1/*
2 * RTC driver for Maxim MAX8998
3 *
4 * Copyright (C) 2010 Samsung Electronics Co.Ltd
5 * Author: Minkyu Kang <mk7.kang@samsung.com>
6 * Author: Joonyoung Shim <jy0922.shim@samsung.com>
7 *
8 *  This program is free software; you can redistribute  it and/or modify it
9 *  under  the terms of  the GNU General  Public License as published by the
10 *  Free Software Foundation;  either version 2 of the  License, or (at your
11 *  option) any later version.
12 *
13 */
14
15#include <linux/module.h>
16#include <linux/i2c.h>
17#include <linux/slab.h>
18#include <linux/bcd.h>
19#include <linux/irqdomain.h>
20#include <linux/rtc.h>
21#include <linux/platform_device.h>
22#include <linux/mfd/max8998.h>
23#include <linux/mfd/max8998-private.h>
24#include <linux/delay.h>
25
26#define MAX8998_RTC_SEC			0x00
27#define MAX8998_RTC_MIN			0x01
28#define MAX8998_RTC_HOUR		0x02
29#define MAX8998_RTC_WEEKDAY		0x03
30#define MAX8998_RTC_DATE		0x04
31#define MAX8998_RTC_MONTH		0x05
32#define MAX8998_RTC_YEAR1		0x06
33#define MAX8998_RTC_YEAR2		0x07
34#define MAX8998_ALARM0_SEC		0x08
35#define MAX8998_ALARM0_MIN		0x09
36#define MAX8998_ALARM0_HOUR		0x0a
37#define MAX8998_ALARM0_WEEKDAY		0x0b
38#define MAX8998_ALARM0_DATE		0x0c
39#define MAX8998_ALARM0_MONTH		0x0d
40#define MAX8998_ALARM0_YEAR1		0x0e
41#define MAX8998_ALARM0_YEAR2		0x0f
42#define MAX8998_ALARM1_SEC		0x10
43#define MAX8998_ALARM1_MIN		0x11
44#define MAX8998_ALARM1_HOUR		0x12
45#define MAX8998_ALARM1_WEEKDAY		0x13
46#define MAX8998_ALARM1_DATE		0x14
47#define MAX8998_ALARM1_MONTH		0x15
48#define MAX8998_ALARM1_YEAR1		0x16
49#define MAX8998_ALARM1_YEAR2		0x17
50#define MAX8998_ALARM0_CONF		0x18
51#define MAX8998_ALARM1_CONF		0x19
52#define MAX8998_RTC_STATUS		0x1a
53#define MAX8998_WTSR_SMPL_CNTL		0x1b
54#define MAX8998_TEST			0x1f
55
56#define HOUR_12				(1 << 7)
57#define HOUR_PM				(1 << 5)
58#define ALARM0_STATUS			(1 << 1)
59#define ALARM1_STATUS			(1 << 2)
60
61enum {
62	RTC_SEC = 0,
63	RTC_MIN,
64	RTC_HOUR,
65	RTC_WEEKDAY,
66	RTC_DATE,
67	RTC_MONTH,
68	RTC_YEAR1,
69	RTC_YEAR2,
70};
71
72struct max8998_rtc_info {
73	struct device		*dev;
74	struct max8998_dev	*max8998;
75	struct i2c_client	*rtc;
76	struct rtc_device	*rtc_dev;
77	int irq;
78	bool lp3974_bug_workaround;
79};
80
81static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
82{
83	tm->tm_sec = bcd2bin(data[RTC_SEC]);
84	tm->tm_min = bcd2bin(data[RTC_MIN]);
85	if (data[RTC_HOUR] & HOUR_12) {
86		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
87		if (data[RTC_HOUR] & HOUR_PM)
88			tm->tm_hour += 12;
89	} else
90		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
91
92	tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
93	tm->tm_mday = bcd2bin(data[RTC_DATE]);
94	tm->tm_mon = bcd2bin(data[RTC_MONTH]);
95	tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
96	tm->tm_year -= 1900;
97}
98
99static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
100{
101	data[RTC_SEC] = bin2bcd(tm->tm_sec);
102	data[RTC_MIN] = bin2bcd(tm->tm_min);
103	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
104	data[RTC_WEEKDAY] = tm->tm_wday;
105	data[RTC_DATE] = bin2bcd(tm->tm_mday);
106	data[RTC_MONTH] = bin2bcd(tm->tm_mon);
107	data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
108	data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
109}
110
111static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
112{
113	struct max8998_rtc_info *info = dev_get_drvdata(dev);
114	u8 data[8];
115	int ret;
116
117	ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
118	if (ret < 0)
119		return ret;
120
121	max8998_data_to_tm(data, tm);
122
123	return rtc_valid_tm(tm);
124}
125
126static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
127{
128	struct max8998_rtc_info *info = dev_get_drvdata(dev);
129	u8 data[8];
130	int ret;
131
132	max8998_tm_to_data(tm, data);
133
134	ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
135
136	if (info->lp3974_bug_workaround)
137		msleep(2000);
138
139	return ret;
140}
141
142static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
143{
144	struct max8998_rtc_info *info = dev_get_drvdata(dev);
145	u8 data[8];
146	u8 val;
147	int ret;
148
149	ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
150	if (ret < 0)
151		return ret;
152
153	max8998_data_to_tm(data, &alrm->time);
154
155	ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
156	if (ret < 0)
157		return ret;
158
159	alrm->enabled = !!val;
160
161	ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
162	if (ret < 0)
163		return ret;
164
165	if (val & ALARM0_STATUS)
166		alrm->pending = 1;
167	else
168		alrm->pending = 0;
169
170	return 0;
171}
172
173static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
174{
175	int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
176
177	if (info->lp3974_bug_workaround)
178		msleep(2000);
179
180	return ret;
181}
182
183static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
184{
185	int ret;
186	u8 alarm0_conf = 0x77;
187
188	/* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
189	if (info->lp3974_bug_workaround)
190		alarm0_conf = 0x57;
191
192	ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
193
194	if (info->lp3974_bug_workaround)
195		msleep(2000);
196
197	return ret;
198}
199
200static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
201{
202	struct max8998_rtc_info *info = dev_get_drvdata(dev);
203	u8 data[8];
204	int ret;
205
206	max8998_tm_to_data(&alrm->time, data);
207
208	ret = max8998_rtc_stop_alarm(info);
209	if (ret < 0)
210		return ret;
211
212	ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
213	if (ret < 0)
214		return ret;
215
216	if (info->lp3974_bug_workaround)
217		msleep(2000);
218
219	if (alrm->enabled)
220		ret = max8998_rtc_start_alarm(info);
221
222	return ret;
223}
224
225static int max8998_rtc_alarm_irq_enable(struct device *dev,
226					unsigned int enabled)
227{
228	struct max8998_rtc_info *info = dev_get_drvdata(dev);
229
230	if (enabled)
231		return max8998_rtc_start_alarm(info);
232	else
233		return max8998_rtc_stop_alarm(info);
234}
235
236static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
237{
238	struct max8998_rtc_info *info = data;
239
240	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
241
242	return IRQ_HANDLED;
243}
244
245static const struct rtc_class_ops max8998_rtc_ops = {
246	.read_time = max8998_rtc_read_time,
247	.set_time = max8998_rtc_set_time,
248	.read_alarm = max8998_rtc_read_alarm,
249	.set_alarm = max8998_rtc_set_alarm,
250	.alarm_irq_enable = max8998_rtc_alarm_irq_enable,
251};
252
253static int max8998_rtc_probe(struct platform_device *pdev)
254{
255	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);
256	struct max8998_platform_data *pdata = max8998->pdata;
257	struct max8998_rtc_info *info;
258	int ret;
259
260	info = devm_kzalloc(&pdev->dev, sizeof(struct max8998_rtc_info),
261			GFP_KERNEL);
262	if (!info)
263		return -ENOMEM;
264
265	info->dev = &pdev->dev;
266	info->max8998 = max8998;
267	info->rtc = max8998->rtc;
268
269	platform_set_drvdata(pdev, info);
270
271	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8998-rtc",
272			&max8998_rtc_ops, THIS_MODULE);
273
274	if (IS_ERR(info->rtc_dev)) {
275		ret = PTR_ERR(info->rtc_dev);
276		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
277		return ret;
278	}
279
280	if (!max8998->irq_domain)
281		goto no_irq;
282
283	info->irq = irq_create_mapping(max8998->irq_domain, MAX8998_IRQ_ALARM0);
284	if (!info->irq) {
285		dev_warn(&pdev->dev, "Failed to map alarm IRQ\n");
286		goto no_irq;
287	}
288
289	ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
290				max8998_rtc_alarm_irq, 0, "rtc-alarm0", info);
291
292	if (ret < 0)
293		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
294			info->irq, ret);
295
296no_irq:
297	dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
298	if (pdata && pdata->rtc_delay) {
299		info->lp3974_bug_workaround = true;
300		dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
301				" RTC updates will be extremely slow.\n");
302	}
303
304	return 0;
305}
306
307static const struct platform_device_id max8998_rtc_id[] = {
308	{ "max8998-rtc", TYPE_MAX8998 },
309	{ "lp3974-rtc", TYPE_LP3974 },
310	{ }
311};
312
313static struct platform_driver max8998_rtc_driver = {
314	.driver		= {
315		.name	= "max8998-rtc",
316	},
317	.probe		= max8998_rtc_probe,
318	.id_table	= max8998_rtc_id,
319};
320
321module_platform_driver(max8998_rtc_driver);
322
323MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
324MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
325MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
326MODULE_LICENSE("GPL");
327