tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * SiRFSoC Real Time Clock interface for Linux
3 *
4 * Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
5 *
6 * Licensed under GPLv2 or later.
7 */
8
9#include <linux/module.h>
10#include <linux/err.h>
11#include <linux/rtc.h>
12#include <linux/platform_device.h>
13#include <linux/slab.h>
14#include <linux/io.h>
15#include <linux/of.h>
16#include <linux/rtc/sirfsoc_rtciobrg.h>
17
18
19#define RTC_CN 0x00
20#define RTC_ALARM0 0x04
21#define RTC_ALARM1 0x18
22#define RTC_STATUS 0x08
23#define RTC_SW_VALUE 0x40
24#define SIRFSOC_RTC_AL1E (1<<6)
25#define SIRFSOC_RTC_AL1 (1<<4)
26#define SIRFSOC_RTC_HZE (1<<3)
27#define SIRFSOC_RTC_AL0E (1<<2)
28#define SIRFSOC_RTC_HZ (1<<1)
29#define SIRFSOC_RTC_AL0 (1<<0)
30#define RTC_DIV 0x0c
31#define RTC_DEEP_CTRL 0x14
32#define RTC_CLOCK_SWITCH 0x1c
33#define SIRFSOC_RTC_CLK 0x03 /* others are reserved */
34
35/* Refer to RTC DIV switch */
36#define RTC_HZ 16
37
38/* This macro is also defined in arch/arm/plat-sirfsoc/cpu.c */
39#define RTC_SHIFT 4
40
41#define INTR_SYSRTC_CN 0x48
42
43struct sirfsoc_rtc_drv {
44 struct rtc_device *rtc;
45 u32 rtc_base;
46 u32 irq;
47 unsigned irq_wake;
48 /* Overflow for every 8 years extra time */
49 u32 overflow_rtc;
50#ifdef CONFIG_PM
51 u32 saved_counter;
52 u32 saved_overflow_rtc;
53#endif
54};
55
56static int sirfsoc_rtc_read_alarm(struct device *dev,
57 struct rtc_wkalrm *alrm)
58{
59 unsigned long rtc_alarm, rtc_count;
60 struct sirfsoc_rtc_drv *rtcdrv;
61
62 rtcdrv = dev_get_drvdata(dev);
63
64 local_irq_disable();
65
66 rtc_count = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
67
68 rtc_alarm = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_ALARM0);
69 memset(alrm, 0, sizeof(struct rtc_wkalrm));
70
71 /*
72 * assume alarm interval not beyond one round counter overflow_rtc:
73 * 0->0xffffffff
74 */
75 /* if alarm is in next overflow cycle */
76 if (rtc_count > rtc_alarm)
77 rtc_time_to_tm((rtcdrv->overflow_rtc + 1)
78 << (BITS_PER_LONG - RTC_SHIFT)
79 | rtc_alarm >> RTC_SHIFT, &(alrm->time));
80 else
81 rtc_time_to_tm(rtcdrv->overflow_rtc
82 << (BITS_PER_LONG - RTC_SHIFT)
83 | rtc_alarm >> RTC_SHIFT, &(alrm->time));
84 if (sirfsoc_rtc_iobrg_readl(
85 rtcdrv->rtc_base + RTC_STATUS) & SIRFSOC_RTC_AL0E)
86 alrm->enabled = 1;
87 local_irq_enable();
88
89 return 0;
90}
91
92static int sirfsoc_rtc_set_alarm(struct device *dev,
93 struct rtc_wkalrm *alrm)
94{
95 unsigned long rtc_status_reg, rtc_alarm;
96 struct sirfsoc_rtc_drv *rtcdrv;
97 rtcdrv = dev_get_drvdata(dev);
98
99 if (alrm->enabled) {
100 rtc_tm_to_time(&(alrm->time), &rtc_alarm);
101
102 local_irq_disable();
103
104 rtc_status_reg = sirfsoc_rtc_iobrg_readl(
105 rtcdrv->rtc_base + RTC_STATUS);
106 if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
107 /*
108 * An ongoing alarm in progress - ingore it and not
109 * to return EBUSY
110 */
111 dev_info(dev, "An old alarm was set, will be replaced by a new one\n");
112 }
113
114 sirfsoc_rtc_iobrg_writel(
115 rtc_alarm << RTC_SHIFT, rtcdrv->rtc_base + RTC_ALARM0);
116 rtc_status_reg &= ~0x07; /* mask out the lower status bits */
117 /*
118 * This bit RTC_AL sets it as a wake-up source for Sleep Mode
119 * Writing 1 into this bit will clear it
120 */
121 rtc_status_reg |= SIRFSOC_RTC_AL0;
122 /* enable the RTC alarm interrupt */
123 rtc_status_reg |= SIRFSOC_RTC_AL0E;
124 sirfsoc_rtc_iobrg_writel(
125 rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
126 local_irq_enable();
127 } else {
128 /*
129 * if this function was called with enabled=0
130 * then it could mean that the application is
131 * trying to cancel an ongoing alarm
132 */
133 local_irq_disable();
134
135 rtc_status_reg = sirfsoc_rtc_iobrg_readl(
136 rtcdrv->rtc_base + RTC_STATUS);
137 if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
138 /* clear the RTC status register's alarm bit */
139 rtc_status_reg &= ~0x07;
140 /* write 1 into SIRFSOC_RTC_AL0 to force a clear */
141 rtc_status_reg |= (SIRFSOC_RTC_AL0);
142 /* Clear the Alarm enable bit */
143 rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
144
145 sirfsoc_rtc_iobrg_writel(rtc_status_reg,
146 rtcdrv->rtc_base + RTC_STATUS);
147 }
148
149 local_irq_enable();
150 }
151
152 return 0;
153}
154
155static int sirfsoc_rtc_read_time(struct device *dev,
156 struct rtc_time *tm)
157{
158 unsigned long tmp_rtc = 0;
159 struct sirfsoc_rtc_drv *rtcdrv;
160 rtcdrv = dev_get_drvdata(dev);
161 /*
162 * This patch is taken from WinCE - Need to validate this for
163 * correctness. To work around sirfsoc RTC counter double sync logic
164 * fail, read several times to make sure get stable value.
165 */
166 do {
167 tmp_rtc = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
168 cpu_relax();
169 } while (tmp_rtc != sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN));
170
171 rtc_time_to_tm(rtcdrv->overflow_rtc << (BITS_PER_LONG - RTC_SHIFT) |
172 tmp_rtc >> RTC_SHIFT, tm);
173 return 0;
174}
175
176static int sirfsoc_rtc_set_time(struct device *dev,
177 struct rtc_time *tm)
178{
179 unsigned long rtc_time;
180 struct sirfsoc_rtc_drv *rtcdrv;
181 rtcdrv = dev_get_drvdata(dev);
182
183 rtc_tm_to_time(tm, &rtc_time);
184
185 rtcdrv->overflow_rtc = rtc_time >> (BITS_PER_LONG - RTC_SHIFT);
186
187 sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
188 rtcdrv->rtc_base + RTC_SW_VALUE);
189 sirfsoc_rtc_iobrg_writel(
190 rtc_time << RTC_SHIFT, rtcdrv->rtc_base + RTC_CN);
191
192 return 0;
193}
194
195static int sirfsoc_rtc_ioctl(struct device *dev, unsigned int cmd,
196 unsigned long arg)
197{
198 switch (cmd) {
199 case RTC_PIE_ON:
200 case RTC_PIE_OFF:
201 case RTC_UIE_ON:
202 case RTC_UIE_OFF:
203 case RTC_AIE_ON:
204 case RTC_AIE_OFF:
205 return 0;
206
207 default:
208 return -ENOIOCTLCMD;
209 }
210}
211
212static const struct rtc_class_ops sirfsoc_rtc_ops = {
213 .read_time = sirfsoc_rtc_read_time,
214 .set_time = sirfsoc_rtc_set_time,
215 .read_alarm = sirfsoc_rtc_read_alarm,
216 .set_alarm = sirfsoc_rtc_set_alarm,
217 .ioctl = sirfsoc_rtc_ioctl
218};
219
220static irqreturn_t sirfsoc_rtc_irq_handler(int irq, void *pdata)
221{
222 struct sirfsoc_rtc_drv *rtcdrv = pdata;
223 unsigned long rtc_status_reg = 0x0;
224 unsigned long events = 0x0;
225
226 rtc_status_reg = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_STATUS);
227 /* this bit will be set ONLY if an alarm was active
228 * and it expired NOW
229 * So this is being used as an ASSERT
230 */
231 if (rtc_status_reg & SIRFSOC_RTC_AL0) {
232 /*
233 * clear the RTC status register's alarm bit
234 * mask out the lower status bits
235 */
236 rtc_status_reg &= ~0x07;
237 /* write 1 into SIRFSOC_RTC_AL0 to ACK the alarm interrupt */
238 rtc_status_reg |= (SIRFSOC_RTC_AL0);
239 /* Clear the Alarm enable bit */
240 rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
241 }
242 sirfsoc_rtc_iobrg_writel(rtc_status_reg, rtcdrv->rtc_base + RTC_STATUS);
243 /* this should wake up any apps polling/waiting on the read
244 * after setting the alarm
245 */
246 events |= RTC_IRQF | RTC_AF;
247 rtc_update_irq(rtcdrv->rtc, 1, events);
248
249 return IRQ_HANDLED;
250}
251
252static const struct of_device_id sirfsoc_rtc_of_match[] = {
253 { .compatible = "sirf,prima2-sysrtc"},
254 {},
255};
256MODULE_DEVICE_TABLE(of, sirfsoc_rtc_of_match);
257
258static int sirfsoc_rtc_probe(struct platform_device *pdev)
259{
260 int err;
261 unsigned long rtc_div;
262 struct sirfsoc_rtc_drv *rtcdrv;
263 struct device_node *np = pdev->dev.of_node;
264
265 rtcdrv = devm_kzalloc(&pdev->dev,
266 sizeof(struct sirfsoc_rtc_drv), GFP_KERNEL);
267 if (rtcdrv == NULL)
268 return -ENOMEM;
269
270 err = of_property_read_u32(np, "reg", &rtcdrv->rtc_base);
271 if (err) {
272 dev_err(&pdev->dev, "unable to find base address of rtc node in dtb\n");
273 return err;
274 }
275
276 platform_set_drvdata(pdev, rtcdrv);
277
278 /* Register rtc alarm as a wakeup source */
279 device_init_wakeup(&pdev->dev, 1);
280
281 /*
282 * Set SYS_RTC counter in RTC_HZ HZ Units
283 * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
284 * If 16HZ, therefore RTC_DIV = 1023;
285 */
286 rtc_div = ((32768 / RTC_HZ) / 2) - 1;
287 sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
288
289 rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
290 &sirfsoc_rtc_ops, THIS_MODULE);
291 if (IS_ERR(rtcdrv->rtc)) {
292 err = PTR_ERR(rtcdrv->rtc);
293 dev_err(&pdev->dev, "can't register RTC device\n");
294 return err;
295 }
296
297 /* 0x3 -> RTC_CLK */
298 sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
299 rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
300
301 /* reset SYS RTC ALARM0 */
302 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
303
304 /* reset SYS RTC ALARM1 */
305 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
306
307 /* Restore RTC Overflow From Register After Command Reboot */
308 rtcdrv->overflow_rtc =
309 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
310
311 rtcdrv->irq = platform_get_irq(pdev, 0);
312 err = devm_request_irq(
313 &pdev->dev,
314 rtcdrv->irq,
315 sirfsoc_rtc_irq_handler,
316 IRQF_SHARED,
317 pdev->name,
318 rtcdrv);
319 if (err) {
320 dev_err(&pdev->dev, "Unable to register for the SiRF SOC RTC IRQ\n");
321 return err;
322 }
323
324 return 0;
325}
326
327static int sirfsoc_rtc_remove(struct platform_device *pdev)
328{
329 device_init_wakeup(&pdev->dev, 0);
330
331 return 0;
332}
333
334#ifdef CONFIG_PM_SLEEP
335static int sirfsoc_rtc_suspend(struct device *dev)
336{
337 struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
338 rtcdrv->overflow_rtc =
339 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_SW_VALUE);
340
341 rtcdrv->saved_counter =
342 sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
343 rtcdrv->saved_overflow_rtc = rtcdrv->overflow_rtc;
344 if (device_may_wakeup(dev) && !enable_irq_wake(rtcdrv->irq))
345 rtcdrv->irq_wake = 1;
346
347 return 0;
348}
349
350static int sirfsoc_rtc_resume(struct device *dev)
351{
352 u32 tmp;
353 struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
354
355 /*
356 * if resume from snapshot and the rtc power is lost,
357 * restroe the rtc settings
358 */
359 if (SIRFSOC_RTC_CLK != sirfsoc_rtc_iobrg_readl(
360 rtcdrv->rtc_base + RTC_CLOCK_SWITCH)) {
361 u32 rtc_div;
362 /* 0x3 -> RTC_CLK */
363 sirfsoc_rtc_iobrg_writel(SIRFSOC_RTC_CLK,
364 rtcdrv->rtc_base + RTC_CLOCK_SWITCH);
365 /*
366 * Set SYS_RTC counter in RTC_HZ HZ Units
367 * We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
368 * If 16HZ, therefore RTC_DIV = 1023;
369 */
370 rtc_div = ((32768 / RTC_HZ) / 2) - 1;
371
372 sirfsoc_rtc_iobrg_writel(rtc_div, rtcdrv->rtc_base + RTC_DIV);
373
374 /* reset SYS RTC ALARM0 */
375 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM0);
376
377 /* reset SYS RTC ALARM1 */
378 sirfsoc_rtc_iobrg_writel(0x0, rtcdrv->rtc_base + RTC_ALARM1);
379 }
380 rtcdrv->overflow_rtc = rtcdrv->saved_overflow_rtc;
381
382 /*
383 * if current counter is small than previous,
384 * it means overflow in sleep
385 */
386 tmp = sirfsoc_rtc_iobrg_readl(rtcdrv->rtc_base + RTC_CN);
387 if (tmp <= rtcdrv->saved_counter)
388 rtcdrv->overflow_rtc++;
389 /*
390 *PWRC Value Be Changed When Suspend, Restore Overflow
391 * In Memory To Register
392 */
393 sirfsoc_rtc_iobrg_writel(rtcdrv->overflow_rtc,
394 rtcdrv->rtc_base + RTC_SW_VALUE);
395
396 if (device_may_wakeup(dev) && rtcdrv->irq_wake) {
397 disable_irq_wake(rtcdrv->irq);
398 rtcdrv->irq_wake = 0;
399 }
400
401 return 0;
402}
403#endif
404
405static SIMPLE_DEV_PM_OPS(sirfsoc_rtc_pm_ops,
406 sirfsoc_rtc_suspend, sirfsoc_rtc_resume);
407
408static struct platform_driver sirfsoc_rtc_driver = {
409 .driver = {
410 .name = "sirfsoc-rtc",
411 .owner = THIS_MODULE,
412 .pm = &sirfsoc_rtc_pm_ops,
413 .of_match_table = sirfsoc_rtc_of_match,
414 },
415 .probe = sirfsoc_rtc_probe,
416 .remove = sirfsoc_rtc_remove,
417};
418module_platform_driver(sirfsoc_rtc_driver);
419
420MODULE_DESCRIPTION("SiRF SoC rtc driver");
421MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
422MODULE_LICENSE("GPL v2");
423MODULE_ALIAS("platform:sirfsoc-rtc");