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/irq.h>
27#include <linux/kernel.h>
28#include <linux/mfd/tps6586x.h>
29#include <linux/module.h>
30#include <linux/platform_device.h>
31#include <linux/pm_runtime.h>
32#include <linux/rtc.h>
33#include <linux/slab.h>
34
35#define RTC_CTRL			0xc0
36#define POR_RESET_N			BIT(7)
37#define OSC_SRC_SEL			BIT(6)
38#define RTC_ENABLE			BIT(5)	/* enables alarm */
39#define RTC_BUF_ENABLE			BIT(4)	/* 32 KHz buffer enable */
40#define PRE_BYPASS			BIT(3)	/* 0=1KHz or 1=32KHz updates */
41#define CL_SEL_MASK			(BIT(2)|BIT(1))
42#define CL_SEL_POS			1
43#define RTC_ALARM1_HI			0xc1
44#define RTC_COUNT4			0xc6
45
46/* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
47#define RTC_COUNT4_DUMMYREAD		0xc5
48
49/*only 14-bits width in second*/
50#define ALM1_VALID_RANGE_IN_SEC		0x3FFF
51
52#define TPS6586X_RTC_CL_SEL_1_5PF	0x0
53#define TPS6586X_RTC_CL_SEL_6_5PF	0x1
54#define TPS6586X_RTC_CL_SEL_7_5PF	0x2
55#define TPS6586X_RTC_CL_SEL_12_5PF	0x3
56
57struct tps6586x_rtc {
58	struct device		*dev;
59	struct rtc_device	*rtc;
60	int			irq;
61	bool			irq_en;
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 device *tps_dev = to_tps6586x_dev(dev);
72	unsigned long long ticks = 0;
73	time64_t seconds;
74	u8 buff[6];
75	int ret;
76	int i;
77
78	ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
79	if (ret < 0) {
80		dev_err(dev, "read counter failed with err %d\n", ret);
81		return ret;
82	}
83
84	for (i = 1; i < sizeof(buff); i++) {
85		ticks <<= 8;
86		ticks |= buff[i];
87	}
88
89	seconds = ticks >> 10;
90	rtc_time64_to_tm(seconds, tm);
91
92	return 0;
93}
94
95static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
96{
97	struct device *tps_dev = to_tps6586x_dev(dev);
98	unsigned long long ticks;
99	time64_t seconds;
100	u8 buff[5];
101	int ret;
102
103	seconds = rtc_tm_to_time64(tm);
104
105	ticks = (unsigned long long)seconds << 10;
106	buff[0] = (ticks >> 32) & 0xff;
107	buff[1] = (ticks >> 24) & 0xff;
108	buff[2] = (ticks >> 16) & 0xff;
109	buff[3] = (ticks >> 8) & 0xff;
110	buff[4] = ticks & 0xff;
111
112	/* Disable RTC before changing time */
113	ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
114	if (ret < 0) {
115		dev_err(dev, "failed to clear RTC_ENABLE\n");
116		return ret;
117	}
118
119	ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
120	if (ret < 0) {
121		dev_err(dev, "failed to program new time\n");
122		return ret;
123	}
124
125	/* Enable RTC */
126	ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
127	if (ret < 0) {
128		dev_err(dev, "failed to set RTC_ENABLE\n");
129		return ret;
130	}
131	return 0;
132}
133
134static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
135			 unsigned int enabled)
136{
137	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
138
139	if (enabled && !rtc->irq_en) {
140		enable_irq(rtc->irq);
141		rtc->irq_en = true;
142	} else if (!enabled && rtc->irq_en)  {
143		disable_irq(rtc->irq);
144		rtc->irq_en = false;
145	}
146	return 0;
147}
148
149static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
150{
151	struct device *tps_dev = to_tps6586x_dev(dev);
152	time64_t seconds;
153	unsigned long ticks;
154	unsigned long rtc_current_time;
155	unsigned long long rticks = 0;
156	u8 buff[3];
157	u8 rbuff[6];
158	int ret;
159	int i;
160
161	seconds = rtc_tm_to_time64(&alrm->time);
162
163	ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
164	if (ret < 0) {
165		dev_err(dev, "can't set alarm irq, err %d\n", ret);
166		return ret;
167	}
168
169	ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
170			sizeof(rbuff), rbuff);
171	if (ret < 0) {
172		dev_err(dev, "read counter failed with err %d\n", ret);
173		return ret;
174	}
175
176	for (i = 1; i < sizeof(rbuff); i++) {
177		rticks <<= 8;
178		rticks |= rbuff[i];
179	}
180
181	rtc_current_time = rticks >> 10;
182	if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
183		seconds = rtc_current_time - 1;
184
185	ticks = (unsigned long long)seconds << 10;
186	buff[0] = (ticks >> 16) & 0xff;
187	buff[1] = (ticks >> 8) & 0xff;
188	buff[2] = ticks & 0xff;
189
190	ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
191	if (ret)
192		dev_err(dev, "programming alarm failed with err %d\n", ret);
193
194	return ret;
195}
196
197static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
198{
199	struct device *tps_dev = to_tps6586x_dev(dev);
200	unsigned long ticks;
201	time64_t seconds;
202	u8 buff[3];
203	int ret;
204
205	ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
206	if (ret) {
207		dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
208		return ret;
209	}
210
211	ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
212	seconds = ticks >> 10;
213
214	rtc_time64_to_tm(seconds, &alrm->time);
215	return 0;
216}
217
218static const struct rtc_class_ops tps6586x_rtc_ops = {
219	.read_time	= tps6586x_rtc_read_time,
220	.set_time	= tps6586x_rtc_set_time,
221	.set_alarm	= tps6586x_rtc_set_alarm,
222	.read_alarm	= tps6586x_rtc_read_alarm,
223	.alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
224};
225
226static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
227{
228	struct tps6586x_rtc *rtc = data;
229
230	rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
231	return IRQ_HANDLED;
232}
233
234static int tps6586x_rtc_probe(struct platform_device *pdev)
235{
236	struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
237	struct tps6586x_rtc *rtc;
238	int ret;
239
240	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
241	if (!rtc)
242		return -ENOMEM;
243
244	rtc->dev = &pdev->dev;
245	rtc->irq = platform_get_irq(pdev, 0);
246
247	/* 1 kHz tick mode, enable tick counting */
248	ret = tps6586x_update(tps_dev, RTC_CTRL,
249		RTC_ENABLE | OSC_SRC_SEL |
250		((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
251		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
252	if (ret < 0) {
253		dev_err(&pdev->dev, "unable to start counter\n");
254		return ret;
255	}
256
257	device_init_wakeup(&pdev->dev, 1);
258
259	platform_set_drvdata(pdev, rtc);
260	rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
261	if (IS_ERR(rtc->rtc)) {
262		ret = PTR_ERR(rtc->rtc);
263		goto fail_rtc_register;
264	}
265
266	rtc->rtc->ops = &tps6586x_rtc_ops;
267	rtc->rtc->range_max = (1ULL << 30) - 1; /* 30-bit seconds */
268	rtc->rtc->start_secs = mktime64(2009, 1, 1, 0, 0, 0);
269	rtc->rtc->set_start_time = true;
270
271	irq_set_status_flags(rtc->irq, IRQ_NOAUTOEN);
272
273	ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
274				tps6586x_rtc_irq,
275				IRQF_ONESHOT,
276				dev_name(&pdev->dev), rtc);
277	if (ret < 0) {
278		dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
279				rtc->irq, ret);
280		goto fail_rtc_register;
281	}
282
283	ret = rtc_register_device(rtc->rtc);
284	if (ret)
285		goto fail_rtc_register;
286
287	return 0;
288
289fail_rtc_register:
290	tps6586x_update(tps_dev, RTC_CTRL, 0,
291		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
292	return ret;
293};
294
295static int tps6586x_rtc_remove(struct platform_device *pdev)
296{
297	struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
298
299	tps6586x_update(tps_dev, RTC_CTRL, 0,
300		RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
301	return 0;
302}
303
304#ifdef CONFIG_PM_SLEEP
305static int tps6586x_rtc_suspend(struct device *dev)
306{
307	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
308
309	if (device_may_wakeup(dev))
310		enable_irq_wake(rtc->irq);
311	return 0;
312}
313
314static int tps6586x_rtc_resume(struct device *dev)
315{
316	struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
317
318	if (device_may_wakeup(dev))
319		disable_irq_wake(rtc->irq);
320	return 0;
321}
322#endif
323
324static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
325			tps6586x_rtc_resume);
326
327static struct platform_driver tps6586x_rtc_driver = {
328	.driver	= {
329		.name	= "tps6586x-rtc",
330		.pm	= &tps6586x_pm_ops,
331	},
332	.probe	= tps6586x_rtc_probe,
333	.remove	= tps6586x_rtc_remove,
334};
335module_platform_driver(tps6586x_rtc_driver);
336
337MODULE_ALIAS("platform:tps6586x-rtc");
338MODULE_DESCRIPTION("TI TPS6586x RTC driver");
339MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
340MODULE_LICENSE("GPL v2");
341