1// SPDX-License-Identifier: GPL-2.0+
2//
3// RTC driver for Maxim MAX8998
4//
5// Copyright (C) 2010 Samsung Electronics Co.Ltd
6// Author: Minkyu Kang <mk7.kang@samsung.com>
7// Author: Joonyoung Shim <jy0922.shim@samsung.com>
8
9#include <linux/module.h>
10#include <linux/i2c.h>
11#include <linux/slab.h>
12#include <linux/bcd.h>
13#include <linux/irqdomain.h>
14#include <linux/rtc.h>
15#include <linux/platform_device.h>
16#include <linux/mfd/max8998.h>
17#include <linux/mfd/max8998-private.h>
18#include <linux/delay.h>
19
20#define MAX8998_RTC_SEC			0x00
21#define MAX8998_RTC_MIN			0x01
22#define MAX8998_RTC_HOUR		0x02
23#define MAX8998_RTC_WEEKDAY		0x03
24#define MAX8998_RTC_DATE		0x04
25#define MAX8998_RTC_MONTH		0x05
26#define MAX8998_RTC_YEAR1		0x06
27#define MAX8998_RTC_YEAR2		0x07
28#define MAX8998_ALARM0_SEC		0x08
29#define MAX8998_ALARM0_MIN		0x09
30#define MAX8998_ALARM0_HOUR		0x0a
31#define MAX8998_ALARM0_WEEKDAY		0x0b
32#define MAX8998_ALARM0_DATE		0x0c
33#define MAX8998_ALARM0_MONTH		0x0d
34#define MAX8998_ALARM0_YEAR1		0x0e
35#define MAX8998_ALARM0_YEAR2		0x0f
36#define MAX8998_ALARM1_SEC		0x10
37#define MAX8998_ALARM1_MIN		0x11
38#define MAX8998_ALARM1_HOUR		0x12
39#define MAX8998_ALARM1_WEEKDAY		0x13
40#define MAX8998_ALARM1_DATE		0x14
41#define MAX8998_ALARM1_MONTH		0x15
42#define MAX8998_ALARM1_YEAR1		0x16
43#define MAX8998_ALARM1_YEAR2		0x17
44#define MAX8998_ALARM0_CONF		0x18
45#define MAX8998_ALARM1_CONF		0x19
46#define MAX8998_RTC_STATUS		0x1a
47#define MAX8998_WTSR_SMPL_CNTL		0x1b
48#define MAX8998_TEST			0x1f
49
50#define HOUR_12				(1 << 7)
51#define HOUR_PM				(1 << 5)
52#define ALARM0_STATUS			(1 << 1)
53#define ALARM1_STATUS			(1 << 2)
54
55enum {
56	RTC_SEC = 0,
57	RTC_MIN,
58	RTC_HOUR,
59	RTC_WEEKDAY,
60	RTC_DATE,
61	RTC_MONTH,
62	RTC_YEAR1,
63	RTC_YEAR2,
64};
65
66struct max8998_rtc_info {
67	struct device		*dev;
68	struct max8998_dev	*max8998;
69	struct i2c_client	*rtc;
70	struct rtc_device	*rtc_dev;
71	int irq;
72	bool lp3974_bug_workaround;
73};
74
75static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
76{
77	tm->tm_sec = bcd2bin(data[RTC_SEC]);
78	tm->tm_min = bcd2bin(data[RTC_MIN]);
79	if (data[RTC_HOUR] & HOUR_12) {
80		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
81		if (data[RTC_HOUR] & HOUR_PM)
82			tm->tm_hour += 12;
83	} else
84		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
85
86	tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
87	tm->tm_mday = bcd2bin(data[RTC_DATE]);
88	tm->tm_mon = bcd2bin(data[RTC_MONTH]);
89	tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
90	tm->tm_year -= 1900;
91}
92
93static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
94{
95	data[RTC_SEC] = bin2bcd(tm->tm_sec);
96	data[RTC_MIN] = bin2bcd(tm->tm_min);
97	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
98	data[RTC_WEEKDAY] = tm->tm_wday;
99	data[RTC_DATE] = bin2bcd(tm->tm_mday);
100	data[RTC_MONTH] = bin2bcd(tm->tm_mon);
101	data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
102	data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
103}
104
105static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
106{
107	struct max8998_rtc_info *info = dev_get_drvdata(dev);
108	u8 data[8];
109	int ret;
110
111	ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
112	if (ret < 0)
113		return ret;
114
115	max8998_data_to_tm(data, tm);
116
117	return 0;
118}
119
120static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
121{
122	struct max8998_rtc_info *info = dev_get_drvdata(dev);
123	u8 data[8];
124	int ret;
125
126	max8998_tm_to_data(tm, data);
127
128	ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
129
130	if (info->lp3974_bug_workaround)
131		msleep(2000);
132
133	return ret;
134}
135
136static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
137{
138	struct max8998_rtc_info *info = dev_get_drvdata(dev);
139	u8 data[8];
140	u8 val;
141	int ret;
142
143	ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
144	if (ret < 0)
145		return ret;
146
147	max8998_data_to_tm(data, &alrm->time);
148
149	ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
150	if (ret < 0)
151		return ret;
152
153	alrm->enabled = !!val;
154
155	ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
156	if (ret < 0)
157		return ret;
158
159	if (val & ALARM0_STATUS)
160		alrm->pending = 1;
161	else
162		alrm->pending = 0;
163
164	return 0;
165}
166
167static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
168{
169	int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
170
171	if (info->lp3974_bug_workaround)
172		msleep(2000);
173
174	return ret;
175}
176
177static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
178{
179	int ret;
180	u8 alarm0_conf = 0x77;
181
182	/* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
183	if (info->lp3974_bug_workaround)
184		alarm0_conf = 0x57;
185
186	ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
187
188	if (info->lp3974_bug_workaround)
189		msleep(2000);
190
191	return ret;
192}
193
194static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
195{
196	struct max8998_rtc_info *info = dev_get_drvdata(dev);
197	u8 data[8];
198	int ret;
199
200	max8998_tm_to_data(&alrm->time, data);
201
202	ret = max8998_rtc_stop_alarm(info);
203	if (ret < 0)
204		return ret;
205
206	ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
207	if (ret < 0)
208		return ret;
209
210	if (info->lp3974_bug_workaround)
211		msleep(2000);
212
213	if (alrm->enabled)
214		ret = max8998_rtc_start_alarm(info);
215
216	return ret;
217}
218
219static int max8998_rtc_alarm_irq_enable(struct device *dev,
220					unsigned int enabled)
221{
222	struct max8998_rtc_info *info = dev_get_drvdata(dev);
223
224	if (enabled)
225		return max8998_rtc_start_alarm(info);
226	else
227		return max8998_rtc_stop_alarm(info);
228}
229
230static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
231{
232	struct max8998_rtc_info *info = data;
233
234	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
235
236	return IRQ_HANDLED;
237}
238
239static const struct rtc_class_ops max8998_rtc_ops = {
240	.read_time = max8998_rtc_read_time,
241	.set_time = max8998_rtc_set_time,
242	.read_alarm = max8998_rtc_read_alarm,
243	.set_alarm = max8998_rtc_set_alarm,
244	.alarm_irq_enable = max8998_rtc_alarm_irq_enable,
245};
246
247static int max8998_rtc_probe(struct platform_device *pdev)
248{
249	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
250	struct max8998_platform_data *pdata = max8998->pdata;
251	struct max8998_rtc_info *info;
252	int ret;
253
254	info = devm_kzalloc(&pdev->dev, sizeof(struct max8998_rtc_info),
255			GFP_KERNEL);
256	if (!info)
257		return -ENOMEM;
258
259	info->dev = &pdev->dev;
260	info->max8998 = max8998;
261	info->rtc = max8998->rtc;
262
263	platform_set_drvdata(pdev, info);
264
265	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8998-rtc",
266			&max8998_rtc_ops, THIS_MODULE);
267
268	if (IS_ERR(info->rtc_dev)) {
269		ret = PTR_ERR(info->rtc_dev);
270		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
271		return ret;
272	}
273
274	if (!max8998->irq_domain)
275		goto no_irq;
276
277	info->irq = irq_create_mapping(max8998->irq_domain, MAX8998_IRQ_ALARM0);
278	if (!info->irq) {
279		dev_warn(&pdev->dev, "Failed to map alarm IRQ\n");
280		goto no_irq;
281	}
282
283	ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
284				max8998_rtc_alarm_irq, 0, "rtc-alarm0", info);
285
286	if (ret < 0)
287		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
288			info->irq, ret);
289
290no_irq:
291	dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
292	if (pdata && pdata->rtc_delay) {
293		info->lp3974_bug_workaround = true;
294		dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
295				" RTC updates will be extremely slow.\n");
296	}
297
298	return 0;
299}
300
301static const struct platform_device_id max8998_rtc_id[] = {
302	{ "max8998-rtc", TYPE_MAX8998 },
303	{ "lp3974-rtc", TYPE_LP3974 },
304	{ }
305};
306MODULE_DEVICE_TABLE(platform, max8998_rtc_id);
307
308static struct platform_driver max8998_rtc_driver = {
309	.driver		= {
310		.name	= "max8998-rtc",
311	},
312	.probe		= max8998_rtc_probe,
313	.id_table	= max8998_rtc_id,
314};
315
316module_platform_driver(max8998_rtc_driver);
317
318MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
319MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
320MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
321MODULE_LICENSE("GPL");
322