Commit | Line | Data |
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179a502f SG |
1 | /* |
2 | * Copyright (C) 2011-2012 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * The code contained herein is licensed under the GNU General Public | |
5 | * License. You may obtain a copy of the GNU General Public License | |
6 | * Version 2 or later at the following locations: | |
7 | * | |
8 | * http://www.opensource.org/licenses/gpl-license.html | |
9 | * http://www.gnu.org/copyleft/gpl.html | |
10 | */ | |
11 | ||
12 | #include <linux/init.h> | |
13 | #include <linux/io.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/of.h> | |
17 | #include <linux/of_device.h> | |
18 | #include <linux/platform_device.h> | |
19 | #include <linux/rtc.h> | |
7f899399 | 20 | #include <linux/clk.h> |
d482893b FL |
21 | #include <linux/mfd/syscon.h> |
22 | #include <linux/regmap.h> | |
23 | ||
24 | #define SNVS_LPREGISTER_OFFSET 0x34 | |
179a502f SG |
25 | |
26 | /* These register offsets are relative to LP (Low Power) range */ | |
27 | #define SNVS_LPCR 0x04 | |
28 | #define SNVS_LPSR 0x18 | |
29 | #define SNVS_LPSRTCMR 0x1c | |
30 | #define SNVS_LPSRTCLR 0x20 | |
31 | #define SNVS_LPTAR 0x24 | |
32 | #define SNVS_LPPGDR 0x30 | |
33 | ||
34 | #define SNVS_LPCR_SRTC_ENV (1 << 0) | |
35 | #define SNVS_LPCR_LPTA_EN (1 << 1) | |
36 | #define SNVS_LPCR_LPWUI_EN (1 << 3) | |
37 | #define SNVS_LPSR_LPTA (1 << 0) | |
38 | ||
39 | #define SNVS_LPPGDR_INIT 0x41736166 | |
40 | #define CNTR_TO_SECS_SH 15 | |
41 | ||
42 | struct snvs_rtc_data { | |
43 | struct rtc_device *rtc; | |
d482893b FL |
44 | struct regmap *regmap; |
45 | int offset; | |
179a502f | 46 | int irq; |
7f899399 | 47 | struct clk *clk; |
179a502f SG |
48 | }; |
49 | ||
f1e1eb5c TP |
50 | /* Read 64 bit timer register, which could be in inconsistent state */ |
51 | static u64 rtc_read_lpsrt(struct snvs_rtc_data *data) | |
52 | { | |
53 | u32 msb, lsb; | |
54 | ||
55 | regmap_read(data->regmap, data->offset + SNVS_LPSRTCMR, &msb); | |
56 | regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &lsb); | |
57 | return (u64)msb << 32 | lsb; | |
58 | } | |
59 | ||
60 | /* Read the secure real time counter, taking care to deal with the cases of the | |
61 | * counter updating while being read. | |
62 | */ | |
d482893b | 63 | static u32 rtc_read_lp_counter(struct snvs_rtc_data *data) |
179a502f SG |
64 | { |
65 | u64 read1, read2; | |
f1e1eb5c | 66 | unsigned int timeout = 100; |
179a502f | 67 | |
f1e1eb5c TP |
68 | /* As expected, the registers might update between the read of the LSB |
69 | * reg and the MSB reg. It's also possible that one register might be | |
70 | * in partially modified state as well. | |
71 | */ | |
72 | read1 = rtc_read_lpsrt(data); | |
179a502f | 73 | do { |
f1e1eb5c TP |
74 | read2 = read1; |
75 | read1 = rtc_read_lpsrt(data); | |
76 | } while (read1 != read2 && --timeout); | |
77 | if (!timeout) | |
78 | dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n"); | |
179a502f SG |
79 | |
80 | /* Convert 47-bit counter to 32-bit raw second count */ | |
81 | return (u32) (read1 >> CNTR_TO_SECS_SH); | |
82 | } | |
83 | ||
f1e1eb5c TP |
84 | /* Just read the lsb from the counter, dealing with inconsistent state */ |
85 | static int rtc_read_lp_counter_lsb(struct snvs_rtc_data *data, u32 *lsb) | |
86 | { | |
87 | u32 count1, count2; | |
88 | unsigned int timeout = 100; | |
89 | ||
90 | regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1); | |
91 | do { | |
92 | count2 = count1; | |
93 | regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1); | |
94 | } while (count1 != count2 && --timeout); | |
95 | if (!timeout) { | |
96 | dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n"); | |
97 | return -ETIMEDOUT; | |
98 | } | |
99 | ||
100 | *lsb = count1; | |
101 | return 0; | |
102 | } | |
103 | ||
104 | static int rtc_write_sync_lp(struct snvs_rtc_data *data) | |
179a502f | 105 | { |
f1e1eb5c TP |
106 | u32 count1, count2; |
107 | u32 elapsed; | |
108 | unsigned int timeout = 1000; | |
109 | int ret; | |
110 | ||
111 | ret = rtc_read_lp_counter_lsb(data, &count1); | |
112 | if (ret) | |
113 | return ret; | |
114 | ||
115 | /* Wait for 3 CKIL cycles, about 61.0-91.5 µs */ | |
116 | do { | |
117 | ret = rtc_read_lp_counter_lsb(data, &count2); | |
118 | if (ret) | |
119 | return ret; | |
120 | elapsed = count2 - count1; /* wrap around _is_ handled! */ | |
121 | } while (elapsed < 3 && --timeout); | |
122 | if (!timeout) { | |
123 | dev_err(&data->rtc->dev, "Timeout waiting for LPSRT Counter to change\n"); | |
124 | return -ETIMEDOUT; | |
179a502f | 125 | } |
f1e1eb5c | 126 | return 0; |
179a502f SG |
127 | } |
128 | ||
129 | static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) | |
130 | { | |
179a502f SG |
131 | int timeout = 1000; |
132 | u32 lpcr; | |
133 | ||
d482893b FL |
134 | regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_SRTC_ENV, |
135 | enable ? SNVS_LPCR_SRTC_ENV : 0); | |
179a502f SG |
136 | |
137 | while (--timeout) { | |
d482893b | 138 | regmap_read(data->regmap, data->offset + SNVS_LPCR, &lpcr); |
179a502f SG |
139 | |
140 | if (enable) { | |
141 | if (lpcr & SNVS_LPCR_SRTC_ENV) | |
142 | break; | |
143 | } else { | |
144 | if (!(lpcr & SNVS_LPCR_SRTC_ENV)) | |
145 | break; | |
146 | } | |
147 | } | |
148 | ||
149 | if (!timeout) | |
150 | return -ETIMEDOUT; | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
156 | { | |
157 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
d482893b | 158 | unsigned long time = rtc_read_lp_counter(data); |
179a502f SG |
159 | |
160 | rtc_time_to_tm(time, tm); | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
166 | { | |
167 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
168 | unsigned long time; | |
731d965a | 169 | int ret; |
179a502f SG |
170 | |
171 | rtc_tm_to_time(tm, &time); | |
172 | ||
173 | /* Disable RTC first */ | |
731d965a BD |
174 | ret = snvs_rtc_enable(data, false); |
175 | if (ret) | |
176 | return ret; | |
179a502f SG |
177 | |
178 | /* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */ | |
d482893b FL |
179 | regmap_write(data->regmap, data->offset + SNVS_LPSRTCLR, time << CNTR_TO_SECS_SH); |
180 | regmap_write(data->regmap, data->offset + SNVS_LPSRTCMR, time >> (32 - CNTR_TO_SECS_SH)); | |
179a502f SG |
181 | |
182 | /* Enable RTC again */ | |
731d965a | 183 | ret = snvs_rtc_enable(data, true); |
179a502f | 184 | |
731d965a | 185 | return ret; |
179a502f SG |
186 | } |
187 | ||
188 | static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
189 | { | |
190 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
191 | u32 lptar, lpsr; | |
192 | ||
d482893b | 193 | regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar); |
179a502f SG |
194 | rtc_time_to_tm(lptar, &alrm->time); |
195 | ||
d482893b | 196 | regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr); |
179a502f SG |
197 | alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0; |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) | |
203 | { | |
204 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
179a502f | 205 | |
d482893b FL |
206 | regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, |
207 | (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN), | |
208 | enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0); | |
179a502f | 209 | |
f1e1eb5c | 210 | return rtc_write_sync_lp(data); |
179a502f SG |
211 | } |
212 | ||
213 | static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) | |
214 | { | |
215 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
216 | struct rtc_time *alrm_tm = &alrm->time; | |
217 | unsigned long time; | |
f1e1eb5c | 218 | int ret; |
179a502f SG |
219 | |
220 | rtc_tm_to_time(alrm_tm, &time); | |
221 | ||
d482893b | 222 | regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0); |
f1e1eb5c TP |
223 | ret = rtc_write_sync_lp(data); |
224 | if (ret) | |
225 | return ret; | |
d482893b | 226 | regmap_write(data->regmap, data->offset + SNVS_LPTAR, time); |
179a502f SG |
227 | |
228 | /* Clear alarm interrupt status bit */ | |
d482893b | 229 | regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA); |
179a502f SG |
230 | |
231 | return snvs_rtc_alarm_irq_enable(dev, alrm->enabled); | |
232 | } | |
233 | ||
234 | static const struct rtc_class_ops snvs_rtc_ops = { | |
235 | .read_time = snvs_rtc_read_time, | |
236 | .set_time = snvs_rtc_set_time, | |
237 | .read_alarm = snvs_rtc_read_alarm, | |
238 | .set_alarm = snvs_rtc_set_alarm, | |
239 | .alarm_irq_enable = snvs_rtc_alarm_irq_enable, | |
240 | }; | |
241 | ||
242 | static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id) | |
243 | { | |
244 | struct device *dev = dev_id; | |
245 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
246 | u32 lpsr; | |
247 | u32 events = 0; | |
248 | ||
d482893b | 249 | regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr); |
179a502f SG |
250 | |
251 | if (lpsr & SNVS_LPSR_LPTA) { | |
252 | events |= (RTC_AF | RTC_IRQF); | |
253 | ||
254 | /* RTC alarm should be one-shot */ | |
255 | snvs_rtc_alarm_irq_enable(dev, 0); | |
256 | ||
257 | rtc_update_irq(data->rtc, 1, events); | |
258 | } | |
259 | ||
260 | /* clear interrupt status */ | |
d482893b | 261 | regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr); |
179a502f SG |
262 | |
263 | return events ? IRQ_HANDLED : IRQ_NONE; | |
264 | } | |
265 | ||
d482893b FL |
266 | static const struct regmap_config snvs_rtc_config = { |
267 | .reg_bits = 32, | |
268 | .val_bits = 32, | |
269 | .reg_stride = 4, | |
270 | }; | |
271 | ||
5a167f45 | 272 | static int snvs_rtc_probe(struct platform_device *pdev) |
179a502f SG |
273 | { |
274 | struct snvs_rtc_data *data; | |
275 | struct resource *res; | |
276 | int ret; | |
d482893b | 277 | void __iomem *mmio; |
179a502f SG |
278 | |
279 | data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); | |
280 | if (!data) | |
281 | return -ENOMEM; | |
282 | ||
d482893b FL |
283 | data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap"); |
284 | ||
285 | if (IS_ERR(data->regmap)) { | |
286 | dev_warn(&pdev->dev, "snvs rtc: you use old dts file, please update it\n"); | |
287 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
288 | ||
289 | mmio = devm_ioremap_resource(&pdev->dev, res); | |
290 | if (IS_ERR(mmio)) | |
291 | return PTR_ERR(mmio); | |
292 | ||
293 | data->regmap = devm_regmap_init_mmio(&pdev->dev, mmio, &snvs_rtc_config); | |
294 | } else { | |
295 | data->offset = SNVS_LPREGISTER_OFFSET; | |
296 | of_property_read_u32(pdev->dev.of_node, "offset", &data->offset); | |
297 | } | |
298 | ||
75892900 | 299 | if (IS_ERR(data->regmap)) { |
d482893b FL |
300 | dev_err(&pdev->dev, "Can't find snvs syscon\n"); |
301 | return -ENODEV; | |
302 | } | |
179a502f SG |
303 | |
304 | data->irq = platform_get_irq(pdev, 0); | |
305 | if (data->irq < 0) | |
306 | return data->irq; | |
307 | ||
7f899399 SM |
308 | data->clk = devm_clk_get(&pdev->dev, "snvs-rtc"); |
309 | if (IS_ERR(data->clk)) { | |
310 | data->clk = NULL; | |
311 | } else { | |
312 | ret = clk_prepare_enable(data->clk); | |
313 | if (ret) { | |
314 | dev_err(&pdev->dev, | |
315 | "Could not prepare or enable the snvs clock\n"); | |
316 | return ret; | |
317 | } | |
318 | } | |
319 | ||
179a502f SG |
320 | platform_set_drvdata(pdev, data); |
321 | ||
179a502f | 322 | /* Initialize glitch detect */ |
d482893b | 323 | regmap_write(data->regmap, data->offset + SNVS_LPPGDR, SNVS_LPPGDR_INIT); |
179a502f SG |
324 | |
325 | /* Clear interrupt status */ | |
d482893b | 326 | regmap_write(data->regmap, data->offset + SNVS_LPSR, 0xffffffff); |
179a502f SG |
327 | |
328 | /* Enable RTC */ | |
731d965a BD |
329 | ret = snvs_rtc_enable(data, true); |
330 | if (ret) { | |
331 | dev_err(&pdev->dev, "failed to enable rtc %d\n", ret); | |
332 | goto error_rtc_device_register; | |
333 | } | |
179a502f SG |
334 | |
335 | device_init_wakeup(&pdev->dev, true); | |
336 | ||
337 | ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler, | |
338 | IRQF_SHARED, "rtc alarm", &pdev->dev); | |
339 | if (ret) { | |
340 | dev_err(&pdev->dev, "failed to request irq %d: %d\n", | |
341 | data->irq, ret); | |
7f899399 | 342 | goto error_rtc_device_register; |
179a502f SG |
343 | } |
344 | ||
904784c1 | 345 | data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, |
179a502f SG |
346 | &snvs_rtc_ops, THIS_MODULE); |
347 | if (IS_ERR(data->rtc)) { | |
348 | ret = PTR_ERR(data->rtc); | |
349 | dev_err(&pdev->dev, "failed to register rtc: %d\n", ret); | |
7f899399 | 350 | goto error_rtc_device_register; |
179a502f SG |
351 | } |
352 | ||
353 | return 0; | |
7f899399 SM |
354 | |
355 | error_rtc_device_register: | |
356 | if (data->clk) | |
357 | clk_disable_unprepare(data->clk); | |
358 | ||
359 | return ret; | |
179a502f SG |
360 | } |
361 | ||
179a502f SG |
362 | #ifdef CONFIG_PM_SLEEP |
363 | static int snvs_rtc_suspend(struct device *dev) | |
364 | { | |
365 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
366 | ||
367 | if (device_may_wakeup(dev)) | |
a350259d | 368 | return enable_irq_wake(data->irq); |
179a502f | 369 | |
119434f4 SA |
370 | return 0; |
371 | } | |
372 | ||
373 | static int snvs_rtc_suspend_noirq(struct device *dev) | |
374 | { | |
375 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
376 | ||
7f899399 SM |
377 | if (data->clk) |
378 | clk_disable_unprepare(data->clk); | |
379 | ||
179a502f SG |
380 | return 0; |
381 | } | |
382 | ||
383 | static int snvs_rtc_resume(struct device *dev) | |
384 | { | |
385 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
386 | ||
387 | if (device_may_wakeup(dev)) | |
119434f4 | 388 | return disable_irq_wake(data->irq); |
179a502f | 389 | |
119434f4 SA |
390 | return 0; |
391 | } | |
392 | ||
393 | static int snvs_rtc_resume_noirq(struct device *dev) | |
394 | { | |
395 | struct snvs_rtc_data *data = dev_get_drvdata(dev); | |
396 | ||
397 | if (data->clk) | |
398 | return clk_prepare_enable(data->clk); | |
7f899399 | 399 | |
179a502f SG |
400 | return 0; |
401 | } | |
179a502f | 402 | |
7654e9d4 | 403 | static const struct dev_pm_ops snvs_rtc_pm_ops = { |
119434f4 SA |
404 | .suspend = snvs_rtc_suspend, |
405 | .suspend_noirq = snvs_rtc_suspend_noirq, | |
406 | .resume = snvs_rtc_resume, | |
407 | .resume_noirq = snvs_rtc_resume_noirq, | |
7654e9d4 | 408 | }; |
179a502f | 409 | |
88221c32 GR |
410 | #define SNVS_RTC_PM_OPS (&snvs_rtc_pm_ops) |
411 | ||
412 | #else | |
413 | ||
414 | #define SNVS_RTC_PM_OPS NULL | |
415 | ||
416 | #endif | |
417 | ||
5a167f45 | 418 | static const struct of_device_id snvs_dt_ids[] = { |
179a502f SG |
419 | { .compatible = "fsl,sec-v4.0-mon-rtc-lp", }, |
420 | { /* sentinel */ } | |
421 | }; | |
422 | MODULE_DEVICE_TABLE(of, snvs_dt_ids); | |
423 | ||
424 | static struct platform_driver snvs_rtc_driver = { | |
425 | .driver = { | |
426 | .name = "snvs_rtc", | |
88221c32 | 427 | .pm = SNVS_RTC_PM_OPS, |
c39b3717 | 428 | .of_match_table = snvs_dt_ids, |
179a502f SG |
429 | }, |
430 | .probe = snvs_rtc_probe, | |
179a502f SG |
431 | }; |
432 | module_platform_driver(snvs_rtc_driver); | |
433 | ||
434 | MODULE_AUTHOR("Freescale Semiconductor, Inc."); | |
435 | MODULE_DESCRIPTION("Freescale SNVS RTC Driver"); | |
436 | MODULE_LICENSE("GPL"); |