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
55 enum {
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
66 struct 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
max8998_data_to_tm(u8 * data,struct rtc_time * tm)75 static 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
max8998_tm_to_data(struct rtc_time * tm,u8 * data)93 static 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
max8998_rtc_read_time(struct device * dev,struct rtc_time * tm)105 static 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
max8998_rtc_set_time(struct device * dev,struct rtc_time * tm)120 static 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
max8998_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)136 static 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
max8998_rtc_stop_alarm(struct max8998_rtc_info * info)167 static 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
max8998_rtc_start_alarm(struct max8998_rtc_info * info)177 static 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
max8998_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)194 static 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
max8998_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)219 static 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
max8998_rtc_alarm_irq(int irq,void * data)230 static 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
239 static 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
max8998_rtc_probe(struct platform_device * pdev)247 static 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
290 no_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
301 static const struct platform_device_id max8998_rtc_id[] = {
302 { "max8998-rtc", TYPE_MAX8998 },
303 { "lp3974-rtc", TYPE_LP3974 },
304 { }
305 };
306 MODULE_DEVICE_TABLE(platform, max8998_rtc_id);
307
308 static 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
316 module_platform_driver(max8998_rtc_driver);
317
318 MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
319 MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
320 MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
321 MODULE_LICENSE("GPL");
322