1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * An rtc driver for the Dallas DS1553 |
4 | * |
5 | * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> |
6 | */ |
7 | |
8 | #include <linux/bcd.h> |
9 | #include <linux/init.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/gfp.h> |
12 | #include <linux/delay.h> |
13 | #include <linux/jiffies.h> |
14 | #include <linux/interrupt.h> |
15 | #include <linux/rtc.h> |
16 | #include <linux/platform_device.h> |
17 | #include <linux/io.h> |
18 | #include <linux/module.h> |
19 | |
20 | #define RTC_REG_SIZE 0x2000 |
21 | #define RTC_OFFSET 0x1ff0 |
22 | |
23 | #define RTC_FLAGS (RTC_OFFSET + 0) |
24 | #define RTC_SECONDS_ALARM (RTC_OFFSET + 2) |
25 | #define RTC_MINUTES_ALARM (RTC_OFFSET + 3) |
26 | #define RTC_HOURS_ALARM (RTC_OFFSET + 4) |
27 | #define RTC_DATE_ALARM (RTC_OFFSET + 5) |
28 | #define RTC_INTERRUPTS (RTC_OFFSET + 6) |
29 | #define RTC_WATCHDOG (RTC_OFFSET + 7) |
30 | #define RTC_CONTROL (RTC_OFFSET + 8) |
31 | #define RTC_CENTURY (RTC_OFFSET + 8) |
32 | #define RTC_SECONDS (RTC_OFFSET + 9) |
33 | #define RTC_MINUTES (RTC_OFFSET + 10) |
34 | #define RTC_HOURS (RTC_OFFSET + 11) |
35 | #define RTC_DAY (RTC_OFFSET + 12) |
36 | #define RTC_DATE (RTC_OFFSET + 13) |
37 | #define RTC_MONTH (RTC_OFFSET + 14) |
38 | #define RTC_YEAR (RTC_OFFSET + 15) |
39 | |
40 | #define RTC_CENTURY_MASK 0x3f |
41 | #define RTC_SECONDS_MASK 0x7f |
42 | #define RTC_DAY_MASK 0x07 |
43 | |
44 | /* Bits in the Control/Century register */ |
45 | #define RTC_WRITE 0x80 |
46 | #define RTC_READ 0x40 |
47 | |
48 | /* Bits in the Seconds register */ |
49 | #define RTC_STOP 0x80 |
50 | |
51 | /* Bits in the Flags register */ |
52 | #define RTC_FLAGS_AF 0x40 |
53 | #define RTC_FLAGS_BLF 0x10 |
54 | |
55 | /* Bits in the Interrupts register */ |
56 | #define RTC_INTS_AE 0x80 |
57 | |
58 | struct rtc_plat_data { |
59 | struct rtc_device *rtc; |
60 | void __iomem *ioaddr; |
61 | unsigned long last_jiffies; |
62 | int irq; |
63 | unsigned int irqen; |
64 | int alrm_sec; |
65 | int alrm_min; |
66 | int alrm_hour; |
67 | int alrm_mday; |
68 | spinlock_t lock; |
69 | }; |
70 | |
71 | static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm) |
72 | { |
73 | struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
74 | void __iomem *ioaddr = pdata->ioaddr; |
75 | u8 century; |
76 | |
77 | century = bin2bcd((tm->tm_year + 1900) / 100); |
78 | |
79 | writeb(RTC_WRITE, addr: pdata->ioaddr + RTC_CONTROL); |
80 | |
81 | writeb(bin2bcd(tm->tm_year % 100), addr: ioaddr + RTC_YEAR); |
82 | writeb(bin2bcd(tm->tm_mon + 1), addr: ioaddr + RTC_MONTH); |
83 | writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, addr: ioaddr + RTC_DAY); |
84 | writeb(bin2bcd(tm->tm_mday), addr: ioaddr + RTC_DATE); |
85 | writeb(bin2bcd(tm->tm_hour), addr: ioaddr + RTC_HOURS); |
86 | writeb(bin2bcd(tm->tm_min), addr: ioaddr + RTC_MINUTES); |
87 | writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, addr: ioaddr + RTC_SECONDS); |
88 | |
89 | /* RTC_CENTURY and RTC_CONTROL share same register */ |
90 | writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), addr: ioaddr + RTC_CENTURY); |
91 | writeb(val: century & RTC_CENTURY_MASK, addr: ioaddr + RTC_CONTROL); |
92 | return 0; |
93 | } |
94 | |
95 | static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm) |
96 | { |
97 | struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
98 | void __iomem *ioaddr = pdata->ioaddr; |
99 | unsigned int year, month, day, hour, minute, second, week; |
100 | unsigned int century; |
101 | |
102 | /* give enough time to update RTC in case of continuous read */ |
103 | if (pdata->last_jiffies == jiffies) |
104 | msleep(msecs: 1); |
105 | pdata->last_jiffies = jiffies; |
106 | writeb(RTC_READ, addr: ioaddr + RTC_CONTROL); |
107 | second = readb(addr: ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; |
108 | minute = readb(addr: ioaddr + RTC_MINUTES); |
109 | hour = readb(addr: ioaddr + RTC_HOURS); |
110 | day = readb(addr: ioaddr + RTC_DATE); |
111 | week = readb(addr: ioaddr + RTC_DAY) & RTC_DAY_MASK; |
112 | month = readb(addr: ioaddr + RTC_MONTH); |
113 | year = readb(addr: ioaddr + RTC_YEAR); |
114 | century = readb(addr: ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; |
115 | writeb(val: 0, addr: ioaddr + RTC_CONTROL); |
116 | tm->tm_sec = bcd2bin(second); |
117 | tm->tm_min = bcd2bin(minute); |
118 | tm->tm_hour = bcd2bin(hour); |
119 | tm->tm_mday = bcd2bin(day); |
120 | tm->tm_wday = bcd2bin(week); |
121 | tm->tm_mon = bcd2bin(month) - 1; |
122 | /* year is 1900 + tm->tm_year */ |
123 | tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; |
124 | |
125 | return 0; |
126 | } |
127 | |
128 | static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata) |
129 | { |
130 | void __iomem *ioaddr = pdata->ioaddr; |
131 | unsigned long flags; |
132 | |
133 | spin_lock_irqsave(&pdata->lock, flags); |
134 | writeb(val: pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? |
135 | 0x80 : bin2bcd(pdata->alrm_mday), |
136 | addr: ioaddr + RTC_DATE_ALARM); |
137 | writeb(val: pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? |
138 | 0x80 : bin2bcd(pdata->alrm_hour), |
139 | addr: ioaddr + RTC_HOURS_ALARM); |
140 | writeb(val: pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? |
141 | 0x80 : bin2bcd(pdata->alrm_min), |
142 | addr: ioaddr + RTC_MINUTES_ALARM); |
143 | writeb(val: pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? |
144 | 0x80 : bin2bcd(pdata->alrm_sec), |
145 | addr: ioaddr + RTC_SECONDS_ALARM); |
146 | writeb(val: pdata->irqen ? RTC_INTS_AE : 0, addr: ioaddr + RTC_INTERRUPTS); |
147 | readb(addr: ioaddr + RTC_FLAGS); /* clear interrupts */ |
148 | spin_unlock_irqrestore(lock: &pdata->lock, flags); |
149 | } |
150 | |
151 | static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
152 | { |
153 | struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
154 | |
155 | if (pdata->irq <= 0) |
156 | return -EINVAL; |
157 | pdata->alrm_mday = alrm->time.tm_mday; |
158 | pdata->alrm_hour = alrm->time.tm_hour; |
159 | pdata->alrm_min = alrm->time.tm_min; |
160 | pdata->alrm_sec = alrm->time.tm_sec; |
161 | if (alrm->enabled) |
162 | pdata->irqen |= RTC_AF; |
163 | ds1553_rtc_update_alarm(pdata); |
164 | return 0; |
165 | } |
166 | |
167 | static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
168 | { |
169 | struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
170 | |
171 | if (pdata->irq <= 0) |
172 | return -EINVAL; |
173 | alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; |
174 | alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; |
175 | alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; |
176 | alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; |
177 | alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; |
178 | return 0; |
179 | } |
180 | |
181 | static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id) |
182 | { |
183 | struct platform_device *pdev = dev_id; |
184 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
185 | void __iomem *ioaddr = pdata->ioaddr; |
186 | unsigned long events = 0; |
187 | |
188 | spin_lock(lock: &pdata->lock); |
189 | /* read and clear interrupt */ |
190 | if (readb(addr: ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { |
191 | events = RTC_IRQF; |
192 | if (readb(addr: ioaddr + RTC_SECONDS_ALARM) & 0x80) |
193 | events |= RTC_UF; |
194 | else |
195 | events |= RTC_AF; |
196 | rtc_update_irq(rtc: pdata->rtc, num: 1, events); |
197 | } |
198 | spin_unlock(lock: &pdata->lock); |
199 | return events ? IRQ_HANDLED : IRQ_NONE; |
200 | } |
201 | |
202 | static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
203 | { |
204 | struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
205 | |
206 | if (pdata->irq <= 0) |
207 | return -EINVAL; |
208 | if (enabled) |
209 | pdata->irqen |= RTC_AF; |
210 | else |
211 | pdata->irqen &= ~RTC_AF; |
212 | ds1553_rtc_update_alarm(pdata); |
213 | return 0; |
214 | } |
215 | |
216 | static const struct rtc_class_ops ds1553_rtc_ops = { |
217 | .read_time = ds1553_rtc_read_time, |
218 | .set_time = ds1553_rtc_set_time, |
219 | .read_alarm = ds1553_rtc_read_alarm, |
220 | .set_alarm = ds1553_rtc_set_alarm, |
221 | .alarm_irq_enable = ds1553_rtc_alarm_irq_enable, |
222 | }; |
223 | |
224 | static int ds1553_nvram_read(void *priv, unsigned int pos, void *val, |
225 | size_t bytes) |
226 | { |
227 | struct platform_device *pdev = priv; |
228 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
229 | void __iomem *ioaddr = pdata->ioaddr; |
230 | u8 *buf = val; |
231 | |
232 | for (; bytes; bytes--) |
233 | *buf++ = readb(addr: ioaddr + pos++); |
234 | return 0; |
235 | } |
236 | |
237 | static int ds1553_nvram_write(void *priv, unsigned int pos, void *val, |
238 | size_t bytes) |
239 | { |
240 | struct platform_device *pdev = priv; |
241 | struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
242 | void __iomem *ioaddr = pdata->ioaddr; |
243 | u8 *buf = val; |
244 | |
245 | for (; bytes; bytes--) |
246 | writeb(val: *buf++, addr: ioaddr + pos++); |
247 | return 0; |
248 | } |
249 | |
250 | static int ds1553_rtc_probe(struct platform_device *pdev) |
251 | { |
252 | unsigned int cen, sec; |
253 | struct rtc_plat_data *pdata; |
254 | void __iomem *ioaddr; |
255 | int ret = 0; |
256 | struct nvmem_config nvmem_cfg = { |
257 | .name = "ds1553_nvram" , |
258 | .word_size = 1, |
259 | .stride = 1, |
260 | .size = RTC_OFFSET, |
261 | .reg_read = ds1553_nvram_read, |
262 | .reg_write = ds1553_nvram_write, |
263 | .priv = pdev, |
264 | }; |
265 | |
266 | pdata = devm_kzalloc(dev: &pdev->dev, size: sizeof(*pdata), GFP_KERNEL); |
267 | if (!pdata) |
268 | return -ENOMEM; |
269 | |
270 | ioaddr = devm_platform_ioremap_resource(pdev, index: 0); |
271 | if (IS_ERR(ptr: ioaddr)) |
272 | return PTR_ERR(ptr: ioaddr); |
273 | pdata->ioaddr = ioaddr; |
274 | pdata->irq = platform_get_irq(pdev, 0); |
275 | |
276 | /* turn RTC on if it was not on */ |
277 | sec = readb(addr: ioaddr + RTC_SECONDS); |
278 | if (sec & RTC_STOP) { |
279 | sec &= RTC_SECONDS_MASK; |
280 | cen = readb(addr: ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK; |
281 | writeb(RTC_WRITE, addr: ioaddr + RTC_CONTROL); |
282 | writeb(val: sec, addr: ioaddr + RTC_SECONDS); |
283 | writeb(val: cen & RTC_CENTURY_MASK, addr: ioaddr + RTC_CONTROL); |
284 | } |
285 | if (readb(addr: ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF) |
286 | dev_warn(&pdev->dev, "voltage-low detected.\n" ); |
287 | |
288 | spin_lock_init(&pdata->lock); |
289 | pdata->last_jiffies = jiffies; |
290 | platform_set_drvdata(pdev, data: pdata); |
291 | |
292 | pdata->rtc = devm_rtc_allocate_device(dev: &pdev->dev); |
293 | if (IS_ERR(ptr: pdata->rtc)) |
294 | return PTR_ERR(ptr: pdata->rtc); |
295 | |
296 | pdata->rtc->ops = &ds1553_rtc_ops; |
297 | |
298 | ret = devm_rtc_register_device(pdata->rtc); |
299 | if (ret) |
300 | return ret; |
301 | |
302 | if (pdata->irq > 0) { |
303 | writeb(val: 0, addr: ioaddr + RTC_INTERRUPTS); |
304 | if (devm_request_irq(dev: &pdev->dev, irq: pdata->irq, |
305 | handler: ds1553_rtc_interrupt, |
306 | irqflags: 0, devname: pdev->name, dev_id: pdev) < 0) { |
307 | dev_warn(&pdev->dev, "interrupt not available.\n" ); |
308 | pdata->irq = 0; |
309 | } |
310 | } |
311 | |
312 | devm_rtc_nvmem_register(rtc: pdata->rtc, nvmem_config: &nvmem_cfg); |
313 | |
314 | return 0; |
315 | } |
316 | |
317 | /* work with hotplug and coldplug */ |
318 | MODULE_ALIAS("platform:rtc-ds1553" ); |
319 | |
320 | static struct platform_driver ds1553_rtc_driver = { |
321 | .probe = ds1553_rtc_probe, |
322 | .driver = { |
323 | .name = "rtc-ds1553" , |
324 | }, |
325 | }; |
326 | |
327 | module_platform_driver(ds1553_rtc_driver); |
328 | |
329 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>" ); |
330 | MODULE_DESCRIPTION("Dallas DS1553 RTC driver" ); |
331 | MODULE_LICENSE("GPL" ); |
332 | |