xref: /openbmc/linux/drivers/rtc/rtc-88pm860x.c (revision e23feb16)
1 /*
2  * Real Time Clock driver for Marvell 88PM860x PMIC
3  *
4  * Copyright (c) 2010 Marvell International Ltd.
5  * Author:	Haojian Zhuang <haojian.zhuang@marvell.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/slab.h>
17 #include <linux/mutex.h>
18 #include <linux/rtc.h>
19 #include <linux/delay.h>
20 #include <linux/mfd/core.h>
21 #include <linux/mfd/88pm860x.h>
22 
23 #define VRTC_CALIBRATION
24 
25 struct pm860x_rtc_info {
26 	struct pm860x_chip	*chip;
27 	struct i2c_client	*i2c;
28 	struct rtc_device	*rtc_dev;
29 	struct device		*dev;
30 	struct delayed_work	calib_work;
31 
32 	int			irq;
33 	int			vrtc;
34 	int			(*sync)(unsigned int ticks);
35 };
36 
37 #define REG_VRTC_MEAS1		0x7D
38 
39 #define REG0_ADDR		0xB0
40 #define REG1_ADDR		0xB2
41 #define REG2_ADDR		0xB4
42 #define REG3_ADDR		0xB6
43 
44 #define REG0_DATA		0xB1
45 #define REG1_DATA		0xB3
46 #define REG2_DATA		0xB5
47 #define REG3_DATA		0xB7
48 
49 /* bit definitions of Measurement Enable Register 2 (0x51) */
50 #define MEAS2_VRTC		(1 << 0)
51 
52 /* bit definitions of RTC Register 1 (0xA0) */
53 #define ALARM_EN		(1 << 3)
54 #define ALARM_WAKEUP		(1 << 4)
55 #define ALARM			(1 << 5)
56 #define RTC1_USE_XO		(1 << 7)
57 
58 #define VRTC_CALIB_INTERVAL	(HZ * 60 * 10)		/* 10 minutes */
59 
60 static irqreturn_t rtc_update_handler(int irq, void *data)
61 {
62 	struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
63 	int mask;
64 
65 	mask = ALARM | ALARM_WAKEUP;
66 	pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
67 	rtc_update_irq(info->rtc_dev, 1, RTC_AF);
68 	return IRQ_HANDLED;
69 }
70 
71 static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
72 {
73 	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
74 
75 	if (enabled)
76 		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
77 	else
78 		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
79 	return 0;
80 }
81 
82 /*
83  * Calculate the next alarm time given the requested alarm time mask
84  * and the current time.
85  */
86 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
87 				struct rtc_time *alrm)
88 {
89 	unsigned long next_time;
90 	unsigned long now_time;
91 
92 	next->tm_year = now->tm_year;
93 	next->tm_mon = now->tm_mon;
94 	next->tm_mday = now->tm_mday;
95 	next->tm_hour = alrm->tm_hour;
96 	next->tm_min = alrm->tm_min;
97 	next->tm_sec = alrm->tm_sec;
98 
99 	rtc_tm_to_time(now, &now_time);
100 	rtc_tm_to_time(next, &next_time);
101 
102 	if (next_time < now_time) {
103 		/* Advance one day */
104 		next_time += 60 * 60 * 24;
105 		rtc_time_to_tm(next_time, next);
106 	}
107 }
108 
109 static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
110 {
111 	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
112 	unsigned char buf[8];
113 	unsigned long ticks, base, data;
114 
115 	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
116 	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
117 		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
118 	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
119 
120 	/* load 32-bit read-only counter */
121 	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
122 	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
123 	ticks = base + data;
124 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
125 		base, data, ticks);
126 
127 	rtc_time_to_tm(ticks, tm);
128 
129 	return 0;
130 }
131 
132 static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
133 {
134 	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
135 	unsigned char buf[4];
136 	unsigned long ticks, base, data;
137 
138 	if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
139 		dev_dbg(info->dev, "Set time %d out of range. "
140 			"Please set time between 1970 to 2038.\n",
141 			1900 + tm->tm_year);
142 		return -EINVAL;
143 	}
144 	rtc_tm_to_time(tm, &ticks);
145 
146 	/* load 32-bit read-only counter */
147 	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
148 	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
149 	base = ticks - data;
150 	dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
151 		base, data, ticks);
152 
153 	pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
154 	pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
155 	pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
156 	pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
157 
158 	if (info->sync)
159 		info->sync(ticks);
160 	return 0;
161 }
162 
163 static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
164 {
165 	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
166 	unsigned char buf[8];
167 	unsigned long ticks, base, data;
168 	int ret;
169 
170 	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
171 	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
172 		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
173 	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
174 
175 	pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
176 	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
177 	ticks = base + data;
178 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
179 		base, data, ticks);
180 
181 	rtc_time_to_tm(ticks, &alrm->time);
182 	ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
183 	alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
184 	alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
185 	return 0;
186 }
187 
188 static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
189 {
190 	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
191 	struct rtc_time now_tm, alarm_tm;
192 	unsigned long ticks, base, data;
193 	unsigned char buf[8];
194 	int mask;
195 
196 	pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
197 
198 	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
199 	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
200 		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
201 	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
202 
203 	/* load 32-bit read-only counter */
204 	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
205 	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
206 	ticks = base + data;
207 	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
208 		base, data, ticks);
209 
210 	rtc_time_to_tm(ticks, &now_tm);
211 	rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
212 	/* get new ticks for alarm in 24 hours */
213 	rtc_tm_to_time(&alarm_tm, &ticks);
214 	data = ticks - base;
215 
216 	buf[0] = data & 0xff;
217 	buf[1] = (data >> 8) & 0xff;
218 	buf[2] = (data >> 16) & 0xff;
219 	buf[3] = (data >> 24) & 0xff;
220 	pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
221 	if (alrm->enabled) {
222 		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
223 		pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
224 	} else {
225 		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
226 		pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
227 				ALARM | ALARM_WAKEUP);
228 	}
229 	return 0;
230 }
231 
232 static const struct rtc_class_ops pm860x_rtc_ops = {
233 	.read_time	= pm860x_rtc_read_time,
234 	.set_time	= pm860x_rtc_set_time,
235 	.read_alarm	= pm860x_rtc_read_alarm,
236 	.set_alarm	= pm860x_rtc_set_alarm,
237 	.alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
238 };
239 
240 #ifdef VRTC_CALIBRATION
241 static void calibrate_vrtc_work(struct work_struct *work)
242 {
243 	struct pm860x_rtc_info *info = container_of(work,
244 		struct pm860x_rtc_info, calib_work.work);
245 	unsigned char buf[2];
246 	unsigned int sum, data, mean, vrtc_set;
247 	int i;
248 
249 	for (i = 0, sum = 0; i < 16; i++) {
250 		msleep(100);
251 		pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
252 		data = (buf[0] << 4) | buf[1];
253 		data = (data * 5400) >> 12;	/* convert to mv */
254 		sum += data;
255 	}
256 	mean = sum >> 4;
257 	vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
258 	dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
259 
260 	sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
261 	data = sum & 0x3;
262 	if ((mean + 200) < vrtc_set) {
263 		/* try higher voltage */
264 		if (++data == 4)
265 			goto out;
266 		data = (sum & 0xf8) | (data & 0x3);
267 		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
268 	} else if ((mean - 200) > vrtc_set) {
269 		/* try lower voltage */
270 		if (data-- == 0)
271 			goto out;
272 		data = (sum & 0xf8) | (data & 0x3);
273 		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
274 	} else
275 		goto out;
276 	dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
277 	/* trigger next calibration since VRTC is updated */
278 	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
279 	return;
280 out:
281 	/* disable measurement */
282 	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
283 	dev_dbg(info->dev, "finish VRTC calibration\n");
284 	return;
285 }
286 #endif
287 
288 #ifdef CONFIG_OF
289 static int pm860x_rtc_dt_init(struct platform_device *pdev,
290 			      struct pm860x_rtc_info *info)
291 {
292 	struct device_node *np = pdev->dev.parent->of_node;
293 	int ret;
294 	if (!np)
295 		return -ENODEV;
296 	np = of_find_node_by_name(np, "rtc");
297 	if (!np) {
298 		dev_err(&pdev->dev, "failed to find rtc node\n");
299 		return -ENODEV;
300 	}
301 	ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
302 	if (ret)
303 		info->vrtc = 0;
304 	return 0;
305 }
306 #else
307 #define pm860x_rtc_dt_init(x, y)	(-1)
308 #endif
309 
310 static int pm860x_rtc_probe(struct platform_device *pdev)
311 {
312 	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
313 	struct pm860x_rtc_pdata *pdata = NULL;
314 	struct pm860x_rtc_info *info;
315 	struct rtc_time tm;
316 	unsigned long ticks = 0;
317 	int ret;
318 
319 	pdata = pdev->dev.platform_data;
320 
321 	info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
322 			    GFP_KERNEL);
323 	if (!info)
324 		return -ENOMEM;
325 	info->irq = platform_get_irq(pdev, 0);
326 	if (info->irq < 0) {
327 		dev_err(&pdev->dev, "No IRQ resource!\n");
328 		return info->irq;
329 	}
330 
331 	info->chip = chip;
332 	info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
333 	info->dev = &pdev->dev;
334 	dev_set_drvdata(&pdev->dev, info);
335 
336 	ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
337 					rtc_update_handler, IRQF_ONESHOT, "rtc",
338 					info);
339 	if (ret < 0) {
340 		dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
341 			info->irq, ret);
342 		return ret;
343 	}
344 
345 	/* set addresses of 32-bit base value for RTC time */
346 	pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
347 	pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
348 	pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
349 	pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
350 
351 	ret = pm860x_rtc_read_time(&pdev->dev, &tm);
352 	if (ret < 0) {
353 		dev_err(&pdev->dev, "Failed to read initial time.\n");
354 		return ret;
355 	}
356 	if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
357 		tm.tm_year = 70;
358 		tm.tm_mon = 0;
359 		tm.tm_mday = 1;
360 		tm.tm_hour = 0;
361 		tm.tm_min = 0;
362 		tm.tm_sec = 0;
363 		ret = pm860x_rtc_set_time(&pdev->dev, &tm);
364 		if (ret < 0) {
365 			dev_err(&pdev->dev, "Failed to set initial time.\n");
366 			return ret;
367 		}
368 	}
369 	rtc_tm_to_time(&tm, &ticks);
370 	if (pm860x_rtc_dt_init(pdev, info)) {
371 		if (pdata && pdata->sync) {
372 			pdata->sync(ticks);
373 			info->sync = pdata->sync;
374 		}
375 	}
376 
377 	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm860x-rtc",
378 					    &pm860x_rtc_ops, THIS_MODULE);
379 	ret = PTR_ERR(info->rtc_dev);
380 	if (IS_ERR(info->rtc_dev)) {
381 		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
382 		return ret;
383 	}
384 
385 	/*
386 	 * enable internal XO instead of internal 3.25MHz clock since it can
387 	 * free running in PMIC power-down state.
388 	 */
389 	pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
390 
391 #ifdef VRTC_CALIBRATION
392 	/* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
393 	if (pm860x_rtc_dt_init(pdev, info)) {
394 		if (pdata && pdata->vrtc)
395 			info->vrtc = pdata->vrtc & 0x3;
396 		else
397 			info->vrtc = 1;
398 	}
399 	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
400 
401 	/* calibrate VRTC */
402 	INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
403 	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
404 #endif	/* VRTC_CALIBRATION */
405 
406 	device_init_wakeup(&pdev->dev, 1);
407 
408 	return 0;
409 }
410 
411 static int pm860x_rtc_remove(struct platform_device *pdev)
412 {
413 	struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
414 
415 #ifdef VRTC_CALIBRATION
416 	flush_scheduled_work();
417 	/* disable measurement */
418 	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
419 #endif	/* VRTC_CALIBRATION */
420 
421 	return 0;
422 }
423 
424 #ifdef CONFIG_PM_SLEEP
425 static int pm860x_rtc_suspend(struct device *dev)
426 {
427 	struct platform_device *pdev = to_platform_device(dev);
428 	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
429 
430 	if (device_may_wakeup(dev))
431 		chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
432 	return 0;
433 }
434 static int pm860x_rtc_resume(struct device *dev)
435 {
436 	struct platform_device *pdev = to_platform_device(dev);
437 	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
438 
439 	if (device_may_wakeup(dev))
440 		chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
441 	return 0;
442 }
443 #endif
444 
445 static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
446 
447 static struct platform_driver pm860x_rtc_driver = {
448 	.driver		= {
449 		.name	= "88pm860x-rtc",
450 		.owner	= THIS_MODULE,
451 		.pm	= &pm860x_rtc_pm_ops,
452 	},
453 	.probe		= pm860x_rtc_probe,
454 	.remove		= pm860x_rtc_remove,
455 };
456 
457 module_platform_driver(pm860x_rtc_driver);
458 
459 MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
460 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
461 MODULE_LICENSE("GPL");
462