1 /*
2 * rtc-tps80031.c -- TI TPS80031/TPS80032 RTC driver
3 *
4 * RTC driver for TI TPS80031/TPS80032 Fully Integrated
5 * Power Management with Power Path and Battery Charger
6 *
7 * Copyright (c) 2012, NVIDIA Corporation.
8 *
9 * Author: Laxman Dewangan <ldewangan@nvidia.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation version 2.
14 *
15 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
16 * whether express or implied; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23 * 02111-1307, USA
24 */
25
26 #include <linux/bcd.h>
27 #include <linux/device.h>
28 #include <linux/err.h>
29 #include <linux/init.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/mfd/tps80031.h>
33 #include <linux/platform_device.h>
34 #include <linux/pm.h>
35 #include <linux/rtc.h>
36 #include <linux/slab.h>
37
38 #define ENABLE_ALARM_INT 0x08
39 #define ALARM_INT_STATUS 0x40
40
41 /**
42 * Setting bit to 1 in STOP_RTC will run the RTC and
43 * setting this bit to 0 will freeze RTC.
44 */
45 #define STOP_RTC 0x1
46
47 /* Power on reset Values of RTC registers */
48 #define TPS80031_RTC_POR_YEAR 0
49 #define TPS80031_RTC_POR_MONTH 1
50 #define TPS80031_RTC_POR_DAY 1
51
52 /* Numbers of registers for time and alarms */
53 #define TPS80031_RTC_TIME_NUM_REGS 7
54 #define TPS80031_RTC_ALARM_NUM_REGS 6
55
56 /**
57 * PMU RTC have only 2 nibbles to store year information, so using an
58 * offset of 100 to set the base year as 2000 for our driver.
59 */
60 #define RTC_YEAR_OFFSET 100
61
62 struct tps80031_rtc {
63 struct rtc_device *rtc;
64 int irq;
65 };
66
tps80031_rtc_read_time(struct device * dev,struct rtc_time * tm)67 static int tps80031_rtc_read_time(struct device *dev, struct rtc_time *tm)
68 {
69 u8 buff[TPS80031_RTC_TIME_NUM_REGS];
70 int ret;
71
72 ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
73 TPS80031_SECONDS_REG, TPS80031_RTC_TIME_NUM_REGS, buff);
74 if (ret < 0) {
75 dev_err(dev, "reading RTC_SECONDS_REG failed, err = %d\n", ret);
76 return ret;
77 }
78
79 tm->tm_sec = bcd2bin(buff[0]);
80 tm->tm_min = bcd2bin(buff[1]);
81 tm->tm_hour = bcd2bin(buff[2]);
82 tm->tm_mday = bcd2bin(buff[3]);
83 tm->tm_mon = bcd2bin(buff[4]) - 1;
84 tm->tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
85 tm->tm_wday = bcd2bin(buff[6]);
86 return 0;
87 }
88
tps80031_rtc_set_time(struct device * dev,struct rtc_time * tm)89 static int tps80031_rtc_set_time(struct device *dev, struct rtc_time *tm)
90 {
91 u8 buff[7];
92 int ret;
93
94 buff[0] = bin2bcd(tm->tm_sec);
95 buff[1] = bin2bcd(tm->tm_min);
96 buff[2] = bin2bcd(tm->tm_hour);
97 buff[3] = bin2bcd(tm->tm_mday);
98 buff[4] = bin2bcd(tm->tm_mon + 1);
99 buff[5] = bin2bcd(tm->tm_year % RTC_YEAR_OFFSET);
100 buff[6] = bin2bcd(tm->tm_wday);
101
102 /* Stop RTC while updating the RTC time registers */
103 ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
104 TPS80031_RTC_CTRL_REG, STOP_RTC);
105 if (ret < 0) {
106 dev_err(dev->parent, "Stop RTC failed, err = %d\n", ret);
107 return ret;
108 }
109
110 ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
111 TPS80031_SECONDS_REG,
112 TPS80031_RTC_TIME_NUM_REGS, buff);
113 if (ret < 0) {
114 dev_err(dev, "writing RTC_SECONDS_REG failed, err %d\n", ret);
115 return ret;
116 }
117
118 ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
119 TPS80031_RTC_CTRL_REG, STOP_RTC);
120 if (ret < 0)
121 dev_err(dev->parent, "Start RTC failed, err = %d\n", ret);
122 return ret;
123 }
124
tps80031_rtc_alarm_irq_enable(struct device * dev,unsigned int enable)125 static int tps80031_rtc_alarm_irq_enable(struct device *dev,
126 unsigned int enable)
127 {
128 int ret;
129
130 if (enable)
131 ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
132 TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
133 else
134 ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
135 TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
136 if (ret < 0) {
137 dev_err(dev, "Update on RTC_INT failed, err = %d\n", ret);
138 return ret;
139 }
140 return 0;
141 }
142
tps80031_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)143 static int tps80031_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
144 {
145 u8 buff[TPS80031_RTC_ALARM_NUM_REGS];
146 int ret;
147
148 buff[0] = bin2bcd(alrm->time.tm_sec);
149 buff[1] = bin2bcd(alrm->time.tm_min);
150 buff[2] = bin2bcd(alrm->time.tm_hour);
151 buff[3] = bin2bcd(alrm->time.tm_mday);
152 buff[4] = bin2bcd(alrm->time.tm_mon + 1);
153 buff[5] = bin2bcd(alrm->time.tm_year % RTC_YEAR_OFFSET);
154 ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
155 TPS80031_ALARM_SECONDS_REG,
156 TPS80031_RTC_ALARM_NUM_REGS, buff);
157 if (ret < 0) {
158 dev_err(dev, "Writing RTC_ALARM failed, err %d\n", ret);
159 return ret;
160 }
161 return tps80031_rtc_alarm_irq_enable(dev, alrm->enabled);
162 }
163
tps80031_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)164 static int tps80031_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
165 {
166 u8 buff[6];
167 int ret;
168
169 ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
170 TPS80031_ALARM_SECONDS_REG,
171 TPS80031_RTC_ALARM_NUM_REGS, buff);
172 if (ret < 0) {
173 dev_err(dev->parent,
174 "reading RTC_ALARM failed, err = %d\n", ret);
175 return ret;
176 }
177
178 alrm->time.tm_sec = bcd2bin(buff[0]);
179 alrm->time.tm_min = bcd2bin(buff[1]);
180 alrm->time.tm_hour = bcd2bin(buff[2]);
181 alrm->time.tm_mday = bcd2bin(buff[3]);
182 alrm->time.tm_mon = bcd2bin(buff[4]) - 1;
183 alrm->time.tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
184 return 0;
185 }
186
clear_alarm_int_status(struct device * dev,struct tps80031_rtc * rtc)187 static int clear_alarm_int_status(struct device *dev, struct tps80031_rtc *rtc)
188 {
189 int ret;
190 u8 buf;
191
192 /**
193 * As per datasheet, A dummy read of this RTC_STATUS_REG register
194 * is necessary before each I2C read in order to update the status
195 * register value.
196 */
197 ret = tps80031_read(dev->parent, TPS80031_SLAVE_ID1,
198 TPS80031_RTC_STATUS_REG, &buf);
199 if (ret < 0) {
200 dev_err(dev, "reading RTC_STATUS failed. err = %d\n", ret);
201 return ret;
202 }
203
204 /* clear Alarm status bits.*/
205 ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
206 TPS80031_RTC_STATUS_REG, ALARM_INT_STATUS);
207 if (ret < 0) {
208 dev_err(dev, "clear Alarm INT failed, err = %d\n", ret);
209 return ret;
210 }
211 return 0;
212 }
213
tps80031_rtc_irq(int irq,void * data)214 static irqreturn_t tps80031_rtc_irq(int irq, void *data)
215 {
216 struct device *dev = data;
217 struct tps80031_rtc *rtc = dev_get_drvdata(dev);
218 int ret;
219
220 ret = clear_alarm_int_status(dev, rtc);
221 if (ret < 0)
222 return ret;
223
224 rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
225 return IRQ_HANDLED;
226 }
227
228 static const struct rtc_class_ops tps80031_rtc_ops = {
229 .read_time = tps80031_rtc_read_time,
230 .set_time = tps80031_rtc_set_time,
231 .set_alarm = tps80031_rtc_set_alarm,
232 .read_alarm = tps80031_rtc_read_alarm,
233 .alarm_irq_enable = tps80031_rtc_alarm_irq_enable,
234 };
235
tps80031_rtc_probe(struct platform_device * pdev)236 static int tps80031_rtc_probe(struct platform_device *pdev)
237 {
238 struct tps80031_rtc *rtc;
239 struct rtc_time tm;
240 int ret;
241
242 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
243 if (!rtc)
244 return -ENOMEM;
245
246 rtc->irq = platform_get_irq(pdev, 0);
247 platform_set_drvdata(pdev, rtc);
248
249 /* Start RTC */
250 ret = tps80031_set_bits(pdev->dev.parent, TPS80031_SLAVE_ID1,
251 TPS80031_RTC_CTRL_REG, STOP_RTC);
252 if (ret < 0) {
253 dev_err(&pdev->dev, "failed to start RTC. err = %d\n", ret);
254 return ret;
255 }
256
257 /* If RTC have POR values, set time 01:01:2000 */
258 tps80031_rtc_read_time(&pdev->dev, &tm);
259 if ((tm.tm_year == RTC_YEAR_OFFSET + TPS80031_RTC_POR_YEAR) &&
260 (tm.tm_mon == (TPS80031_RTC_POR_MONTH - 1)) &&
261 (tm.tm_mday == TPS80031_RTC_POR_DAY)) {
262 tm.tm_year = 2000;
263 tm.tm_mday = 1;
264 tm.tm_mon = 1;
265 ret = tps80031_rtc_set_time(&pdev->dev, &tm);
266 if (ret < 0) {
267 dev_err(&pdev->dev,
268 "RTC set time failed, err = %d\n", ret);
269 return ret;
270 }
271 }
272
273 /* Clear alarm intretupt status if it is there */
274 ret = clear_alarm_int_status(&pdev->dev, rtc);
275 if (ret < 0) {
276 dev_err(&pdev->dev, "Clear alarm int failed, err = %d\n", ret);
277 return ret;
278 }
279
280 rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
281 &tps80031_rtc_ops, THIS_MODULE);
282 if (IS_ERR(rtc->rtc)) {
283 ret = PTR_ERR(rtc->rtc);
284 dev_err(&pdev->dev, "RTC registration failed, err %d\n", ret);
285 return ret;
286 }
287
288 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
289 tps80031_rtc_irq,
290 IRQF_ONESHOT,
291 dev_name(&pdev->dev), rtc);
292 if (ret < 0) {
293 dev_err(&pdev->dev, "request IRQ:%d failed, err = %d\n",
294 rtc->irq, ret);
295 return ret;
296 }
297 device_set_wakeup_capable(&pdev->dev, 1);
298 return 0;
299 }
300
301 #ifdef CONFIG_PM_SLEEP
tps80031_rtc_suspend(struct device * dev)302 static int tps80031_rtc_suspend(struct device *dev)
303 {
304 struct tps80031_rtc *rtc = dev_get_drvdata(dev);
305
306 if (device_may_wakeup(dev))
307 enable_irq_wake(rtc->irq);
308 return 0;
309 }
310
tps80031_rtc_resume(struct device * dev)311 static int tps80031_rtc_resume(struct device *dev)
312 {
313 struct tps80031_rtc *rtc = dev_get_drvdata(dev);
314
315 if (device_may_wakeup(dev))
316 disable_irq_wake(rtc->irq);
317 return 0;
318 };
319 #endif
320
321 static SIMPLE_DEV_PM_OPS(tps80031_pm_ops, tps80031_rtc_suspend,
322 tps80031_rtc_resume);
323
324 static struct platform_driver tps80031_rtc_driver = {
325 .driver = {
326 .name = "tps80031-rtc",
327 .pm = &tps80031_pm_ops,
328 },
329 .probe = tps80031_rtc_probe,
330 };
331
332 module_platform_driver(tps80031_rtc_driver);
333
334 MODULE_ALIAS("platform:tps80031-rtc");
335 MODULE_DESCRIPTION("TI TPS80031/TPS80032 RTC driver");
336 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
337 MODULE_LICENSE("GPL v2");
338