1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Freescale STMP37XX/STMP378X Real Time Clock driver
4 *
5 * Copyright (c) 2007 Sigmatel, Inc.
6 * Peter Hartley, <peter.hartley@sigmatel.com>
7 *
8 * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
9 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
10 * Copyright 2011 Wolfram Sang, Pengutronix e.K.
11 */
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/io.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/interrupt.h>
18 #include <linux/delay.h>
19 #include <linux/rtc.h>
20 #include <linux/slab.h>
21 #include <linux/of.h>
22 #include <linux/stmp_device.h>
23 #include <linux/stmp3xxx_rtc_wdt.h>
24
25 #define STMP3XXX_RTC_CTRL 0x0
26 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001
27 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002
28 #define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004
29 #define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010
30
31 #define STMP3XXX_RTC_STAT 0x10
32 #define STMP3XXX_RTC_STAT_STALE_SHIFT 16
33 #define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000
34 #define STMP3XXX_RTC_STAT_XTAL32000_PRESENT 0x10000000
35 #define STMP3XXX_RTC_STAT_XTAL32768_PRESENT 0x08000000
36
37 #define STMP3XXX_RTC_SECONDS 0x30
38
39 #define STMP3XXX_RTC_ALARM 0x40
40
41 #define STMP3XXX_RTC_WATCHDOG 0x50
42
43 #define STMP3XXX_RTC_PERSISTENT0 0x60
44 #define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE (1 << 0)
45 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN (1 << 1)
46 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN (1 << 2)
47 #define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4)
48 #define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5)
49 #define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ (1 << 6)
50 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE (1 << 7)
51
52 #define STMP3XXX_RTC_PERSISTENT1 0x70
53 /* missing bitmask in headers */
54 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000
55
56 struct stmp3xxx_rtc_data {
57 struct rtc_device *rtc;
58 void __iomem *io;
59 int irq_alarm;
60 };
61
62 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
63 /**
64 * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
65 * @dev: the parent device of the watchdog (= the RTC)
66 * @timeout: the desired value for the timeout register of the watchdog.
67 * 0 disables the watchdog
68 *
69 * The watchdog needs one register and two bits which are in the RTC domain.
70 * To handle the resource conflict, the RTC driver will create another
71 * platform_device for the watchdog driver as a child of the RTC device.
72 * The watchdog driver is passed the below accessor function via platform_data
73 * to configure the watchdog. Locking is not needed because accessing SET/CLR
74 * registers is atomic.
75 */
76
stmp3xxx_wdt_set_timeout(struct device * dev,u32 timeout)77 static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
78 {
79 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
80
81 if (timeout) {
82 writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
83 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
84 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
85 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
86 rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET);
87 } else {
88 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
89 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
90 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
91 rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR);
92 }
93 }
94
95 static struct stmp3xxx_wdt_pdata wdt_pdata = {
96 .wdt_set_timeout = stmp3xxx_wdt_set_timeout,
97 };
98
stmp3xxx_wdt_register(struct platform_device * rtc_pdev)99 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
100 {
101 int rc = -1;
102 struct platform_device *wdt_pdev =
103 platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
104
105 if (wdt_pdev) {
106 wdt_pdev->dev.parent = &rtc_pdev->dev;
107 wdt_pdev->dev.platform_data = &wdt_pdata;
108 rc = platform_device_add(wdt_pdev);
109 if (rc)
110 platform_device_put(wdt_pdev);
111 }
112
113 if (rc)
114 dev_err(&rtc_pdev->dev,
115 "failed to register stmp3xxx_rtc_wdt\n");
116 }
117 #else
stmp3xxx_wdt_register(struct platform_device * rtc_pdev)118 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
119 {
120 }
121 #endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
122
stmp3xxx_wait_time(struct stmp3xxx_rtc_data * rtc_data)123 static int stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
124 {
125 int timeout = 5000; /* 3ms according to i.MX28 Ref Manual */
126 /*
127 * The i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
128 * states:
129 * | The order in which registers are updated is
130 * | Persistent 0, 1, 2, 3, 4, 5, Alarm, Seconds.
131 * | (This list is in bitfield order, from LSB to MSB, as they would
132 * | appear in the STALE_REGS and NEW_REGS bitfields of the HW_RTC_STAT
133 * | register. For example, the Seconds register corresponds to
134 * | STALE_REGS or NEW_REGS containing 0x80.)
135 */
136 do {
137 if (!(readl(rtc_data->io + STMP3XXX_RTC_STAT) &
138 (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)))
139 return 0;
140 udelay(1);
141 } while (--timeout > 0);
142 return (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
143 (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT)) ? -ETIME : 0;
144 }
145
146 /* Time read/write */
stmp3xxx_rtc_gettime(struct device * dev,struct rtc_time * rtc_tm)147 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
148 {
149 int ret;
150 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
151
152 ret = stmp3xxx_wait_time(rtc_data);
153 if (ret)
154 return ret;
155
156 rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
157 return 0;
158 }
159
stmp3xxx_rtc_settime(struct device * dev,struct rtc_time * rtc_tm)160 static int stmp3xxx_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
161 {
162 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
163
164 writel(rtc_tm_to_time64(rtc_tm), rtc_data->io + STMP3XXX_RTC_SECONDS);
165 return stmp3xxx_wait_time(rtc_data);
166 }
167
168 /* interrupt(s) handler */
stmp3xxx_rtc_interrupt(int irq,void * dev_id)169 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
170 {
171 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
172 u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
173
174 if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
175 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
176 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
177 rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
178 return IRQ_HANDLED;
179 }
180
181 return IRQ_NONE;
182 }
183
stmp3xxx_alarm_irq_enable(struct device * dev,unsigned int enabled)184 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
185 {
186 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
187
188 if (enabled) {
189 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
190 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
191 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
192 STMP_OFFSET_REG_SET);
193 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
194 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
195 } else {
196 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
197 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
198 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
199 STMP_OFFSET_REG_CLR);
200 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
201 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
202 }
203 return 0;
204 }
205
stmp3xxx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alm)206 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
207 {
208 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
209
210 rtc_time64_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
211 return 0;
212 }
213
stmp3xxx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alm)214 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
215 {
216 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
217
218 writel(rtc_tm_to_time64(&alm->time), rtc_data->io + STMP3XXX_RTC_ALARM);
219
220 stmp3xxx_alarm_irq_enable(dev, alm->enabled);
221
222 return 0;
223 }
224
225 static const struct rtc_class_ops stmp3xxx_rtc_ops = {
226 .alarm_irq_enable =
227 stmp3xxx_alarm_irq_enable,
228 .read_time = stmp3xxx_rtc_gettime,
229 .set_time = stmp3xxx_rtc_settime,
230 .read_alarm = stmp3xxx_rtc_read_alarm,
231 .set_alarm = stmp3xxx_rtc_set_alarm,
232 };
233
stmp3xxx_rtc_remove(struct platform_device * pdev)234 static void stmp3xxx_rtc_remove(struct platform_device *pdev)
235 {
236 struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
237
238 if (!rtc_data)
239 return;
240
241 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
242 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
243 }
244
stmp3xxx_rtc_probe(struct platform_device * pdev)245 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
246 {
247 struct stmp3xxx_rtc_data *rtc_data;
248 struct resource *r;
249 u32 rtc_stat;
250 u32 pers0_set, pers0_clr;
251 u32 crystalfreq = 0;
252 int err;
253
254 rtc_data = devm_kzalloc(&pdev->dev, sizeof(*rtc_data), GFP_KERNEL);
255 if (!rtc_data)
256 return -ENOMEM;
257
258 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
259 if (!r) {
260 dev_err(&pdev->dev, "failed to get resource\n");
261 return -ENXIO;
262 }
263
264 rtc_data->io = devm_ioremap(&pdev->dev, r->start, resource_size(r));
265 if (!rtc_data->io) {
266 dev_err(&pdev->dev, "ioremap failed\n");
267 return -EIO;
268 }
269
270 rtc_data->irq_alarm = platform_get_irq(pdev, 0);
271
272 rtc_stat = readl(rtc_data->io + STMP3XXX_RTC_STAT);
273 if (!(rtc_stat & STMP3XXX_RTC_STAT_RTC_PRESENT)) {
274 dev_err(&pdev->dev, "no device onboard\n");
275 return -ENODEV;
276 }
277
278 platform_set_drvdata(pdev, rtc_data);
279
280 /*
281 * Resetting the rtc stops the watchdog timer that is potentially
282 * running. So (assuming it is running on purpose) don't reset if the
283 * watchdog is enabled.
284 */
285 if (readl(rtc_data->io + STMP3XXX_RTC_CTRL) &
286 STMP3XXX_RTC_CTRL_WATCHDOGEN) {
287 dev_info(&pdev->dev,
288 "Watchdog is running, skip resetting rtc\n");
289 } else {
290 err = stmp_reset_block(rtc_data->io);
291 if (err) {
292 dev_err(&pdev->dev, "stmp_reset_block failed: %d\n",
293 err);
294 return err;
295 }
296 }
297
298 /*
299 * Obviously the rtc needs a clock input to be able to run.
300 * This clock can be provided by an external 32k crystal. If that one is
301 * missing XTAL must not be disabled in suspend which consumes a
302 * lot of power. Normally the presence and exact frequency (supported
303 * are 32000 Hz and 32768 Hz) is detectable from fuses, but as reality
304 * proves these fuses are not blown correctly on all machines, so the
305 * frequency can be overridden in the device tree.
306 */
307 if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32000_PRESENT)
308 crystalfreq = 32000;
309 else if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32768_PRESENT)
310 crystalfreq = 32768;
311
312 of_property_read_u32(pdev->dev.of_node, "stmp,crystal-freq",
313 &crystalfreq);
314
315 switch (crystalfreq) {
316 case 32000:
317 /* keep 32kHz crystal running in low-power mode */
318 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ |
319 STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
320 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
321 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
322 break;
323 case 32768:
324 /* keep 32.768kHz crystal running in low-power mode */
325 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
326 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
327 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP |
328 STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ;
329 break;
330 default:
331 dev_warn(&pdev->dev,
332 "invalid crystal-freq specified in device-tree. Assuming no crystal\n");
333 fallthrough;
334 case 0:
335 /* keep XTAL on in low-power mode */
336 pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
337 pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
338 STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
339 }
340
341 writel(pers0_set, rtc_data->io + STMP3XXX_RTC_PERSISTENT0 +
342 STMP_OFFSET_REG_SET);
343
344 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
345 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
346 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE | pers0_clr,
347 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR);
348
349 writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
350 STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
351 rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
352
353 rtc_data->rtc = devm_rtc_allocate_device(&pdev->dev);
354 if (IS_ERR(rtc_data->rtc))
355 return PTR_ERR(rtc_data->rtc);
356
357 err = devm_request_irq(&pdev->dev, rtc_data->irq_alarm,
358 stmp3xxx_rtc_interrupt, 0, "RTC alarm", &pdev->dev);
359 if (err) {
360 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
361 rtc_data->irq_alarm);
362 return err;
363 }
364
365 rtc_data->rtc->ops = &stmp3xxx_rtc_ops;
366 rtc_data->rtc->range_max = U32_MAX;
367
368 err = devm_rtc_register_device(rtc_data->rtc);
369 if (err)
370 return err;
371
372 stmp3xxx_wdt_register(pdev);
373 return 0;
374 }
375
376 #ifdef CONFIG_PM_SLEEP
stmp3xxx_rtc_suspend(struct device * dev)377 static int stmp3xxx_rtc_suspend(struct device *dev)
378 {
379 return 0;
380 }
381
stmp3xxx_rtc_resume(struct device * dev)382 static int stmp3xxx_rtc_resume(struct device *dev)
383 {
384 struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
385
386 stmp_reset_block(rtc_data->io);
387 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
388 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
389 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
390 rtc_data->io + STMP3XXX_RTC_PERSISTENT0 + STMP_OFFSET_REG_CLR);
391 return 0;
392 }
393 #endif
394
395 static SIMPLE_DEV_PM_OPS(stmp3xxx_rtc_pm_ops, stmp3xxx_rtc_suspend,
396 stmp3xxx_rtc_resume);
397
398 static const struct of_device_id rtc_dt_ids[] = {
399 { .compatible = "fsl,stmp3xxx-rtc", },
400 { /* sentinel */ }
401 };
402 MODULE_DEVICE_TABLE(of, rtc_dt_ids);
403
404 static struct platform_driver stmp3xxx_rtcdrv = {
405 .probe = stmp3xxx_rtc_probe,
406 .remove = stmp3xxx_rtc_remove,
407 .driver = {
408 .name = "stmp3xxx-rtc",
409 .pm = &stmp3xxx_rtc_pm_ops,
410 .of_match_table = rtc_dt_ids,
411 },
412 };
413
414 module_platform_driver(stmp3xxx_rtcdrv);
415
416 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
417 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
418 "Wolfram Sang <kernel@pengutronix.de>");
419 MODULE_LICENSE("GPL");
420