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Linux/drivers/rtc/rtc-tps80031.c

  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 
 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 
 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 
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 
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 
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 
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 
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 
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 | IRQF_EARLY_RESUME,
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
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 
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                 .owner  = THIS_MODULE,
328                 .pm     = &tps80031_pm_ops,
329         },
330         .probe  = tps80031_rtc_probe,
331 };
332 
333 module_platform_driver(tps80031_rtc_driver);
334 
335 MODULE_ALIAS("platform:tps80031-rtc");
336 MODULE_DESCRIPTION("TI TPS80031/TPS80032 RTC driver");
337 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
338 MODULE_LICENSE("GPL v2");
339 

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