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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) ST-Ericsson SA 2010
4 *
5 * Author: Virupax Sadashivpetimath <[email protected]>
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 <[email protected]>
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 return retval;
288 }
289
290 return sysfs_emit(buf, "%d\n", calibration);
291}
292
293static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR,
294 ab8500_sysfs_show_rtc_calibration,
295 ab8500_sysfs_store_rtc_calibration);
296
297static struct attribute *ab8500_rtc_attrs[] = {
298 &dev_attr_rtc_calibration.attr,
299 NULL
300};
301
302static const struct attribute_group ab8500_rtc_sysfs_files = {
303 .attrs = ab8500_rtc_attrs,
304};
305
306static irqreturn_t rtc_alarm_handler(int irq, void *data)
307{
308 struct rtc_device *rtc = data;
309 unsigned long events = RTC_IRQF | RTC_AF;
310
311 dev_dbg(&rtc->dev, "%s\n", __func__);
312 rtc_update_irq(rtc, 1, events);
313
314 return IRQ_HANDLED;
315}
316
317static const struct rtc_class_ops ab8500_rtc_ops = {
318 .read_time = ab8500_rtc_read_time,
319 .set_time = ab8500_rtc_set_time,
320 .read_alarm = ab8500_rtc_read_alarm,
321 .set_alarm = ab8500_rtc_set_alarm,
322 .alarm_irq_enable = ab8500_rtc_irq_enable,
323};
324
325static const struct platform_device_id ab85xx_rtc_ids[] = {
326 { .name = "ab8500-rtc" },
327 { /* sentinel */ }
328};
329MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids);
330
331static int ab8500_rtc_probe(struct platform_device *pdev)
332{
333 int err;
334 struct rtc_device *rtc;
335 u8 rtc_ctrl;
336 int irq;
337
338 irq = platform_get_irq_byname(pdev, "ALARM");
339 if (irq < 0)
340 return irq;
341
342 /* For RTC supply test */
343 err = abx500_mask_and_set_register_interruptible(&pdev->dev, AB8500_RTC,
344 AB8500_RTC_STAT_REG, RTC_STATUS_DATA, RTC_STATUS_DATA);
345 if (err < 0)
346 return err;
347
348 /* Wait for reset by the PorRtc */
349 usleep_range(1000, 5000);
350
351 err = abx500_get_register_interruptible(&pdev->dev, AB8500_RTC,
352 AB8500_RTC_STAT_REG, &rtc_ctrl);
353 if (err < 0)
354 return err;
355
356 /* Check if the RTC Supply fails */
357 if (!(rtc_ctrl & RTC_STATUS_DATA)) {
358 dev_err(&pdev->dev, "RTC supply failure\n");
359 return -ENODEV;
360 }
361
362 devm_device_init_wakeup(&pdev->dev);
363
364 rtc = devm_rtc_allocate_device(&pdev->dev);
365 if (IS_ERR(rtc))
366 return PTR_ERR(rtc);
367
368 rtc->ops = &ab8500_rtc_ops;
369
370 err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
371 rtc_alarm_handler, IRQF_ONESHOT,
372 "ab8500-rtc", rtc);
373 if (err < 0)
374 return err;
375
376 devm_pm_set_wake_irq(&pdev->dev, irq);
377 platform_set_drvdata(pdev, rtc);
378
379 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
380 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
381
382 rtc->range_max = (1ULL << 24) * 60 - 1; // 24-bit minutes + 59 secs
383 rtc->start_secs = RTC_TIMESTAMP_BEGIN_2000;
384 rtc->set_start_time = true;
385
386 err = rtc_add_group(rtc, &ab8500_rtc_sysfs_files);
387 if (err)
388 return err;
389
390 return devm_rtc_register_device(rtc);
391}
392
393static struct platform_driver ab8500_rtc_driver = {
394 .driver = {
395 .name = "ab8500-rtc",
396 },
397 .probe = ab8500_rtc_probe,
398 .id_table = ab85xx_rtc_ids,
399};
400
401module_platform_driver(ab8500_rtc_driver);
402
403MODULE_AUTHOR("Virupax Sadashivpetimath <[email protected]>");
404MODULE_DESCRIPTION("AB8500 RTC Driver");
405MODULE_LICENSE("GPL v2");