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 <milo.kim@ti.com>
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, 1);
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");
323