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