Commit | Line | Data |
---|---|---|
ff859ba6 AC |
1 | /* |
2 | * An RTC driver for the NVIDIA Tegra 200 series internal RTC. | |
3 | * | |
4 | * Copyright (c) 2010, NVIDIA Corporation. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | * more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License along | |
17 | * with this program; if not, write to the Free Software Foundation, Inc., | |
18 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
19 | */ | |
0ae20595 | 20 | |
5fa40869 | 21 | #include <linux/clk.h> |
0ae20595 | 22 | #include <linux/delay.h> |
ff859ba6 | 23 | #include <linux/init.h> |
ff859ba6 | 24 | #include <linux/io.h> |
0ae20595 TR |
25 | #include <linux/irq.h> |
26 | #include <linux/kernel.h> | |
27 | #include <linux/module.h> | |
ac316725 | 28 | #include <linux/mod_devicetable.h> |
ff859ba6 | 29 | #include <linux/platform_device.h> |
3443ad09 | 30 | #include <linux/pm.h> |
0ae20595 TR |
31 | #include <linux/rtc.h> |
32 | #include <linux/slab.h> | |
ff859ba6 AC |
33 | |
34 | /* set to 1 = busy every eight 32kHz clocks during copy of sec+msec to AHB */ | |
35 | #define TEGRA_RTC_REG_BUSY 0x004 | |
36 | #define TEGRA_RTC_REG_SECONDS 0x008 | |
37 | /* when msec is read, the seconds are buffered into shadow seconds. */ | |
38 | #define TEGRA_RTC_REG_SHADOW_SECONDS 0x00c | |
39 | #define TEGRA_RTC_REG_MILLI_SECONDS 0x010 | |
40 | #define TEGRA_RTC_REG_SECONDS_ALARM0 0x014 | |
41 | #define TEGRA_RTC_REG_SECONDS_ALARM1 0x018 | |
42 | #define TEGRA_RTC_REG_MILLI_SECONDS_ALARM0 0x01c | |
43 | #define TEGRA_RTC_REG_INTR_MASK 0x028 | |
44 | /* write 1 bits to clear status bits */ | |
45 | #define TEGRA_RTC_REG_INTR_STATUS 0x02c | |
46 | ||
47 | /* bits in INTR_MASK */ | |
48 | #define TEGRA_RTC_INTR_MASK_MSEC_CDN_ALARM (1<<4) | |
49 | #define TEGRA_RTC_INTR_MASK_SEC_CDN_ALARM (1<<3) | |
50 | #define TEGRA_RTC_INTR_MASK_MSEC_ALARM (1<<2) | |
51 | #define TEGRA_RTC_INTR_MASK_SEC_ALARM1 (1<<1) | |
52 | #define TEGRA_RTC_INTR_MASK_SEC_ALARM0 (1<<0) | |
53 | ||
54 | /* bits in INTR_STATUS */ | |
55 | #define TEGRA_RTC_INTR_STATUS_MSEC_CDN_ALARM (1<<4) | |
56 | #define TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM (1<<3) | |
57 | #define TEGRA_RTC_INTR_STATUS_MSEC_ALARM (1<<2) | |
58 | #define TEGRA_RTC_INTR_STATUS_SEC_ALARM1 (1<<1) | |
59 | #define TEGRA_RTC_INTR_STATUS_SEC_ALARM0 (1<<0) | |
60 | ||
61 | struct tegra_rtc_info { | |
62 | struct platform_device *pdev; | |
63 | struct rtc_device *rtc_dev; | |
64 | void __iomem *rtc_base; /* NULL if not initialized. */ | |
5fa40869 | 65 | struct clk *clk; |
ff859ba6 AC |
66 | int tegra_rtc_irq; /* alarm and periodic irq */ |
67 | spinlock_t tegra_rtc_lock; | |
68 | }; | |
69 | ||
70 | /* RTC hardware is busy when it is updating its values over AHB once | |
71 | * every eight 32kHz clocks (~250uS). | |
72 | * outside of these updates the CPU is free to write. | |
73 | * CPU is always free to read. | |
74 | */ | |
75 | static inline u32 tegra_rtc_check_busy(struct tegra_rtc_info *info) | |
76 | { | |
77 | return readl(info->rtc_base + TEGRA_RTC_REG_BUSY) & 1; | |
78 | } | |
79 | ||
80 | /* Wait for hardware to be ready for writing. | |
81 | * This function tries to maximize the amount of time before the next update. | |
82 | * It does this by waiting for the RTC to become busy with its periodic update, | |
83 | * then returning once the RTC first becomes not busy. | |
84 | * This periodic update (where the seconds and milliseconds are copied to the | |
85 | * AHB side) occurs every eight 32kHz clocks (~250uS). | |
86 | * The behavior of this function allows us to make some assumptions without | |
87 | * introducing a race, because 250uS is plenty of time to read/write a value. | |
88 | */ | |
89 | static int tegra_rtc_wait_while_busy(struct device *dev) | |
90 | { | |
91 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
92 | ||
93 | int retries = 500; /* ~490 us is the worst case, ~250 us is best. */ | |
94 | ||
95 | /* first wait for the RTC to become busy. this is when it | |
96 | * posts its updated seconds+msec registers to AHB side. */ | |
97 | while (tegra_rtc_check_busy(info)) { | |
98 | if (!retries--) | |
99 | goto retry_failed; | |
100 | udelay(1); | |
101 | } | |
102 | ||
103 | /* now we have about 250 us to manipulate registers */ | |
104 | return 0; | |
105 | ||
106 | retry_failed: | |
107 | dev_err(dev, "write failed:retry count exceeded.\n"); | |
108 | return -ETIMEDOUT; | |
109 | } | |
110 | ||
111 | static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
112 | { | |
113 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
114 | unsigned long sec, msec; | |
115 | unsigned long sl_irq_flags; | |
116 | ||
117 | /* RTC hardware copies seconds to shadow seconds when a read | |
118 | * of milliseconds occurs. use a lock to keep other threads out. */ | |
119 | spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); | |
120 | ||
121 | msec = readl(info->rtc_base + TEGRA_RTC_REG_MILLI_SECONDS); | |
122 | sec = readl(info->rtc_base + TEGRA_RTC_REG_SHADOW_SECONDS); | |
123 | ||
124 | spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); | |
125 | ||
126 | rtc_time_to_tm(sec, tm); | |
127 | ||
d54fb486 | 128 | dev_vdbg(dev, "time read as %lu. %ptR\n", sec, tm); |
ff859ba6 AC |
129 | |
130 | return 0; | |
131 | } | |
132 | ||
133 | static int tegra_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
134 | { | |
135 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
136 | unsigned long sec; | |
137 | int ret; | |
138 | ||
139 | /* convert tm to seconds. */ | |
ff859ba6 AC |
140 | rtc_tm_to_time(tm, &sec); |
141 | ||
d54fb486 | 142 | dev_vdbg(dev, "time set to %lu. %ptR\n", sec, tm); |
ff859ba6 AC |
143 | |
144 | /* seconds only written if wait succeeded. */ | |
145 | ret = tegra_rtc_wait_while_busy(dev); | |
146 | if (!ret) | |
147 | writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS); | |
148 | ||
149 | dev_vdbg(dev, "time read back as %d\n", | |
150 | readl(info->rtc_base + TEGRA_RTC_REG_SECONDS)); | |
151 | ||
152 | return ret; | |
153 | } | |
154 | ||
155 | static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
156 | { | |
157 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
158 | unsigned long sec; | |
159 | unsigned tmp; | |
160 | ||
161 | sec = readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0); | |
162 | ||
163 | if (sec == 0) { | |
164 | /* alarm is disabled. */ | |
165 | alarm->enabled = 0; | |
ff859ba6 AC |
166 | } else { |
167 | /* alarm is enabled. */ | |
168 | alarm->enabled = 1; | |
169 | rtc_time_to_tm(sec, &alarm->time); | |
170 | } | |
171 | ||
172 | tmp = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); | |
173 | alarm->pending = (tmp & TEGRA_RTC_INTR_STATUS_SEC_ALARM0) != 0; | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | static int tegra_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) | |
179 | { | |
180 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
181 | unsigned status; | |
182 | unsigned long sl_irq_flags; | |
183 | ||
184 | tegra_rtc_wait_while_busy(dev); | |
185 | spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); | |
186 | ||
187 | /* read the original value, and OR in the flag. */ | |
188 | status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_MASK); | |
189 | if (enabled) | |
190 | status |= TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* set it */ | |
191 | else | |
192 | status &= ~TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* clear it */ | |
193 | ||
194 | writel(status, info->rtc_base + TEGRA_RTC_REG_INTR_MASK); | |
195 | ||
196 | spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); | |
197 | ||
198 | return 0; | |
199 | } | |
200 | ||
201 | static int tegra_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
202 | { | |
203 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
204 | unsigned long sec; | |
205 | ||
206 | if (alarm->enabled) | |
207 | rtc_tm_to_time(&alarm->time, &sec); | |
208 | else | |
209 | sec = 0; | |
210 | ||
211 | tegra_rtc_wait_while_busy(dev); | |
212 | writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0); | |
213 | dev_vdbg(dev, "alarm read back as %d\n", | |
214 | readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0)); | |
215 | ||
216 | /* if successfully written and alarm is enabled ... */ | |
217 | if (sec) { | |
218 | tegra_rtc_alarm_irq_enable(dev, 1); | |
d54fb486 | 219 | dev_vdbg(dev, "alarm set as %lu. %ptR\n", sec, &alarm->time); |
ff859ba6 AC |
220 | } else { |
221 | /* disable alarm if 0 or write error. */ | |
222 | dev_vdbg(dev, "alarm disabled\n"); | |
223 | tegra_rtc_alarm_irq_enable(dev, 0); | |
224 | } | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | static int tegra_rtc_proc(struct device *dev, struct seq_file *seq) | |
230 | { | |
231 | if (!dev || !dev->driver) | |
232 | return 0; | |
233 | ||
4395eb1f JP |
234 | seq_printf(seq, "name\t\t: %s\n", dev_name(dev)); |
235 | ||
236 | return 0; | |
ff859ba6 AC |
237 | } |
238 | ||
239 | static irqreturn_t tegra_rtc_irq_handler(int irq, void *data) | |
240 | { | |
241 | struct device *dev = data; | |
242 | struct tegra_rtc_info *info = dev_get_drvdata(dev); | |
243 | unsigned long events = 0; | |
244 | unsigned status; | |
245 | unsigned long sl_irq_flags; | |
246 | ||
247 | status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); | |
248 | if (status) { | |
249 | /* clear the interrupt masks and status on any irq. */ | |
250 | tegra_rtc_wait_while_busy(dev); | |
251 | spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags); | |
252 | writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK); | |
253 | writel(status, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); | |
254 | spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags); | |
255 | } | |
256 | ||
257 | /* check if Alarm */ | |
258 | if ((status & TEGRA_RTC_INTR_STATUS_SEC_ALARM0)) | |
259 | events |= RTC_IRQF | RTC_AF; | |
260 | ||
261 | /* check if Periodic */ | |
262 | if ((status & TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM)) | |
263 | events |= RTC_IRQF | RTC_PF; | |
264 | ||
265 | rtc_update_irq(info->rtc_dev, 1, events); | |
266 | ||
267 | return IRQ_HANDLED; | |
268 | } | |
269 | ||
34c7b3ac | 270 | static const struct rtc_class_ops tegra_rtc_ops = { |
ff859ba6 AC |
271 | .read_time = tegra_rtc_read_time, |
272 | .set_time = tegra_rtc_set_time, | |
273 | .read_alarm = tegra_rtc_read_alarm, | |
274 | .set_alarm = tegra_rtc_set_alarm, | |
275 | .proc = tegra_rtc_proc, | |
276 | .alarm_irq_enable = tegra_rtc_alarm_irq_enable, | |
277 | }; | |
278 | ||
2d79cf8a JL |
279 | static const struct of_device_id tegra_rtc_dt_match[] = { |
280 | { .compatible = "nvidia,tegra20-rtc", }, | |
281 | {} | |
282 | }; | |
283 | MODULE_DEVICE_TABLE(of, tegra_rtc_dt_match); | |
284 | ||
51b38c62 | 285 | static int __init tegra_rtc_probe(struct platform_device *pdev) |
ff859ba6 AC |
286 | { |
287 | struct tegra_rtc_info *info; | |
288 | struct resource *res; | |
289 | int ret; | |
290 | ||
621bae79 HH |
291 | info = devm_kzalloc(&pdev->dev, sizeof(struct tegra_rtc_info), |
292 | GFP_KERNEL); | |
ff859ba6 AC |
293 | if (!info) |
294 | return -ENOMEM; | |
295 | ||
296 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
8cbce1e5 TR |
297 | info->rtc_base = devm_ioremap_resource(&pdev->dev, res); |
298 | if (IS_ERR(info->rtc_base)) | |
299 | return PTR_ERR(info->rtc_base); | |
ff859ba6 | 300 | |
fe0b5ced TR |
301 | ret = platform_get_irq(pdev, 0); |
302 | if (ret <= 0) { | |
303 | dev_err(&pdev->dev, "failed to get platform IRQ: %d\n", ret); | |
304 | return ret; | |
305 | } | |
306 | ||
307 | info->tegra_rtc_irq = ret; | |
ff859ba6 | 308 | |
5fa40869 TR |
309 | info->clk = devm_clk_get(&pdev->dev, NULL); |
310 | if (IS_ERR(info->clk)) | |
311 | return PTR_ERR(info->clk); | |
312 | ||
313 | ret = clk_prepare_enable(info->clk); | |
314 | if (ret < 0) | |
315 | return ret; | |
316 | ||
ff859ba6 AC |
317 | /* set context info. */ |
318 | info->pdev = pdev; | |
e57ee017 | 319 | spin_lock_init(&info->tegra_rtc_lock); |
ff859ba6 AC |
320 | |
321 | platform_set_drvdata(pdev, info); | |
322 | ||
323 | /* clear out the hardware. */ | |
324 | writel(0, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0); | |
325 | writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); | |
326 | writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK); | |
327 | ||
328 | device_init_wakeup(&pdev->dev, 1); | |
329 | ||
68567112 LD |
330 | info->rtc_dev = devm_rtc_device_register(&pdev->dev, |
331 | dev_name(&pdev->dev), &tegra_rtc_ops, | |
332 | THIS_MODULE); | |
ff859ba6 AC |
333 | if (IS_ERR(info->rtc_dev)) { |
334 | ret = PTR_ERR(info->rtc_dev); | |
68567112 | 335 | dev_err(&pdev->dev, "Unable to register device (err=%d).\n", |
ff859ba6 | 336 | ret); |
5fa40869 | 337 | goto disable_clk; |
ff859ba6 AC |
338 | } |
339 | ||
621bae79 HH |
340 | ret = devm_request_irq(&pdev->dev, info->tegra_rtc_irq, |
341 | tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH, | |
57bff981 | 342 | dev_name(&pdev->dev), &pdev->dev); |
ff859ba6 AC |
343 | if (ret) { |
344 | dev_err(&pdev->dev, | |
345 | "Unable to request interrupt for device (err=%d).\n", | |
346 | ret); | |
5fa40869 | 347 | goto disable_clk; |
ff859ba6 AC |
348 | } |
349 | ||
350 | dev_notice(&pdev->dev, "Tegra internal Real Time Clock\n"); | |
351 | ||
5fa40869 TR |
352 | return 0; |
353 | ||
354 | disable_clk: | |
355 | clk_disable_unprepare(info->clk); | |
356 | return ret; | |
357 | } | |
358 | ||
359 | static int tegra_rtc_remove(struct platform_device *pdev) | |
360 | { | |
361 | struct tegra_rtc_info *info = platform_get_drvdata(pdev); | |
362 | ||
363 | clk_disable_unprepare(info->clk); | |
364 | ||
ff859ba6 AC |
365 | return 0; |
366 | } | |
367 | ||
38a6276e | 368 | #ifdef CONFIG_PM_SLEEP |
3443ad09 | 369 | static int tegra_rtc_suspend(struct device *dev) |
ff859ba6 | 370 | { |
3443ad09 | 371 | struct tegra_rtc_info *info = dev_get_drvdata(dev); |
ff859ba6 AC |
372 | |
373 | tegra_rtc_wait_while_busy(dev); | |
374 | ||
375 | /* only use ALARM0 as a wake source. */ | |
376 | writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS); | |
377 | writel(TEGRA_RTC_INTR_STATUS_SEC_ALARM0, | |
378 | info->rtc_base + TEGRA_RTC_REG_INTR_MASK); | |
379 | ||
380 | dev_vdbg(dev, "alarm sec = %d\n", | |
381 | readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0)); | |
382 | ||
383 | dev_vdbg(dev, "Suspend (device_may_wakeup=%d) irq:%d\n", | |
384 | device_may_wakeup(dev), info->tegra_rtc_irq); | |
385 | ||
386 | /* leave the alarms on as a wake source. */ | |
387 | if (device_may_wakeup(dev)) | |
388 | enable_irq_wake(info->tegra_rtc_irq); | |
389 | ||
390 | return 0; | |
391 | } | |
392 | ||
3443ad09 | 393 | static int tegra_rtc_resume(struct device *dev) |
ff859ba6 | 394 | { |
3443ad09 | 395 | struct tegra_rtc_info *info = dev_get_drvdata(dev); |
ff859ba6 AC |
396 | |
397 | dev_vdbg(dev, "Resume (device_may_wakeup=%d)\n", | |
398 | device_may_wakeup(dev)); | |
399 | /* alarms were left on as a wake source, turn them off. */ | |
400 | if (device_may_wakeup(dev)) | |
401 | disable_irq_wake(info->tegra_rtc_irq); | |
402 | ||
403 | return 0; | |
404 | } | |
405 | #endif | |
406 | ||
3443ad09 LD |
407 | static SIMPLE_DEV_PM_OPS(tegra_rtc_pm_ops, tegra_rtc_suspend, tegra_rtc_resume); |
408 | ||
ff859ba6 AC |
409 | static void tegra_rtc_shutdown(struct platform_device *pdev) |
410 | { | |
411 | dev_vdbg(&pdev->dev, "disabling interrupts.\n"); | |
412 | tegra_rtc_alarm_irq_enable(&pdev->dev, 0); | |
413 | } | |
414 | ||
415 | MODULE_ALIAS("platform:tegra_rtc"); | |
416 | static struct platform_driver tegra_rtc_driver = { | |
5fa40869 | 417 | .remove = tegra_rtc_remove, |
ff859ba6 AC |
418 | .shutdown = tegra_rtc_shutdown, |
419 | .driver = { | |
420 | .name = "tegra_rtc", | |
2d79cf8a | 421 | .of_match_table = tegra_rtc_dt_match, |
3443ad09 | 422 | .pm = &tegra_rtc_pm_ops, |
ff859ba6 | 423 | }, |
ff859ba6 AC |
424 | }; |
425 | ||
0e2c481d | 426 | module_platform_driver_probe(tegra_rtc_driver, tegra_rtc_probe); |
ff859ba6 AC |
427 | |
428 | MODULE_AUTHOR("Jon Mayo <jmayo@nvidia.com>"); | |
429 | MODULE_DESCRIPTION("driver for Tegra internal RTC"); | |
430 | MODULE_LICENSE("GPL"); |