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1 | /* |
2 | * Copyright (C) ST-Ericsson SA 2010 | |
3 | * | |
4 | * License terms: GNU General Public License (GPL) version 2 | |
5 | * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com> | |
6 | * | |
7 | * RTC clock driver for the RTC part of the AB8500 Power management chip. | |
8 | * Based on RTC clock driver for the AB3100 Analog Baseband Chip by | |
9 | * Linus Walleij <linus.walleij@stericsson.com> | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/platform_device.h> | |
16 | #include <linux/rtc.h> | |
17 | #include <linux/mfd/ab8500.h> | |
18 | #include <linux/delay.h> | |
19 | ||
20 | #define AB8500_RTC_SOFF_STAT_REG 0x0F00 | |
21 | #define AB8500_RTC_CC_CONF_REG 0x0F01 | |
22 | #define AB8500_RTC_READ_REQ_REG 0x0F02 | |
23 | #define AB8500_RTC_WATCH_TSECMID_REG 0x0F03 | |
24 | #define AB8500_RTC_WATCH_TSECHI_REG 0x0F04 | |
25 | #define AB8500_RTC_WATCH_TMIN_LOW_REG 0x0F05 | |
26 | #define AB8500_RTC_WATCH_TMIN_MID_REG 0x0F06 | |
27 | #define AB8500_RTC_WATCH_TMIN_HI_REG 0x0F07 | |
28 | #define AB8500_RTC_ALRM_MIN_LOW_REG 0x0F08 | |
29 | #define AB8500_RTC_ALRM_MIN_MID_REG 0x0F09 | |
30 | #define AB8500_RTC_ALRM_MIN_HI_REG 0x0F0A | |
31 | #define AB8500_RTC_STAT_REG 0x0F0B | |
32 | #define AB8500_RTC_BKUP_CHG_REG 0x0F0C | |
33 | #define AB8500_RTC_FORCE_BKUP_REG 0x0F0D | |
34 | #define AB8500_RTC_CALIB_REG 0x0F0E | |
35 | #define AB8500_RTC_SWITCH_STAT_REG 0x0F0F | |
36 | #define AB8500_REV_REG 0x1080 | |
37 | ||
38 | /* RtcReadRequest bits */ | |
39 | #define RTC_READ_REQUEST 0x01 | |
40 | #define RTC_WRITE_REQUEST 0x02 | |
41 | ||
42 | /* RtcCtrl bits */ | |
43 | #define RTC_ALARM_ENA 0x04 | |
44 | #define RTC_STATUS_DATA 0x01 | |
45 | ||
46 | #define COUNTS_PER_SEC (0xF000 / 60) | |
47 | #define AB8500_RTC_EPOCH 2000 | |
48 | ||
49 | static const unsigned long ab8500_rtc_time_regs[] = { | |
50 | AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG, | |
51 | AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG, | |
52 | AB8500_RTC_WATCH_TSECMID_REG | |
53 | }; | |
54 | ||
55 | static const unsigned long ab8500_rtc_alarm_regs[] = { | |
56 | AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG, | |
57 | AB8500_RTC_ALRM_MIN_LOW_REG | |
58 | }; | |
59 | ||
60 | /* Calculate the seconds from 1970 to 01-01-2000 00:00:00 */ | |
61 | static unsigned long get_elapsed_seconds(int year) | |
62 | { | |
63 | unsigned long secs; | |
64 | struct rtc_time tm = { | |
65 | .tm_year = year - 1900, | |
66 | .tm_mday = 1, | |
67 | }; | |
68 | ||
69 | /* | |
70 | * This function calculates secs from 1970 and not from | |
71 | * 1900, even if we supply the offset from year 1900. | |
72 | */ | |
73 | rtc_tm_to_time(&tm, &secs); | |
74 | return secs; | |
75 | } | |
76 | ||
77 | static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
78 | { | |
79 | struct ab8500 *ab8500 = dev_get_drvdata(dev->parent); | |
80 | unsigned long timeout = jiffies + HZ; | |
81 | int retval, i; | |
82 | unsigned long mins, secs; | |
83 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
84 | ||
85 | /* Request a data read */ | |
86 | retval = ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG, | |
87 | RTC_READ_REQUEST); | |
88 | if (retval < 0) | |
89 | return retval; | |
90 | ||
91 | /* Early AB8500 chips will not clear the rtc read request bit */ | |
92 | if (ab8500->revision == 0) { | |
93 | msleep(1); | |
94 | } else { | |
95 | /* Wait for some cycles after enabling the rtc read in ab8500 */ | |
96 | while (time_before(jiffies, timeout)) { | |
97 | retval = ab8500_read(ab8500, AB8500_RTC_READ_REQ_REG); | |
98 | if (retval < 0) | |
99 | return retval; | |
100 | ||
101 | if (!(retval & RTC_READ_REQUEST)) | |
102 | break; | |
103 | ||
104 | msleep(1); | |
105 | } | |
106 | } | |
107 | ||
108 | /* Read the Watchtime registers */ | |
109 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
110 | retval = ab8500_read(ab8500, ab8500_rtc_time_regs[i]); | |
111 | if (retval < 0) | |
112 | return retval; | |
113 | buf[i] = retval; | |
114 | } | |
115 | ||
116 | mins = (buf[0] << 16) | (buf[1] << 8) | buf[2]; | |
117 | ||
118 | secs = (buf[3] << 8) | buf[4]; | |
119 | secs = secs / COUNTS_PER_SEC; | |
120 | secs = secs + (mins * 60); | |
121 | ||
122 | /* Add back the initially subtracted number of seconds */ | |
123 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
124 | ||
125 | rtc_time_to_tm(secs, tm); | |
126 | return rtc_valid_tm(tm); | |
127 | } | |
128 | ||
129 | static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
130 | { | |
131 | struct ab8500 *ab8500 = dev_get_drvdata(dev->parent); | |
132 | int retval, i; | |
133 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)]; | |
134 | unsigned long no_secs, no_mins, secs = 0; | |
135 | ||
136 | if (tm->tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
137 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
138 | AB8500_RTC_EPOCH); | |
139 | return -EINVAL; | |
140 | } | |
141 | ||
142 | /* Get the number of seconds since 1970 */ | |
143 | rtc_tm_to_time(tm, &secs); | |
144 | ||
145 | /* | |
146 | * Convert it to the number of seconds since 01-01-2000 00:00:00, since | |
147 | * we only have a small counter in the RTC. | |
148 | */ | |
149 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
150 | ||
151 | no_mins = secs / 60; | |
152 | ||
153 | no_secs = secs % 60; | |
154 | /* Make the seconds count as per the RTC resolution */ | |
155 | no_secs = no_secs * COUNTS_PER_SEC; | |
156 | ||
157 | buf[4] = no_secs & 0xFF; | |
158 | buf[3] = (no_secs >> 8) & 0xFF; | |
159 | ||
160 | buf[2] = no_mins & 0xFF; | |
161 | buf[1] = (no_mins >> 8) & 0xFF; | |
162 | buf[0] = (no_mins >> 16) & 0xFF; | |
163 | ||
164 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) { | |
165 | retval = ab8500_write(ab8500, ab8500_rtc_time_regs[i], buf[i]); | |
166 | if (retval < 0) | |
167 | return retval; | |
168 | } | |
169 | ||
170 | /* Request a data write */ | |
171 | return ab8500_write(ab8500, AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST); | |
172 | } | |
173 | ||
174 | static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
175 | { | |
176 | struct ab8500 *ab8500 = dev_get_drvdata(dev->parent); | |
177 | int retval, i; | |
178 | int rtc_ctrl; | |
179 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; | |
180 | unsigned long secs, mins; | |
181 | ||
182 | /* Check if the alarm is enabled or not */ | |
183 | rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG); | |
184 | if (rtc_ctrl < 0) | |
185 | return rtc_ctrl; | |
186 | ||
187 | if (rtc_ctrl & RTC_ALARM_ENA) | |
188 | alarm->enabled = 1; | |
189 | else | |
190 | alarm->enabled = 0; | |
191 | ||
192 | alarm->pending = 0; | |
193 | ||
194 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
195 | retval = ab8500_read(ab8500, ab8500_rtc_alarm_regs[i]); | |
196 | if (retval < 0) | |
197 | return retval; | |
198 | buf[i] = retval; | |
199 | } | |
200 | ||
201 | mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]); | |
202 | secs = mins * 60; | |
203 | ||
204 | /* Add back the initially subtracted number of seconds */ | |
205 | secs += get_elapsed_seconds(AB8500_RTC_EPOCH); | |
206 | ||
207 | rtc_time_to_tm(secs, &alarm->time); | |
208 | ||
209 | return rtc_valid_tm(&alarm->time); | |
210 | } | |
211 | ||
212 | static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled) | |
213 | { | |
214 | struct ab8500 *ab8500 = dev_get_drvdata(dev->parent); | |
215 | ||
216 | return ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_ALARM_ENA, | |
217 | enabled ? RTC_ALARM_ENA : 0); | |
218 | } | |
219 | ||
220 | static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) | |
221 | { | |
222 | struct ab8500 *ab8500 = dev_get_drvdata(dev->parent); | |
223 | int retval, i; | |
224 | unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)]; | |
225 | unsigned long mins, secs = 0; | |
226 | ||
227 | if (alarm->time.tm_year < (AB8500_RTC_EPOCH - 1900)) { | |
228 | dev_dbg(dev, "year should be equal to or greater than %d\n", | |
229 | AB8500_RTC_EPOCH); | |
230 | return -EINVAL; | |
231 | } | |
232 | ||
233 | /* Get the number of seconds since 1970 */ | |
234 | rtc_tm_to_time(&alarm->time, &secs); | |
235 | ||
236 | /* | |
237 | * Convert it to the number of seconds since 01-01-2000 00:00:00, since | |
238 | * we only have a small counter in the RTC. | |
239 | */ | |
240 | secs -= get_elapsed_seconds(AB8500_RTC_EPOCH); | |
241 | ||
242 | mins = secs / 60; | |
243 | ||
244 | buf[2] = mins & 0xFF; | |
245 | buf[1] = (mins >> 8) & 0xFF; | |
246 | buf[0] = (mins >> 16) & 0xFF; | |
247 | ||
248 | /* Set the alarm time */ | |
249 | for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) { | |
250 | retval = ab8500_write(ab8500, ab8500_rtc_alarm_regs[i], buf[i]); | |
251 | if (retval < 0) | |
252 | return retval; | |
253 | } | |
254 | ||
255 | return ab8500_rtc_irq_enable(dev, alarm->enabled); | |
256 | } | |
257 | ||
258 | static irqreturn_t rtc_alarm_handler(int irq, void *data) | |
259 | { | |
260 | struct rtc_device *rtc = data; | |
261 | unsigned long events = RTC_IRQF | RTC_AF; | |
262 | ||
263 | dev_dbg(&rtc->dev, "%s\n", __func__); | |
264 | rtc_update_irq(rtc, 1, events); | |
265 | ||
266 | return IRQ_HANDLED; | |
267 | } | |
268 | ||
269 | static const struct rtc_class_ops ab8500_rtc_ops = { | |
270 | .read_time = ab8500_rtc_read_time, | |
271 | .set_time = ab8500_rtc_set_time, | |
272 | .read_alarm = ab8500_rtc_read_alarm, | |
273 | .set_alarm = ab8500_rtc_set_alarm, | |
274 | .alarm_irq_enable = ab8500_rtc_irq_enable, | |
275 | }; | |
276 | ||
277 | static int __devinit ab8500_rtc_probe(struct platform_device *pdev) | |
278 | { | |
279 | struct ab8500 *ab8500 = dev_get_drvdata(pdev->dev.parent); | |
280 | int err; | |
281 | struct rtc_device *rtc; | |
282 | int rtc_ctrl; | |
283 | int irq; | |
284 | ||
285 | irq = platform_get_irq_byname(pdev, "ALARM"); | |
286 | if (irq < 0) | |
287 | return irq; | |
288 | ||
289 | /* For RTC supply test */ | |
290 | err = ab8500_set_bits(ab8500, AB8500_RTC_STAT_REG, RTC_STATUS_DATA, | |
291 | RTC_STATUS_DATA); | |
292 | if (err < 0) | |
293 | return err; | |
294 | ||
295 | /* Wait for reset by the PorRtc */ | |
296 | msleep(1); | |
297 | ||
298 | rtc_ctrl = ab8500_read(ab8500, AB8500_RTC_STAT_REG); | |
299 | if (rtc_ctrl < 0) | |
300 | return rtc_ctrl; | |
301 | ||
302 | /* Check if the RTC Supply fails */ | |
303 | if (!(rtc_ctrl & RTC_STATUS_DATA)) { | |
304 | dev_err(&pdev->dev, "RTC supply failure\n"); | |
305 | return -ENODEV; | |
306 | } | |
307 | ||
308 | rtc = rtc_device_register("ab8500-rtc", &pdev->dev, &ab8500_rtc_ops, | |
309 | THIS_MODULE); | |
310 | if (IS_ERR(rtc)) { | |
311 | dev_err(&pdev->dev, "Registration failed\n"); | |
312 | err = PTR_ERR(rtc); | |
313 | return err; | |
314 | } | |
315 | ||
316 | err = request_threaded_irq(irq, NULL, rtc_alarm_handler, 0, | |
317 | "ab8500-rtc", rtc); | |
318 | if (err < 0) { | |
319 | rtc_device_unregister(rtc); | |
320 | return err; | |
321 | } | |
322 | ||
323 | platform_set_drvdata(pdev, rtc); | |
324 | ||
325 | return 0; | |
326 | } | |
327 | ||
328 | static int __devexit ab8500_rtc_remove(struct platform_device *pdev) | |
329 | { | |
330 | struct rtc_device *rtc = platform_get_drvdata(pdev); | |
331 | int irq = platform_get_irq_byname(pdev, "ALARM"); | |
332 | ||
333 | free_irq(irq, rtc); | |
334 | rtc_device_unregister(rtc); | |
335 | platform_set_drvdata(pdev, NULL); | |
336 | ||
337 | return 0; | |
338 | } | |
339 | ||
340 | static struct platform_driver ab8500_rtc_driver = { | |
341 | .driver = { | |
342 | .name = "ab8500-rtc", | |
343 | .owner = THIS_MODULE, | |
344 | }, | |
345 | .probe = ab8500_rtc_probe, | |
346 | .remove = __devexit_p(ab8500_rtc_remove), | |
347 | }; | |
348 | ||
349 | static int __init ab8500_rtc_init(void) | |
350 | { | |
351 | return platform_driver_register(&ab8500_rtc_driver); | |
352 | } | |
353 | ||
354 | static void __exit ab8500_rtc_exit(void) | |
355 | { | |
356 | platform_driver_unregister(&ab8500_rtc_driver); | |
357 | } | |
358 | ||
359 | module_init(ab8500_rtc_init); | |
360 | module_exit(ab8500_rtc_exit); | |
361 | MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>"); | |
362 | MODULE_DESCRIPTION("AB8500 RTC Driver"); | |
363 | MODULE_LICENSE("GPL v2"); |