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Linux/drivers/rtc/rtc-max8907.c

  1 /*
  2  * RTC driver for Maxim MAX8907
  3  *
  4  * Copyright (c) 2011-2012, NVIDIA Corporation.
  5  *
  6  * Based on drivers/rtc/rtc-max8925.c,
  7  * Copyright (C) 2009-2010 Marvell International Ltd.
  8  *
  9  * This program is free software; you can redistribute it and/or modify
 10  * it under the terms of the GNU General Public License version 2 as
 11  * published by the Free Software Foundation.
 12  */
 13 
 14 #include <linux/bcd.h>
 15 #include <linux/i2c.h>
 16 #include <linux/mfd/max8907.h>
 17 #include <linux/module.h>
 18 #include <linux/platform_device.h>
 19 #include <linux/regmap.h>
 20 #include <linux/rtc.h>
 21 #include <linux/slab.h>
 22 
 23 enum {
 24         RTC_SEC = 0,
 25         RTC_MIN,
 26         RTC_HOUR,
 27         RTC_WEEKDAY,
 28         RTC_DATE,
 29         RTC_MONTH,
 30         RTC_YEAR1,
 31         RTC_YEAR2,
 32 };
 33 
 34 #define TIME_NUM                        8
 35 #define ALARM_1SEC                      (1 << 7)
 36 #define HOUR_12                         (1 << 7)
 37 #define HOUR_AM_PM                      (1 << 5)
 38 #define ALARM0_IRQ                      (1 << 3)
 39 #define ALARM1_IRQ                      (1 << 2)
 40 #define ALARM0_STATUS                   (1 << 2)
 41 #define ALARM1_STATUS                   (1 << 1)
 42 
 43 struct max8907_rtc {
 44         struct max8907          *max8907;
 45         struct regmap           *regmap;
 46         struct rtc_device       *rtc_dev;
 47         int                     irq;
 48 };
 49 
 50 static irqreturn_t max8907_irq_handler(int irq, void *data)
 51 {
 52         struct max8907_rtc *rtc = data;
 53 
 54         regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
 55 
 56         rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
 57 
 58         return IRQ_HANDLED;
 59 }
 60 
 61 static void regs_to_tm(u8 *regs, struct rtc_time *tm)
 62 {
 63         tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
 64                 bcd2bin(regs[RTC_YEAR1]) - 1900;
 65         tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
 66         tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
 67         tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07);
 68         if (regs[RTC_HOUR] & HOUR_12) {
 69                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
 70                 if (tm->tm_hour == 12)
 71                         tm->tm_hour = 0;
 72                 if (regs[RTC_HOUR] & HOUR_AM_PM)
 73                         tm->tm_hour += 12;
 74         } else {
 75                 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
 76         }
 77         tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
 78         tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
 79 }
 80 
 81 static void tm_to_regs(struct rtc_time *tm, u8 *regs)
 82 {
 83         u8 high, low;
 84 
 85         high = (tm->tm_year + 1900) / 100;
 86         low = tm->tm_year % 100;
 87         regs[RTC_YEAR2] = bin2bcd(high);
 88         regs[RTC_YEAR1] = bin2bcd(low);
 89         regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
 90         regs[RTC_DATE] = bin2bcd(tm->tm_mday);
 91         regs[RTC_WEEKDAY] = tm->tm_wday;
 92         regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
 93         regs[RTC_MIN] = bin2bcd(tm->tm_min);
 94         regs[RTC_SEC] = bin2bcd(tm->tm_sec);
 95 }
 96 
 97 static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
 98 {
 99         struct max8907_rtc *rtc = dev_get_drvdata(dev);
100         u8 regs[TIME_NUM];
101         int ret;
102 
103         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
104                                TIME_NUM);
105         if (ret < 0)
106                 return ret;
107 
108         regs_to_tm(regs, tm);
109 
110         return 0;
111 }
112 
113 static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
114 {
115         struct max8907_rtc *rtc = dev_get_drvdata(dev);
116         u8 regs[TIME_NUM];
117 
118         tm_to_regs(tm, regs);
119 
120         return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
121                                  TIME_NUM);
122 }
123 
124 static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
125 {
126         struct max8907_rtc *rtc = dev_get_drvdata(dev);
127         u8 regs[TIME_NUM];
128         unsigned int val;
129         int ret;
130 
131         ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
132                                TIME_NUM);
133         if (ret < 0)
134                 return ret;
135 
136         regs_to_tm(regs, &alrm->time);
137 
138         ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
139         if (ret < 0)
140                 return ret;
141 
142         alrm->enabled = !!(val & 0x7f);
143 
144         return 0;
145 }
146 
147 static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
148 {
149         struct max8907_rtc *rtc = dev_get_drvdata(dev);
150         u8 regs[TIME_NUM];
151         int ret;
152 
153         tm_to_regs(&alrm->time, regs);
154 
155         /* Disable alarm while we update the target time */
156         ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
157         if (ret < 0)
158                 return ret;
159 
160         ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
161                                 TIME_NUM);
162         if (ret < 0)
163                 return ret;
164 
165         if (alrm->enabled)
166                 ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x77);
167 
168         return ret;
169 }
170 
171 static const struct rtc_class_ops max8907_rtc_ops = {
172         .read_time      = max8907_rtc_read_time,
173         .set_time       = max8907_rtc_set_time,
174         .read_alarm     = max8907_rtc_read_alarm,
175         .set_alarm      = max8907_rtc_set_alarm,
176 };
177 
178 static int max8907_rtc_probe(struct platform_device *pdev)
179 {
180         struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
181         struct max8907_rtc *rtc;
182         int ret;
183 
184         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
185         if (!rtc)
186                 return -ENOMEM;
187         platform_set_drvdata(pdev, rtc);
188 
189         rtc->max8907 = max8907;
190         rtc->regmap = max8907->regmap_rtc;
191 
192         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8907-rtc",
193                                         &max8907_rtc_ops, THIS_MODULE);
194         if (IS_ERR(rtc->rtc_dev)) {
195                 ret = PTR_ERR(rtc->rtc_dev);
196                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
197                 return ret;
198         }
199 
200         rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
201                                        MAX8907_IRQ_RTC_ALARM0);
202         if (rtc->irq < 0)
203                 return rtc->irq;
204 
205         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
206                                 max8907_irq_handler,
207                                 IRQF_ONESHOT, "max8907-alarm0", rtc);
208         if (ret < 0)
209                 dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
210                         rtc->irq, ret);
211 
212         return ret;
213 }
214 
215 static struct platform_driver max8907_rtc_driver = {
216         .driver = {
217                 .name = "max8907-rtc",
218                 .owner = THIS_MODULE,
219         },
220         .probe = max8907_rtc_probe,
221 };
222 module_platform_driver(max8907_rtc_driver);
223 
224 MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
225 MODULE_LICENSE("GPL v2");
226 

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