blob: 2fda03125e555fe977ef20b8bcf6da2f1f9b15b9 [file] [log] [blame]
Virupax Sadashivpetimath0af62f42010-05-26 14:42:14 -07001/*
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
49static 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
55static 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 */
61static 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
77static 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
129static 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
174static 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
212static 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
220static 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
258static 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
269static 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
277static 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
328static 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
340static 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
349static int __init ab8500_rtc_init(void)
350{
351 return platform_driver_register(&ab8500_rtc_driver);
352}
353
354static void __exit ab8500_rtc_exit(void)
355{
356 platform_driver_unregister(&ab8500_rtc_driver);
357}
358
359module_init(ab8500_rtc_init);
360module_exit(ab8500_rtc_exit);
361MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
362MODULE_DESCRIPTION("AB8500 RTC Driver");
363MODULE_LICENSE("GPL v2");