1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Real time clock driver for DA9052
4 *
5 * Copyright(c) 2012 Dialog Semiconductor Ltd.
6 *
7 * Author: Dajun Dajun Chen <dajun.chen@diasemi.com>
8 */
9
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/rtc.h>
13#include <linux/err.h>
14#include <linux/delay.h>
15
16#include <linux/mfd/da9052/da9052.h>
17#include <linux/mfd/da9052/reg.h>
18
19#define rtc_err(rtc, fmt, ...) \
20		dev_err(rtc->da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__)
21
22#define DA9052_GET_TIME_RETRIES 5
23
24struct da9052_rtc {
25	struct rtc_device *rtc;
26	struct da9052 *da9052;
27};
28
29static int da9052_rtc_enable_alarm(struct da9052_rtc *rtc, bool enable)
30{
31	int ret;
32	if (enable) {
33		ret = da9052_reg_update(rtc->da9052, DA9052_ALARM_Y_REG,
34				DA9052_ALARM_Y_ALARM_ON|DA9052_ALARM_Y_TICK_ON,
35				DA9052_ALARM_Y_ALARM_ON);
36		if (ret != 0)
37			rtc_err(rtc, "Failed to enable ALM: %d\n", ret);
38	} else {
39		ret = da9052_reg_update(rtc->da9052, DA9052_ALARM_Y_REG,
40			DA9052_ALARM_Y_ALARM_ON|DA9052_ALARM_Y_TICK_ON, 0);
41		if (ret != 0)
42			rtc_err(rtc, "Write error: %d\n", ret);
43	}
44	return ret;
45}
46
47static irqreturn_t da9052_rtc_irq(int irq, void *data)
48{
49	struct da9052_rtc *rtc = data;
50
51	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
52
53	return IRQ_HANDLED;
54}
55
56static int da9052_read_alarm(struct da9052_rtc *rtc, struct rtc_time *rtc_tm)
57{
58	int ret;
59	uint8_t v[2][5];
60	int idx = 1;
61	int timeout = DA9052_GET_TIME_RETRIES;
62
63	ret = da9052_group_read(rtc->da9052, DA9052_ALARM_MI_REG, 5, &v[0][0]);
64	if (ret) {
65		rtc_err(rtc, "Failed to group read ALM: %d\n", ret);
66		return ret;
67	}
68
69	do {
70		ret = da9052_group_read(rtc->da9052,
71					DA9052_ALARM_MI_REG, 5, &v[idx][0]);
72		if (ret) {
73			rtc_err(rtc, "Failed to group read ALM: %d\n", ret);
74			return ret;
75		}
76
77		if (memcmp(&v[0][0], &v[1][0], 5) == 0) {
78			rtc_tm->tm_year = (v[0][4] & DA9052_RTC_YEAR) + 100;
79			rtc_tm->tm_mon  = (v[0][3] & DA9052_RTC_MONTH) - 1;
80			rtc_tm->tm_mday = v[0][2] & DA9052_RTC_DAY;
81			rtc_tm->tm_hour = v[0][1] & DA9052_RTC_HOUR;
82			rtc_tm->tm_min  = v[0][0] & DA9052_RTC_MIN;
83			rtc_tm->tm_sec = 0;
84
85			ret = rtc_valid_tm(rtc_tm);
86			return ret;
87		}
88
89		idx = (1-idx);
90		msleep(20);
91
92	} while (timeout--);
93
94	rtc_err(rtc, "Timed out reading alarm time\n");
95
96	return -EIO;
97}
98
99static int da9052_set_alarm(struct da9052_rtc *rtc, struct rtc_time *rtc_tm)
100{
101	struct da9052 *da9052 = rtc->da9052;
102	unsigned long alm_time;
103	int ret;
104	uint8_t v[3];
105
106	alm_time = rtc_tm_to_time64(rtc_tm);
107
108	if (rtc_tm->tm_sec > 0) {
109		alm_time += 60 - rtc_tm->tm_sec;
110		rtc_time64_to_tm(alm_time, rtc_tm);
111	}
112	BUG_ON(rtc_tm->tm_sec); /* it will cause repeated irqs if not zero */
113
114	rtc_tm->tm_year -= 100;
115	rtc_tm->tm_mon += 1;
116
117	ret = da9052_reg_update(da9052, DA9052_ALARM_MI_REG,
118				DA9052_RTC_MIN, rtc_tm->tm_min);
119	if (ret != 0) {
120		rtc_err(rtc, "Failed to write ALRM MIN: %d\n", ret);
121		return ret;
122	}
123
124	v[0] = rtc_tm->tm_hour;
125	v[1] = rtc_tm->tm_mday;
126	v[2] = rtc_tm->tm_mon;
127
128	ret = da9052_group_write(da9052, DA9052_ALARM_H_REG, 3, v);
129	if (ret < 0)
130		return ret;
131
132	ret = da9052_reg_update(da9052, DA9052_ALARM_Y_REG,
133				DA9052_RTC_YEAR, rtc_tm->tm_year);
134	if (ret != 0)
135		rtc_err(rtc, "Failed to write ALRM YEAR: %d\n", ret);
136
137	return ret;
138}
139
140static int da9052_rtc_get_alarm_status(struct da9052_rtc *rtc)
141{
142	int ret;
143
144	ret = da9052_reg_read(rtc->da9052, DA9052_ALARM_Y_REG);
145	if (ret < 0) {
146		rtc_err(rtc, "Failed to read ALM: %d\n", ret);
147		return ret;
148	}
149
150	return !!(ret&DA9052_ALARM_Y_ALARM_ON);
151}
152
153static int da9052_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
154{
155	struct da9052_rtc *rtc = dev_get_drvdata(dev);
156	int ret;
157	uint8_t v[2][6];
158	int idx = 1;
159	int timeout = DA9052_GET_TIME_RETRIES;
160
161	ret = da9052_group_read(rtc->da9052, DA9052_COUNT_S_REG, 6, &v[0][0]);
162	if (ret) {
163		rtc_err(rtc, "Failed to read RTC time : %d\n", ret);
164		return ret;
165	}
166
167	do {
168		ret = da9052_group_read(rtc->da9052,
169					DA9052_COUNT_S_REG, 6, &v[idx][0]);
170		if (ret) {
171			rtc_err(rtc, "Failed to read RTC time : %d\n", ret);
172			return ret;
173		}
174
175		if (memcmp(&v[0][0], &v[1][0], 6) == 0) {
176			rtc_tm->tm_year = (v[0][5] & DA9052_RTC_YEAR) + 100;
177			rtc_tm->tm_mon  = (v[0][4] & DA9052_RTC_MONTH) - 1;
178			rtc_tm->tm_mday = v[0][3] & DA9052_RTC_DAY;
179			rtc_tm->tm_hour = v[0][2] & DA9052_RTC_HOUR;
180			rtc_tm->tm_min  = v[0][1] & DA9052_RTC_MIN;
181			rtc_tm->tm_sec  = v[0][0] & DA9052_RTC_SEC;
182
183			return 0;
184		}
185
186		idx = (1-idx);
187		msleep(20);
188
189	} while (timeout--);
190
191	rtc_err(rtc, "Timed out reading time\n");
192
193	return -EIO;
194}
195
196static int da9052_rtc_set_time(struct device *dev, struct rtc_time *tm)
197{
198	struct da9052_rtc *rtc;
199	uint8_t v[6];
200	int ret;
201
202	/* DA9052 only has 6 bits for year - to represent 2000-2063 */
203	if ((tm->tm_year < 100) || (tm->tm_year > 163))
204		return -EINVAL;
205
206	rtc = dev_get_drvdata(dev);
207
208	v[0] = tm->tm_sec;
209	v[1] = tm->tm_min;
210	v[2] = tm->tm_hour;
211	v[3] = tm->tm_mday;
212	v[4] = tm->tm_mon + 1;
213	v[5] = tm->tm_year - 100;
214
215	ret = da9052_group_write(rtc->da9052, DA9052_COUNT_S_REG, 6, v);
216	if (ret < 0)
217		rtc_err(rtc, "failed to set RTC time: %d\n", ret);
218	return ret;
219}
220
221static int da9052_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
222{
223	int ret;
224	struct rtc_time *tm = &alrm->time;
225	struct da9052_rtc *rtc = dev_get_drvdata(dev);
226
227	ret = da9052_read_alarm(rtc, tm);
228	if (ret < 0) {
229		rtc_err(rtc, "failed to read RTC alarm: %d\n", ret);
230		return ret;
231	}
232
233	alrm->enabled = da9052_rtc_get_alarm_status(rtc);
234	return 0;
235}
236
237static int da9052_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
238{
239	int ret;
240	struct rtc_time *tm = &alrm->time;
241	struct da9052_rtc *rtc = dev_get_drvdata(dev);
242
243	/* DA9052 only has 6 bits for year - to represent 2000-2063 */
244	if ((tm->tm_year < 100) || (tm->tm_year > 163))
245		return -EINVAL;
246
247	ret = da9052_rtc_enable_alarm(rtc, 0);
248	if (ret < 0)
249		return ret;
250
251	ret = da9052_set_alarm(rtc, tm);
252	if (ret < 0)
253		return ret;
254
255	ret = da9052_rtc_enable_alarm(rtc, 1);
256	return ret;
257}
258
259static int da9052_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
260{
261	struct da9052_rtc *rtc = dev_get_drvdata(dev);
262
263	return da9052_rtc_enable_alarm(rtc, enabled);
264}
265
266static const struct rtc_class_ops da9052_rtc_ops = {
267	.read_time	= da9052_rtc_read_time,
268	.set_time	= da9052_rtc_set_time,
269	.read_alarm	= da9052_rtc_read_alarm,
270	.set_alarm	= da9052_rtc_set_alarm,
271	.alarm_irq_enable = da9052_rtc_alarm_irq_enable,
272};
273
274static int da9052_rtc_probe(struct platform_device *pdev)
275{
276	struct da9052_rtc *rtc;
277	int ret;
278
279	rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9052_rtc), GFP_KERNEL);
280	if (!rtc)
281		return -ENOMEM;
282
283	rtc->da9052 = dev_get_drvdata(pdev->dev.parent);
284	platform_set_drvdata(pdev, rtc);
285
286	ret = da9052_reg_write(rtc->da9052, DA9052_BBAT_CONT_REG, 0xFE);
287	if (ret < 0) {
288		rtc_err(rtc,
289			"Failed to setup RTC battery charging: %d\n", ret);
290		return ret;
291	}
292
293	ret = da9052_reg_update(rtc->da9052, DA9052_ALARM_Y_REG,
294				DA9052_ALARM_Y_TICK_ON, 0);
295	if (ret != 0)
296		rtc_err(rtc, "Failed to disable TICKS: %d\n", ret);
297
298	device_init_wakeup(&pdev->dev, true);
299	rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
300	if (IS_ERR(rtc->rtc))
301		return PTR_ERR(rtc->rtc);
302
303	rtc->rtc->ops = &da9052_rtc_ops;
304	rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
305	rtc->rtc->range_max = RTC_TIMESTAMP_END_2063;
306
307	ret = devm_rtc_register_device(rtc->rtc);
308	if (ret)
309		return ret;
310
311	ret = da9052_request_irq(rtc->da9052, DA9052_IRQ_ALARM, "ALM",
312				da9052_rtc_irq, rtc);
313	if (ret != 0) {
314		rtc_err(rtc, "irq registration failed: %d\n", ret);
315		return ret;
316	}
317
318	return 0;
319}
320
321static struct platform_driver da9052_rtc_driver = {
322	.probe	= da9052_rtc_probe,
323	.driver = {
324		.name	= "da9052-rtc",
325	},
326};
327
328module_platform_driver(da9052_rtc_driver);
329
330MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
331MODULE_DESCRIPTION("RTC driver for Dialog DA9052 PMIC");
332MODULE_LICENSE("GPL");
333MODULE_ALIAS("platform:da9052-rtc");
334