xref: /openbmc/linux/drivers/rtc/rtc-asm9260.c (revision ad01bf83)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Oleksij Rempel <linux@rempel-privat.de>
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/rtc.h>
13 
14 /* Miscellaneous registers */
15 /* Interrupt Location Register */
16 #define HW_ILR			0x00
17 #define BM_RTCALF		BIT(1)
18 #define BM_RTCCIF		BIT(0)
19 
20 /* Clock Control Register */
21 #define HW_CCR			0x08
22 /* Calibration counter disable */
23 #define BM_CCALOFF		BIT(4)
24 /* Reset internal oscillator divider */
25 #define BM_CTCRST		BIT(1)
26 /* Clock Enable */
27 #define BM_CLKEN		BIT(0)
28 
29 /* Counter Increment Interrupt Register */
30 #define HW_CIIR			0x0C
31 #define BM_CIIR_IMYEAR		BIT(7)
32 #define BM_CIIR_IMMON		BIT(6)
33 #define BM_CIIR_IMDOY		BIT(5)
34 #define BM_CIIR_IMDOW		BIT(4)
35 #define BM_CIIR_IMDOM		BIT(3)
36 #define BM_CIIR_IMHOUR		BIT(2)
37 #define BM_CIIR_IMMIN		BIT(1)
38 #define BM_CIIR_IMSEC		BIT(0)
39 
40 /* Alarm Mask Register */
41 #define HW_AMR			0x10
42 #define BM_AMR_IMYEAR		BIT(7)
43 #define BM_AMR_IMMON		BIT(6)
44 #define BM_AMR_IMDOY		BIT(5)
45 #define BM_AMR_IMDOW		BIT(4)
46 #define BM_AMR_IMDOM		BIT(3)
47 #define BM_AMR_IMHOUR		BIT(2)
48 #define BM_AMR_IMMIN		BIT(1)
49 #define BM_AMR_IMSEC		BIT(0)
50 #define BM_AMR_OFF		0xff
51 
52 /* Consolidated time registers */
53 #define HW_CTIME0		0x14
54 #define BM_CTIME0_DOW_S		24
55 #define BM_CTIME0_DOW_M		0x7
56 #define BM_CTIME0_HOUR_S	16
57 #define BM_CTIME0_HOUR_M	0x1f
58 #define BM_CTIME0_MIN_S		8
59 #define BM_CTIME0_MIN_M		0x3f
60 #define BM_CTIME0_SEC_S		0
61 #define BM_CTIME0_SEC_M		0x3f
62 
63 #define HW_CTIME1		0x18
64 #define BM_CTIME1_YEAR_S	16
65 #define BM_CTIME1_YEAR_M	0xfff
66 #define BM_CTIME1_MON_S		8
67 #define BM_CTIME1_MON_M		0xf
68 #define BM_CTIME1_DOM_S		0
69 #define BM_CTIME1_DOM_M		0x1f
70 
71 #define HW_CTIME2		0x1C
72 #define BM_CTIME2_DOY_S		0
73 #define BM_CTIME2_DOY_M		0xfff
74 
75 /* Time counter registers */
76 #define HW_SEC			0x20
77 #define HW_MIN			0x24
78 #define HW_HOUR			0x28
79 #define HW_DOM			0x2C
80 #define HW_DOW			0x30
81 #define HW_DOY			0x34
82 #define HW_MONTH		0x38
83 #define HW_YEAR			0x3C
84 
85 #define HW_CALIBRATION		0x40
86 #define BM_CALDIR_BACK		BIT(17)
87 #define BM_CALVAL_M		0x1ffff
88 
89 /* General purpose registers */
90 #define HW_GPREG0		0x44
91 #define HW_GPREG1		0x48
92 #define HW_GPREG2		0x4C
93 #define HW_GPREG3		0x50
94 #define HW_GPREG4		0x54
95 
96 /* Alarm register group */
97 #define HW_ALSEC		0x60
98 #define HW_ALMIN		0x64
99 #define HW_ALHOUR		0x68
100 #define HW_ALDOM		0x6C
101 #define HW_ALDOW		0x70
102 #define HW_ALDOY		0x74
103 #define HW_ALMON		0x78
104 #define HW_ALYEAR		0x7C
105 
106 struct asm9260_rtc_priv {
107 	struct device		*dev;
108 	void __iomem		*iobase;
109 	struct rtc_device	*rtc;
110 	struct clk		*clk;
111 };
112 
asm9260_rtc_irq(int irq,void * dev_id)113 static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
114 {
115 	struct asm9260_rtc_priv *priv = dev_id;
116 	u32 isr;
117 	unsigned long events = 0;
118 
119 	rtc_lock(priv->rtc);
120 	isr = ioread32(priv->iobase + HW_CIIR);
121 	if (!isr) {
122 		rtc_unlock(priv->rtc);
123 		return IRQ_NONE;
124 	}
125 
126 	iowrite32(0, priv->iobase + HW_CIIR);
127 	rtc_unlock(priv->rtc);
128 
129 	events |= RTC_AF | RTC_IRQF;
130 
131 	rtc_update_irq(priv->rtc, 1, events);
132 
133 	return IRQ_HANDLED;
134 }
135 
asm9260_rtc_read_time(struct device * dev,struct rtc_time * tm)136 static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
137 {
138 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
139 	u32 ctime0, ctime1, ctime2;
140 
141 	ctime0 = ioread32(priv->iobase + HW_CTIME0);
142 	ctime1 = ioread32(priv->iobase + HW_CTIME1);
143 	ctime2 = ioread32(priv->iobase + HW_CTIME2);
144 
145 	if (ctime1 != ioread32(priv->iobase + HW_CTIME1)) {
146 		/*
147 		 * woops, counter flipped right now. Now we are safe
148 		 * to reread.
149 		 */
150 		ctime0 = ioread32(priv->iobase + HW_CTIME0);
151 		ctime1 = ioread32(priv->iobase + HW_CTIME1);
152 		ctime2 = ioread32(priv->iobase + HW_CTIME2);
153 	}
154 
155 	tm->tm_sec  = (ctime0 >> BM_CTIME0_SEC_S)  & BM_CTIME0_SEC_M;
156 	tm->tm_min  = (ctime0 >> BM_CTIME0_MIN_S)  & BM_CTIME0_MIN_M;
157 	tm->tm_hour = (ctime0 >> BM_CTIME0_HOUR_S) & BM_CTIME0_HOUR_M;
158 	tm->tm_wday = (ctime0 >> BM_CTIME0_DOW_S)  & BM_CTIME0_DOW_M;
159 
160 	tm->tm_mday = (ctime1 >> BM_CTIME1_DOM_S)  & BM_CTIME1_DOM_M;
161 	tm->tm_mon  = (ctime1 >> BM_CTIME1_MON_S)  & BM_CTIME1_MON_M;
162 	tm->tm_year = (ctime1 >> BM_CTIME1_YEAR_S) & BM_CTIME1_YEAR_M;
163 
164 	tm->tm_yday = (ctime2 >> BM_CTIME2_DOY_S)  & BM_CTIME2_DOY_M;
165 
166 	return 0;
167 }
168 
asm9260_rtc_set_time(struct device * dev,struct rtc_time * tm)169 static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
170 {
171 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
172 
173 	/*
174 	 * make sure SEC counter will not flip other counter on write time,
175 	 * real value will be written at the enf of sequence.
176 	 */
177 	iowrite32(0, priv->iobase + HW_SEC);
178 
179 	iowrite32(tm->tm_year, priv->iobase + HW_YEAR);
180 	iowrite32(tm->tm_mon,  priv->iobase + HW_MONTH);
181 	iowrite32(tm->tm_mday, priv->iobase + HW_DOM);
182 	iowrite32(tm->tm_wday, priv->iobase + HW_DOW);
183 	iowrite32(tm->tm_yday, priv->iobase + HW_DOY);
184 	iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
185 	iowrite32(tm->tm_min,  priv->iobase + HW_MIN);
186 	iowrite32(tm->tm_sec,  priv->iobase + HW_SEC);
187 
188 	return 0;
189 }
190 
asm9260_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)191 static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
192 {
193 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
194 
195 	alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
196 	alrm->time.tm_mon  = ioread32(priv->iobase + HW_ALMON);
197 	alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
198 	alrm->time.tm_wday = ioread32(priv->iobase + HW_ALDOW);
199 	alrm->time.tm_yday = ioread32(priv->iobase + HW_ALDOY);
200 	alrm->time.tm_hour = ioread32(priv->iobase + HW_ALHOUR);
201 	alrm->time.tm_min  = ioread32(priv->iobase + HW_ALMIN);
202 	alrm->time.tm_sec  = ioread32(priv->iobase + HW_ALSEC);
203 
204 	alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
205 	alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
206 
207 	return rtc_valid_tm(&alrm->time);
208 }
209 
asm9260_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)210 static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
211 {
212 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
213 
214 	iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
215 	iowrite32(alrm->time.tm_mon,  priv->iobase + HW_ALMON);
216 	iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
217 	iowrite32(alrm->time.tm_wday, priv->iobase + HW_ALDOW);
218 	iowrite32(alrm->time.tm_yday, priv->iobase + HW_ALDOY);
219 	iowrite32(alrm->time.tm_hour, priv->iobase + HW_ALHOUR);
220 	iowrite32(alrm->time.tm_min,  priv->iobase + HW_ALMIN);
221 	iowrite32(alrm->time.tm_sec,  priv->iobase + HW_ALSEC);
222 
223 	iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
224 
225 	return 0;
226 }
227 
asm9260_alarm_irq_enable(struct device * dev,unsigned int enabled)228 static int asm9260_alarm_irq_enable(struct device *dev, unsigned int enabled)
229 {
230 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
231 
232 	iowrite32(enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
233 	return 0;
234 }
235 
236 static const struct rtc_class_ops asm9260_rtc_ops = {
237 	.read_time		= asm9260_rtc_read_time,
238 	.set_time		= asm9260_rtc_set_time,
239 	.read_alarm		= asm9260_rtc_read_alarm,
240 	.set_alarm		= asm9260_rtc_set_alarm,
241 	.alarm_irq_enable	= asm9260_alarm_irq_enable,
242 };
243 
asm9260_rtc_probe(struct platform_device * pdev)244 static int asm9260_rtc_probe(struct platform_device *pdev)
245 {
246 	struct asm9260_rtc_priv *priv;
247 	struct device *dev = &pdev->dev;
248 	int irq_alarm, ret;
249 	u32 ccr;
250 
251 	priv = devm_kzalloc(dev, sizeof(struct asm9260_rtc_priv), GFP_KERNEL);
252 	if (!priv)
253 		return -ENOMEM;
254 
255 	priv->dev = &pdev->dev;
256 	platform_set_drvdata(pdev, priv);
257 
258 	irq_alarm = platform_get_irq(pdev, 0);
259 	if (irq_alarm < 0)
260 		return irq_alarm;
261 
262 	priv->iobase = devm_platform_ioremap_resource(pdev, 0);
263 	if (IS_ERR(priv->iobase))
264 		return PTR_ERR(priv->iobase);
265 
266 	priv->clk = devm_clk_get(dev, "ahb");
267 	if (IS_ERR(priv->clk))
268 		return PTR_ERR(priv->clk);
269 
270 	ret = clk_prepare_enable(priv->clk);
271 	if (ret) {
272 		dev_err(dev, "Failed to enable clk!\n");
273 		return ret;
274 	}
275 
276 	ccr = ioread32(priv->iobase + HW_CCR);
277 	/* if dev is not enabled, reset it */
278 	if ((ccr & (BM_CLKEN | BM_CTCRST)) != BM_CLKEN) {
279 		iowrite32(BM_CTCRST, priv->iobase + HW_CCR);
280 		ccr = 0;
281 	}
282 
283 	iowrite32(BM_CLKEN | ccr, priv->iobase + HW_CCR);
284 	iowrite32(0, priv->iobase + HW_CIIR);
285 	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
286 
287 	priv->rtc = devm_rtc_device_register(dev, dev_name(dev),
288 					     &asm9260_rtc_ops, THIS_MODULE);
289 	if (IS_ERR(priv->rtc)) {
290 		ret = PTR_ERR(priv->rtc);
291 		dev_err(dev, "Failed to register RTC device: %d\n", ret);
292 		goto err_return;
293 	}
294 
295 	ret = devm_request_threaded_irq(dev, irq_alarm, NULL,
296 					asm9260_rtc_irq, IRQF_ONESHOT,
297 					dev_name(dev), priv);
298 	if (ret < 0) {
299 		dev_err(dev, "can't get irq %i, err %d\n",
300 			irq_alarm, ret);
301 		goto err_return;
302 	}
303 
304 	return 0;
305 
306 err_return:
307 	clk_disable_unprepare(priv->clk);
308 	return ret;
309 }
310 
asm9260_rtc_remove(struct platform_device * pdev)311 static void asm9260_rtc_remove(struct platform_device *pdev)
312 {
313 	struct asm9260_rtc_priv *priv = platform_get_drvdata(pdev);
314 
315 	/* Disable alarm matching */
316 	iowrite32(BM_AMR_OFF, priv->iobase + HW_AMR);
317 	clk_disable_unprepare(priv->clk);
318 }
319 
320 static const struct of_device_id asm9260_dt_ids[] = {
321 	{ .compatible = "alphascale,asm9260-rtc", },
322 	{}
323 };
324 MODULE_DEVICE_TABLE(of, asm9260_dt_ids);
325 
326 static struct platform_driver asm9260_rtc_driver = {
327 	.probe		= asm9260_rtc_probe,
328 	.remove_new	= asm9260_rtc_remove,
329 	.driver		= {
330 		.name	= "asm9260-rtc",
331 		.of_match_table = asm9260_dt_ids,
332 	},
333 };
334 
335 module_platform_driver(asm9260_rtc_driver);
336 
337 MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
338 MODULE_DESCRIPTION("Alphascale asm9260 SoC Realtime Clock Driver (RTC)");
339 MODULE_LICENSE("GPL");
340