1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * Real Time Clock driver for Marvell 88PM860x PMIC
4   *
5   * Copyright (c) 2010 Marvell International Ltd.
6   * Author:	Haojian Zhuang <haojian.zhuang@marvell.com>
7   */
8  
9  #include <linux/kernel.h>
10  #include <linux/module.h>
11  #include <linux/of.h>
12  #include <linux/platform_device.h>
13  #include <linux/slab.h>
14  #include <linux/mutex.h>
15  #include <linux/rtc.h>
16  #include <linux/delay.h>
17  #include <linux/mfd/core.h>
18  #include <linux/mfd/88pm860x.h>
19  
20  #define VRTC_CALIBRATION
21  
22  struct pm860x_rtc_info {
23  	struct pm860x_chip	*chip;
24  	struct i2c_client	*i2c;
25  	struct rtc_device	*rtc_dev;
26  	struct device		*dev;
27  	struct delayed_work	calib_work;
28  
29  	int			irq;
30  	int			vrtc;
31  };
32  
33  #define REG_VRTC_MEAS1		0x7D
34  
35  #define REG0_ADDR		0xB0
36  #define REG1_ADDR		0xB2
37  #define REG2_ADDR		0xB4
38  #define REG3_ADDR		0xB6
39  
40  #define REG0_DATA		0xB1
41  #define REG1_DATA		0xB3
42  #define REG2_DATA		0xB5
43  #define REG3_DATA		0xB7
44  
45  /* bit definitions of Measurement Enable Register 2 (0x51) */
46  #define MEAS2_VRTC		(1 << 0)
47  
48  /* bit definitions of RTC Register 1 (0xA0) */
49  #define ALARM_EN		(1 << 3)
50  #define ALARM_WAKEUP		(1 << 4)
51  #define ALARM			(1 << 5)
52  #define RTC1_USE_XO		(1 << 7)
53  
54  #define VRTC_CALIB_INTERVAL	(HZ * 60 * 10)		/* 10 minutes */
55  
rtc_update_handler(int irq,void * data)56  static irqreturn_t rtc_update_handler(int irq, void *data)
57  {
58  	struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
59  	int mask;
60  
61  	mask = ALARM | ALARM_WAKEUP;
62  	pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
63  	rtc_update_irq(info->rtc_dev, 1, RTC_AF);
64  	return IRQ_HANDLED;
65  }
66  
pm860x_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)67  static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
68  {
69  	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
70  
71  	if (enabled)
72  		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, ALARM_EN);
73  	else
74  		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
75  	return 0;
76  }
77  
pm860x_rtc_read_time(struct device * dev,struct rtc_time * tm)78  static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
79  {
80  	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
81  	unsigned char buf[8];
82  	unsigned long ticks, base, data;
83  
84  	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
85  	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
86  		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
87  	base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
88  		(buf[5] << 8) | buf[7];
89  
90  	/* load 32-bit read-only counter */
91  	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
92  	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
93  		(buf[1] << 8) | buf[0];
94  	ticks = base + data;
95  	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
96  		base, data, ticks);
97  
98  	rtc_time64_to_tm(ticks, tm);
99  
100  	return 0;
101  }
102  
pm860x_rtc_set_time(struct device * dev,struct rtc_time * tm)103  static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
104  {
105  	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
106  	unsigned char buf[4];
107  	unsigned long ticks, base, data;
108  
109  	ticks = rtc_tm_to_time64(tm);
110  
111  	/* load 32-bit read-only counter */
112  	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
113  	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
114  		(buf[1] << 8) | buf[0];
115  	base = ticks - data;
116  	dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
117  		base, data, ticks);
118  
119  	pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
120  	pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
121  	pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
122  	pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
123  
124  	return 0;
125  }
126  
pm860x_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)127  static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
128  {
129  	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
130  	unsigned char buf[8];
131  	unsigned long ticks, base, data;
132  	int ret;
133  
134  	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
135  	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
136  		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
137  	base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
138  		(buf[5] << 8) | buf[7];
139  
140  	pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
141  	data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) |
142  		(buf[1] << 8) | buf[0];
143  	ticks = base + data;
144  	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
145  		base, data, ticks);
146  
147  	rtc_time64_to_tm(ticks, &alrm->time);
148  	ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
149  	alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
150  	alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
151  	return 0;
152  }
153  
pm860x_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)154  static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
155  {
156  	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
157  	unsigned long ticks, base, data;
158  	unsigned char buf[8];
159  	int mask;
160  
161  	pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
162  
163  	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
164  	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
165  		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
166  	base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) |
167  		(buf[5] << 8) | buf[7];
168  
169  	ticks = rtc_tm_to_time64(&alrm->time);
170  	data = ticks - base;
171  
172  	buf[0] = data & 0xff;
173  	buf[1] = (data >> 8) & 0xff;
174  	buf[2] = (data >> 16) & 0xff;
175  	buf[3] = (data >> 24) & 0xff;
176  	pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
177  	if (alrm->enabled) {
178  		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
179  		pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
180  	} else {
181  		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
182  		pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
183  				ALARM | ALARM_WAKEUP);
184  	}
185  	return 0;
186  }
187  
188  static const struct rtc_class_ops pm860x_rtc_ops = {
189  	.read_time	= pm860x_rtc_read_time,
190  	.set_time	= pm860x_rtc_set_time,
191  	.read_alarm	= pm860x_rtc_read_alarm,
192  	.set_alarm	= pm860x_rtc_set_alarm,
193  	.alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
194  };
195  
196  #ifdef VRTC_CALIBRATION
calibrate_vrtc_work(struct work_struct * work)197  static void calibrate_vrtc_work(struct work_struct *work)
198  {
199  	struct pm860x_rtc_info *info = container_of(work,
200  		struct pm860x_rtc_info, calib_work.work);
201  	unsigned char buf[2];
202  	unsigned int sum, data, mean, vrtc_set;
203  	int i;
204  
205  	for (i = 0, sum = 0; i < 16; i++) {
206  		msleep(100);
207  		pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
208  		data = (buf[0] << 4) | buf[1];
209  		data = (data * 5400) >> 12;	/* convert to mv */
210  		sum += data;
211  	}
212  	mean = sum >> 4;
213  	vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
214  	dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
215  
216  	sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
217  	data = sum & 0x3;
218  	if ((mean + 200) < vrtc_set) {
219  		/* try higher voltage */
220  		if (++data == 4)
221  			goto out;
222  		data = (sum & 0xf8) | (data & 0x3);
223  		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
224  	} else if ((mean - 200) > vrtc_set) {
225  		/* try lower voltage */
226  		if (data-- == 0)
227  			goto out;
228  		data = (sum & 0xf8) | (data & 0x3);
229  		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
230  	} else
231  		goto out;
232  	dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
233  	/* trigger next calibration since VRTC is updated */
234  	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
235  	return;
236  out:
237  	/* disable measurement */
238  	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
239  	dev_dbg(info->dev, "finish VRTC calibration\n");
240  	return;
241  }
242  #endif
243  
244  #ifdef CONFIG_OF
pm860x_rtc_dt_init(struct platform_device * pdev,struct pm860x_rtc_info * info)245  static int pm860x_rtc_dt_init(struct platform_device *pdev,
246  			      struct pm860x_rtc_info *info)
247  {
248  	struct device_node *np = pdev->dev.parent->of_node;
249  	int ret;
250  	if (!np)
251  		return -ENODEV;
252  	np = of_get_child_by_name(np, "rtc");
253  	if (!np) {
254  		dev_err(&pdev->dev, "failed to find rtc node\n");
255  		return -ENODEV;
256  	}
257  	ret = of_property_read_u32(np, "marvell,88pm860x-vrtc", &info->vrtc);
258  	if (ret)
259  		info->vrtc = 0;
260  	of_node_put(np);
261  	return 0;
262  }
263  #else
264  #define pm860x_rtc_dt_init(x, y)	do { } while (0)
265  #endif
266  
pm860x_rtc_probe(struct platform_device * pdev)267  static int pm860x_rtc_probe(struct platform_device *pdev)
268  {
269  	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
270  	struct pm860x_rtc_info *info;
271  	int ret;
272  
273  	info = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_rtc_info),
274  			    GFP_KERNEL);
275  	if (!info)
276  		return -ENOMEM;
277  	info->irq = platform_get_irq(pdev, 0);
278  	if (info->irq < 0)
279  		return info->irq;
280  
281  	info->chip = chip;
282  	info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
283  	info->dev = &pdev->dev;
284  	dev_set_drvdata(&pdev->dev, info);
285  
286  	info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
287  	if (IS_ERR(info->rtc_dev))
288  		return PTR_ERR(info->rtc_dev);
289  
290  	ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
291  					rtc_update_handler, IRQF_ONESHOT, "rtc",
292  					info);
293  	if (ret < 0) {
294  		dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
295  			info->irq, ret);
296  		return ret;
297  	}
298  
299  	/* set addresses of 32-bit base value for RTC time */
300  	pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
301  	pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
302  	pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
303  	pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
304  
305  	pm860x_rtc_dt_init(pdev, info);
306  
307  	info->rtc_dev->ops = &pm860x_rtc_ops;
308  	info->rtc_dev->range_max = U32_MAX;
309  
310  	ret = devm_rtc_register_device(info->rtc_dev);
311  	if (ret)
312  		return ret;
313  
314  	/*
315  	 * enable internal XO instead of internal 3.25MHz clock since it can
316  	 * free running in PMIC power-down state.
317  	 */
318  	pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
319  
320  #ifdef VRTC_CALIBRATION
321  	/* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
322  	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
323  
324  	/* calibrate VRTC */
325  	INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
326  	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
327  #endif	/* VRTC_CALIBRATION */
328  
329  	device_init_wakeup(&pdev->dev, 1);
330  
331  	return 0;
332  }
333  
pm860x_rtc_remove(struct platform_device * pdev)334  static void pm860x_rtc_remove(struct platform_device *pdev)
335  {
336  	struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
337  
338  #ifdef VRTC_CALIBRATION
339  	cancel_delayed_work_sync(&info->calib_work);
340  	/* disable measurement */
341  	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
342  #endif	/* VRTC_CALIBRATION */
343  }
344  
345  #ifdef CONFIG_PM_SLEEP
pm860x_rtc_suspend(struct device * dev)346  static int pm860x_rtc_suspend(struct device *dev)
347  {
348  	struct platform_device *pdev = to_platform_device(dev);
349  	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
350  
351  	if (device_may_wakeup(dev))
352  		chip->wakeup_flag |= 1 << PM8607_IRQ_RTC;
353  	return 0;
354  }
pm860x_rtc_resume(struct device * dev)355  static int pm860x_rtc_resume(struct device *dev)
356  {
357  	struct platform_device *pdev = to_platform_device(dev);
358  	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
359  
360  	if (device_may_wakeup(dev))
361  		chip->wakeup_flag &= ~(1 << PM8607_IRQ_RTC);
362  	return 0;
363  }
364  #endif
365  
366  static SIMPLE_DEV_PM_OPS(pm860x_rtc_pm_ops, pm860x_rtc_suspend, pm860x_rtc_resume);
367  
368  static struct platform_driver pm860x_rtc_driver = {
369  	.driver		= {
370  		.name	= "88pm860x-rtc",
371  		.pm	= &pm860x_rtc_pm_ops,
372  	},
373  	.probe		= pm860x_rtc_probe,
374  	.remove_new	= pm860x_rtc_remove,
375  };
376  
377  module_platform_driver(pm860x_rtc_driver);
378  
379  MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
380  MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
381  MODULE_LICENSE("GPL");
382