projects/linux·blob master · refs

220 lines · 5.0 KiB

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