1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) ST-Ericsson SA 2010
4 *
5 * Author: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
6 *
7 * RTC clock driver for the RTC part of the AB8500 Power management chip.
8 * Based on RTC clock driver for the AB3100 Analog Baseband Chip by
9 * Linus Walleij <linus.walleij@stericsson.com>
10 */
11
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/rtc.h>
17#include <linux/mfd/abx500.h>
18#include <linux/mfd/abx500/ab8500.h>
19#include <linux/delay.h>
20#include <linux/of.h>
21#include <linux/pm_wakeirq.h>
22
23#define AB8500_RTC_SOFF_STAT_REG	0x00
24#define AB8500_RTC_CC_CONF_REG		0x01
25#define AB8500_RTC_READ_REQ_REG		0x02
26#define AB8500_RTC_WATCH_TSECMID_REG	0x03
27#define AB8500_RTC_WATCH_TSECHI_REG	0x04
28#define AB8500_RTC_WATCH_TMIN_LOW_REG	0x05
29#define AB8500_RTC_WATCH_TMIN_MID_REG	0x06
30#define AB8500_RTC_WATCH_TMIN_HI_REG	0x07
31#define AB8500_RTC_ALRM_MIN_LOW_REG	0x08
32#define AB8500_RTC_ALRM_MIN_MID_REG	0x09
33#define AB8500_RTC_ALRM_MIN_HI_REG	0x0A
34#define AB8500_RTC_STAT_REG		0x0B
35#define AB8500_RTC_BKUP_CHG_REG		0x0C
36#define AB8500_RTC_FORCE_BKUP_REG	0x0D
37#define AB8500_RTC_CALIB_REG		0x0E
38#define AB8500_RTC_SWITCH_STAT_REG	0x0F
39
40/* RtcReadRequest bits */
41#define RTC_READ_REQUEST		0x01
42#define RTC_WRITE_REQUEST		0x02
43
44/* RtcCtrl bits */
45#define RTC_ALARM_ENA			0x04
46#define RTC_STATUS_DATA			0x01
47
48#define COUNTS_PER_SEC			(0xF000 / 60)
49
50static const u8 ab8500_rtc_time_regs[] = {
51	AB8500_RTC_WATCH_TMIN_HI_REG, AB8500_RTC_WATCH_TMIN_MID_REG,
52	AB8500_RTC_WATCH_TMIN_LOW_REG, AB8500_RTC_WATCH_TSECHI_REG,
53	AB8500_RTC_WATCH_TSECMID_REG
54};
55
56static const u8 ab8500_rtc_alarm_regs[] = {
57	AB8500_RTC_ALRM_MIN_HI_REG, AB8500_RTC_ALRM_MIN_MID_REG,
58	AB8500_RTC_ALRM_MIN_LOW_REG
59};
60
61static int ab8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
62{
63	unsigned long timeout = jiffies + HZ;
64	int retval, i;
65	unsigned long mins, secs;
66	unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
67	u8 value;
68
69	/* Request a data read */
70	retval = abx500_set_register_interruptible(dev,
71		AB8500_RTC, AB8500_RTC_READ_REQ_REG, RTC_READ_REQUEST);
72	if (retval < 0)
73		return retval;
74
75	/* Wait for some cycles after enabling the rtc read in ab8500 */
76	while (time_before(jiffies, timeout)) {
77		retval = abx500_get_register_interruptible(dev,
78			AB8500_RTC, AB8500_RTC_READ_REQ_REG, &value);
79		if (retval < 0)
80			return retval;
81
82		if (!(value & RTC_READ_REQUEST))
83			break;
84
85		usleep_range(1000, 5000);
86	}
87
88	/* Read the Watchtime registers */
89	for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
90		retval = abx500_get_register_interruptible(dev,
91			AB8500_RTC, ab8500_rtc_time_regs[i], &value);
92		if (retval < 0)
93			return retval;
94		buf[i] = value;
95	}
96
97	mins = (buf[0] << 16) | (buf[1] << 8) | buf[2];
98
99	secs =	(buf[3] << 8) | buf[4];
100	secs =	secs / COUNTS_PER_SEC;
101	secs =	secs + (mins * 60);
102
103	rtc_time64_to_tm(secs, tm);
104	return 0;
105}
106
107static int ab8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
108{
109	int retval, i;
110	unsigned char buf[ARRAY_SIZE(ab8500_rtc_time_regs)];
111	unsigned long no_secs, no_mins, secs = 0;
112
113	secs = rtc_tm_to_time64(tm);
114
115	no_mins = secs / 60;
116
117	no_secs = secs % 60;
118	/* Make the seconds count as per the RTC resolution */
119	no_secs = no_secs * COUNTS_PER_SEC;
120
121	buf[4] = no_secs & 0xFF;
122	buf[3] = (no_secs >> 8) & 0xFF;
123
124	buf[2] = no_mins & 0xFF;
125	buf[1] = (no_mins >> 8) & 0xFF;
126	buf[0] = (no_mins >> 16) & 0xFF;
127
128	for (i = 0; i < ARRAY_SIZE(ab8500_rtc_time_regs); i++) {
129		retval = abx500_set_register_interruptible(dev, AB8500_RTC,
130			ab8500_rtc_time_regs[i], buf[i]);
131		if (retval < 0)
132			return retval;
133	}
134
135	/* Request a data write */
136	return abx500_set_register_interruptible(dev, AB8500_RTC,
137		AB8500_RTC_READ_REQ_REG, RTC_WRITE_REQUEST);
138}
139
140static int ab8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
141{
142	int retval, i;
143	u8 rtc_ctrl, value;
144	unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
145	unsigned long secs, mins;
146
147	/* Check if the alarm is enabled or not */
148	retval = abx500_get_register_interruptible(dev, AB8500_RTC,
149		AB8500_RTC_STAT_REG, &rtc_ctrl);
150	if (retval < 0)
151		return retval;
152
153	if (rtc_ctrl & RTC_ALARM_ENA)
154		alarm->enabled = 1;
155	else
156		alarm->enabled = 0;
157
158	alarm->pending = 0;
159
160	for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
161		retval = abx500_get_register_interruptible(dev, AB8500_RTC,
162			ab8500_rtc_alarm_regs[i], &value);
163		if (retval < 0)
164			return retval;
165		buf[i] = value;
166	}
167
168	mins = (buf[0] << 16) | (buf[1] << 8) | (buf[2]);
169	secs = mins * 60;
170
171	rtc_time64_to_tm(secs, &alarm->time);
172
173	return 0;
174}
175
176static int ab8500_rtc_irq_enable(struct device *dev, unsigned int enabled)
177{
178	return abx500_mask_and_set_register_interruptible(dev, AB8500_RTC,
179		AB8500_RTC_STAT_REG, RTC_ALARM_ENA,
180		enabled ? RTC_ALARM_ENA : 0);
181}
182
183static int ab8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
184{
185	int retval, i;
186	unsigned char buf[ARRAY_SIZE(ab8500_rtc_alarm_regs)];
187	unsigned long mins;
188
189	mins = (unsigned long)rtc_tm_to_time64(&alarm->time) / 60;
190
191	buf[2] = mins & 0xFF;
192	buf[1] = (mins >> 8) & 0xFF;
193	buf[0] = (mins >> 16) & 0xFF;
194
195	/* Set the alarm time */
196	for (i = 0; i < ARRAY_SIZE(ab8500_rtc_alarm_regs); i++) {
197		retval = abx500_set_register_interruptible(dev, AB8500_RTC,
198			ab8500_rtc_alarm_regs[i], buf[i]);
199		if (retval < 0)
200			return retval;
201	}
202
203	return ab8500_rtc_irq_enable(dev, alarm->enabled);
204}
205
206static int ab8500_rtc_set_calibration(struct device *dev, int calibration)
207{
208	int retval;
209	u8  rtccal = 0;
210
211	/*
212	 * Check that the calibration value (which is in units of 0.5
213	 * parts-per-million) is in the AB8500's range for RtcCalibration
214	 * register. -128 (0x80) is not permitted because the AB8500 uses
215	 * a sign-bit rather than two's complement, so 0x80 is just another
216	 * representation of zero.
217	 */
218	if ((calibration < -127) || (calibration > 127)) {
219		dev_err(dev, "RtcCalibration value outside permitted range\n");
220		return -EINVAL;
221	}
222
223	/*
224	 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
225	 * so need to convert to this sort of representation before writing
226	 * into RtcCalibration register...
227	 */
228	if (calibration >= 0)
229		rtccal = 0x7F & calibration;
230	else
231		rtccal = ~(calibration - 1) | 0x80;
232
233	retval = abx500_set_register_interruptible(dev, AB8500_RTC,
234			AB8500_RTC_CALIB_REG, rtccal);
235
236	return retval;
237}
238
239static int ab8500_rtc_get_calibration(struct device *dev, int *calibration)
240{
241	int retval;
242	u8  rtccal = 0;
243
244	retval =  abx500_get_register_interruptible(dev, AB8500_RTC,
245			AB8500_RTC_CALIB_REG, &rtccal);
246	if (retval >= 0) {
247		/*
248		 * The AB8500 uses sign (in bit7) and magnitude (in bits0-7)
249		 * so need to convert value from RtcCalibration register into
250		 * a two's complement signed value...
251		 */
252		if (rtccal & 0x80)
253			*calibration = 0 - (rtccal & 0x7F);
254		else
255			*calibration = 0x7F & rtccal;
256	}
257
258	return retval;
259}
260
261static ssize_t ab8500_sysfs_store_rtc_calibration(struct device *dev,
262				struct device_attribute *attr,
263				const char *buf, size_t count)
264{
265	int retval;
266	int calibration = 0;
267
268	if (sscanf(buf, " %i ", &calibration) != 1) {
269		dev_err(dev, "Failed to store RTC calibration attribute\n");
270		return -EINVAL;
271	}
272
273	retval = ab8500_rtc_set_calibration(dev, calibration);
274
275	return retval ? retval : count;
276}
277
278static ssize_t ab8500_sysfs_show_rtc_calibration(struct device *dev,
279				struct device_attribute *attr, char *buf)
280{
281	int  retval = 0;
282	int  calibration = 0;
283
284	retval = ab8500_rtc_get_calibration(dev, &calibration);
285	if (retval < 0) {
286		dev_err(dev, "Failed to read RTC calibration attribute\n");
287		sprintf(buf, "0\n");
288		return retval;
289	}
290
291	return sprintf(buf, "%d\n", calibration);
292}
293
294static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
295		   ab8500_sysfs_show_rtc_calibration,
296		   ab8500_sysfs_store_rtc_calibration);
297
298static struct attribute *ab8500_rtc_attrs[] = {
299	&dev_attr_rtc_calibration.attr,
300	NULL
301};
302
303static const struct attribute_group ab8500_rtc_sysfs_files = {
304	.attrs	= ab8500_rtc_attrs,
305};
306
307static irqreturn_t rtc_alarm_handler(int irq, void *data)
308{
309	struct rtc_device *rtc = data;
310	unsigned long events = RTC_IRQF | RTC_AF;
311
312	dev_dbg(&rtc->dev, "%s\n", __func__);
313	rtc_update_irq(rtc, 1, events);
314
315	return IRQ_HANDLED;
316}
317
318static const struct rtc_class_ops ab8500_rtc_ops = {
319	.read_time		= ab8500_rtc_read_time,
320	.set_time		= ab8500_rtc_set_time,
321	.read_alarm		= ab8500_rtc_read_alarm,
322	.set_alarm		= ab8500_rtc_set_alarm,
323	.alarm_irq_enable	= ab8500_rtc_irq_enable,
324};
325
326static const struct platform_device_id ab85xx_rtc_ids[] = {
327	{ "ab8500-rtc", (kernel_ulong_t)&ab8500_rtc_ops, },
328	{ /* sentinel */ }
329};
330MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
331
332static int ab8500_rtc_probe(struct platform_device *pdev)
333{
334	const struct platform_device_id *platid = platform_get_device_id(pdev);
335	int err;
336	struct rtc_device *rtc;
337	u8 rtc_ctrl;
338	int irq;
339
340	irq = platform_get_irq_byname(pdev, "ALARM");
341	if (irq < 0)
342		return irq;
343
344	/* For RTC supply test */
345	err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
346		AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
347	if (err < 0)
348		return err;
349
350	/* Wait for reset by the PorRtc */
351	usleep_range(1000, 5000);
352
353	err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
354		AB8500_RTC_STAT_REG, &rtc_ctrl);
355	if (err < 0)
356		return err;
357
358	/* Check if the RTC Supply fails */
359	if (!(rtc_ctrl & RTC_STATUS_DATA)) {
360		dev_err(&pdev->dev, "RTC supply failure\n");
361		return -ENODEV;
362	}
363
364	device_init_wakeup(&pdev->dev, true);
365
366	rtc = devm_rtc_allocate_device(&pdev->dev);
367	if (IS_ERR(rtc))
368		return PTR_ERR(rtc);
369
370	rtc->ops = (struct rtc_class_ops *)platid->driver_data;
371
372	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
373			rtc_alarm_handler, IRQF_ONESHOT,
374			"ab8500-rtc", rtc);
375	if (err < 0)
376		return err;
377
378	dev_pm_set_wake_irq(&pdev->dev, irq);
379	platform_set_drvdata(pdev, rtc);
380
381	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
382	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
383
384	rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs
385	rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000;
386	rtc->set_start_time = true;
387
388	err = rtc_add_group(rtc, &ab8500_rtc_sysfs_files);
389	if (err)
390		return err;
391
392	return devm_rtc_register_device(rtc);
393}
394
395static void ab8500_rtc_remove(struct platform_device *pdev)
396{
397	dev_pm_clear_wake_irq(&pdev->dev);
398	device_init_wakeup(&pdev->dev, false);
399}
400
401static struct platform_driver ab8500_rtc_driver = {
402	.driver = {
403		.name = "ab8500-rtc",
404	},
405	.probe	= ab8500_rtc_probe,
406	.remove_new = ab8500_rtc_remove,
407	.id_table = ab85xx_rtc_ids,
408};
409
410module_platform_driver(ab8500_rtc_driver);
411
412MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>");
413MODULE_DESCRIPTION("AB8500 RTC Driver");
414MODULE_LICENSE("GPL v2");
415