1 // SPDX-License-Identifier: GPL-2.0+
3 // Copyright (C) 2011-2012 Freescale Semiconductor, Inc.
5 #include <linux/init.h>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
10 #include <linux/of_device.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
13 #include <linux/clk.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/regmap.h>
17 #define SNVS_LPREGISTER_OFFSET 0x34
19 /* These register offsets are relative to LP (Low Power) range */
20 #define SNVS_LPCR 0x04
21 #define SNVS_LPSR 0x18
22 #define SNVS_LPSRTCMR 0x1c
23 #define SNVS_LPSRTCLR 0x20
24 #define SNVS_LPTAR 0x24
25 #define SNVS_LPPGDR 0x30
27 #define SNVS_LPCR_SRTC_ENV (1 << 0)
28 #define SNVS_LPCR_LPTA_EN (1 << 1)
29 #define SNVS_LPCR_LPWUI_EN (1 << 3)
30 #define SNVS_LPSR_LPTA (1 << 0)
32 #define SNVS_LPPGDR_INIT 0x41736166
33 #define CNTR_TO_SECS_SH 15
35 struct snvs_rtc_data {
36 struct rtc_device *rtc;
37 struct regmap *regmap;
43 /* Read 64 bit timer register, which could be in inconsistent state */
44 static u64 rtc_read_lpsrt(struct snvs_rtc_data *data)
48 regmap_read(data->regmap, data->offset + SNVS_LPSRTCMR, &msb);
49 regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &lsb);
50 return (u64)msb << 32 | lsb;
53 /* Read the secure real time counter, taking care to deal with the cases of the
54 * counter updating while being read.
56 static u32 rtc_read_lp_counter(struct snvs_rtc_data *data)
59 unsigned int timeout = 100;
61 /* As expected, the registers might update between the read of the LSB
62 * reg and the MSB reg. It's also possible that one register might be
63 * in partially modified state as well.
65 read1 = rtc_read_lpsrt(data);
68 read1 = rtc_read_lpsrt(data);
69 } while (read1 != read2 && --timeout);
71 dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n");
73 /* Convert 47-bit counter to 32-bit raw second count */
74 return (u32) (read1 >> CNTR_TO_SECS_SH);
77 /* Just read the lsb from the counter, dealing with inconsistent state */
78 static int rtc_read_lp_counter_lsb(struct snvs_rtc_data *data, u32 *lsb)
81 unsigned int timeout = 100;
83 regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);
86 regmap_read(data->regmap, data->offset + SNVS_LPSRTCLR, &count1);
87 } while (count1 != count2 && --timeout);
89 dev_err(&data->rtc->dev, "Timeout trying to get valid LPSRT Counter read\n");
97 static int rtc_write_sync_lp(struct snvs_rtc_data *data)
101 unsigned int timeout = 1000;
104 ret = rtc_read_lp_counter_lsb(data, &count1);
108 /* Wait for 3 CKIL cycles, about 61.0-91.5 µs */
110 ret = rtc_read_lp_counter_lsb(data, &count2);
113 elapsed = count2 - count1; /* wrap around _is_ handled! */
114 } while (elapsed < 3 && --timeout);
116 dev_err(&data->rtc->dev, "Timeout waiting for LPSRT Counter to change\n");
122 static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
127 regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_SRTC_ENV,
128 enable ? SNVS_LPCR_SRTC_ENV : 0);
131 regmap_read(data->regmap, data->offset + SNVS_LPCR, &lpcr);
134 if (lpcr & SNVS_LPCR_SRTC_ENV)
137 if (!(lpcr & SNVS_LPCR_SRTC_ENV))
148 static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
150 struct snvs_rtc_data *data = dev_get_drvdata(dev);
151 unsigned long time = rtc_read_lp_counter(data);
153 rtc_time_to_tm(time, tm);
158 static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
160 struct snvs_rtc_data *data = dev_get_drvdata(dev);
164 rtc_tm_to_time(tm, &time);
166 /* Disable RTC first */
167 ret = snvs_rtc_enable(data, false);
171 /* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */
172 regmap_write(data->regmap, data->offset + SNVS_LPSRTCLR, time << CNTR_TO_SECS_SH);
173 regmap_write(data->regmap, data->offset + SNVS_LPSRTCMR, time >> (32 - CNTR_TO_SECS_SH));
175 /* Enable RTC again */
176 ret = snvs_rtc_enable(data, true);
181 static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
183 struct snvs_rtc_data *data = dev_get_drvdata(dev);
186 regmap_read(data->regmap, data->offset + SNVS_LPTAR, &lptar);
187 rtc_time_to_tm(lptar, &alrm->time);
189 regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
190 alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0;
195 static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
197 struct snvs_rtc_data *data = dev_get_drvdata(dev);
199 regmap_update_bits(data->regmap, data->offset + SNVS_LPCR,
200 (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN),
201 enable ? (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN) : 0);
203 return rtc_write_sync_lp(data);
206 static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
208 struct snvs_rtc_data *data = dev_get_drvdata(dev);
209 struct rtc_time *alrm_tm = &alrm->time;
213 rtc_tm_to_time(alrm_tm, &time);
215 regmap_update_bits(data->regmap, data->offset + SNVS_LPCR, SNVS_LPCR_LPTA_EN, 0);
216 ret = rtc_write_sync_lp(data);
219 regmap_write(data->regmap, data->offset + SNVS_LPTAR, time);
221 /* Clear alarm interrupt status bit */
222 regmap_write(data->regmap, data->offset + SNVS_LPSR, SNVS_LPSR_LPTA);
224 return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);
227 static const struct rtc_class_ops snvs_rtc_ops = {
228 .read_time = snvs_rtc_read_time,
229 .set_time = snvs_rtc_set_time,
230 .read_alarm = snvs_rtc_read_alarm,
231 .set_alarm = snvs_rtc_set_alarm,
232 .alarm_irq_enable = snvs_rtc_alarm_irq_enable,
235 static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
237 struct device *dev = dev_id;
238 struct snvs_rtc_data *data = dev_get_drvdata(dev);
242 regmap_read(data->regmap, data->offset + SNVS_LPSR, &lpsr);
244 if (lpsr & SNVS_LPSR_LPTA) {
245 events |= (RTC_AF | RTC_IRQF);
247 /* RTC alarm should be one-shot */
248 snvs_rtc_alarm_irq_enable(dev, 0);
250 rtc_update_irq(data->rtc, 1, events);
253 /* clear interrupt status */
254 regmap_write(data->regmap, data->offset + SNVS_LPSR, lpsr);
256 return events ? IRQ_HANDLED : IRQ_NONE;
259 static const struct regmap_config snvs_rtc_config = {
265 static int snvs_rtc_probe(struct platform_device *pdev)
267 struct snvs_rtc_data *data;
268 struct resource *res;
272 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
276 data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
278 if (IS_ERR(data->regmap)) {
279 dev_warn(&pdev->dev, "snvs rtc: you use old dts file, please update it\n");
280 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
282 mmio = devm_ioremap_resource(&pdev->dev, res);
284 return PTR_ERR(mmio);
286 data->regmap = devm_regmap_init_mmio(&pdev->dev, mmio, &snvs_rtc_config);
288 data->offset = SNVS_LPREGISTER_OFFSET;
289 of_property_read_u32(pdev->dev.of_node, "offset", &data->offset);
292 if (IS_ERR(data->regmap)) {
293 dev_err(&pdev->dev, "Can't find snvs syscon\n");
297 data->irq = platform_get_irq(pdev, 0);
301 data->clk = devm_clk_get(&pdev->dev, "snvs-rtc");
302 if (IS_ERR(data->clk)) {
305 ret = clk_prepare_enable(data->clk);
308 "Could not prepare or enable the snvs clock\n");
313 platform_set_drvdata(pdev, data);
315 /* Initialize glitch detect */
316 regmap_write(data->regmap, data->offset + SNVS_LPPGDR, SNVS_LPPGDR_INIT);
318 /* Clear interrupt status */
319 regmap_write(data->regmap, data->offset + SNVS_LPSR, 0xffffffff);
322 ret = snvs_rtc_enable(data, true);
324 dev_err(&pdev->dev, "failed to enable rtc %d\n", ret);
325 goto error_rtc_device_register;
328 device_init_wakeup(&pdev->dev, true);
330 ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,
331 IRQF_SHARED, "rtc alarm", &pdev->dev);
333 dev_err(&pdev->dev, "failed to request irq %d: %d\n",
335 goto error_rtc_device_register;
338 data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
339 &snvs_rtc_ops, THIS_MODULE);
340 if (IS_ERR(data->rtc)) {
341 ret = PTR_ERR(data->rtc);
342 dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
343 goto error_rtc_device_register;
348 error_rtc_device_register:
350 clk_disable_unprepare(data->clk);
355 #ifdef CONFIG_PM_SLEEP
356 static int snvs_rtc_suspend(struct device *dev)
358 struct snvs_rtc_data *data = dev_get_drvdata(dev);
360 if (device_may_wakeup(dev))
361 return enable_irq_wake(data->irq);
366 static int snvs_rtc_suspend_noirq(struct device *dev)
368 struct snvs_rtc_data *data = dev_get_drvdata(dev);
371 clk_disable_unprepare(data->clk);
376 static int snvs_rtc_resume(struct device *dev)
378 struct snvs_rtc_data *data = dev_get_drvdata(dev);
380 if (device_may_wakeup(dev))
381 return disable_irq_wake(data->irq);
386 static int snvs_rtc_resume_noirq(struct device *dev)
388 struct snvs_rtc_data *data = dev_get_drvdata(dev);
391 return clk_prepare_enable(data->clk);
396 static const struct dev_pm_ops snvs_rtc_pm_ops = {
397 .suspend = snvs_rtc_suspend,
398 .suspend_noirq = snvs_rtc_suspend_noirq,
399 .resume = snvs_rtc_resume,
400 .resume_noirq = snvs_rtc_resume_noirq,
403 #define SNVS_RTC_PM_OPS (&snvs_rtc_pm_ops)
407 #define SNVS_RTC_PM_OPS NULL
411 static const struct of_device_id snvs_dt_ids[] = {
412 { .compatible = "fsl,sec-v4.0-mon-rtc-lp", },
415 MODULE_DEVICE_TABLE(of, snvs_dt_ids);
417 static struct platform_driver snvs_rtc_driver = {
420 .pm = SNVS_RTC_PM_OPS,
421 .of_match_table = snvs_dt_ids,
423 .probe = snvs_rtc_probe,
425 module_platform_driver(snvs_rtc_driver);
427 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
428 MODULE_DESCRIPTION("Freescale SNVS RTC Driver");
429 MODULE_LICENSE("GPL");