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f803f0d0 TR |
1 | /* |
2 | * Copyright (C) 2012 Avionic Design GmbH | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <linux/bcd.h> | |
10 | #include <linux/i2c.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/rtc.h> | |
13 | #include <linux/of.h> | |
14 | ||
15 | #define DRIVER_NAME "rtc-pcf8523" | |
16 | ||
17 | #define REG_CONTROL1 0x00 | |
18 | #define REG_CONTROL1_CAP_SEL (1 << 7) | |
19 | #define REG_CONTROL1_STOP (1 << 5) | |
20 | ||
21 | #define REG_CONTROL3 0x02 | |
22 | #define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */ | |
23 | #define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */ | |
24 | #define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */ | |
25 | #define REG_CONTROL3_PM_MASK 0xe0 | |
f32bc70d | 26 | #define REG_CONTROL3_BLF (1 << 2) /* battery low bit, read-only */ |
f803f0d0 TR |
27 | |
28 | #define REG_SECONDS 0x03 | |
29 | #define REG_SECONDS_OS (1 << 7) | |
30 | ||
31 | #define REG_MINUTES 0x04 | |
32 | #define REG_HOURS 0x05 | |
33 | #define REG_DAYS 0x06 | |
34 | #define REG_WEEKDAYS 0x07 | |
35 | #define REG_MONTHS 0x08 | |
36 | #define REG_YEARS 0x09 | |
37 | ||
38 | struct pcf8523 { | |
39 | struct rtc_device *rtc; | |
40 | }; | |
41 | ||
42 | static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep) | |
43 | { | |
44 | struct i2c_msg msgs[2]; | |
45 | u8 value = 0; | |
46 | int err; | |
47 | ||
48 | msgs[0].addr = client->addr; | |
49 | msgs[0].flags = 0; | |
50 | msgs[0].len = sizeof(reg); | |
51 | msgs[0].buf = ® | |
52 | ||
53 | msgs[1].addr = client->addr; | |
54 | msgs[1].flags = I2C_M_RD; | |
55 | msgs[1].len = sizeof(value); | |
56 | msgs[1].buf = &value; | |
57 | ||
58 | err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
59 | if (err < 0) | |
60 | return err; | |
61 | ||
62 | *valuep = value; | |
63 | ||
64 | return 0; | |
65 | } | |
66 | ||
67 | static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) | |
68 | { | |
69 | u8 buffer[2] = { reg, value }; | |
70 | struct i2c_msg msg; | |
71 | int err; | |
72 | ||
73 | msg.addr = client->addr; | |
74 | msg.flags = 0; | |
75 | msg.len = sizeof(buffer); | |
76 | msg.buf = buffer; | |
77 | ||
78 | err = i2c_transfer(client->adapter, &msg, 1); | |
79 | if (err < 0) | |
80 | return err; | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | static int pcf8523_select_capacitance(struct i2c_client *client, bool high) | |
86 | { | |
87 | u8 value; | |
88 | int err; | |
89 | ||
90 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
91 | if (err < 0) | |
92 | return err; | |
93 | ||
94 | if (!high) | |
95 | value &= ~REG_CONTROL1_CAP_SEL; | |
96 | else | |
97 | value |= REG_CONTROL1_CAP_SEL; | |
98 | ||
99 | err = pcf8523_write(client, REG_CONTROL1, value); | |
100 | if (err < 0) | |
101 | return err; | |
102 | ||
103 | return err; | |
104 | } | |
105 | ||
106 | static int pcf8523_set_pm(struct i2c_client *client, u8 pm) | |
107 | { | |
108 | u8 value; | |
109 | int err; | |
110 | ||
111 | err = pcf8523_read(client, REG_CONTROL3, &value); | |
112 | if (err < 0) | |
113 | return err; | |
114 | ||
115 | value = (value & ~REG_CONTROL3_PM_MASK) | pm; | |
116 | ||
117 | err = pcf8523_write(client, REG_CONTROL3, value); | |
118 | if (err < 0) | |
119 | return err; | |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | static int pcf8523_stop_rtc(struct i2c_client *client) | |
125 | { | |
126 | u8 value; | |
127 | int err; | |
128 | ||
129 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
130 | if (err < 0) | |
131 | return err; | |
132 | ||
133 | value |= REG_CONTROL1_STOP; | |
134 | ||
135 | err = pcf8523_write(client, REG_CONTROL1, value); | |
136 | if (err < 0) | |
137 | return err; | |
138 | ||
139 | return 0; | |
140 | } | |
141 | ||
142 | static int pcf8523_start_rtc(struct i2c_client *client) | |
143 | { | |
144 | u8 value; | |
145 | int err; | |
146 | ||
147 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
148 | if (err < 0) | |
149 | return err; | |
150 | ||
151 | value &= ~REG_CONTROL1_STOP; | |
152 | ||
153 | err = pcf8523_write(client, REG_CONTROL1, value); | |
154 | if (err < 0) | |
155 | return err; | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
160 | static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
161 | { | |
162 | struct i2c_client *client = to_i2c_client(dev); | |
163 | u8 start = REG_SECONDS, regs[7]; | |
164 | struct i2c_msg msgs[2]; | |
165 | int err; | |
166 | ||
167 | msgs[0].addr = client->addr; | |
168 | msgs[0].flags = 0; | |
169 | msgs[0].len = 1; | |
170 | msgs[0].buf = &start; | |
171 | ||
172 | msgs[1].addr = client->addr; | |
173 | msgs[1].flags = I2C_M_RD; | |
174 | msgs[1].len = sizeof(regs); | |
175 | msgs[1].buf = regs; | |
176 | ||
177 | err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
178 | if (err < 0) | |
179 | return err; | |
180 | ||
181 | if (regs[0] & REG_SECONDS_OS) { | |
182 | /* | |
183 | * If the oscillator was stopped, try to clear the flag. Upon | |
184 | * power-up the flag is always set, but if we cannot clear it | |
185 | * the oscillator isn't running properly for some reason. The | |
186 | * sensible thing therefore is to return an error, signalling | |
187 | * that the clock cannot be assumed to be correct. | |
188 | */ | |
189 | ||
190 | regs[0] &= ~REG_SECONDS_OS; | |
191 | ||
192 | err = pcf8523_write(client, REG_SECONDS, regs[0]); | |
193 | if (err < 0) | |
194 | return err; | |
195 | ||
196 | err = pcf8523_read(client, REG_SECONDS, ®s[0]); | |
197 | if (err < 0) | |
198 | return err; | |
199 | ||
200 | if (regs[0] & REG_SECONDS_OS) | |
201 | return -EAGAIN; | |
202 | } | |
203 | ||
204 | tm->tm_sec = bcd2bin(regs[0] & 0x7f); | |
205 | tm->tm_min = bcd2bin(regs[1] & 0x7f); | |
206 | tm->tm_hour = bcd2bin(regs[2] & 0x3f); | |
207 | tm->tm_mday = bcd2bin(regs[3] & 0x3f); | |
208 | tm->tm_wday = regs[4] & 0x7; | |
209 | tm->tm_mon = bcd2bin(regs[5] & 0x1f); | |
210 | tm->tm_year = bcd2bin(regs[6]) + 100; | |
211 | ||
212 | return rtc_valid_tm(tm); | |
213 | } | |
214 | ||
215 | static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
216 | { | |
217 | struct i2c_client *client = to_i2c_client(dev); | |
218 | struct i2c_msg msg; | |
219 | u8 regs[8]; | |
220 | int err; | |
221 | ||
222 | err = pcf8523_stop_rtc(client); | |
223 | if (err < 0) | |
224 | return err; | |
225 | ||
226 | regs[0] = REG_SECONDS; | |
227 | regs[1] = bin2bcd(tm->tm_sec); | |
228 | regs[2] = bin2bcd(tm->tm_min); | |
229 | regs[3] = bin2bcd(tm->tm_hour); | |
230 | regs[4] = bin2bcd(tm->tm_mday); | |
231 | regs[5] = tm->tm_wday; | |
232 | regs[6] = bin2bcd(tm->tm_mon); | |
233 | regs[7] = bin2bcd(tm->tm_year - 100); | |
234 | ||
235 | msg.addr = client->addr; | |
236 | msg.flags = 0; | |
237 | msg.len = sizeof(regs); | |
238 | msg.buf = regs; | |
239 | ||
240 | err = i2c_transfer(client->adapter, &msg, 1); | |
241 | if (err < 0) { | |
242 | /* | |
243 | * If the time cannot be set, restart the RTC anyway. Note | |
244 | * that errors are ignored if the RTC cannot be started so | |
245 | * that we have a chance to propagate the original error. | |
246 | */ | |
247 | pcf8523_start_rtc(client); | |
248 | return err; | |
249 | } | |
250 | ||
251 | return pcf8523_start_rtc(client); | |
252 | } | |
253 | ||
f32bc70d JN |
254 | #ifdef CONFIG_RTC_INTF_DEV |
255 | static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, | |
256 | unsigned long arg) | |
257 | { | |
258 | struct i2c_client *client = to_i2c_client(dev); | |
259 | u8 value; | |
260 | int ret = 0, err; | |
261 | ||
262 | switch (cmd) { | |
263 | case RTC_VL_READ: | |
264 | err = pcf8523_read(client, REG_CONTROL3, &value); | |
265 | if (err < 0) | |
266 | return err; | |
267 | ||
268 | if (value & REG_CONTROL3_BLF) | |
269 | ret = 1; | |
270 | ||
271 | if (copy_to_user((void __user *)arg, &ret, sizeof(int))) | |
272 | return -EFAULT; | |
273 | ||
274 | return 0; | |
275 | default: | |
276 | return -ENOIOCTLCMD; | |
277 | } | |
278 | } | |
279 | #else | |
280 | #define pcf8523_rtc_ioctl NULL | |
281 | #endif | |
282 | ||
f803f0d0 TR |
283 | static const struct rtc_class_ops pcf8523_rtc_ops = { |
284 | .read_time = pcf8523_rtc_read_time, | |
285 | .set_time = pcf8523_rtc_set_time, | |
f32bc70d | 286 | .ioctl = pcf8523_rtc_ioctl, |
f803f0d0 TR |
287 | }; |
288 | ||
289 | static int pcf8523_probe(struct i2c_client *client, | |
290 | const struct i2c_device_id *id) | |
291 | { | |
292 | struct pcf8523 *pcf; | |
293 | int err; | |
294 | ||
295 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
296 | return -ENODEV; | |
297 | ||
298 | pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL); | |
299 | if (!pcf) | |
300 | return -ENOMEM; | |
301 | ||
302 | err = pcf8523_select_capacitance(client, true); | |
303 | if (err < 0) | |
304 | return err; | |
305 | ||
306 | err = pcf8523_set_pm(client, 0); | |
307 | if (err < 0) | |
308 | return err; | |
309 | ||
288031bf | 310 | pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME, |
f803f0d0 TR |
311 | &pcf8523_rtc_ops, THIS_MODULE); |
312 | if (IS_ERR(pcf->rtc)) | |
313 | return PTR_ERR(pcf->rtc); | |
314 | ||
315 | i2c_set_clientdata(client, pcf); | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
f803f0d0 TR |
320 | static const struct i2c_device_id pcf8523_id[] = { |
321 | { "pcf8523", 0 }, | |
322 | { } | |
323 | }; | |
324 | MODULE_DEVICE_TABLE(i2c, pcf8523_id); | |
325 | ||
326 | #ifdef CONFIG_OF | |
327 | static const struct of_device_id pcf8523_of_match[] = { | |
328 | { .compatible = "nxp,pcf8523" }, | |
329 | { } | |
330 | }; | |
331 | MODULE_DEVICE_TABLE(of, pcf8523_of_match); | |
332 | #endif | |
333 | ||
334 | static struct i2c_driver pcf8523_driver = { | |
335 | .driver = { | |
336 | .name = DRIVER_NAME, | |
337 | .owner = THIS_MODULE, | |
338 | .of_match_table = of_match_ptr(pcf8523_of_match), | |
339 | }, | |
340 | .probe = pcf8523_probe, | |
f803f0d0 TR |
341 | .id_table = pcf8523_id, |
342 | }; | |
343 | module_i2c_driver(pcf8523_driver); | |
344 | ||
345 | MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>"); | |
346 | MODULE_DESCRIPTION("NXP PCF8523 RTC driver"); | |
347 | MODULE_LICENSE("GPL v2"); |