1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Motorola CPCAP PMIC RTC driver
4 *
5 * Based on cpcap-regulator.c from Motorola Linux kernel tree
6 * Copyright (C) 2009 Motorola, Inc.
7 *
8 * Rewritten for mainline kernel
9 * - use DT
10 * - use regmap
11 * - use standard interrupt framework
12 * - use managed device resources
13 * - remove custom "secure clock daemon" helpers
14 *
15 * Copyright (C) 2017 Sebastian Reichel <sre@kernel.org>
16 */
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/init.h>
21 #include <linux/device.h>
22 #include <linux/platform_device.h>
23 #include <linux/rtc.h>
24 #include <linux/err.h>
25 #include <linux/regmap.h>
26 #include <linux/mfd/motorola-cpcap.h>
27 #include <linux/slab.h>
28 #include <linux/sched.h>
29
30 #define SECS_PER_DAY 86400
31 #define DAY_MASK 0x7FFF
32 #define TOD1_MASK 0x00FF
33 #define TOD2_MASK 0x01FF
34
35 struct cpcap_time {
36 int day;
37 int tod1;
38 int tod2;
39 };
40
41 struct cpcap_rtc {
42 struct regmap *regmap;
43 struct rtc_device *rtc_dev;
44 u16 vendor;
45 int alarm_irq;
46 bool alarm_enabled;
47 int update_irq;
48 bool update_enabled;
49 };
50
cpcap2rtc_time(struct rtc_time * rtc,struct cpcap_time * cpcap)51 static void cpcap2rtc_time(struct rtc_time *rtc, struct cpcap_time *cpcap)
52 {
53 unsigned long int tod;
54 unsigned long int time;
55
56 tod = (cpcap->tod1 & TOD1_MASK) | ((cpcap->tod2 & TOD2_MASK) << 8);
57 time = tod + ((cpcap->day & DAY_MASK) * SECS_PER_DAY);
58
59 rtc_time64_to_tm(time, rtc);
60 }
61
rtc2cpcap_time(struct cpcap_time * cpcap,struct rtc_time * rtc)62 static void rtc2cpcap_time(struct cpcap_time *cpcap, struct rtc_time *rtc)
63 {
64 unsigned long time;
65
66 time = rtc_tm_to_time64(rtc);
67
68 cpcap->day = time / SECS_PER_DAY;
69 time %= SECS_PER_DAY;
70 cpcap->tod2 = (time >> 8) & TOD2_MASK;
71 cpcap->tod1 = time & TOD1_MASK;
72 }
73
cpcap_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)74 static int cpcap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
75 {
76 struct cpcap_rtc *rtc = dev_get_drvdata(dev);
77
78 if (rtc->alarm_enabled == enabled)
79 return 0;
80
81 if (enabled)
82 enable_irq(rtc->alarm_irq);
83 else
84 disable_irq(rtc->alarm_irq);
85
86 rtc->alarm_enabled = !!enabled;
87
88 return 0;
89 }
90
cpcap_rtc_read_time(struct device * dev,struct rtc_time * tm)91 static int cpcap_rtc_read_time(struct device *dev, struct rtc_time *tm)
92 {
93 struct cpcap_rtc *rtc;
94 struct cpcap_time cpcap_tm;
95 int temp_tod2;
96 int ret;
97
98 rtc = dev_get_drvdata(dev);
99
100 ret = regmap_read(rtc->regmap, CPCAP_REG_TOD2, &temp_tod2);
101 ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
102 ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD1, &cpcap_tm.tod1);
103 ret |= regmap_read(rtc->regmap, CPCAP_REG_TOD2, &cpcap_tm.tod2);
104
105 if (temp_tod2 > cpcap_tm.tod2)
106 ret |= regmap_read(rtc->regmap, CPCAP_REG_DAY, &cpcap_tm.day);
107
108 if (ret) {
109 dev_err(dev, "Failed to read time\n");
110 return -EIO;
111 }
112
113 cpcap2rtc_time(tm, &cpcap_tm);
114
115 return 0;
116 }
117
cpcap_rtc_set_time(struct device * dev,struct rtc_time * tm)118 static int cpcap_rtc_set_time(struct device *dev, struct rtc_time *tm)
119 {
120 struct cpcap_rtc *rtc;
121 struct cpcap_time cpcap_tm;
122 int ret = 0;
123
124 rtc = dev_get_drvdata(dev);
125
126 rtc2cpcap_time(&cpcap_tm, tm);
127
128 if (rtc->alarm_enabled)
129 disable_irq(rtc->alarm_irq);
130 if (rtc->update_enabled)
131 disable_irq(rtc->update_irq);
132
133 if (rtc->vendor == CPCAP_VENDOR_ST) {
134 /* The TOD1 and TOD2 registers MUST be written in this order
135 * for the change to properly set.
136 */
137 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
138 TOD1_MASK, cpcap_tm.tod1);
139 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
140 TOD2_MASK, cpcap_tm.tod2);
141 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
142 DAY_MASK, cpcap_tm.day);
143 } else {
144 /* Clearing the upper lower 8 bits of the TOD guarantees that
145 * the upper half of TOD (TOD2) will not increment for 0xFF RTC
146 * ticks (255 seconds). During this time we can safely write
147 * to DAY, TOD2, then TOD1 (in that order) and expect RTC to be
148 * synchronized to the exact time requested upon the final write
149 * to TOD1.
150 */
151 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
152 TOD1_MASK, 0);
153 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_DAY,
154 DAY_MASK, cpcap_tm.day);
155 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD2,
156 TOD2_MASK, cpcap_tm.tod2);
157 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TOD1,
158 TOD1_MASK, cpcap_tm.tod1);
159 }
160
161 if (rtc->update_enabled)
162 enable_irq(rtc->update_irq);
163 if (rtc->alarm_enabled)
164 enable_irq(rtc->alarm_irq);
165
166 return ret;
167 }
168
cpcap_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)169 static int cpcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
170 {
171 struct cpcap_rtc *rtc;
172 struct cpcap_time cpcap_tm;
173 int ret;
174
175 rtc = dev_get_drvdata(dev);
176
177 alrm->enabled = rtc->alarm_enabled;
178
179 ret = regmap_read(rtc->regmap, CPCAP_REG_DAYA, &cpcap_tm.day);
180 ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA2, &cpcap_tm.tod2);
181 ret |= regmap_read(rtc->regmap, CPCAP_REG_TODA1, &cpcap_tm.tod1);
182
183 if (ret) {
184 dev_err(dev, "Failed to read time\n");
185 return -EIO;
186 }
187
188 cpcap2rtc_time(&alrm->time, &cpcap_tm);
189 return rtc_valid_tm(&alrm->time);
190 }
191
cpcap_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)192 static int cpcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
193 {
194 struct cpcap_rtc *rtc;
195 struct cpcap_time cpcap_tm;
196 int ret;
197
198 rtc = dev_get_drvdata(dev);
199
200 rtc2cpcap_time(&cpcap_tm, &alrm->time);
201
202 if (rtc->alarm_enabled)
203 disable_irq(rtc->alarm_irq);
204
205 ret = regmap_update_bits(rtc->regmap, CPCAP_REG_DAYA, DAY_MASK,
206 cpcap_tm.day);
207 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA2, TOD2_MASK,
208 cpcap_tm.tod2);
209 ret |= regmap_update_bits(rtc->regmap, CPCAP_REG_TODA1, TOD1_MASK,
210 cpcap_tm.tod1);
211
212 if (!ret) {
213 enable_irq(rtc->alarm_irq);
214 rtc->alarm_enabled = true;
215 }
216
217 return ret;
218 }
219
220 static const struct rtc_class_ops cpcap_rtc_ops = {
221 .read_time = cpcap_rtc_read_time,
222 .set_time = cpcap_rtc_set_time,
223 .read_alarm = cpcap_rtc_read_alarm,
224 .set_alarm = cpcap_rtc_set_alarm,
225 .alarm_irq_enable = cpcap_rtc_alarm_irq_enable,
226 };
227
cpcap_rtc_alarm_irq(int irq,void * data)228 static irqreturn_t cpcap_rtc_alarm_irq(int irq, void *data)
229 {
230 struct cpcap_rtc *rtc = data;
231
232 rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
233 return IRQ_HANDLED;
234 }
235
cpcap_rtc_update_irq(int irq,void * data)236 static irqreturn_t cpcap_rtc_update_irq(int irq, void *data)
237 {
238 struct cpcap_rtc *rtc = data;
239
240 rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
241 return IRQ_HANDLED;
242 }
243
cpcap_rtc_probe(struct platform_device * pdev)244 static int cpcap_rtc_probe(struct platform_device *pdev)
245 {
246 struct device *dev = &pdev->dev;
247 struct cpcap_rtc *rtc;
248 int err;
249
250 rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
251 if (!rtc)
252 return -ENOMEM;
253
254 rtc->regmap = dev_get_regmap(dev->parent, NULL);
255 if (!rtc->regmap)
256 return -ENODEV;
257
258 platform_set_drvdata(pdev, rtc);
259 rtc->rtc_dev = devm_rtc_allocate_device(dev);
260 if (IS_ERR(rtc->rtc_dev))
261 return PTR_ERR(rtc->rtc_dev);
262
263 rtc->rtc_dev->ops = &cpcap_rtc_ops;
264 rtc->rtc_dev->range_max = (timeu64_t) (DAY_MASK + 1) * SECS_PER_DAY - 1;
265
266 err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor);
267 if (err)
268 return err;
269
270 rtc->alarm_irq = platform_get_irq(pdev, 0);
271 err = devm_request_threaded_irq(dev, rtc->alarm_irq, NULL,
272 cpcap_rtc_alarm_irq,
273 IRQF_TRIGGER_NONE | IRQF_ONESHOT,
274 "rtc_alarm", rtc);
275 if (err) {
276 dev_err(dev, "Could not request alarm irq: %d\n", err);
277 return err;
278 }
279 disable_irq(rtc->alarm_irq);
280
281 /* Stock Android uses the 1 Hz interrupt for "secure clock daemon",
282 * which is not supported by the mainline kernel. The mainline kernel
283 * does not use the irq at the moment, but we explicitly request and
284 * disable it, so that its masked and does not wake up the processor
285 * every second.
286 */
287 rtc->update_irq = platform_get_irq(pdev, 1);
288 err = devm_request_threaded_irq(dev, rtc->update_irq, NULL,
289 cpcap_rtc_update_irq,
290 IRQF_TRIGGER_NONE | IRQF_ONESHOT,
291 "rtc_1hz", rtc);
292 if (err) {
293 dev_err(dev, "Could not request update irq: %d\n", err);
294 return err;
295 }
296 disable_irq(rtc->update_irq);
297
298 err = device_init_wakeup(dev, 1);
299 if (err) {
300 dev_err(dev, "wakeup initialization failed (%d)\n", err);
301 /* ignore error and continue without wakeup support */
302 }
303
304 return devm_rtc_register_device(rtc->rtc_dev);
305 }
306
307 static const struct of_device_id cpcap_rtc_of_match[] = {
308 { .compatible = "motorola,cpcap-rtc", },
309 {},
310 };
311 MODULE_DEVICE_TABLE(of, cpcap_rtc_of_match);
312
313 static struct platform_driver cpcap_rtc_driver = {
314 .probe = cpcap_rtc_probe,
315 .driver = {
316 .name = "cpcap-rtc",
317 .of_match_table = cpcap_rtc_of_match,
318 },
319 };
320
321 module_platform_driver(cpcap_rtc_driver);
322
323 MODULE_ALIAS("platform:cpcap-rtc");
324 MODULE_DESCRIPTION("CPCAP RTC driver");
325 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
326 MODULE_LICENSE("GPL");
327