1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Loongson RTC driver
4 *
5 * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
6 * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
7 * Binbin Zhou <zhoubinbin@loongson.cn>
8 */
9
10 #include <linux/bitfield.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/regmap.h>
15 #include <linux/rtc.h>
16 #include <linux/acpi.h>
17
18 /* Time Of Year(TOY) counters registers */
19 #define TOY_TRIM_REG 0x20 /* Must be initialized to 0 */
20 #define TOY_WRITE0_REG 0x24 /* TOY low 32-bits value (write-only) */
21 #define TOY_WRITE1_REG 0x28 /* TOY high 32-bits value (write-only) */
22 #define TOY_READ0_REG 0x2c /* TOY low 32-bits value (read-only) */
23 #define TOY_READ1_REG 0x30 /* TOY high 32-bits value (read-only) */
24 #define TOY_MATCH0_REG 0x34 /* TOY timing interrupt 0 */
25 #define TOY_MATCH1_REG 0x38 /* TOY timing interrupt 1 */
26 #define TOY_MATCH2_REG 0x3c /* TOY timing interrupt 2 */
27
28 /* RTC counters registers */
29 #define RTC_CTRL_REG 0x40 /* TOY and RTC control register */
30 #define RTC_TRIM_REG 0x60 /* Must be initialized to 0 */
31 #define RTC_WRITE0_REG 0x64 /* RTC counters value (write-only) */
32 #define RTC_READ0_REG 0x68 /* RTC counters value (read-only) */
33 #define RTC_MATCH0_REG 0x6c /* RTC timing interrupt 0 */
34 #define RTC_MATCH1_REG 0x70 /* RTC timing interrupt 1 */
35 #define RTC_MATCH2_REG 0x74 /* RTC timing interrupt 2 */
36
37 /* bitmask of TOY_WRITE0_REG */
38 #define TOY_MON GENMASK(31, 26)
39 #define TOY_DAY GENMASK(25, 21)
40 #define TOY_HOUR GENMASK(20, 16)
41 #define TOY_MIN GENMASK(15, 10)
42 #define TOY_SEC GENMASK(9, 4)
43 #define TOY_MSEC GENMASK(3, 0)
44
45 /* bitmask of TOY_MATCH0/1/2_REG */
46 #define TOY_MATCH_YEAR GENMASK(31, 26)
47 #define TOY_MATCH_MON GENMASK(25, 22)
48 #define TOY_MATCH_DAY GENMASK(21, 17)
49 #define TOY_MATCH_HOUR GENMASK(16, 12)
50 #define TOY_MATCH_MIN GENMASK(11, 6)
51 #define TOY_MATCH_SEC GENMASK(5, 0)
52
53 /* bitmask of RTC_CTRL_REG */
54 #define RTC_ENABLE BIT(13) /* 1: RTC counters enable */
55 #define TOY_ENABLE BIT(11) /* 1: TOY counters enable */
56 #define OSC_ENABLE BIT(8) /* 1: 32.768k crystal enable */
57 #define TOY_ENABLE_MASK (TOY_ENABLE | OSC_ENABLE)
58
59 /* PM domain registers */
60 #define PM1_STS_REG 0x0c /* Power management 1 status register */
61 #define RTC_STS BIT(10) /* RTC status */
62 #define PM1_EN_REG 0x10 /* Power management 1 enable register */
63 #define RTC_EN BIT(10) /* RTC event enable */
64
65 /*
66 * According to the LS1C manual, RTC_CTRL and alarm-related registers are not defined.
67 * Accessing the relevant registers will cause the system to hang.
68 */
69 #define LS1C_RTC_CTRL_WORKAROUND BIT(0)
70
71 struct loongson_rtc_config {
72 u32 pm_offset; /* Offset of PM domain, for RTC alarm wakeup */
73 u32 flags; /* Workaround bits */
74 };
75
76 struct loongson_rtc_priv {
77 spinlock_t lock; /* protects PM registers access */
78 u32 fix_year; /* RTC alarm year compensation value */
79 struct rtc_device *rtcdev;
80 struct regmap *regmap;
81 void __iomem *pm_base; /* PM domain base, for RTC alarm wakeup */
82 const struct loongson_rtc_config *config;
83 };
84
85 static const struct loongson_rtc_config ls1b_rtc_config = {
86 .pm_offset = 0,
87 .flags = 0,
88 };
89
90 static const struct loongson_rtc_config ls1c_rtc_config = {
91 .pm_offset = 0,
92 .flags = LS1C_RTC_CTRL_WORKAROUND,
93 };
94
95 static const struct loongson_rtc_config generic_rtc_config = {
96 .pm_offset = 0x100,
97 .flags = 0,
98 };
99
100 static const struct loongson_rtc_config ls2k1000_rtc_config = {
101 .pm_offset = 0x800,
102 .flags = 0,
103 };
104
105 static const struct regmap_config loongson_rtc_regmap_config = {
106 .reg_bits = 32,
107 .val_bits = 32,
108 .reg_stride = 4,
109 };
110
111 /* RTC alarm irq handler */
loongson_rtc_isr(int irq,void * id)112 static irqreturn_t loongson_rtc_isr(int irq, void *id)
113 {
114 struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
115
116 rtc_update_irq(priv->rtcdev, 1, RTC_AF | RTC_IRQF);
117
118 /*
119 * The TOY_MATCH0_REG should be cleared 0 here,
120 * otherwise the interrupt cannot be cleared.
121 */
122 regmap_write(priv->regmap, TOY_MATCH0_REG, 0);
123
124 return IRQ_HANDLED;
125 }
126
127 /* For ACPI fixed event handler */
loongson_rtc_handler(void * id)128 static u32 loongson_rtc_handler(void *id)
129 {
130 struct loongson_rtc_priv *priv = (struct loongson_rtc_priv *)id;
131
132 spin_lock(&priv->lock);
133 /* Disable RTC alarm wakeup and interrupt */
134 writel(readl(priv->pm_base + PM1_EN_REG) & ~RTC_EN,
135 priv->pm_base + PM1_EN_REG);
136
137 /* Clear RTC interrupt status */
138 writel(RTC_STS, priv->pm_base + PM1_STS_REG);
139 spin_unlock(&priv->lock);
140
141 return ACPI_INTERRUPT_HANDLED;
142 }
143
loongson_rtc_set_enabled(struct device * dev)144 static int loongson_rtc_set_enabled(struct device *dev)
145 {
146 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
147
148 if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
149 return 0;
150
151 /* Enable RTC TOY counters and crystal */
152 return regmap_update_bits(priv->regmap, RTC_CTRL_REG, TOY_ENABLE_MASK,
153 TOY_ENABLE_MASK);
154 }
155
loongson_rtc_get_enabled(struct device * dev)156 static bool loongson_rtc_get_enabled(struct device *dev)
157 {
158 int ret;
159 u32 ctrl_data;
160 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
161
162 if (priv->config->flags & LS1C_RTC_CTRL_WORKAROUND)
163 return true;
164
165 ret = regmap_read(priv->regmap, RTC_CTRL_REG, &ctrl_data);
166 if (ret < 0)
167 return false;
168
169 return ctrl_data & TOY_ENABLE_MASK;
170 }
171
loongson_rtc_read_time(struct device * dev,struct rtc_time * tm)172 static int loongson_rtc_read_time(struct device *dev, struct rtc_time *tm)
173 {
174 int ret;
175 u32 rtc_data[2];
176 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
177
178 if (!loongson_rtc_get_enabled(dev))
179 return -EINVAL;
180
181 ret = regmap_bulk_read(priv->regmap, TOY_READ0_REG, rtc_data,
182 ARRAY_SIZE(rtc_data));
183 if (ret < 0)
184 return ret;
185
186 tm->tm_sec = FIELD_GET(TOY_SEC, rtc_data[0]);
187 tm->tm_min = FIELD_GET(TOY_MIN, rtc_data[0]);
188 tm->tm_hour = FIELD_GET(TOY_HOUR, rtc_data[0]);
189 tm->tm_mday = FIELD_GET(TOY_DAY, rtc_data[0]);
190 tm->tm_mon = FIELD_GET(TOY_MON, rtc_data[0]) - 1;
191 tm->tm_year = rtc_data[1];
192
193 /* Prepare for RTC alarm year compensation value. */
194 priv->fix_year = tm->tm_year / 64 * 64;
195 return 0;
196 }
197
loongson_rtc_set_time(struct device * dev,struct rtc_time * tm)198 static int loongson_rtc_set_time(struct device *dev, struct rtc_time *tm)
199 {
200 int ret;
201 u32 rtc_data[2];
202 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
203
204 rtc_data[0] = FIELD_PREP(TOY_SEC, tm->tm_sec)
205 | FIELD_PREP(TOY_MIN, tm->tm_min)
206 | FIELD_PREP(TOY_HOUR, tm->tm_hour)
207 | FIELD_PREP(TOY_DAY, tm->tm_mday)
208 | FIELD_PREP(TOY_MON, tm->tm_mon + 1);
209 rtc_data[1] = tm->tm_year;
210
211 ret = regmap_bulk_write(priv->regmap, TOY_WRITE0_REG, rtc_data,
212 ARRAY_SIZE(rtc_data));
213 if (ret < 0)
214 return ret;
215
216 return loongson_rtc_set_enabled(dev);
217 }
218
loongson_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)219 static int loongson_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
220 {
221 int ret;
222 u32 alarm_data;
223 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
224
225 ret = regmap_read(priv->regmap, TOY_MATCH0_REG, &alarm_data);
226 if (ret < 0)
227 return ret;
228
229 alrm->time.tm_sec = FIELD_GET(TOY_MATCH_SEC, alarm_data);
230 alrm->time.tm_min = FIELD_GET(TOY_MATCH_MIN, alarm_data);
231 alrm->time.tm_hour = FIELD_GET(TOY_MATCH_HOUR, alarm_data);
232 alrm->time.tm_mday = FIELD_GET(TOY_MATCH_DAY, alarm_data);
233 alrm->time.tm_mon = FIELD_GET(TOY_MATCH_MON, alarm_data) - 1;
234 /*
235 * This is a hardware bug: the year field of SYS_TOYMATCH is only 6 bits,
236 * making it impossible to save year values larger than 64.
237 *
238 * SYS_TOYMATCH is used to match the alarm time value and determine if
239 * an alarm is triggered, so we must keep the lower 6 bits of the year
240 * value constant during the value conversion.
241 *
242 * In summary, we need to manually add 64(or a multiple of 64) to the
243 * year value to avoid the invalid alarm prompt at startup.
244 */
245 alrm->time.tm_year = FIELD_GET(TOY_MATCH_YEAR, alarm_data) + priv->fix_year;
246
247 alrm->enabled = !!(readl(priv->pm_base + PM1_EN_REG) & RTC_EN);
248 return 0;
249 }
250
loongson_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)251 static int loongson_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
252 {
253 u32 val;
254 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
255
256 spin_lock(&priv->lock);
257 val = readl(priv->pm_base + PM1_EN_REG);
258 /* Enable RTC alarm wakeup */
259 writel(enabled ? val | RTC_EN : val & ~RTC_EN,
260 priv->pm_base + PM1_EN_REG);
261 spin_unlock(&priv->lock);
262
263 return 0;
264 }
265
loongson_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)266 static int loongson_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
267 {
268 int ret;
269 u32 alarm_data;
270 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
271
272 alarm_data = FIELD_PREP(TOY_MATCH_SEC, alrm->time.tm_sec)
273 | FIELD_PREP(TOY_MATCH_MIN, alrm->time.tm_min)
274 | FIELD_PREP(TOY_MATCH_HOUR, alrm->time.tm_hour)
275 | FIELD_PREP(TOY_MATCH_DAY, alrm->time.tm_mday)
276 | FIELD_PREP(TOY_MATCH_MON, alrm->time.tm_mon + 1)
277 | FIELD_PREP(TOY_MATCH_YEAR, alrm->time.tm_year - priv->fix_year);
278
279 ret = regmap_write(priv->regmap, TOY_MATCH0_REG, alarm_data);
280 if (ret < 0)
281 return ret;
282
283 return loongson_rtc_alarm_irq_enable(dev, alrm->enabled);
284 }
285
286 static const struct rtc_class_ops loongson_rtc_ops = {
287 .read_time = loongson_rtc_read_time,
288 .set_time = loongson_rtc_set_time,
289 .read_alarm = loongson_rtc_read_alarm,
290 .set_alarm = loongson_rtc_set_alarm,
291 .alarm_irq_enable = loongson_rtc_alarm_irq_enable,
292 };
293
loongson_rtc_probe(struct platform_device * pdev)294 static int loongson_rtc_probe(struct platform_device *pdev)
295 {
296 int ret, alarm_irq;
297 void __iomem *regs;
298 struct loongson_rtc_priv *priv;
299 struct device *dev = &pdev->dev;
300
301 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
302 if (!priv)
303 return -ENOMEM;
304
305 regs = devm_platform_ioremap_resource(pdev, 0);
306 if (IS_ERR(regs))
307 return dev_err_probe(dev, PTR_ERR(regs),
308 "devm_platform_ioremap_resource failed\n");
309
310 priv->regmap = devm_regmap_init_mmio(dev, regs,
311 &loongson_rtc_regmap_config);
312 if (IS_ERR(priv->regmap))
313 return dev_err_probe(dev, PTR_ERR(priv->regmap),
314 "devm_regmap_init_mmio failed\n");
315
316 priv->config = device_get_match_data(dev);
317 spin_lock_init(&priv->lock);
318 platform_set_drvdata(pdev, priv);
319
320 priv->rtcdev = devm_rtc_allocate_device(dev);
321 if (IS_ERR(priv->rtcdev))
322 return dev_err_probe(dev, PTR_ERR(priv->rtcdev),
323 "devm_rtc_allocate_device failed\n");
324
325 /* Get RTC alarm irq */
326 alarm_irq = platform_get_irq(pdev, 0);
327 if (alarm_irq > 0) {
328 ret = devm_request_irq(dev, alarm_irq, loongson_rtc_isr,
329 0, "loongson-alarm", priv);
330 if (ret < 0)
331 return dev_err_probe(dev, ret, "Unable to request irq %d\n",
332 alarm_irq);
333
334 priv->pm_base = regs - priv->config->pm_offset;
335 device_init_wakeup(dev, 1);
336
337 if (has_acpi_companion(dev))
338 acpi_install_fixed_event_handler(ACPI_EVENT_RTC,
339 loongson_rtc_handler, priv);
340 } else {
341 /* Loongson-1C RTC does not support alarm */
342 clear_bit(RTC_FEATURE_ALARM, priv->rtcdev->features);
343 }
344
345 /* Loongson RTC does not support UIE */
346 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, priv->rtcdev->features);
347 priv->rtcdev->ops = &loongson_rtc_ops;
348 priv->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
349 priv->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
350
351 return devm_rtc_register_device(priv->rtcdev);
352 }
353
loongson_rtc_remove(struct platform_device * pdev)354 static void loongson_rtc_remove(struct platform_device *pdev)
355 {
356 struct device *dev = &pdev->dev;
357 struct loongson_rtc_priv *priv = dev_get_drvdata(dev);
358
359 if (!test_bit(RTC_FEATURE_ALARM, priv->rtcdev->features))
360 return;
361
362 if (has_acpi_companion(dev))
363 acpi_remove_fixed_event_handler(ACPI_EVENT_RTC,
364 loongson_rtc_handler);
365
366 device_init_wakeup(dev, 0);
367 loongson_rtc_alarm_irq_enable(dev, 0);
368 }
369
370 static const struct of_device_id loongson_rtc_of_match[] = {
371 { .compatible = "loongson,ls1b-rtc", .data = &ls1b_rtc_config },
372 { .compatible = "loongson,ls1c-rtc", .data = &ls1c_rtc_config },
373 { .compatible = "loongson,ls7a-rtc", .data = &generic_rtc_config },
374 { .compatible = "loongson,ls2k1000-rtc", .data = &ls2k1000_rtc_config },
375 { /* sentinel */ }
376 };
377 MODULE_DEVICE_TABLE(of, loongson_rtc_of_match);
378
379 static const struct acpi_device_id loongson_rtc_acpi_match[] = {
380 { "LOON0001", .driver_data = (kernel_ulong_t)&generic_rtc_config },
381 { }
382 };
383 MODULE_DEVICE_TABLE(acpi, loongson_rtc_acpi_match);
384
385 static struct platform_driver loongson_rtc_driver = {
386 .probe = loongson_rtc_probe,
387 .remove_new = loongson_rtc_remove,
388 .driver = {
389 .name = "loongson-rtc",
390 .of_match_table = loongson_rtc_of_match,
391 .acpi_match_table = loongson_rtc_acpi_match,
392 },
393 };
394 module_platform_driver(loongson_rtc_driver);
395
396 MODULE_DESCRIPTION("Loongson RTC driver");
397 MODULE_AUTHOR("Binbin Zhou <zhoubinbin@loongson.cn>");
398 MODULE_AUTHOR("WANG Xuerui <git@xen0n.name>");
399 MODULE_AUTHOR("Huacai Chen <chenhuacai@kernel.org>");
400 MODULE_LICENSE("GPL");
401