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");