[go: nahoru, domu]
1/*
2 * rtc-tps6586x.c: RTC driver for TI PMIC TPS6586X
3 *
4 * Copyright (c) 2012, NVIDIA Corporation.
5 *
6 * Author: Laxman Dewangan <ldewangan@nvidia.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation version 2.
11 *
12 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
13 * whether express or implied; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 * 02111-1307, USA
21 */
22
23#include <linux/device.h>
24#include <linux/err.h>
25#include <linux/init.h>
26#include <linux/kernel.h>
27#include <linux/mfd/tps6586x.h>
28#include <linux/module.h>
29#include <linux/platform_device.h>
30#include <linux/pm_runtime.h>
31#include <linux/rtc.h>
32#include <linux/slab.h>
33
34#define RTC_CTRL			0xc0
35#define POR_RESET_N			BIT(7)
36#define OSC_SRC_SEL			BIT(6)
37#define RTC_ENABLE			BIT(5)	/* enables alarm */
38#define RTC_BUF_ENABLE			BIT(4)	/* 32 KHz buffer enable */
39#define PRE_BYPASS			BIT(3)	/* 0=1KHz or 1=32KHz updates */
40#define CL_SEL_MASK			(BIT(2)|BIT(1))
41#define CL_SEL_POS			1
42#define RTC_ALARM1_HI			0xc1
43#define RTC_COUNT4			0xc6
44
45/* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
46#define RTC_COUNT4_DUMMYREAD		0xc5
47
48/*only 14-bits width in second*/
49#define ALM1_VALID_RANGE_IN_SEC		0x3FFF
50
51#define TPS6586X_RTC_CL_SEL_1_5PF	0x0
52#define TPS6586X_RTC_CL_SEL_6_5PF	0x1
53#define TPS6586X_RTC_CL_SEL_7_5PF	0x2
54#define TPS6586X_RTC_CL_SEL_12_5PF	0x3
55
56struct tps6586x_rtc {
57	struct device		*dev;
58	struct rtc_device	*rtc;
59	int			irq;
60	bool			irq_en;
61	unsigned long long	epoch_start;
62};
63
64static inline struct device *to_tps6586x_dev(struct device *dev)
65{
66	return dev->parent;
67}
68
69static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
70{
71	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
72	struct device *tps_dev = to_tps6586x_dev(dev);
73	unsigned long long ticks = 0;
74	unsigned long seconds;
75	u8 buff[6];
76	int ret;
77	int i;
78
79	ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
80	if (ret < 0) {
81		dev_err(dev, "read counter failed with err %d\n", ret);
82		return ret;
83	}
84
85	for (i = 1; i < sizeof(buff); i++) {
86		ticks <<= 8;
87		ticks |= buff[i];
88	}
89
90	seconds = ticks >> 10;
91	seconds += rtc->epoch_start;
92	rtc_time_to_tm(seconds, tm);
93	return rtc_valid_tm(tm);
94}
95
96static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
97{
98	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
99	struct device *tps_dev = to_tps6586x_dev(dev);
100	unsigned long long ticks;
101	unsigned long seconds;
102	u8 buff[5];
103	int ret;
104
105	rtc_tm_to_time(tm, &seconds);
106	if (seconds < rtc->epoch_start) {
107		dev_err(dev, "requested time unsupported\n");
108		return -EINVAL;
109	}
110	seconds -= rtc->epoch_start;
111
112	ticks = (unsigned long long)seconds << 10;
113	buff[0] = (ticks >> 32) & 0xff;
114	buff[1] = (ticks >> 24) & 0xff;
115	buff[2] = (ticks >> 16) & 0xff;
116	buff[3] = (ticks >> 8) & 0xff;
117	buff[4] = ticks & 0xff;
118
119	/* Disable RTC before changing time */
120	ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
121	if (ret < 0) {
122		dev_err(dev, "failed to clear RTC_ENABLE\n");
123		return ret;
124	}
125
126	ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
127	if (ret < 0) {
128		dev_err(dev, "failed to program new time\n");
129		return ret;
130	}
131
132	/* Enable RTC */
133	ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
134	if (ret < 0) {
135		dev_err(dev, "failed to set RTC_ENABLE\n");
136		return ret;
137	}
138	return 0;
139}
140
141static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
142			 unsigned int enabled)
143{
144	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
145
146	if (enabled && !rtc->irq_en) {
147		enable_irq(rtc->irq);
148		rtc->irq_en = true;
149	} else if (!enabled && rtc->irq_en)  {
150		disable_irq(rtc->irq);
151		rtc->irq_en = false;
152	}
153	return 0;
154}
155
156static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
157{
158	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
159	struct device *tps_dev = to_tps6586x_dev(dev);
160	unsigned long seconds;
161	unsigned long ticks;
162	unsigned long rtc_current_time;
163	unsigned long long rticks = 0;
164	u8 buff[3];
165	u8 rbuff[6];
166	int ret;
167	int i;
168
169	rtc_tm_to_time(&alrm->time, &seconds);
170
171	if (alrm->enabled && (seconds < rtc->epoch_start)) {
172		dev_err(dev, "can't set alarm to requested time\n");
173		return -EINVAL;
174	}
175
176	ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
177	if (ret < 0) {
178		dev_err(dev, "can't set alarm irq, err %d\n", ret);
179		return ret;
180	}
181
182	seconds -= rtc->epoch_start;
183	ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
184			sizeof(rbuff), rbuff);
185	if (ret < 0) {
186		dev_err(dev, "read counter failed with err %d\n", ret);
187		return ret;
188	}
189
190	for (i = 1; i < sizeof(rbuff); i++) {
191		rticks <<= 8;
192		rticks |= rbuff[i];
193	}
194
195	rtc_current_time = rticks >> 10;
196	if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
197		seconds = rtc_current_time - 1;
198
199	ticks = (unsigned long long)seconds << 10;
200	buff[0] = (ticks >> 16) & 0xff;
201	buff[1] = (ticks >> 8) & 0xff;
202	buff[2] = ticks & 0xff;
203
204	ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
205	if (ret)
206		dev_err(dev, "programming alarm failed with err %d\n", ret);
207
208	return ret;
209}
210
211static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
212{
213	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
214	struct device *tps_dev = to_tps6586x_dev(dev);
215	unsigned long ticks;
216	unsigned long seconds;
217	u8 buff[3];
218	int ret;
219
220	ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
221	if (ret) {
222		dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
223		return ret;
224	}
225
226	ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
227	seconds = ticks >> 10;
228	seconds += rtc->epoch_start;
229
230	rtc_time_to_tm(seconds, &alrm->time);
231	return 0;
232}
233
234static const struct rtc_class_ops tps6586x_rtc_ops = {
235	.read_time	= tps6586x_rtc_read_time,
236	.set_time	= tps6586x_rtc_set_time,
237	.set_alarm	= tps6586x_rtc_set_alarm,
238	.read_alarm	= tps6586x_rtc_read_alarm,
239	.alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
240};
241
242static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
243{
244	struct tps6586x_rtc *rtc = data;
245
246	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
247	return IRQ_HANDLED;
248}
249
250static int tps6586x_rtc_probe(struct platform_device *pdev)
251{
252	struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
253	struct tps6586x_rtc *rtc;
254	int ret;
255
256	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
257	if (!rtc)
258		return -ENOMEM;
259
260	rtc->dev = &pdev->dev;
261	rtc->irq = platform_get_irq(pdev, 0);
262
263	/* Set epoch start as 00:00:00:01:01:2009 */
264	rtc->epoch_start = mktime(2009, 1, 1, 0, 0, 0);
265
266	/* 1 kHz tick mode, enable tick counting */
267	ret = tps6586x_update(tps_dev, RTC_CTRL,
268		RTC_ENABLE | OSC_SRC_SEL |
269		((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
270		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
271	if (ret < 0) {
272		dev_err(&pdev->dev, "unable to start counter\n");
273		return ret;
274	}
275
276	device_init_wakeup(&pdev->dev, 1);
277
278	platform_set_drvdata(pdev, rtc);
279	rtc->rtc = devm_rtc_device_register(&pdev->dev, dev_name(&pdev->dev),
280				       &tps6586x_rtc_ops, THIS_MODULE);
281	if (IS_ERR(rtc->rtc)) {
282		ret = PTR_ERR(rtc->rtc);
283		dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
284		goto fail_rtc_register;
285	}
286
287	ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
288				tps6586x_rtc_irq,
289				IRQF_ONESHOT | IRQF_EARLY_RESUME,
290				dev_name(&pdev->dev), rtc);
291	if (ret < 0) {
292		dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
293				rtc->irq, ret);
294		goto fail_rtc_register;
295	}
296	disable_irq(rtc->irq);
297	return 0;
298
299fail_rtc_register:
300	tps6586x_update(tps_dev, RTC_CTRL, 0,
301		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
302	return ret;
303};
304
305static int tps6586x_rtc_remove(struct platform_device *pdev)
306{
307	struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
308
309	tps6586x_update(tps_dev, RTC_CTRL, 0,
310		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
311	return 0;
312}
313
314#ifdef CONFIG_PM_SLEEP
315static int tps6586x_rtc_suspend(struct device *dev)
316{
317	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
318
319	if (device_may_wakeup(dev))
320		enable_irq_wake(rtc->irq);
321	return 0;
322}
323
324static int tps6586x_rtc_resume(struct device *dev)
325{
326	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
327
328	if (device_may_wakeup(dev))
329		disable_irq_wake(rtc->irq);
330	return 0;
331}
332#endif
333
334static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
335			tps6586x_rtc_resume);
336
337static struct platform_driver tps6586x_rtc_driver = {
338	.driver	= {
339		.name	= "tps6586x-rtc",
340		.owner	= THIS_MODULE,
341		.pm	= &tps6586x_pm_ops,
342	},
343	.probe	= tps6586x_rtc_probe,
344	.remove	= tps6586x_rtc_remove,
345};
346module_platform_driver(tps6586x_rtc_driver);
347
348MODULE_ALIAS("platform:rtc-tps6586x");
349MODULE_DESCRIPTION("TI TPS6586x RTC driver");
350MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
351MODULE_LICENSE("GPL v2");
352