1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * RTC driver for Maxim MAX8907
4 *
5 * Copyright (c) 2011-2012, NVIDIA Corporation.
6 *
7 * Based on drivers/rtc/rtc-max8925.c,
8 * Copyright (C) 2009-2010 Marvell International Ltd.
9 */
10
11 #include <linux/bcd.h>
12 #include <linux/i2c.h>
13 #include <linux/mfd/max8907.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/rtc.h>
18 #include <linux/slab.h>
19
20 enum {
21 RTC_SEC = 0,
22 RTC_MIN,
23 RTC_HOUR,
24 RTC_WEEKDAY,
25 RTC_DATE,
26 RTC_MONTH,
27 RTC_YEAR1,
28 RTC_YEAR2,
29 };
30
31 #define TIME_NUM 8
32 #define ALARM_1SEC (1 << 7)
33 #define HOUR_12 (1 << 7)
34 #define HOUR_AM_PM (1 << 5)
35 #define ALARM0_IRQ (1 << 3)
36 #define ALARM1_IRQ (1 << 2)
37 #define ALARM0_STATUS (1 << 2)
38 #define ALARM1_STATUS (1 << 1)
39
40 struct max8907_rtc {
41 struct max8907 *max8907;
42 struct regmap *regmap;
43 struct rtc_device *rtc_dev;
44 int irq;
45 };
46
max8907_irq_handler(int irq,void * data)47 static irqreturn_t max8907_irq_handler(int irq, void *data)
48 {
49 struct max8907_rtc *rtc = data;
50
51 regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
52
53 rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
54
55 return IRQ_HANDLED;
56 }
57
regs_to_tm(u8 * regs,struct rtc_time * tm)58 static void regs_to_tm(u8 *regs, struct rtc_time *tm)
59 {
60 tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
61 bcd2bin(regs[RTC_YEAR1]) - 1900;
62 tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
63 tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
64 tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07);
65 if (regs[RTC_HOUR] & HOUR_12) {
66 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
67 if (tm->tm_hour == 12)
68 tm->tm_hour = 0;
69 if (regs[RTC_HOUR] & HOUR_AM_PM)
70 tm->tm_hour += 12;
71 } else {
72 tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
73 }
74 tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
75 tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
76 }
77
tm_to_regs(struct rtc_time * tm,u8 * regs)78 static void tm_to_regs(struct rtc_time *tm, u8 *regs)
79 {
80 u8 high, low;
81
82 high = (tm->tm_year + 1900) / 100;
83 low = tm->tm_year % 100;
84 regs[RTC_YEAR2] = bin2bcd(high);
85 regs[RTC_YEAR1] = bin2bcd(low);
86 regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
87 regs[RTC_DATE] = bin2bcd(tm->tm_mday);
88 regs[RTC_WEEKDAY] = tm->tm_wday;
89 regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
90 regs[RTC_MIN] = bin2bcd(tm->tm_min);
91 regs[RTC_SEC] = bin2bcd(tm->tm_sec);
92 }
93
max8907_rtc_read_time(struct device * dev,struct rtc_time * tm)94 static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
95 {
96 struct max8907_rtc *rtc = dev_get_drvdata(dev);
97 u8 regs[TIME_NUM];
98 int ret;
99
100 ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
101 TIME_NUM);
102 if (ret < 0)
103 return ret;
104
105 regs_to_tm(regs, tm);
106
107 return 0;
108 }
109
max8907_rtc_set_time(struct device * dev,struct rtc_time * tm)110 static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
111 {
112 struct max8907_rtc *rtc = dev_get_drvdata(dev);
113 u8 regs[TIME_NUM];
114
115 tm_to_regs(tm, regs);
116
117 return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
118 TIME_NUM);
119 }
120
max8907_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)121 static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
122 {
123 struct max8907_rtc *rtc = dev_get_drvdata(dev);
124 u8 regs[TIME_NUM];
125 unsigned int val;
126 int ret;
127
128 ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
129 TIME_NUM);
130 if (ret < 0)
131 return ret;
132
133 regs_to_tm(regs, &alrm->time);
134
135 ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
136 if (ret < 0)
137 return ret;
138
139 alrm->enabled = !!(val & 0x7f);
140
141 return 0;
142 }
143
max8907_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)144 static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
145 {
146 struct max8907_rtc *rtc = dev_get_drvdata(dev);
147 u8 regs[TIME_NUM];
148 int ret;
149
150 tm_to_regs(&alrm->time, regs);
151
152 /* Disable alarm while we update the target time */
153 ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0);
154 if (ret < 0)
155 return ret;
156
157 ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
158 TIME_NUM);
159 if (ret < 0)
160 return ret;
161
162 if (alrm->enabled)
163 ret = regmap_write(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x77);
164
165 return ret;
166 }
167
168 static const struct rtc_class_ops max8907_rtc_ops = {
169 .read_time = max8907_rtc_read_time,
170 .set_time = max8907_rtc_set_time,
171 .read_alarm = max8907_rtc_read_alarm,
172 .set_alarm = max8907_rtc_set_alarm,
173 };
174
max8907_rtc_probe(struct platform_device * pdev)175 static int max8907_rtc_probe(struct platform_device *pdev)
176 {
177 struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
178 struct max8907_rtc *rtc;
179 int ret;
180
181 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
182 if (!rtc)
183 return -ENOMEM;
184 platform_set_drvdata(pdev, rtc);
185
186 rtc->max8907 = max8907;
187 rtc->regmap = max8907->regmap_rtc;
188
189 rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8907-rtc",
190 &max8907_rtc_ops, THIS_MODULE);
191 if (IS_ERR(rtc->rtc_dev)) {
192 ret = PTR_ERR(rtc->rtc_dev);
193 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
194 return ret;
195 }
196
197 rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
198 MAX8907_IRQ_RTC_ALARM0);
199 if (rtc->irq < 0)
200 return rtc->irq;
201
202 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
203 max8907_irq_handler,
204 IRQF_ONESHOT, "max8907-alarm0", rtc);
205 if (ret < 0)
206 dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
207 rtc->irq, ret);
208
209 return ret;
210 }
211
212 static struct platform_driver max8907_rtc_driver = {
213 .driver = {
214 .name = "max8907-rtc",
215 },
216 .probe = max8907_rtc_probe,
217 };
218 module_platform_driver(max8907_rtc_driver);
219
220 MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
221 MODULE_LICENSE("GPL v2");
222