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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 | ||
bc3bee02 RK |
38 | #define REG_OFFSET 0x0e |
39 | #define REG_OFFSET_MODE BIT(7) | |
40 | ||
f803f0d0 TR |
41 | struct pcf8523 { |
42 | struct rtc_device *rtc; | |
43 | }; | |
44 | ||
45 | static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep) | |
46 | { | |
47 | struct i2c_msg msgs[2]; | |
48 | u8 value = 0; | |
49 | int err; | |
50 | ||
51 | msgs[0].addr = client->addr; | |
52 | msgs[0].flags = 0; | |
53 | msgs[0].len = sizeof(reg); | |
54 | msgs[0].buf = ® | |
55 | ||
56 | msgs[1].addr = client->addr; | |
57 | msgs[1].flags = I2C_M_RD; | |
58 | msgs[1].len = sizeof(value); | |
59 | msgs[1].buf = &value; | |
60 | ||
61 | err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
62 | if (err < 0) | |
63 | return err; | |
64 | ||
65 | *valuep = value; | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
70 | static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) | |
71 | { | |
72 | u8 buffer[2] = { reg, value }; | |
73 | struct i2c_msg msg; | |
74 | int err; | |
75 | ||
76 | msg.addr = client->addr; | |
77 | msg.flags = 0; | |
78 | msg.len = sizeof(buffer); | |
79 | msg.buf = buffer; | |
80 | ||
81 | err = i2c_transfer(client->adapter, &msg, 1); | |
82 | if (err < 0) | |
83 | return err; | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static int pcf8523_select_capacitance(struct i2c_client *client, bool high) | |
89 | { | |
90 | u8 value; | |
91 | int err; | |
92 | ||
93 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
94 | if (err < 0) | |
95 | return err; | |
96 | ||
97 | if (!high) | |
98 | value &= ~REG_CONTROL1_CAP_SEL; | |
99 | else | |
100 | value |= REG_CONTROL1_CAP_SEL; | |
101 | ||
102 | err = pcf8523_write(client, REG_CONTROL1, value); | |
103 | if (err < 0) | |
104 | return err; | |
105 | ||
106 | return err; | |
107 | } | |
108 | ||
109 | static int pcf8523_set_pm(struct i2c_client *client, u8 pm) | |
110 | { | |
111 | u8 value; | |
112 | int err; | |
113 | ||
114 | err = pcf8523_read(client, REG_CONTROL3, &value); | |
115 | if (err < 0) | |
116 | return err; | |
117 | ||
118 | value = (value & ~REG_CONTROL3_PM_MASK) | pm; | |
119 | ||
120 | err = pcf8523_write(client, REG_CONTROL3, value); | |
121 | if (err < 0) | |
122 | return err; | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
127 | static int pcf8523_stop_rtc(struct i2c_client *client) | |
128 | { | |
129 | u8 value; | |
130 | int err; | |
131 | ||
132 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
133 | if (err < 0) | |
134 | return err; | |
135 | ||
136 | value |= REG_CONTROL1_STOP; | |
137 | ||
138 | err = pcf8523_write(client, REG_CONTROL1, value); | |
139 | if (err < 0) | |
140 | return err; | |
141 | ||
142 | return 0; | |
143 | } | |
144 | ||
145 | static int pcf8523_start_rtc(struct i2c_client *client) | |
146 | { | |
147 | u8 value; | |
148 | int err; | |
149 | ||
150 | err = pcf8523_read(client, REG_CONTROL1, &value); | |
151 | if (err < 0) | |
152 | return err; | |
153 | ||
154 | value &= ~REG_CONTROL1_STOP; | |
155 | ||
156 | err = pcf8523_write(client, REG_CONTROL1, value); | |
157 | if (err < 0) | |
158 | return err; | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
164 | { | |
165 | struct i2c_client *client = to_i2c_client(dev); | |
166 | u8 start = REG_SECONDS, regs[7]; | |
167 | struct i2c_msg msgs[2]; | |
168 | int err; | |
169 | ||
170 | msgs[0].addr = client->addr; | |
171 | msgs[0].flags = 0; | |
172 | msgs[0].len = 1; | |
173 | msgs[0].buf = &start; | |
174 | ||
175 | msgs[1].addr = client->addr; | |
176 | msgs[1].flags = I2C_M_RD; | |
177 | msgs[1].len = sizeof(regs); | |
178 | msgs[1].buf = regs; | |
179 | ||
180 | err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
181 | if (err < 0) | |
182 | return err; | |
183 | ||
ede44c90 AB |
184 | if (regs[0] & REG_SECONDS_OS) |
185 | return -EINVAL; | |
f803f0d0 TR |
186 | |
187 | tm->tm_sec = bcd2bin(regs[0] & 0x7f); | |
188 | tm->tm_min = bcd2bin(regs[1] & 0x7f); | |
189 | tm->tm_hour = bcd2bin(regs[2] & 0x3f); | |
190 | tm->tm_mday = bcd2bin(regs[3] & 0x3f); | |
191 | tm->tm_wday = regs[4] & 0x7; | |
35738392 | 192 | tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1; |
f803f0d0 TR |
193 | tm->tm_year = bcd2bin(regs[6]) + 100; |
194 | ||
195 | return rtc_valid_tm(tm); | |
196 | } | |
197 | ||
198 | static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
199 | { | |
200 | struct i2c_client *client = to_i2c_client(dev); | |
201 | struct i2c_msg msg; | |
202 | u8 regs[8]; | |
203 | int err; | |
204 | ||
fbbf53f7 UKK |
205 | /* |
206 | * The hardware can only store values between 0 and 99 in it's YEAR | |
207 | * register (with 99 overflowing to 0 on increment). | |
208 | * After 2100-02-28 we could start interpreting the year to be in the | |
209 | * interval [2100, 2199], but there is no path to switch in a smooth way | |
210 | * because the chip handles YEAR=0x00 (and the out-of-spec | |
211 | * YEAR=0xa0) as a leap year, but 2100 isn't. | |
212 | */ | |
213 | if (tm->tm_year < 100 || tm->tm_year >= 200) | |
214 | return -EINVAL; | |
215 | ||
f803f0d0 TR |
216 | err = pcf8523_stop_rtc(client); |
217 | if (err < 0) | |
218 | return err; | |
219 | ||
220 | regs[0] = REG_SECONDS; | |
ede44c90 | 221 | /* This will purposely overwrite REG_SECONDS_OS */ |
f803f0d0 TR |
222 | regs[1] = bin2bcd(tm->tm_sec); |
223 | regs[2] = bin2bcd(tm->tm_min); | |
224 | regs[3] = bin2bcd(tm->tm_hour); | |
225 | regs[4] = bin2bcd(tm->tm_mday); | |
226 | regs[5] = tm->tm_wday; | |
35738392 | 227 | regs[6] = bin2bcd(tm->tm_mon + 1); |
f803f0d0 TR |
228 | regs[7] = bin2bcd(tm->tm_year - 100); |
229 | ||
230 | msg.addr = client->addr; | |
231 | msg.flags = 0; | |
232 | msg.len = sizeof(regs); | |
233 | msg.buf = regs; | |
234 | ||
235 | err = i2c_transfer(client->adapter, &msg, 1); | |
236 | if (err < 0) { | |
237 | /* | |
238 | * If the time cannot be set, restart the RTC anyway. Note | |
239 | * that errors are ignored if the RTC cannot be started so | |
240 | * that we have a chance to propagate the original error. | |
241 | */ | |
242 | pcf8523_start_rtc(client); | |
243 | return err; | |
244 | } | |
245 | ||
246 | return pcf8523_start_rtc(client); | |
247 | } | |
248 | ||
f32bc70d JN |
249 | #ifdef CONFIG_RTC_INTF_DEV |
250 | static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, | |
251 | unsigned long arg) | |
252 | { | |
253 | struct i2c_client *client = to_i2c_client(dev); | |
254 | u8 value; | |
255 | int ret = 0, err; | |
256 | ||
257 | switch (cmd) { | |
258 | case RTC_VL_READ: | |
259 | err = pcf8523_read(client, REG_CONTROL3, &value); | |
260 | if (err < 0) | |
261 | return err; | |
262 | ||
263 | if (value & REG_CONTROL3_BLF) | |
264 | ret = 1; | |
265 | ||
266 | if (copy_to_user((void __user *)arg, &ret, sizeof(int))) | |
267 | return -EFAULT; | |
268 | ||
269 | return 0; | |
270 | default: | |
271 | return -ENOIOCTLCMD; | |
272 | } | |
273 | } | |
274 | #else | |
275 | #define pcf8523_rtc_ioctl NULL | |
276 | #endif | |
277 | ||
bc3bee02 RK |
278 | static int pcf8523_rtc_read_offset(struct device *dev, long *offset) |
279 | { | |
280 | struct i2c_client *client = to_i2c_client(dev); | |
281 | int err; | |
282 | u8 value; | |
283 | s8 val; | |
284 | ||
285 | err = pcf8523_read(client, REG_OFFSET, &value); | |
286 | if (err < 0) | |
287 | return err; | |
288 | ||
289 | /* sign extend the 7-bit offset value */ | |
290 | val = value << 1; | |
291 | *offset = (value & REG_OFFSET_MODE ? 4069 : 4340) * (val >> 1); | |
292 | ||
293 | return 0; | |
294 | } | |
295 | ||
296 | static int pcf8523_rtc_set_offset(struct device *dev, long offset) | |
297 | { | |
298 | struct i2c_client *client = to_i2c_client(dev); | |
299 | long reg_m0, reg_m1; | |
300 | u8 value; | |
301 | ||
302 | reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L); | |
303 | reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L); | |
304 | ||
305 | if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset)) | |
306 | value = reg_m0 & 0x7f; | |
307 | else | |
308 | value = (reg_m1 & 0x7f) | REG_OFFSET_MODE; | |
309 | ||
310 | return pcf8523_write(client, REG_OFFSET, value); | |
311 | } | |
312 | ||
f803f0d0 TR |
313 | static const struct rtc_class_ops pcf8523_rtc_ops = { |
314 | .read_time = pcf8523_rtc_read_time, | |
315 | .set_time = pcf8523_rtc_set_time, | |
f32bc70d | 316 | .ioctl = pcf8523_rtc_ioctl, |
bc3bee02 RK |
317 | .read_offset = pcf8523_rtc_read_offset, |
318 | .set_offset = pcf8523_rtc_set_offset, | |
f803f0d0 TR |
319 | }; |
320 | ||
321 | static int pcf8523_probe(struct i2c_client *client, | |
322 | const struct i2c_device_id *id) | |
323 | { | |
324 | struct pcf8523 *pcf; | |
325 | int err; | |
326 | ||
327 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
328 | return -ENODEV; | |
329 | ||
330 | pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL); | |
331 | if (!pcf) | |
332 | return -ENOMEM; | |
333 | ||
334 | err = pcf8523_select_capacitance(client, true); | |
335 | if (err < 0) | |
336 | return err; | |
337 | ||
338 | err = pcf8523_set_pm(client, 0); | |
339 | if (err < 0) | |
340 | return err; | |
341 | ||
288031bf | 342 | pcf->rtc = devm_rtc_device_register(&client->dev, DRIVER_NAME, |
f803f0d0 TR |
343 | &pcf8523_rtc_ops, THIS_MODULE); |
344 | if (IS_ERR(pcf->rtc)) | |
345 | return PTR_ERR(pcf->rtc); | |
346 | ||
347 | i2c_set_clientdata(client, pcf); | |
348 | ||
349 | return 0; | |
350 | } | |
351 | ||
f803f0d0 TR |
352 | static const struct i2c_device_id pcf8523_id[] = { |
353 | { "pcf8523", 0 }, | |
354 | { } | |
355 | }; | |
356 | MODULE_DEVICE_TABLE(i2c, pcf8523_id); | |
357 | ||
358 | #ifdef CONFIG_OF | |
359 | static const struct of_device_id pcf8523_of_match[] = { | |
360 | { .compatible = "nxp,pcf8523" }, | |
361 | { } | |
362 | }; | |
363 | MODULE_DEVICE_TABLE(of, pcf8523_of_match); | |
364 | #endif | |
365 | ||
366 | static struct i2c_driver pcf8523_driver = { | |
367 | .driver = { | |
368 | .name = DRIVER_NAME, | |
f803f0d0 TR |
369 | .of_match_table = of_match_ptr(pcf8523_of_match), |
370 | }, | |
371 | .probe = pcf8523_probe, | |
f803f0d0 TR |
372 | .id_table = pcf8523_id, |
373 | }; | |
374 | module_i2c_driver(pcf8523_driver); | |
375 | ||
376 | MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>"); | |
377 | MODULE_DESCRIPTION("NXP PCF8523 RTC driver"); | |
378 | MODULE_LICENSE("GPL v2"); |