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Linux/drivers/rtc/rtc-88pm860x.c

  1 /*
  2  * Real Time Clock driver for Marvell 88PM860x PMIC
  3  *
  4  * Copyright (c) 2010 Marvell International Ltd.
  5  * Author:      Haojian Zhuang <haojian.zhuang@marvell.com>
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License version 2 as
  9  * published by the Free Software Foundation.
 10  */
 11 
 12 #include <linux/kernel.h>
 13 #include <linux/module.h>
 14 #include <linux/of.h>
 15 #include <linux/platform_device.h>
 16 #include <linux/slab.h>
 17 #include <linux/mutex.h>
 18 #include <linux/rtc.h>
 19 #include <linux/delay.h>
 20 #include <linux/mfd/core.h>
 21 #include <linux/mfd/88pm860x.h>
 22 
 23 #define VRTC_CALIBRATION
 24 
 25 struct pm860x_rtc_info {
 26         struct pm860x_chip      *chip;
 27         struct i2c_client       *i2c;
 28         struct rtc_device       *rtc_dev;
 29         struct device           *dev;
 30         struct delayed_work     calib_work;
 31 
 32         int                     irq;
 33         int                     vrtc;
 34         int                     (*sync)(unsigned int ticks);
 35 };
 36 
 37 #define REG_VRTC_MEAS1          0x7D
 38 
 39 #define REG0_ADDR               0xB0
 40 #define REG1_ADDR               0xB2
 41 #define REG2_ADDR               0xB4
 42 #define REG3_ADDR               0xB6
 43 
 44 #define REG0_DATA               0xB1
 45 #define REG1_DATA               0xB3
 46 #define REG2_DATA               0xB5
 47 #define REG3_DATA               0xB7
 48 
 49 /* bit definitions of Measurement Enable Register 2 (0x51) */
 50 #define MEAS2_VRTC              (1 << 0)
 51 
 52 /* bit definitions of RTC Register 1 (0xA0) */
 53 #define ALARM_EN                (1 << 3)
 54 #define ALARM_WAKEUP            (1 << 4)
 55 #define ALARM                   (1 << 5)
 56 #define RTC1_USE_XO             (1 << 7)
 57 
 58 #define VRTC_CALIB_INTERVAL     (HZ * 60 * 10)          /* 10 minutes */
 59 
 60 static irqreturn_t rtc_update_handler(int irq, void *data)
 61 {
 62         struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
 63         int mask;
 64 
 65         mask = ALARM | ALARM_WAKEUP;
 66         pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
 67         rtc_update_irq(info->rtc_dev, 1, RTC_AF);
 68         return IRQ_HANDLED;
 69 }
 70 
 71 static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 72 {
 73         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
 74 
 75         if (enabled)
 76                 pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
 77         else
 78                 pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
 79         return 0;
 80 }
 81 
 82 /*
 83  * Calculate the next alarm time given the requested alarm time mask
 84  * and the current time.
 85  */
 86 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
 87                                 struct rtc_time *alrm)
 88 {
 89         unsigned long next_time;
 90         unsigned long now_time;
 91 
 92         next->tm_year = now->tm_year;
 93         next->tm_mon = now->tm_mon;
 94         next->tm_mday = now->tm_mday;
 95         next->tm_hour = alrm->tm_hour;
 96         next->tm_min = alrm->tm_min;
 97         next->tm_sec = alrm->tm_sec;
 98 
 99         rtc_tm_to_time(now, &now_time);
100         rtc_tm_to_time(next, &next_time);
101 
102         if (next_time < now_time) {
103                 /* Advance one day */
104                 next_time += 60 * 60 * 24;
105                 rtc_time_to_tm(next_time, next);
106         }
107 }
108 
109 static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
110 {
111         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
112         unsigned char buf[8];
113         unsigned long ticks, base, data;
114 
115         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
116         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
117                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
118         base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
119 
120         /* load 32-bit read-only counter */
121         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
122         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
123         ticks = base + data;
124         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
125                 base, data, ticks);
126 
127         rtc_time_to_tm(ticks, tm);
128 
129         return 0;
130 }
131 
132 static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
133 {
134         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
135         unsigned char buf[4];
136         unsigned long ticks, base, data;
137 
138         if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
139                 dev_dbg(info->dev, "Set time %d out of range. "
140                         "Please set time between 1970 to 2038.\n",
141                         1900 + tm->tm_year);
142                 return -EINVAL;
143         }
144         rtc_tm_to_time(tm, &ticks);
145 
146         /* load 32-bit read-only counter */
147         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
148         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
149         base = ticks - data;
150         dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
151                 base, data, ticks);
152 
153         pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
154         pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
155         pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
156         pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
157 
158         if (info->sync)
159                 info->sync(ticks);
160         return 0;
161 }
162 
163 static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
164 {
165         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
166         unsigned char buf[8];
167         unsigned long ticks, base, data;
168         int ret;
169 
170         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
171         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
172                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
173         base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
174 
175         pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
176         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
177         ticks = base + data;
178         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
179                 base, data, ticks);
180 
181         rtc_time_to_tm(ticks, &alrm->time);
182         ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
183         alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
184         alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
185         return 0;
186 }
187 
188 static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
189 {
190         struct pm860x_rtc_info *info = dev_get_drvdata(dev);
191         struct rtc_time now_tm, alarm_tm;
192         unsigned long ticks, base, data;
193         unsigned char buf[8];
194         int mask;
195 
196         pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
197 
198         pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
199         dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
200                 buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
201         base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
202 
203         /* load 32-bit read-only counter */
204         pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
205         data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
206         ticks = base + data;
207         dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
208                 base, data, ticks);
209 
210         rtc_time_to_tm(ticks, &now_tm);
211         rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
212         /* get new ticks for alarm in 24 hours */
213         rtc_tm_to_time(&alarm_tm, &ticks);
214         data = ticks - base;
215 
216         buf[0] = data & 0xff;
217         buf[1] = (data >> 8) & 0xff;
218         buf[2] = (data >> 16) & 0xff;
219         buf[3] = (data >> 24) & 0xff;
220         pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
221         if (alrm->enabled) {
222                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
223                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
224         } else {
225                 mask = ALARM | ALARM_WAKEUP | ALARM_EN;
226                 pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
227                                 ALARM | ALARM_WAKEUP);
228         }
229         return 0;
230 }
231 
232 static const struct rtc_class_ops pm860x_rtc_ops = {
233         .read_time      = pm860x_rtc_read_time,
234         .set_time       = pm860x_rtc_set_time,
235         .read_alarm     = pm860x_rtc_read_alarm,
236         .set_alarm      = pm860x_rtc_set_alarm,
237         .alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
238 };
239 
240 #ifdef VRTC_CALIBRATION
241 static void calibrate_vrtc_work(struct work_struct *work)
242 {
243         struct pm860x_rtc_info *info = container_of(work,
244                 struct pm860x_rtc_info, calib_work.work);
245         unsigned char buf[2];
246         unsigned int sum, data, mean, vrtc_set;
247         int i;
248 
249         for (i = 0, sum = 0; i < 16; i++) {
250                 msleep(100);
251                 pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
252                 data = (buf[0] << 4) | buf[1];
253                 data = (data * 5400) >> 12;     /* convert to mv */
254                 sum += data;
255         }
256         mean = sum >> 4;
257         vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
258         dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
259 
260         sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
261         data = sum & 0x3;
262         if ((mean + 200) < vrtc_set) {
263                 /* try higher voltage */
264                 if (++data == 4)
265                         goto out;
266                 data = (sum & 0xf8) | (data & 0x3);
267                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
268         } else if ((mean - 200) > vrtc_set) {
269                 /* try lower voltage */
270                 if (data-- == 0)
271                         goto out;
272                 data = (sum & 0xf8) | (data & 0x3);
273                 pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
274         } else
275                 goto out;
276         dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
277         /* trigger next calibration since VRTC is updated */
278         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
279         return;
280 out:
281         /* disable measurement */
282         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
283         dev_dbg(info->dev, "finish VRTC calibration\n");
284         return;
285 }
286 #endif
287 
288 #ifdef CONFIG_OF
289 static int pm860x_rtc_dt_init(struct platform_device *pdev,
290                               struct pm860x_rtc_info *info)
291 {
292         struct device_node *np = pdev->dev.parent->of_node;
293         int ret;
294         if (!np)
295                 return -ENODEV;
296         np = of_find_node_by_name(np, "rtc");
297         if (!np) {
298                 dev_err(&pdev->dev, "failed to find rtc node\n");
299                 return -ENODEV;
300         }
301         ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
302         if (ret)
303                 info->vrtc = 0;
304         return 0;
305 }
306 #else
307 #define pm860x_rtc_dt_init(x, y)        (-1)
308 #endif
309 
310 static int pm860x_rtc_probe(struct platform_device *pdev)
311 {
312         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
313         struct pm860x_rtc_pdata *pdata = NULL;
314         struct pm860x_rtc_info *info;
315         struct rtc_time tm;
316         unsigned long ticks = 0;
317         int ret;
318 
319         pdata = dev_get_platdata(&pdev->dev);
320 
321         info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
322                             GFP_KERNEL);
323         if (!info)
324                 return -ENOMEM;
325         info->irq = platform_get_irq(pdev, 0);
326         if (info->irq < 0) {
327                 dev_err(&pdev->dev, "No IRQ resource!\n");
328                 return info->irq;
329         }
330 
331         info->chip = chip;
332         info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
333         info->dev = &pdev->dev;
334         dev_set_drvdata(&pdev->dev, info);
335 
336         ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
337                                         rtc_update_handler, IRQF_ONESHOT, "rtc",
338                                         info);
339         if (ret < 0) {
340                 dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
341                         info->irq, ret);
342                 return ret;
343         }
344 
345         /* set addresses of 32-bit base value for RTC time */
346         pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
347         pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
348         pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
349         pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
350 
351         ret = pm860x_rtc_read_time(&pdev->dev, &tm);
352         if (ret < 0) {
353                 dev_err(&pdev->dev, "Failed to read initial time.\n");
354                 return ret;
355         }
356         if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
357                 tm.tm_year = 70;
358                 tm.tm_mon = 0;
359                 tm.tm_mday = 1;
360                 tm.tm_hour = 0;
361                 tm.tm_min = 0;
362                 tm.tm_sec = 0;
363                 ret = pm860x_rtc_set_time(&pdev->dev, &tm);
364                 if (ret < 0) {
365                         dev_err(&pdev->dev, "Failed to set initial time.\n");
366                         return ret;
367                 }
368         }
369         rtc_tm_to_time(&tm, &ticks);
370         if (pm860x_rtc_dt_init(pdev, info)) {
371                 if (pdata && pdata->sync) {
372                         pdata->sync(ticks);
373                         info->sync = pdata->sync;
374                 }
375         }
376 
377         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm860x-rtc",
378                                             &pm860x_rtc_ops, THIS_MODULE);
379         ret = PTR_ERR(info->rtc_dev);
380         if (IS_ERR(info->rtc_dev)) {
381                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
382                 return ret;
383         }
384 
385         /*
386          * enable internal XO instead of internal 3.25MHz clock since it can
387          * free running in PMIC power-down state.
388          */
389         pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
390 
391 #ifdef VRTC_CALIBRATION
392         /* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
393         if (pm860x_rtc_dt_init(pdev, info)) {
394                 if (pdata && pdata->vrtc)
395                         info->vrtc = pdata->vrtc & 0x3;
396                 else
397                         info->vrtc = 1;
398         }
399         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
400 
401         /* calibrate VRTC */
402         INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
403         schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
404 #endif  /* VRTC_CALIBRATION */
405 
406         device_init_wakeup(&pdev->dev, 1);
407 
408         return 0;
409 }
410 
411 static int pm860x_rtc_remove(struct platform_device *pdev)
412 {
413         struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
414 
415 #ifdef VRTC_CALIBRATION
416         flush_scheduled_work();
417         /* disable measurement */
418         pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
419 #endif  /* VRTC_CALIBRATION */
420 
421         return 0;
422 }
423 
424 #ifdef CONFIG_PM_SLEEP
425 static int pm860x_rtc_suspend(struct device *dev)
426 {
427         struct platform_device *pdev = to_platform_device(dev);
428         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
429 
430         if (device_may_wakeup(dev))
431                 chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
432         return 0;
433 }
434 static int pm860x_rtc_resume(struct device *dev)
435 {
436         struct platform_device *pdev = to_platform_device(dev);
437         struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
438 
439         if (device_may_wakeup(dev))
440                 chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
441         return 0;
442 }
443 #endif
444 
445 static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
446 
447 static struct platform_driver pm860x_rtc_driver = {
448         .driver         = {
449                 .name   = "88pm860x-rtc",
450                 .owner  = THIS_MODULE,
451                 .pm     = &pm860x_rtc_pm_ops,
452         },
453         .probe          = pm860x_rtc_probe,
454         .remove         = pm860x_rtc_remove,
455 };
456 
457 module_platform_driver(pm860x_rtc_driver);
458 
459 MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
460 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
461 MODULE_LICENSE("GPL");
462 

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