xref: /linux/drivers/rtc/rtc-max8907.c (revision c79c3c34f75d72a066e292b10aa50fc758c97c89)
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 
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 
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 
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 
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 
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 
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 
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 
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