1/*
2 * TI LP8788 MFD - rtc driver
3 *
4 * Copyright 2012 Texas Instruments
5 *
6 * Author: Milo(Woogyom) Kim <milo.kim@ti.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 version 2 as
10 * published by the Free Software Foundation.
11 *
12 */
13
14#include <linux/err.h>
15#include <linux/irqdomain.h>
16#include <linux/mfd/lp8788.h>
17#include <linux/module.h>
18#include <linux/platform_device.h>
19#include <linux/rtc.h>
20#include <linux/slab.h>
21
22/* register address */
23#define LP8788_INTEN_3			0x05
24#define LP8788_RTC_UNLOCK		0x64
25#define LP8788_RTC_SEC			0x70
26#define LP8788_ALM1_SEC			0x77
27#define LP8788_ALM1_EN			0x7D
28#define LP8788_ALM2_SEC			0x7E
29#define LP8788_ALM2_EN			0x84
30
31/* mask/shift bits */
32#define LP8788_INT_RTC_ALM1_M		BIT(1)	/* Addr 05h */
33#define LP8788_INT_RTC_ALM1_S		1
34#define LP8788_INT_RTC_ALM2_M		BIT(2)	/* Addr 05h */
35#define LP8788_INT_RTC_ALM2_S		2
36#define LP8788_ALM_EN_M			BIT(7)	/* Addr 7Dh or 84h */
37#define LP8788_ALM_EN_S			7
38
39#define DEFAULT_ALARM_SEL		LP8788_ALARM_1
40#define LP8788_MONTH_OFFSET		1
41#define LP8788_BASE_YEAR		2000
42#define MAX_WDAY_BITS			7
43#define LP8788_WDAY_SET			1
44#define RTC_UNLOCK			0x1
45#define RTC_LATCH			0x2
46#define ALARM_IRQ_FLAG			(RTC_IRQF | RTC_AF)
47
48enum lp8788_time {
49	LPTIME_SEC,
50	LPTIME_MIN,
51	LPTIME_HOUR,
52	LPTIME_MDAY,
53	LPTIME_MON,
54	LPTIME_YEAR,
55	LPTIME_WDAY,
56	LPTIME_MAX,
57};
58
59struct lp8788_rtc {
60	struct lp8788 *lp;
61	struct rtc_device *rdev;
62	enum lp8788_alarm_sel alarm;
63	int irq;
64};
65
66static const u8 addr_alarm_sec[LP8788_ALARM_MAX] = {
67	LP8788_ALM1_SEC,
68	LP8788_ALM2_SEC,
69};
70
71static const u8 addr_alarm_en[LP8788_ALARM_MAX] = {
72	LP8788_ALM1_EN,
73	LP8788_ALM2_EN,
74};
75
76static const u8 mask_alarm_en[LP8788_ALARM_MAX] = {
77	LP8788_INT_RTC_ALM1_M,
78	LP8788_INT_RTC_ALM2_M,
79};
80
81static const u8 shift_alarm_en[LP8788_ALARM_MAX] = {
82	LP8788_INT_RTC_ALM1_S,
83	LP8788_INT_RTC_ALM2_S,
84};
85
86static int _to_tm_wday(u8 lp8788_wday)
87{
88	int i;
89
90	if (lp8788_wday == 0)
91		return 0;
92
93	/* lookup defined weekday from read register value */
94	for (i = 0; i < MAX_WDAY_BITS; i++) {
95		if ((lp8788_wday >> i) == LP8788_WDAY_SET)
96			break;
97	}
98
99	return i + 1;
100}
101
102static inline int _to_lp8788_wday(int tm_wday)
103{
104	return LP8788_WDAY_SET << (tm_wday - 1);
105}
106
107static void lp8788_rtc_unlock(struct lp8788 *lp)
108{
109	lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_UNLOCK);
110	lp8788_write_byte(lp, LP8788_RTC_UNLOCK, RTC_LATCH);
111}
112
113static int lp8788_rtc_read_time(struct device *dev, struct rtc_time *tm)
114{
115	struct lp8788_rtc *rtc = dev_get_drvdata(dev);
116	struct lp8788 *lp = rtc->lp;
117	u8 data[LPTIME_MAX];
118	int ret;
119
120	lp8788_rtc_unlock(lp);
121
122	ret = lp8788_read_multi_bytes(lp, LP8788_RTC_SEC, data,	LPTIME_MAX);
123	if (ret)
124		return ret;
125
126	tm->tm_sec  = data[LPTIME_SEC];
127	tm->tm_min  = data[LPTIME_MIN];
128	tm->tm_hour = data[LPTIME_HOUR];
129	tm->tm_mday = data[LPTIME_MDAY];
130	tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
131	tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
132	tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
133
134	return 0;
135}
136
137static int lp8788_rtc_set_time(struct device *dev, struct rtc_time *tm)
138{
139	struct lp8788_rtc *rtc = dev_get_drvdata(dev);
140	struct lp8788 *lp = rtc->lp;
141	u8 data[LPTIME_MAX - 1];
142	int ret, i, year;
143
144	year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
145	if (year < 0) {
146		dev_err(lp->dev, "invalid year: %d\n", year);
147		return -EINVAL;
148	}
149
150	/* because rtc weekday is a readonly register, do not update */
151	data[LPTIME_SEC]  = tm->tm_sec;
152	data[LPTIME_MIN]  = tm->tm_min;
153	data[LPTIME_HOUR] = tm->tm_hour;
154	data[LPTIME_MDAY] = tm->tm_mday;
155	data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
156	data[LPTIME_YEAR] = year;
157
158	for (i = 0; i < ARRAY_SIZE(data); i++) {
159		ret = lp8788_write_byte(lp, LP8788_RTC_SEC + i, data[i]);
160		if (ret)
161			return ret;
162	}
163
164	return 0;
165}
166
167static int lp8788_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
168{
169	struct lp8788_rtc *rtc = dev_get_drvdata(dev);
170	struct lp8788 *lp = rtc->lp;
171	struct rtc_time *tm = &alarm->time;
172	u8 addr, data[LPTIME_MAX];
173	int ret;
174
175	addr = addr_alarm_sec[rtc->alarm];
176	ret = lp8788_read_multi_bytes(lp, addr, data, LPTIME_MAX);
177	if (ret)
178		return ret;
179
180	tm->tm_sec  = data[LPTIME_SEC];
181	tm->tm_min  = data[LPTIME_MIN];
182	tm->tm_hour = data[LPTIME_HOUR];
183	tm->tm_mday = data[LPTIME_MDAY];
184	tm->tm_mon  = data[LPTIME_MON] - LP8788_MONTH_OFFSET;
185	tm->tm_year = data[LPTIME_YEAR] + LP8788_BASE_YEAR - 1900;
186	tm->tm_wday = _to_tm_wday(data[LPTIME_WDAY]);
187	alarm->enabled = data[LPTIME_WDAY] & LP8788_ALM_EN_M;
188
189	return 0;
190}
191
192static int lp8788_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
193{
194	struct lp8788_rtc *rtc = dev_get_drvdata(dev);
195	struct lp8788 *lp = rtc->lp;
196	struct rtc_time *tm = &alarm->time;
197	u8 addr, data[LPTIME_MAX];
198	int ret, i, year;
199
200	year = tm->tm_year + 1900 - LP8788_BASE_YEAR;
201	if (year < 0) {
202		dev_err(lp->dev, "invalid year: %d\n", year);
203		return -EINVAL;
204	}
205
206	data[LPTIME_SEC]  = tm->tm_sec;
207	data[LPTIME_MIN]  = tm->tm_min;
208	data[LPTIME_HOUR] = tm->tm_hour;
209	data[LPTIME_MDAY] = tm->tm_mday;
210	data[LPTIME_MON]  = tm->tm_mon + LP8788_MONTH_OFFSET;
211	data[LPTIME_YEAR] = year;
212	data[LPTIME_WDAY] = _to_lp8788_wday(tm->tm_wday);
213
214	for (i = 0; i < ARRAY_SIZE(data); i++) {
215		addr = addr_alarm_sec[rtc->alarm] + i;
216		ret = lp8788_write_byte(lp, addr, data[i]);
217		if (ret)
218			return ret;
219	}
220
221	alarm->enabled = 1;
222	addr = addr_alarm_en[rtc->alarm];
223
224	return lp8788_update_bits(lp, addr, LP8788_ALM_EN_M,
225				alarm->enabled << LP8788_ALM_EN_S);
226}
227
228static int lp8788_alarm_irq_enable(struct device *dev, unsigned int enable)
229{
230	struct lp8788_rtc *rtc = dev_get_drvdata(dev);
231	struct lp8788 *lp = rtc->lp;
232	u8 mask, shift;
233
234	if (!rtc->irq)
235		return -EIO;
236
237	mask = mask_alarm_en[rtc->alarm];
238	shift = shift_alarm_en[rtc->alarm];
239
240	return lp8788_update_bits(lp, LP8788_INTEN_3, mask, enable << shift);
241}
242
243static const struct rtc_class_ops lp8788_rtc_ops = {
244	.read_time = lp8788_rtc_read_time,
245	.set_time = lp8788_rtc_set_time,
246	.read_alarm = lp8788_read_alarm,
247	.set_alarm = lp8788_set_alarm,
248	.alarm_irq_enable = lp8788_alarm_irq_enable,
249};
250
251static irqreturn_t lp8788_alarm_irq_handler(int irq, void *ptr)
252{
253	struct lp8788_rtc *rtc = ptr;
254
255	rtc_update_irq(rtc->rdev, 1, ALARM_IRQ_FLAG);
256	return IRQ_HANDLED;
257}
258
259static int lp8788_alarm_irq_register(struct platform_device *pdev,
260				struct lp8788_rtc *rtc)
261{
262	struct resource *r;
263	struct lp8788 *lp = rtc->lp;
264	struct irq_domain *irqdm = lp->irqdm;
265	int irq;
266
267	rtc->irq = 0;
268
269	/* even the alarm IRQ number is not specified, rtc time should work */
270	r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, LP8788_ALM_IRQ);
271	if (!r)
272		return 0;
273
274	if (rtc->alarm == LP8788_ALARM_1)
275		irq = r->start;
276	else
277		irq = r->end;
278
279	rtc->irq = irq_create_mapping(irqdm, irq);
280
281	return devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
282				lp8788_alarm_irq_handler,
283				0, LP8788_ALM_IRQ, rtc);
284}
285
286static int lp8788_rtc_probe(struct platform_device *pdev)
287{
288	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
289	struct lp8788_rtc *rtc;
290	struct device *dev = &pdev->dev;
291
292	rtc = devm_kzalloc(dev, sizeof(struct lp8788_rtc), GFP_KERNEL);
293	if (!rtc)
294		return -ENOMEM;
295
296	rtc->lp = lp;
297	rtc->alarm = lp->pdata ? lp->pdata->alarm_sel : DEFAULT_ALARM_SEL;
298	platform_set_drvdata(pdev, rtc);
299
300	device_init_wakeup(dev, 1);
301
302	rtc->rdev = devm_rtc_device_register(dev, "lp8788_rtc",
303					&lp8788_rtc_ops, THIS_MODULE);
304	if (IS_ERR(rtc->rdev)) {
305		dev_err(dev, "can not register rtc device\n");
306		return PTR_ERR(rtc->rdev);
307	}
308
309	if (lp8788_alarm_irq_register(pdev, rtc))
310		dev_warn(lp->dev, "no rtc irq handler\n");
311
312	return 0;
313}
314
315static struct platform_driver lp8788_rtc_driver = {
316	.probe = lp8788_rtc_probe,
317	.driver = {
318		.name = LP8788_DEV_RTC,
319		.owner = THIS_MODULE,
320	},
321};
322module_platform_driver(lp8788_rtc_driver);
323
324MODULE_DESCRIPTION("Texas Instruments LP8788 RTC Driver");
325MODULE_AUTHOR("Milo Kim");
326MODULE_LICENSE("GPL");
327MODULE_ALIAS("platform:lp8788-rtc");
328