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Linux/drivers/rtc/rtc-tps6586x.c

  1 /*
  2  * rtc-tps6586x.c: RTC driver for TI PMIC TPS6586X
  3  *
  4  * Copyright (c) 2012, NVIDIA Corporation.
  5  *
  6  * Author: Laxman Dewangan <ldewangan@nvidia.com>
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public License as
 10  * published by the Free Software Foundation version 2.
 11  *
 12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
 13  * whether express or implied; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 15  * General Public License for more details.
 16  *
 17  * You should have received a copy of the GNU General Public License
 18  * along with this program; if not, write to the Free Software
 19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 20  * 02111-1307, USA
 21  */
 22 
 23 #include <linux/device.h>
 24 #include <linux/err.h>
 25 #include <linux/init.h>
 26 #include <linux/kernel.h>
 27 #include <linux/mfd/tps6586x.h>
 28 #include <linux/module.h>
 29 #include <linux/platform_device.h>
 30 #include <linux/pm_runtime.h>
 31 #include <linux/rtc.h>
 32 #include <linux/slab.h>
 33 
 34 #define RTC_CTRL                        0xc0
 35 #define POR_RESET_N                     BIT(7)
 36 #define OSC_SRC_SEL                     BIT(6)
 37 #define RTC_ENABLE                      BIT(5)  /* enables alarm */
 38 #define RTC_BUF_ENABLE                  BIT(4)  /* 32 KHz buffer enable */
 39 #define PRE_BYPASS                      BIT(3)  /* 0=1KHz or 1=32KHz updates */
 40 #define CL_SEL_MASK                     (BIT(2)|BIT(1))
 41 #define CL_SEL_POS                      1
 42 #define RTC_ALARM1_HI                   0xc1
 43 #define RTC_COUNT4                      0xc6
 44 
 45 /* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
 46 #define RTC_COUNT4_DUMMYREAD            0xc5
 47 
 48 /*only 14-bits width in second*/
 49 #define ALM1_VALID_RANGE_IN_SEC         0x3FFF
 50 
 51 #define TPS6586X_RTC_CL_SEL_1_5PF       0x0
 52 #define TPS6586X_RTC_CL_SEL_6_5PF       0x1
 53 #define TPS6586X_RTC_CL_SEL_7_5PF       0x2
 54 #define TPS6586X_RTC_CL_SEL_12_5PF      0x3
 55 
 56 struct tps6586x_rtc {
 57         struct device           *dev;
 58         struct rtc_device       *rtc;
 59         int                     irq;
 60         bool                    irq_en;
 61         unsigned long long      epoch_start;
 62 };
 63 
 64 static inline struct device *to_tps6586x_dev(struct device *dev)
 65 {
 66         return dev->parent;
 67 }
 68 
 69 static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 70 {
 71         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 72         struct device *tps_dev = to_tps6586x_dev(dev);
 73         unsigned long long ticks = 0;
 74         unsigned long seconds;
 75         u8 buff[6];
 76         int ret;
 77         int i;
 78 
 79         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
 80         if (ret < 0) {
 81                 dev_err(dev, "read counter failed with err %d\n", ret);
 82                 return ret;
 83         }
 84 
 85         for (i = 1; i < sizeof(buff); i++) {
 86                 ticks <<= 8;
 87                 ticks |= buff[i];
 88         }
 89 
 90         seconds = ticks >> 10;
 91         seconds += rtc->epoch_start;
 92         rtc_time_to_tm(seconds, tm);
 93         return rtc_valid_tm(tm);
 94 }
 95 
 96 static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 97 {
 98         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 99         struct device *tps_dev = to_tps6586x_dev(dev);
100         unsigned long long ticks;
101         unsigned long seconds;
102         u8 buff[5];
103         int ret;
104 
105         rtc_tm_to_time(tm, &seconds);
106         if (seconds < rtc->epoch_start) {
107                 dev_err(dev, "requested time unsupported\n");
108                 return -EINVAL;
109         }
110         seconds -= rtc->epoch_start;
111 
112         ticks = (unsigned long long)seconds << 10;
113         buff[0] = (ticks >> 32) & 0xff;
114         buff[1] = (ticks >> 24) & 0xff;
115         buff[2] = (ticks >> 16) & 0xff;
116         buff[3] = (ticks >> 8) & 0xff;
117         buff[4] = ticks & 0xff;
118 
119         /* Disable RTC before changing time */
120         ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
121         if (ret < 0) {
122                 dev_err(dev, "failed to clear RTC_ENABLE\n");
123                 return ret;
124         }
125 
126         ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
127         if (ret < 0) {
128                 dev_err(dev, "failed to program new time\n");
129                 return ret;
130         }
131 
132         /* Enable RTC */
133         ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
134         if (ret < 0) {
135                 dev_err(dev, "failed to set RTC_ENABLE\n");
136                 return ret;
137         }
138         return 0;
139 }
140 
141 static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
142                          unsigned int enabled)
143 {
144         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
145 
146         if (enabled && !rtc->irq_en) {
147                 enable_irq(rtc->irq);
148                 rtc->irq_en = true;
149         } else if (!enabled && rtc->irq_en)  {
150                 disable_irq(rtc->irq);
151                 rtc->irq_en = false;
152         }
153         return 0;
154 }
155 
156 static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
157 {
158         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
159         struct device *tps_dev = to_tps6586x_dev(dev);
160         unsigned long seconds;
161         unsigned long ticks;
162         unsigned long rtc_current_time;
163         unsigned long long rticks = 0;
164         u8 buff[3];
165         u8 rbuff[6];
166         int ret;
167         int i;
168 
169         rtc_tm_to_time(&alrm->time, &seconds);
170 
171         if (alrm->enabled && (seconds < rtc->epoch_start)) {
172                 dev_err(dev, "can't set alarm to requested time\n");
173                 return -EINVAL;
174         }
175 
176         ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
177         if (ret < 0) {
178                 dev_err(dev, "can't set alarm irq, err %d\n", ret);
179                 return ret;
180         }
181 
182         seconds -= rtc->epoch_start;
183         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
184                         sizeof(rbuff), rbuff);
185         if (ret < 0) {
186                 dev_err(dev, "read counter failed with err %d\n", ret);
187                 return ret;
188         }
189 
190         for (i = 1; i < sizeof(rbuff); i++) {
191                 rticks <<= 8;
192                 rticks |= rbuff[i];
193         }
194 
195         rtc_current_time = rticks >> 10;
196         if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
197                 seconds = rtc_current_time - 1;
198 
199         ticks = (unsigned long long)seconds << 10;
200         buff[0] = (ticks >> 16) & 0xff;
201         buff[1] = (ticks >> 8) & 0xff;
202         buff[2] = ticks & 0xff;
203 
204         ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
205         if (ret)
206                 dev_err(dev, "programming alarm failed with err %d\n", ret);
207 
208         return ret;
209 }
210 
211 static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
212 {
213         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
214         struct device *tps_dev = to_tps6586x_dev(dev);
215         unsigned long ticks;
216         unsigned long seconds;
217         u8 buff[3];
218         int ret;
219 
220         ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
221         if (ret) {
222                 dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
223                 return ret;
224         }
225 
226         ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
227         seconds = ticks >> 10;
228         seconds += rtc->epoch_start;
229 
230         rtc_time_to_tm(seconds, &alrm->time);
231         return 0;
232 }
233 
234 static const struct rtc_class_ops tps6586x_rtc_ops = {
235         .read_time      = tps6586x_rtc_read_time,
236         .set_time       = tps6586x_rtc_set_time,
237         .set_alarm      = tps6586x_rtc_set_alarm,
238         .read_alarm     = tps6586x_rtc_read_alarm,
239         .alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
240 };
241 
242 static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
243 {
244         struct tps6586x_rtc *rtc = data;
245 
246         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
247         return IRQ_HANDLED;
248 }
249 
250 static int tps6586x_rtc_probe(struct platform_device *pdev)
251 {
252         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
253         struct tps6586x_rtc *rtc;
254         int ret;
255 
256         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
257         if (!rtc)
258                 return -ENOMEM;
259 
260         rtc->dev = &pdev->dev;
261         rtc->irq = platform_get_irq(pdev, 0);
262 
263         /* Set epoch start as 00:00:00:01:01:2009 */
264         rtc->epoch_start = mktime(2009, 1, 1, 0, 0, 0);
265 
266         /* 1 kHz tick mode, enable tick counting */
267         ret = tps6586x_update(tps_dev, RTC_CTRL,
268                 RTC_ENABLE | OSC_SRC_SEL |
269                 ((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
270                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
271         if (ret < 0) {
272                 dev_err(&pdev->dev, "unable to start counter\n");
273                 return ret;
274         }
275 
276         device_init_wakeup(&pdev->dev, 1);
277 
278         platform_set_drvdata(pdev, rtc);
279         rtc->rtc = devm_rtc_device_register(&pdev->dev, dev_name(&pdev->dev),
280                                        &tps6586x_rtc_ops, THIS_MODULE);
281         if (IS_ERR(rtc->rtc)) {
282                 ret = PTR_ERR(rtc->rtc);
283                 dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
284                 goto fail_rtc_register;
285         }
286 
287         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
288                                 tps6586x_rtc_irq,
289                                 IRQF_ONESHOT | IRQF_EARLY_RESUME,
290                                 dev_name(&pdev->dev), rtc);
291         if (ret < 0) {
292                 dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
293                                 rtc->irq, ret);
294                 goto fail_rtc_register;
295         }
296         disable_irq(rtc->irq);
297         return 0;
298 
299 fail_rtc_register:
300         tps6586x_update(tps_dev, RTC_CTRL, 0,
301                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
302         return ret;
303 };
304 
305 static int tps6586x_rtc_remove(struct platform_device *pdev)
306 {
307         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
308 
309         tps6586x_update(tps_dev, RTC_CTRL, 0,
310                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
311         return 0;
312 }
313 
314 #ifdef CONFIG_PM_SLEEP
315 static int tps6586x_rtc_suspend(struct device *dev)
316 {
317         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
318 
319         if (device_may_wakeup(dev))
320                 enable_irq_wake(rtc->irq);
321         return 0;
322 }
323 
324 static int tps6586x_rtc_resume(struct device *dev)
325 {
326         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
327 
328         if (device_may_wakeup(dev))
329                 disable_irq_wake(rtc->irq);
330         return 0;
331 }
332 #endif
333 
334 static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
335                         tps6586x_rtc_resume);
336 
337 static struct platform_driver tps6586x_rtc_driver = {
338         .driver = {
339                 .name   = "tps6586x-rtc",
340                 .owner  = THIS_MODULE,
341                 .pm     = &tps6586x_pm_ops,
342         },
343         .probe  = tps6586x_rtc_probe,
344         .remove = tps6586x_rtc_remove,
345 };
346 module_platform_driver(tps6586x_rtc_driver);
347 
348 MODULE_ALIAS("platform:rtc-tps6586x");
349 MODULE_DESCRIPTION("TI TPS6586x RTC driver");
350 MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
351 MODULE_LICENSE("GPL v2");
352 

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