1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Xilinx Zynq Ultrascale+ MPSoC Real Time Clock Driver
4 *
5 * Copyright (C) 2015 Xilinx, Inc.
6 *
7 */
8
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/rtc.h>
17
18 /* RTC Registers */
19 #define RTC_SET_TM_WR 0x00
20 #define RTC_SET_TM_RD 0x04
21 #define RTC_CALIB_WR 0x08
22 #define RTC_CALIB_RD 0x0C
23 #define RTC_CUR_TM 0x10
24 #define RTC_CUR_TICK 0x14
25 #define RTC_ALRM 0x18
26 #define RTC_INT_STS 0x20
27 #define RTC_INT_MASK 0x24
28 #define RTC_INT_EN 0x28
29 #define RTC_INT_DIS 0x2C
30 #define RTC_CTRL 0x40
31
32 #define RTC_FR_EN BIT(20)
33 #define RTC_FR_DATSHIFT 16
34 #define RTC_TICK_MASK 0xFFFF
35 #define RTC_INT_SEC BIT(0)
36 #define RTC_INT_ALRM BIT(1)
37 #define RTC_OSC_EN BIT(24)
38 #define RTC_BATT_EN BIT(31)
39
40 #define RTC_CALIB_DEF 0x7FFF
41 #define RTC_CALIB_MASK 0x1FFFFF
42 #define RTC_ALRM_MASK BIT(1)
43 #define RTC_MSEC 1000
44 #define RTC_FR_MASK 0xF0000
45 #define RTC_FR_MAX_TICKS 16
46 #define RTC_PPB 1000000000LL
47 #define RTC_MIN_OFFSET -32768000
48 #define RTC_MAX_OFFSET 32767000
49
50 struct xlnx_rtc_dev {
51 struct rtc_device *rtc;
52 void __iomem *reg_base;
53 int alarm_irq;
54 int sec_irq;
55 struct clk *rtc_clk;
56 unsigned int freq;
57 };
58
xlnx_rtc_set_time(struct device * dev,struct rtc_time * tm)59 static int xlnx_rtc_set_time(struct device *dev, struct rtc_time *tm)
60 {
61 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
62 unsigned long new_time;
63
64 /*
65 * The value written will be updated after 1 sec into the
66 * seconds read register, so we need to program time +1 sec
67 * to get the correct time on read.
68 */
69 new_time = rtc_tm_to_time64(tm) + 1;
70
71 writel(new_time, xrtcdev->reg_base + RTC_SET_TM_WR);
72
73 /*
74 * Clear the rtc interrupt status register after setting the
75 * time. During a read_time function, the code should read the
76 * RTC_INT_STATUS register and if bit 0 is still 0, it means
77 * that one second has not elapsed yet since RTC was set and
78 * the current time should be read from SET_TIME_READ register;
79 * otherwise, CURRENT_TIME register is read to report the time
80 */
81 writel(RTC_INT_SEC, xrtcdev->reg_base + RTC_INT_STS);
82
83 return 0;
84 }
85
xlnx_rtc_read_time(struct device * dev,struct rtc_time * tm)86 static int xlnx_rtc_read_time(struct device *dev, struct rtc_time *tm)
87 {
88 u32 status;
89 unsigned long read_time;
90 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
91
92 status = readl(xrtcdev->reg_base + RTC_INT_STS);
93
94 if (status & RTC_INT_SEC) {
95 /*
96 * RTC has updated the CURRENT_TIME with the time written into
97 * SET_TIME_WRITE register.
98 */
99 read_time = readl(xrtcdev->reg_base + RTC_CUR_TM);
100 } else {
101 /*
102 * Time written in SET_TIME_WRITE has not yet updated into
103 * the seconds read register, so read the time from the
104 * SET_TIME_WRITE instead of CURRENT_TIME register.
105 * Since we add +1 sec while writing, we need to -1 sec while
106 * reading.
107 */
108 read_time = readl(xrtcdev->reg_base + RTC_SET_TM_RD) - 1;
109 }
110 rtc_time64_to_tm(read_time, tm);
111
112 return 0;
113 }
114
xlnx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)115 static int xlnx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
116 {
117 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
118
119 rtc_time64_to_tm(readl(xrtcdev->reg_base + RTC_ALRM), &alrm->time);
120 alrm->enabled = readl(xrtcdev->reg_base + RTC_INT_MASK) & RTC_INT_ALRM;
121
122 return 0;
123 }
124
xlnx_rtc_alarm_irq_enable(struct device * dev,u32 enabled)125 static int xlnx_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
126 {
127 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
128 unsigned int status;
129 ulong timeout;
130
131 timeout = jiffies + msecs_to_jiffies(RTC_MSEC);
132
133 if (enabled) {
134 while (1) {
135 status = readl(xrtcdev->reg_base + RTC_INT_STS);
136 if (!((status & RTC_ALRM_MASK) == RTC_ALRM_MASK))
137 break;
138
139 if (time_after_eq(jiffies, timeout)) {
140 dev_err(dev, "Time out occur, while clearing alarm status bit\n");
141 return -ETIMEDOUT;
142 }
143 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_STS);
144 }
145
146 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_EN);
147 } else {
148 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
149 }
150
151 return 0;
152 }
153
xlnx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)154 static int xlnx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
155 {
156 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
157 unsigned long alarm_time;
158
159 alarm_time = rtc_tm_to_time64(&alrm->time);
160
161 writel((u32)alarm_time, (xrtcdev->reg_base + RTC_ALRM));
162
163 xlnx_rtc_alarm_irq_enable(dev, alrm->enabled);
164
165 return 0;
166 }
167
xlnx_init_rtc(struct xlnx_rtc_dev * xrtcdev)168 static void xlnx_init_rtc(struct xlnx_rtc_dev *xrtcdev)
169 {
170 u32 rtc_ctrl;
171
172 /* Enable RTC switch to battery when VCC_PSAUX is not available */
173 rtc_ctrl = readl(xrtcdev->reg_base + RTC_CTRL);
174 rtc_ctrl |= RTC_BATT_EN;
175 writel(rtc_ctrl, xrtcdev->reg_base + RTC_CTRL);
176 }
177
xlnx_rtc_read_offset(struct device * dev,long * offset)178 static int xlnx_rtc_read_offset(struct device *dev, long *offset)
179 {
180 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
181 unsigned long long rtc_ppb = RTC_PPB;
182 unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
183 unsigned int calibval;
184 long offset_val;
185
186 calibval = readl(xrtcdev->reg_base + RTC_CALIB_RD);
187 /* Offset with seconds ticks */
188 offset_val = calibval & RTC_TICK_MASK;
189 offset_val = offset_val - RTC_CALIB_DEF;
190 offset_val = offset_val * tick_mult;
191
192 /* Offset with fractional ticks */
193 if (calibval & RTC_FR_EN)
194 offset_val += ((calibval & RTC_FR_MASK) >> RTC_FR_DATSHIFT)
195 * (tick_mult / RTC_FR_MAX_TICKS);
196 *offset = offset_val;
197
198 return 0;
199 }
200
xlnx_rtc_set_offset(struct device * dev,long offset)201 static int xlnx_rtc_set_offset(struct device *dev, long offset)
202 {
203 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
204 unsigned long long rtc_ppb = RTC_PPB;
205 unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
206 unsigned char fract_tick = 0;
207 unsigned int calibval;
208 short int max_tick;
209 int fract_offset;
210
211 if (offset < RTC_MIN_OFFSET || offset > RTC_MAX_OFFSET)
212 return -ERANGE;
213
214 /* Number ticks for given offset */
215 max_tick = div_s64_rem(offset, tick_mult, &fract_offset);
216
217 /* Number fractional ticks for given offset */
218 if (fract_offset) {
219 if (fract_offset < 0) {
220 fract_offset = fract_offset + tick_mult;
221 max_tick--;
222 }
223 if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
224 for (fract_tick = 1; fract_tick < 16; fract_tick++) {
225 if (fract_offset <=
226 (fract_tick *
227 (tick_mult / RTC_FR_MAX_TICKS)))
228 break;
229 }
230 }
231 }
232
233 /* Zynqmp RTC uses second and fractional tick
234 * counters for compensation
235 */
236 calibval = max_tick + RTC_CALIB_DEF;
237
238 if (fract_tick)
239 calibval |= RTC_FR_EN;
240
241 calibval |= (fract_tick << RTC_FR_DATSHIFT);
242
243 writel(calibval, (xrtcdev->reg_base + RTC_CALIB_WR));
244
245 return 0;
246 }
247
248 static const struct rtc_class_ops xlnx_rtc_ops = {
249 .set_time = xlnx_rtc_set_time,
250 .read_time = xlnx_rtc_read_time,
251 .read_alarm = xlnx_rtc_read_alarm,
252 .set_alarm = xlnx_rtc_set_alarm,
253 .alarm_irq_enable = xlnx_rtc_alarm_irq_enable,
254 .read_offset = xlnx_rtc_read_offset,
255 .set_offset = xlnx_rtc_set_offset,
256 };
257
xlnx_rtc_interrupt(int irq,void * id)258 static irqreturn_t xlnx_rtc_interrupt(int irq, void *id)
259 {
260 struct xlnx_rtc_dev *xrtcdev = (struct xlnx_rtc_dev *)id;
261 unsigned int status;
262
263 status = readl(xrtcdev->reg_base + RTC_INT_STS);
264 /* Check if interrupt asserted */
265 if (!(status & (RTC_INT_SEC | RTC_INT_ALRM)))
266 return IRQ_NONE;
267
268 /* Disable RTC_INT_ALRM interrupt only */
269 writel(RTC_INT_ALRM, xrtcdev->reg_base + RTC_INT_DIS);
270
271 if (status & RTC_INT_ALRM)
272 rtc_update_irq(xrtcdev->rtc, 1, RTC_IRQF | RTC_AF);
273
274 return IRQ_HANDLED;
275 }
276
xlnx_rtc_probe(struct platform_device * pdev)277 static int xlnx_rtc_probe(struct platform_device *pdev)
278 {
279 struct xlnx_rtc_dev *xrtcdev;
280 int ret;
281
282 xrtcdev = devm_kzalloc(&pdev->dev, sizeof(*xrtcdev), GFP_KERNEL);
283 if (!xrtcdev)
284 return -ENOMEM;
285
286 platform_set_drvdata(pdev, xrtcdev);
287
288 xrtcdev->rtc = devm_rtc_allocate_device(&pdev->dev);
289 if (IS_ERR(xrtcdev->rtc))
290 return PTR_ERR(xrtcdev->rtc);
291
292 xrtcdev->rtc->ops = &xlnx_rtc_ops;
293 xrtcdev->rtc->range_max = U32_MAX;
294
295 xrtcdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
296 if (IS_ERR(xrtcdev->reg_base))
297 return PTR_ERR(xrtcdev->reg_base);
298
299 xrtcdev->alarm_irq = platform_get_irq_byname(pdev, "alarm");
300 if (xrtcdev->alarm_irq < 0)
301 return xrtcdev->alarm_irq;
302 ret = devm_request_irq(&pdev->dev, xrtcdev->alarm_irq,
303 xlnx_rtc_interrupt, 0,
304 dev_name(&pdev->dev), xrtcdev);
305 if (ret) {
306 dev_err(&pdev->dev, "request irq failed\n");
307 return ret;
308 }
309
310 xrtcdev->sec_irq = platform_get_irq_byname(pdev, "sec");
311 if (xrtcdev->sec_irq < 0)
312 return xrtcdev->sec_irq;
313 ret = devm_request_irq(&pdev->dev, xrtcdev->sec_irq,
314 xlnx_rtc_interrupt, 0,
315 dev_name(&pdev->dev), xrtcdev);
316 if (ret) {
317 dev_err(&pdev->dev, "request irq failed\n");
318 return ret;
319 }
320
321 /* Getting the rtc_clk info */
322 xrtcdev->rtc_clk = devm_clk_get_optional(&pdev->dev, "rtc_clk");
323 if (IS_ERR(xrtcdev->rtc_clk)) {
324 if (PTR_ERR(xrtcdev->rtc_clk) != -EPROBE_DEFER)
325 dev_warn(&pdev->dev, "Device clock not found.\n");
326 }
327 xrtcdev->freq = clk_get_rate(xrtcdev->rtc_clk);
328 if (!xrtcdev->freq) {
329 ret = of_property_read_u32(pdev->dev.of_node, "calibration",
330 &xrtcdev->freq);
331 if (ret)
332 xrtcdev->freq = RTC_CALIB_DEF;
333 }
334 ret = readl(xrtcdev->reg_base + RTC_CALIB_RD);
335 if (!ret)
336 writel(xrtcdev->freq, (xrtcdev->reg_base + RTC_CALIB_WR));
337
338 xlnx_init_rtc(xrtcdev);
339
340 device_init_wakeup(&pdev->dev, 1);
341
342 return devm_rtc_register_device(xrtcdev->rtc);
343 }
344
xlnx_rtc_remove(struct platform_device * pdev)345 static void xlnx_rtc_remove(struct platform_device *pdev)
346 {
347 xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
348 device_init_wakeup(&pdev->dev, 0);
349 }
350
xlnx_rtc_suspend(struct device * dev)351 static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
352 {
353 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
354
355 if (device_may_wakeup(dev))
356 enable_irq_wake(xrtcdev->alarm_irq);
357 else
358 xlnx_rtc_alarm_irq_enable(dev, 0);
359
360 return 0;
361 }
362
xlnx_rtc_resume(struct device * dev)363 static int __maybe_unused xlnx_rtc_resume(struct device *dev)
364 {
365 struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
366
367 if (device_may_wakeup(dev))
368 disable_irq_wake(xrtcdev->alarm_irq);
369 else
370 xlnx_rtc_alarm_irq_enable(dev, 1);
371
372 return 0;
373 }
374
375 static SIMPLE_DEV_PM_OPS(xlnx_rtc_pm_ops, xlnx_rtc_suspend, xlnx_rtc_resume);
376
377 static const struct of_device_id xlnx_rtc_of_match[] = {
378 {.compatible = "xlnx,zynqmp-rtc" },
379 { }
380 };
381 MODULE_DEVICE_TABLE(of, xlnx_rtc_of_match);
382
383 static struct platform_driver xlnx_rtc_driver = {
384 .probe = xlnx_rtc_probe,
385 .remove_new = xlnx_rtc_remove,
386 .driver = {
387 .name = KBUILD_MODNAME,
388 .pm = &xlnx_rtc_pm_ops,
389 .of_match_table = xlnx_rtc_of_match,
390 },
391 };
392
393 module_platform_driver(xlnx_rtc_driver);
394
395 MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
396 MODULE_AUTHOR("Xilinx Inc.");
397 MODULE_LICENSE("GPL v2");
398