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Linux/drivers/rtc/rtc-lp8788.c

  1 /*
  2  * TI LP8788 MFD - rtc driver
  3  *
  4  * Copyright 2012 Texas Instruments
  5  *
  6  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License version 2 as
 10  * published by the Free Software Foundation.
 11  *
 12  */
 13 
 14 #include <linux/err.h>
 15 #include <linux/irqdomain.h>
 16 #include <linux/mfd/lp8788.h>
 17 #include <linux/module.h>
 18 #include <linux/platform_device.h>
 19 #include <linux/rtc.h>
 20 #include <linux/slab.h>
 21 
 22 /* register address */
 23 #define LP8788_INTEN_3                  0x05
 24 #define LP8788_RTC_UNLOCK               0x64
 25 #define LP8788_RTC_SEC                  0x70
 26 #define LP8788_ALM1_SEC                 0x77
 27 #define LP8788_ALM1_EN                  0x7D
 28 #define LP8788_ALM2_SEC                 0x7E
 29 #define LP8788_ALM2_EN                  0x84
 30 
 31 /* mask/shift bits */
 32 #define LP8788_INT_RTC_ALM1_M           BIT(1)  /* Addr 05h */
 33 #define LP8788_INT_RTC_ALM1_S           1
 34 #define LP8788_INT_RTC_ALM2_M           BIT(2)  /* Addr 05h */
 35 #define LP8788_INT_RTC_ALM2_S           2
 36 #define LP8788_ALM_EN_M                 BIT(7)  /* Addr 7Dh or 84h */
 37 #define LP8788_ALM_EN_S                 7
 38 
 39 #define DEFAULT_ALARM_SEL               LP8788_ALARM_1
 40 #define LP8788_MONTH_OFFSET             1
 41 #define LP8788_BASE_YEAR                2000
 42 #define MAX_WDAY_BITS                   7
 43 #define LP8788_WDAY_SET                 1
 44 #define RTC_UNLOCK                      0x1
 45 #define RTC_LATCH                       0x2
 46 #define ALARM_IRQ_FLAG                  (RTC_IRQF | RTC_AF)
 47 
 48 enum lp8788_time {
 49         LPTIME_SEC,
 50         LPTIME_MIN,
 51         LPTIME_HOUR,
 52         LPTIME_MDAY,
 53         LPTIME_MON,
 54         LPTIME_YEAR,
 55         LPTIME_WDAY,
 56         LPTIME_MAX,
 57 };
 58 
 59 struct lp8788_rtc {
 60         struct lp8788 *lp;
 61         struct rtc_device *rdev;
 62         enum lp8788_alarm_sel alarm;
 63         int irq;
 64 };
 65 
 66 static const u8 addr_alarm_sec[LP8788_ALARM_MAX] = {
 67         LP8788_ALM1_SEC,
 68         LP8788_ALM2_SEC,
 69 };
 70 
 71 static const u8 addr_alarm_en[LP8788_ALARM_MAX] = {
 72         LP8788_ALM1_EN,
 73         LP8788_ALM2_EN,
 74 };
 75 
 76 static const u8 mask_alarm_en[LP8788_ALARM_MAX] = {
 77         LP8788_INT_RTC_ALM1_M,
 78         LP8788_INT_RTC_ALM2_M,
 79 };
 80 
 81 static const u8 shift_alarm_en[LP8788_ALARM_MAX] = {
 82         LP8788_INT_RTC_ALM1_S,
 83         LP8788_INT_RTC_ALM2_S,
 84 };
 85 
 86 static int _to_tm_wday(u8 lp8788_wday)
 87 {
 88         int i;
 89 
 90         if (lp8788_wday == 0)
 91                 return 0;
 92 
 93         /* lookup defined weekday from read register value */
 94         for (i = 0; i < MAX_WDAY_BITS; i++) {
 95                 if ((lp8788_wday >> i) == LP8788_WDAY_SET)
 96                         break;
 97         }
 98 
 99         return i + 1;
100 }
101 
102 static inline int _to_lp8788_wday(int tm_wday)
103 {
104         return LP8788_WDAY_SET << (tm_wday - 1);
105 }
106 
107 static void lp8788_rtc_unlock(struct lp8788 *lp)
108 {
109         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_UNLOCK);
110         lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_LATCH);
111 }
112 
113 static int lp8788_rtc_read_time(struct device *dev, struct rtc_time *tm)
114 {
115         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
116         struct lp8788 *lp = rtc->lp;
117         u8 data[LPTIME_MAX];
118         int ret;
119 
120         lp8788_rtc_unlock(lp);
121 
122         ret = lp8788_read_multi_bytes(lp, LP8788_RTC_SEC, data, LPTIME_MAX);
123         if (ret)
124                 return ret;
125 
126         tm->tm_sec  = data[LPTIME_SEC];
127         tm->tm_min  = data[LPTIME_MIN];
128         tm->tm_hour = data[LPTIME_HOUR];
129         tm->tm_mday = data[LPTIME_MDAY];
130         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
131         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
132         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
133 
134         return 0;
135 }
136 
137 static int lp8788_rtc_set_time(struct device *dev, struct rtc_time *tm)
138 {
139         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
140         struct lp8788 *lp = rtc->lp;
141         u8 data[LPTIME_MAX - 1];
142         int ret, i, year;
143 
144         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
145         if (year < 0) {
146                 dev_err(lp->dev, "invalid year: %d\n", year);
147                 return -EINVAL;
148         }
149 
150         /* because rtc weekday is a readonly register, do not update */
151         data[LPTIME_SEC]  = tm->tm_sec;
152         data[LPTIME_MIN]  = tm->tm_min;
153         data[LPTIME_HOUR] = tm->tm_hour;
154         data[LPTIME_MDAY] = tm->tm_mday;
155         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
156         data[LPTIME_YEAR] = year;
157 
158         for (i = 0; i < ARRAY_SIZE(data); i++) {
159                 ret = lp8788_write_byte(lp, LP8788_RTC_SEC + i, data[i]);
160                 if (ret)
161                         return ret;
162         }
163 
164         return 0;
165 }
166 
167 static int lp8788_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
168 {
169         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
170         struct lp8788 *lp = rtc->lp;
171         struct rtc_time *tm = &alarm->time;
172         u8 addr, data[LPTIME_MAX];
173         int ret;
174 
175         addr = addr_alarm_sec[rtc->alarm];
176         ret = lp8788_read_multi_bytes(lp, addr, data, LPTIME_MAX);
177         if (ret)
178                 return ret;
179 
180         tm->tm_sec  = data[LPTIME_SEC];
181         tm->tm_min  = data[LPTIME_MIN];
182         tm->tm_hour = data[LPTIME_HOUR];
183         tm->tm_mday = data[LPTIME_MDAY];
184         tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
185         tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
186         tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
187         alarm->enabled = data[LPTIME_WDAY] & LP8788_ALM_EN_M;
188 
189         return 0;
190 }
191 
192 static int lp8788_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
193 {
194         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
195         struct lp8788 *lp = rtc->lp;
196         struct rtc_time *tm = &alarm->time;
197         u8 addr, data[LPTIME_MAX];
198         int ret, i, year;
199 
200         year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
201         if (year < 0) {
202                 dev_err(lp->dev, "invalid year: %d\n", year);
203                 return -EINVAL;
204         }
205 
206         data[LPTIME_SEC]  = tm->tm_sec;
207         data[LPTIME_MIN]  = tm->tm_min;
208         data[LPTIME_HOUR] = tm->tm_hour;
209         data[LPTIME_MDAY] = tm->tm_mday;
210         data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
211         data[LPTIME_YEAR] = year;
212         data[LPTIME_WDAY] = _to_lp8788_wday(tm->tm_wday);
213 
214         for (i = 0; i < ARRAY_SIZE(data); i++) {
215                 addr = addr_alarm_sec[rtc->alarm] + i;
216                 ret = lp8788_write_byte(lp, addr, data[i]);
217                 if (ret)
218                         return ret;
219         }
220 
221         alarm->enabled = 1;
222         addr = addr_alarm_en[rtc->alarm];
223 
224         return lp8788_update_bits(lp, addr, LP8788_ALM_EN_M,
225                                 alarm->enabled << LP8788_ALM_EN_S);
226 }
227 
228 static int lp8788_alarm_irq_enable(struct device *dev, unsigned int enable)
229 {
230         struct lp8788_rtc *rtc = dev_get_drvdata(dev);
231         struct lp8788 *lp = rtc->lp;
232         u8 mask, shift;
233 
234         if (!rtc->irq)
235                 return -EIO;
236 
237         mask = mask_alarm_en[rtc->alarm];
238         shift = shift_alarm_en[rtc->alarm];
239 
240         return lp8788_update_bits(lp, LP8788_INTEN_3, mask, enable << shift);
241 }
242 
243 static const struct rtc_class_ops lp8788_rtc_ops = {
244         .read_time = lp8788_rtc_read_time,
245         .set_time = lp8788_rtc_set_time,
246         .read_alarm = lp8788_read_alarm,
247         .set_alarm = lp8788_set_alarm,
248         .alarm_irq_enable = lp8788_alarm_irq_enable,
249 };
250 
251 static irqreturn_t lp8788_alarm_irq_handler(int irq, void *ptr)
252 {
253         struct lp8788_rtc *rtc = ptr;
254 
255         rtc_update_irq(rtc->rdev, 1, ALARM_IRQ_FLAG);
256         return IRQ_HANDLED;
257 }
258 
259 static int lp8788_alarm_irq_register(struct platform_device *pdev,
260                                 struct lp8788_rtc *rtc)
261 {
262         struct resource *r;
263         struct lp8788 *lp = rtc->lp;
264         struct irq_domain *irqdm = lp->irqdm;
265         int irq;
266 
267         rtc->irq = 0;
268 
269         /* even the alarm IRQ number is not specified, rtc time should work */
270         r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, LP8788_ALM_IRQ);
271         if (!r)
272                 return 0;
273 
274         if (rtc->alarm == LP8788_ALARM_1)
275                 irq = r->start;
276         else
277                 irq = r->end;
278 
279         rtc->irq = irq_create_mapping(irqdm, irq);
280 
281         return devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
282                                 lp8788_alarm_irq_handler,
283                                 0, LP8788_ALM_IRQ, rtc);
284 }
285 
286 static int lp8788_rtc_probe(struct platform_device *pdev)
287 {
288         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
289         struct lp8788_rtc *rtc;
290         struct device *dev = &pdev->dev;
291 
292         rtc = devm_kzalloc(dev, sizeof(struct lp8788_rtc), GFP_KERNEL);
293         if (!rtc)
294                 return -ENOMEM;
295 
296         rtc->lp = lp;
297         rtc->alarm = lp->pdata ? lp->pdata->alarm_sel : DEFAULT_ALARM_SEL;
298         platform_set_drvdata(pdev, rtc);
299 
300         device_init_wakeup(dev, 1);
301 
302         rtc->rdev = devm_rtc_device_register(dev, "lp8788_rtc",
303                                         &lp8788_rtc_ops, THIS_MODULE);
304         if (IS_ERR(rtc->rdev)) {
305                 dev_err(dev, "can not register rtc device\n");
306                 return PTR_ERR(rtc->rdev);
307         }
308 
309         if (lp8788_alarm_irq_register(pdev, rtc))
310                 dev_warn(lp->dev, "no rtc irq handler\n");
311 
312         return 0;
313 }
314 
315 static struct platform_driver lp8788_rtc_driver = {
316         .probe = lp8788_rtc_probe,
317         .driver = {
318                 .name = LP8788_DEV_RTC,
319                 .owner = THIS_MODULE,
320         },
321 };
322 module_platform_driver(lp8788_rtc_driver);
323 
324 MODULE_DESCRIPTION("Texas Instruments LP8788 RTC Driver");
325 MODULE_AUTHOR("Milo Kim");
326 MODULE_LICENSE("GPL");
327 MODULE_ALIAS("platform:lp8788-rtc");
328 

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