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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * TI LP8788 MFD - rtc driver
4 *
5 * Copyright 2012 Texas Instruments
6 *
7 * Author: Milo(Woogyom) Kim <[email protected]>
8 */
9
10#include <linux/err.h>
11#include <linux/irqdomain.h>
12#include <linux/mfd/lp8788.h>
13#include <linux/module.h>
14#include <linux/platform_device.h>
15#include <linux/rtc.h>
16#include <linux/slab.h>
17
18/* register address */
19#define LP8788_INTEN_3 0x05
20#define LP8788_RTC_UNLOCK 0x64
21#define LP8788_RTC_SEC 0x70
22#define LP8788_ALM1_SEC 0x77
23#define LP8788_ALM1_EN 0x7D
24#define LP8788_ALM2_SEC 0x7E
25#define LP8788_ALM2_EN 0x84
26
27/* mask/shift bits */
28#define LP8788_INT_RTC_ALM1_M BIT(1) /* Addr 05h */
29#define LP8788_INT_RTC_ALM1_S 1
30#define LP8788_INT_RTC_ALM2_M BIT(2) /* Addr 05h */
31#define LP8788_INT_RTC_ALM2_S 2
32#define LP8788_ALM_EN_M BIT(7) /* Addr 7Dh or 84h */
33#define LP8788_ALM_EN_S 7
34
35#define DEFAULT_ALARM_SEL LP8788_ALARM_1
36#define LP8788_MONTH_OFFSET 1
37#define LP8788_BASE_YEAR 2000
38#define MAX_WDAY_BITS 7
39#define LP8788_WDAY_SET 1
40#define RTC_UNLOCK 0x1
41#define RTC_LATCH 0x2
42#define ALARM_IRQ_FLAG (RTC_IRQF | RTC_AF)
43
44enum lp8788_time {
45 LPTIME_SEC,
46 LPTIME_MIN,
47 LPTIME_HOUR,
48 LPTIME_MDAY,
49 LPTIME_MON,
50 LPTIME_YEAR,
51 LPTIME_WDAY,
52 LPTIME_MAX,
53};
54
55struct lp8788_rtc {
56 struct lp8788 *lp;
57 struct rtc_device *rdev;
58 enum lp8788_alarm_sel alarm;
59 int irq;
60};
61
62static const u8 addr_alarm_sec[LP8788_ALARM_MAX] = {
63 LP8788_ALM1_SEC,
64 LP8788_ALM2_SEC,
65};
66
67static const u8 addr_alarm_en[LP8788_ALARM_MAX] = {
68 LP8788_ALM1_EN,
69 LP8788_ALM2_EN,
70};
71
72static const u8 mask_alarm_en[LP8788_ALARM_MAX] = {
73 LP8788_INT_RTC_ALM1_M,
74 LP8788_INT_RTC_ALM2_M,
75};
76
77static const u8 shift_alarm_en[LP8788_ALARM_MAX] = {
78 LP8788_INT_RTC_ALM1_S,
79 LP8788_INT_RTC_ALM2_S,
80};
81
82static int _to_tm_wday(u8 lp8788_wday)
83{
84 int i;
85
86 if (lp8788_wday == 0)
87 return 0;
88
89 /* lookup defined weekday from read register value */
90 for (i = 0; i < MAX_WDAY_BITS; i++) {
91 if ((lp8788_wday >> i) == LP8788_WDAY_SET)
92 break;
93 }
94
95 return i + 1;
96}
97
98static inline int _to_lp8788_wday(int tm_wday)
99{
100 return LP8788_WDAY_SET << (tm_wday - 1);
101}
102
103static void lp8788_rtc_unlock(struct lp8788 *lp)
104{
105 lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_UNLOCK);
106 lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_LATCH);
107}
108
109static int lp8788_rtc_read_time(struct device *dev, struct rtc_time *tm)
110{
111 struct lp8788_rtc *rtc = dev_get_drvdata(dev);
112 struct lp8788 *lp = rtc->lp;
113 u8 data[LPTIME_MAX];
114 int ret;
115
116 lp8788_rtc_unlock(lp);
117
118 ret = lp8788_read_multi_bytes(lp, LP8788_RTC_SEC, data, LPTIME_MAX);
119 if (ret)
120 return ret;
121
122 tm->tm_sec = data[LPTIME_SEC];
123 tm->tm_min = data[LPTIME_MIN];
124 tm->tm_hour = data[LPTIME_HOUR];
125 tm->tm_mday = data[LPTIME_MDAY];
126 tm->tm_mon = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
127 tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
128 tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
129
130 return 0;
131}
132
133static int lp8788_rtc_set_time(struct device *dev, struct rtc_time *tm)
134{
135 struct lp8788_rtc *rtc = dev_get_drvdata(dev);
136 struct lp8788 *lp = rtc->lp;
137 u8 data[LPTIME_MAX - 1];
138 int ret, i, year;
139
140 year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
141 if (year < 0) {
142 dev_err(lp->dev, "invalid year: %d\n", year);
143 return -EINVAL;
144 }
145
146 /* because rtc weekday is a readonly register, do not update */
147 data[LPTIME_SEC] = tm->tm_sec;
148 data[LPTIME_MIN] = tm->tm_min;
149 data[LPTIME_HOUR] = tm->tm_hour;
150 data[LPTIME_MDAY] = tm->tm_mday;
151 data[LPTIME_MON] = tm->tm_mon + LP8788_MONTH_OFFSET;
152 data[LPTIME_YEAR] = year;
153
154 for (i = 0; i < ARRAY_SIZE(data); i++) {
155 ret = lp8788_write_byte(lp, LP8788_RTC_SEC + i, data[i]);
156 if (ret)
157 return ret;
158 }
159
160 return 0;
161}
162
163static int lp8788_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
164{
165 struct lp8788_rtc *rtc = dev_get_drvdata(dev);
166 struct lp8788 *lp = rtc->lp;
167 struct rtc_time *tm = &alarm->time;
168 u8 addr, data[LPTIME_MAX];
169 int ret;
170
171 addr = addr_alarm_sec[rtc->alarm];
172 ret = lp8788_read_multi_bytes(lp, addr, data, LPTIME_MAX);
173 if (ret)
174 return ret;
175
176 tm->tm_sec = data[LPTIME_SEC];
177 tm->tm_min = data[LPTIME_MIN];
178 tm->tm_hour = data[LPTIME_HOUR];
179 tm->tm_mday = data[LPTIME_MDAY];
180 tm->tm_mon = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
181 tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
182 tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
183 alarm->enabled = data[LPTIME_WDAY] & LP8788_ALM_EN_M;
184
185 return 0;
186}
187
188static int lp8788_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
189{
190 struct lp8788_rtc *rtc = dev_get_drvdata(dev);
191 struct lp8788 *lp = rtc->lp;
192 struct rtc_time *tm = &alarm->time;
193 u8 addr, data[LPTIME_MAX];
194 int ret, i, year;
195
196 year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
197 if (year < 0) {
198 dev_err(lp->dev, "invalid year: %d\n", year);
199 return -EINVAL;
200 }
201
202 data[LPTIME_SEC] = tm->tm_sec;
203 data[LPTIME_MIN] = tm->tm_min;
204 data[LPTIME_HOUR] = tm->tm_hour;
205 data[LPTIME_MDAY] = tm->tm_mday;
206 data[LPTIME_MON] = tm->tm_mon + LP8788_MONTH_OFFSET;
207 data[LPTIME_YEAR] = year;
208 data[LPTIME_WDAY] = _to_lp8788_wday(tm->tm_wday);
209
210 for (i = 0; i < ARRAY_SIZE(data); i++) {
211 addr = addr_alarm_sec[rtc->alarm] + i;
212 ret = lp8788_write_byte(lp, addr, data[i]);
213 if (ret)
214 return ret;
215 }
216
217 alarm->enabled = 1;
218 addr = addr_alarm_en[rtc->alarm];
219
220 return lp8788_update_bits(lp, addr, LP8788_ALM_EN_M,
221 alarm->enabled << LP8788_ALM_EN_S);
222}
223
224static int lp8788_alarm_irq_enable(struct device *dev, unsigned int enable)
225{
226 struct lp8788_rtc *rtc = dev_get_drvdata(dev);
227 struct lp8788 *lp = rtc->lp;
228 u8 mask, shift;
229
230 if (!rtc->irq)
231 return -EIO;
232
233 mask = mask_alarm_en[rtc->alarm];
234 shift = shift_alarm_en[rtc->alarm];
235
236 return lp8788_update_bits(lp, LP8788_INTEN_3, mask, enable << shift);
237}
238
239static const struct rtc_class_ops lp8788_rtc_ops = {
240 .read_time = lp8788_rtc_read_time,
241 .set_time = lp8788_rtc_set_time,
242 .read_alarm = lp8788_read_alarm,
243 .set_alarm = lp8788_set_alarm,
244 .alarm_irq_enable = lp8788_alarm_irq_enable,
245};
246
247static irqreturn_t lp8788_alarm_irq_handler(int irq, void *ptr)
248{
249 struct lp8788_rtc *rtc = ptr;
250
251 rtc_update_irq(rtc->rdev, 1, ALARM_IRQ_FLAG);
252 return IRQ_HANDLED;
253}
254
255static int lp8788_alarm_irq_register(struct platform_device *pdev,
256 struct lp8788_rtc *rtc)
257{
258 struct resource *r;
259 struct lp8788 *lp = rtc->lp;
260 struct irq_domain *irqdm = lp->irqdm;
261 int irq;
262
263 rtc->irq = 0;
264
265 /* even the alarm IRQ number is not specified, rtc time should work */
266 r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, LP8788_ALM_IRQ);
267 if (!r)
268 return 0;
269
270 if (rtc->alarm == LP8788_ALARM_1)
271 irq = r->start;
272 else
273 irq = r->end;
274
275 rtc->irq = irq_create_mapping(irqdm, irq);
276
277 return devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
278 lp8788_alarm_irq_handler,
279 0, LP8788_ALM_IRQ, rtc);
280}
281
282static int lp8788_rtc_probe(struct platform_device *pdev)
283{
284 struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
285 struct lp8788_rtc *rtc;
286 struct device *dev = &pdev->dev;
287
288 rtc = devm_kzalloc(dev, sizeof(struct lp8788_rtc), GFP_KERNEL);
289 if (!rtc)
290 return -ENOMEM;
291
292 rtc->lp = lp;
293 rtc->alarm = lp->pdata ? lp->pdata->alarm_sel : DEFAULT_ALARM_SEL;
294 platform_set_drvdata(pdev, rtc);
295
296 device_init_wakeup(dev, true);
297
298 rtc->rdev = devm_rtc_device_register(dev, "lp8788_rtc",
299 &lp8788_rtc_ops, THIS_MODULE);
300 if (IS_ERR(rtc->rdev)) {
301 dev_err(dev, "can not register rtc device\n");
302 return PTR_ERR(rtc->rdev);
303 }
304
305 if (lp8788_alarm_irq_register(pdev, rtc))
306 dev_warn(lp->dev, "no rtc irq handler\n");
307
308 return 0;
309}
310
311static struct platform_driver lp8788_rtc_driver = {
312 .probe = lp8788_rtc_probe,
313 .driver = {
314 .name = LP8788_DEV_RTC,
315 },
316};
317module_platform_driver(lp8788_rtc_driver);
318
319MODULE_DESCRIPTION("Texas Instruments LP8788 RTC Driver");
320MODULE_AUTHOR("Milo Kim");
321MODULE_LICENSE("GPL");
322MODULE_ALIAS("platform:lp8788-rtc");