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 | |
50 | static 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 | |
56 | static 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 | |
61 | static 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: &value); |
79 | if (retval < 0) |
80 | return retval; |
81 | |
82 | if (!(value & RTC_READ_REQUEST)) |
83 | break; |
84 | |
85 | usleep_range(min: 1000, max: 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, reg: ab8500_rtc_time_regs[i], value: &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(time: secs, tm); |
104 | return 0; |
105 | } |
106 | |
107 | static 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 | reg: ab8500_rtc_time_regs[i], value: 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 | |
140 | static 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, value: &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 | reg: ab8500_rtc_alarm_regs[i], value: &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(time: secs, tm: &alarm->time); |
172 | |
173 | return 0; |
174 | } |
175 | |
176 | static 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 | bitvalues: enabled ? RTC_ALARM_ENA : 0); |
181 | } |
182 | |
183 | static 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(tm: &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 | reg: ab8500_rtc_alarm_regs[i], value: buf[i]); |
199 | if (retval < 0) |
200 | return retval; |
201 | } |
202 | |
203 | return ab8500_rtc_irq_enable(dev, enabled: alarm->enabled); |
204 | } |
205 | |
206 | static 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, value: rtccal); |
235 | |
236 | return retval; |
237 | } |
238 | |
239 | static 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, value: &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 | |
261 | static 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 | |
278 | static 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: &calibration); |
285 | if (retval < 0) { |
286 | dev_err(dev, "Failed to read RTC calibration attribute\n" ); |
287 | sprintf(buf, fmt: "0\n" ); |
288 | return retval; |
289 | } |
290 | |
291 | return sprintf(buf, fmt: "%d\n" , calibration); |
292 | } |
293 | |
294 | static DEVICE_ATTR(rtc_calibration, S_IRUGO | S_IWUSR, |
295 | ab8500_sysfs_show_rtc_calibration, |
296 | ab8500_sysfs_store_rtc_calibration); |
297 | |
298 | static struct attribute *ab8500_rtc_attrs[] = { |
299 | &dev_attr_rtc_calibration.attr, |
300 | NULL |
301 | }; |
302 | |
303 | static const struct attribute_group ab8500_rtc_sysfs_files = { |
304 | .attrs = ab8500_rtc_attrs, |
305 | }; |
306 | |
307 | static 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, num: 1, events); |
314 | |
315 | return IRQ_HANDLED; |
316 | } |
317 | |
318 | static 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 | |
326 | static const struct platform_device_id ab85xx_rtc_ids[] = { |
327 | { "ab8500-rtc" , (kernel_ulong_t)&ab8500_rtc_ops, }, |
328 | { /* sentinel */ } |
329 | }; |
330 | MODULE_DEVICE_TABLE(platform, ab85xx_rtc_ids); |
331 | |
332 | static 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(dev: &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(min: 1000, max: 5000); |
352 | |
353 | err = abx500_get_register_interruptible(dev: &pdev->dev, AB8500_RTC, |
354 | AB8500_RTC_STAT_REG, value: &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(dev: &pdev->dev, enable: true); |
365 | |
366 | rtc = devm_rtc_allocate_device(dev: &pdev->dev); |
367 | if (IS_ERR(ptr: rtc)) |
368 | return PTR_ERR(ptr: rtc); |
369 | |
370 | rtc->ops = (struct rtc_class_ops *)platid->driver_data; |
371 | |
372 | err = devm_request_threaded_irq(dev: &pdev->dev, irq, NULL, |
373 | thread_fn: rtc_alarm_handler, IRQF_ONESHOT, |
374 | devname: "ab8500-rtc" , dev_id: rtc); |
375 | if (err < 0) |
376 | return err; |
377 | |
378 | dev_pm_set_wake_irq(dev: &pdev->dev, irq); |
379 | platform_set_drvdata(pdev, data: rtc); |
380 | |
381 | set_bit(RTC_FEATURE_ALARM_RES_MINUTE, addr: rtc->features); |
382 | clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, addr: 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, grp: &ab8500_rtc_sysfs_files); |
389 | if (err) |
390 | return err; |
391 | |
392 | return devm_rtc_register_device(rtc); |
393 | } |
394 | |
395 | static void ab8500_rtc_remove(struct platform_device *pdev) |
396 | { |
397 | dev_pm_clear_wake_irq(dev: &pdev->dev); |
398 | device_init_wakeup(dev: &pdev->dev, enable: false); |
399 | } |
400 | |
401 | static 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 | |
410 | module_platform_driver(ab8500_rtc_driver); |
411 | |
412 | MODULE_AUTHOR("Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>" ); |
413 | MODULE_DESCRIPTION("AB8500 RTC Driver" ); |
414 | MODULE_LICENSE("GPL v2" ); |
415 | |