtc_time64_to_tm(secs, time);
179 static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
181 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
183 return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
186 static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
188 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
192 secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
194 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
196 alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
197 alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
199 rtc_time64_to_tm(secs, &alrm->time);
201 return rtc_valid_tm(&alrm->time);
204 static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
207 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
208 uint32_t secs = lower_32_bits(rtc_tm_to_time64(&alrm->time));
210 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, secs);
212 ret = jz4740_rtc_ctrl_set_bits(rtc,
213 JZ_RTC_CTRL_AE | JZ_RTC_CTRL_AF_IRQ, alrm->enabled);
218 static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
220 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
221 return jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ, enable);
224 static const struct rtc_class_ops jz4740_rtc_ops = {
225 .read_time = jz4740_rtc_read_time,
226 .set_mmss = jz4740_rtc_set_mmss,
227 .read_alarm = jz4740_rtc_read_alarm,
228 .set_alarm = jz4740_rtc_set_alarm,
229 .alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
232 static irqreturn_t jz4740_rtc_irq(int irq, void *data)
234 struct jz4740_rtc *rtc = data;
236 unsigned long events = 0;
238 ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
240 if (ctrl & JZ_RTC_CTRL_1HZ)
241 events |= (RTC_UF | RTC_IRQF);
243 if (ctrl & JZ_RTC_CTRL_AF)
244 events |= (RTC_AF | RTC_IRQF);
246 rtc_update_irq(rtc->rtc, 1, events);
248 jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, false);
253 static void jz4740_rtc_poweroff(struct device *dev)
255 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
256 jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
259 static void jz4740_rtc_power_off(void)
261 struct jz4740_rtc *rtc = dev_get_drvdata(dev_for_power_off);
262 unsigned long rtc_rate;
263 unsigned long wakeup_filter_ticks;
264 unsigned long reset_counter_ticks;
266 clk_prepare_enable(rtc->clk);
268 rtc_rate = clk_get_rate(rtc->clk);
271 * Set minimum wakeup pin assertion time: 100 ms.
272 * Range is 0 to 2 sec if RTC is clocked at 32 kHz.
274 wakeup_filter_ticks =
275 (rtc->min_wakeup_pin_assert_time * rtc_rate) / 1000;
276 if (wakeup_filter_ticks < JZ_RTC_WAKEUP_FILTER_MASK)
277 wakeup_filter_ticks &= JZ_RTC_WAKEUP_FILTER_MASK;
279 wakeup_filter_ticks = JZ_RTC_WAKEUP_FILTER_MASK;
280 jz4740_rtc_reg_write(rtc,
281 JZ_REG_RTC_WAKEUP_FILTER, wakeup_filter_ticks);
284 * Set reset pin low-level assertion time after wakeup: 60 ms.
285 * Range is 0 to 125 ms if RTC is clocked at 32 kHz.
287 reset_counter_ticks = (rtc->reset_pin_assert_time * rtc_rate) / 1000;
288 if (reset_counter_ticks < JZ_RTC_RESET_COUNTER_MASK)
289 reset_counter_ticks &= JZ_RTC_RESET_COUNTER_MASK;
291 reset_counter_ticks = JZ_RTC_RESET_COUNTER_MASK;
292 jz4740_rtc_reg_write(rtc,
293 JZ_REG_RTC_RESET_COUNTER, reset_counter_ticks);
295 jz4740_rtc_poweroff(dev_for_power_off);
299 static const struct of_device_id jz4740_rtc_of_match[] = {
300 { .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
301 { .compatible = "ingenic,jz4780-rtc", .data = (void *)ID_JZ4780 },
304 MODULE_DEVICE_TABLE(of, jz4740_rtc_of_match);
306 static int jz4740_rtc_probe(struct platform_device *pdev)
309 struct jz4740_rtc *rtc;
311 struct resource *mem;
312 const struct platform_device_id *id = platform_get_device_id(pdev);
313 const struct of_device_id *of_id = of_match_device(
314 jz4740_rtc_of_match, &pdev->dev);
315 struct device_node *np = pdev->dev.of_node;
317 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
322 rtc->type = (enum jz4740_rtc_type)of_id->data;
324 rtc->type = id->driver_data;
326 rtc->irq = platform_get_irq(pdev, 0);
328 dev_err(&pdev->dev, "Failed to get platform irq\n");
332 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
333 rtc->base = devm_ioremap_resource(&pdev->dev, mem);
334 if (IS_ERR(rtc->base))
335 return PTR_ERR(rtc->base);
337 rtc->clk = devm_clk_get(&pdev->dev, "rtc");
338 if (IS_ERR(rtc->clk)) {
339 dev_err(&pdev->dev, "Failed to get RTC clock\n");
340 return PTR_ERR(rtc->clk);
343 spin_lock_init(&rtc->lock);
345 platform_set_drvdata(pdev, rtc);
347 device_init_wakeup(&pdev->dev, 1);
349 rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
350 if (IS_ERR(rtc->rtc)) {
351 ret = PTR_ERR(rtc->rtc);
352 dev_err(&pdev->dev, "Failed to allocate rtc device: %d\n", ret);
356 rtc->rtc->ops = &jz4740_rtc_ops;
357 rtc->rtc->range_max = U32_MAX;
359 ret = rtc_register_device(rtc->rtc);
361 dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
365 ret = devm_request_irq(&pdev->dev, rtc->irq, jz4740_rtc_irq, 0,
368 dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
372 scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
373 if (scratchpad != 0x12345678) {
374 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
375 ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
377 dev_err(&pdev->dev, "Could not write to RTC registers\n");
382 if (np && of_device_is_system_power_controller(np)) {
385 rtc->reset_pin_assert_time = 60;
386 of_property_read_u32(np, "reset-pin-assert-time-ms",
387 &rtc->reset_pin_assert_time);
390 rtc->min_wakeup_pin_assert_time = 100;
391 of_property_read_u32(np,
392 "min-wakeup-pin-assert-time-ms",
393 &rtc->min_wakeup_pin_assert_time);
395 dev_for_power_off = &pdev->dev;
396 pm_power_off = jz4740_rtc_power_off;
399 "Poweroff handler already present!\n");
407 static int jz4740_rtc_suspend(struct device *dev)
409 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
411 if (device_may_wakeup(dev))
412 enable_irq_wake(rtc->irq);
416 static int jz4740_rtc_resume(struct device *dev)
418 struct jz4740_rtc *rtc = dev_get_drvdata(dev);
420 if (device_may_wakeup(dev))
421 disable_irq_wake(rtc->irq);
425 static const struct dev_pm_ops jz4740_pm_ops = {
426 .suspend = jz4740_rtc_suspend,
427 .resume = jz4740_rtc_resume,
429 #define JZ4740_RTC_PM_OPS (&jz4740_pm_ops)
432 #define JZ4740_RTC_PM_OPS NULL
433 #endif /* CONFIG_PM */
435 static const struct platform_device_id jz4740_rtc_ids[] = {
436 { "jz4740-rtc", ID_JZ4740 },
437 { "jz4780-rtc", ID_JZ4780 },
440 MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids);
442 static struct platform_driver jz4740_rtc_driver = {
443 .probe = jz4740_rtc_probe,
445 .name = "jz4740-rtc",
446 .pm = JZ4740_RTC_PM_OPS,
447 .of_match_table = of_match_ptr(jz4740_rtc_of_match),
449 .id_table = jz4740_rtc_ids,
452 module_platform_driver(jz4740_rtc_driver);
454 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
455 MODULE_LICENSE("GPL");
456 MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
457 MODULE_ALIAS("platform:jz4740-rtc");