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1ce7c83f PZ |
1 | /* |
2 | * Driver for TI BQ32000 RTC. | |
3 | * | |
4 | * Copyright (C) 2009 Semihalf. | |
765a98a6 | 5 | * Copyright (C) 2014 Pavel Machek <pavel@denx.de> |
1ce7c83f PZ |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
765a98a6 PM |
10 | * |
11 | * You can get hardware description at | |
12 | * http://www.ti.com/lit/ds/symlink/bq32000.pdf | |
1ce7c83f PZ |
13 | */ |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/rtc.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/bcd.h> | |
21 | ||
22 | #define BQ32K_SECONDS 0x00 /* Seconds register address */ | |
23 | #define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ | |
24 | #define BQ32K_STOP 0x80 /* Oscillator Stop flat */ | |
25 | ||
26 | #define BQ32K_MINUTES 0x01 /* Minutes register address */ | |
27 | #define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ | |
28 | #define BQ32K_OF 0x80 /* Oscillator Failure flag */ | |
29 | ||
30 | #define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ | |
31 | #define BQ32K_CENT 0x40 /* Century flag */ | |
32 | #define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ | |
33 | ||
765a98a6 PM |
34 | #define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */ |
35 | #define BQ32K_TCH2 0x08 /* Trickle charge enable */ | |
36 | #define BQ32K_CFG2 0x09 /* Trickle charger control */ | |
4c466872 | 37 | #define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */ |
765a98a6 | 38 | |
1ce7c83f PZ |
39 | struct bq32k_regs { |
40 | uint8_t seconds; | |
41 | uint8_t minutes; | |
42 | uint8_t cent_hours; | |
43 | uint8_t day; | |
44 | uint8_t date; | |
45 | uint8_t month; | |
46 | uint8_t years; | |
47 | }; | |
48 | ||
49 | static struct i2c_driver bq32k_driver; | |
50 | ||
51 | static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) | |
52 | { | |
53 | struct i2c_client *client = to_i2c_client(dev); | |
54 | struct i2c_msg msgs[] = { | |
55 | { | |
56 | .addr = client->addr, | |
57 | .flags = 0, | |
58 | .len = 1, | |
59 | .buf = &off, | |
60 | }, { | |
61 | .addr = client->addr, | |
62 | .flags = I2C_M_RD, | |
63 | .len = len, | |
64 | .buf = data, | |
65 | } | |
66 | }; | |
67 | ||
68 | if (i2c_transfer(client->adapter, msgs, 2) == 2) | |
69 | return 0; | |
70 | ||
71 | return -EIO; | |
72 | } | |
73 | ||
74 | static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) | |
75 | { | |
76 | struct i2c_client *client = to_i2c_client(dev); | |
77 | uint8_t buffer[len + 1]; | |
78 | ||
79 | buffer[0] = off; | |
80 | memcpy(&buffer[1], data, len); | |
81 | ||
82 | if (i2c_master_send(client, buffer, len + 1) == len + 1) | |
83 | return 0; | |
84 | ||
85 | return -EIO; | |
86 | } | |
87 | ||
88 | static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
89 | { | |
90 | struct bq32k_regs regs; | |
91 | int error; | |
92 | ||
93 | error = bq32k_read(dev, ®s, 0, sizeof(regs)); | |
94 | if (error) | |
95 | return error; | |
96 | ||
421a5ba2 JÖ |
97 | /* |
98 | * In case of oscillator failure, the register contents should be | |
99 | * considered invalid. The flag is cleared the next time the RTC is set. | |
100 | */ | |
101 | if (regs.minutes & BQ32K_OF) | |
102 | return -EINVAL; | |
103 | ||
1ce7c83f | 104 | tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); |
6ed1a51e | 105 | tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK); |
1ce7c83f PZ |
106 | tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); |
107 | tm->tm_mday = bcd2bin(regs.date); | |
108 | tm->tm_wday = bcd2bin(regs.day) - 1; | |
109 | tm->tm_mon = bcd2bin(regs.month) - 1; | |
110 | tm->tm_year = bcd2bin(regs.years) + | |
111 | ((regs.cent_hours & BQ32K_CENT) ? 100 : 0); | |
112 | ||
113 | return rtc_valid_tm(tm); | |
114 | } | |
115 | ||
116 | static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
117 | { | |
118 | struct bq32k_regs regs; | |
119 | ||
120 | regs.seconds = bin2bcd(tm->tm_sec); | |
121 | regs.minutes = bin2bcd(tm->tm_min); | |
122 | regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; | |
123 | regs.day = bin2bcd(tm->tm_wday + 1); | |
124 | regs.date = bin2bcd(tm->tm_mday); | |
125 | regs.month = bin2bcd(tm->tm_mon + 1); | |
126 | ||
127 | if (tm->tm_year >= 100) { | |
128 | regs.cent_hours |= BQ32K_CENT; | |
129 | regs.years = bin2bcd(tm->tm_year - 100); | |
130 | } else | |
131 | regs.years = bin2bcd(tm->tm_year); | |
132 | ||
133 | return bq32k_write(dev, ®s, 0, sizeof(regs)); | |
134 | } | |
135 | ||
136 | static const struct rtc_class_ops bq32k_rtc_ops = { | |
137 | .read_time = bq32k_rtc_read_time, | |
138 | .set_time = bq32k_rtc_set_time, | |
139 | }; | |
140 | ||
765a98a6 PM |
141 | static int trickle_charger_of_init(struct device *dev, struct device_node *node) |
142 | { | |
143 | unsigned char reg; | |
144 | int error; | |
145 | u32 ohms = 0; | |
146 | ||
147 | if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms)) | |
148 | return 0; | |
149 | ||
150 | switch (ohms) { | |
151 | case 180+940: | |
152 | /* | |
153 | * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging | |
154 | * over diode and 940ohm resistor) | |
155 | */ | |
156 | ||
157 | if (of_property_read_bool(node, "trickle-diode-disable")) { | |
158 | dev_err(dev, "diode and resistor mismatch\n"); | |
159 | return -EINVAL; | |
160 | } | |
161 | reg = 0x05; | |
162 | break; | |
163 | ||
164 | case 180+20000: | |
165 | /* diode disabled */ | |
166 | ||
167 | if (!of_property_read_bool(node, "trickle-diode-disable")) { | |
168 | dev_err(dev, "bq32k: diode and resistor mismatch\n"); | |
169 | return -EINVAL; | |
170 | } | |
5a6e7599 | 171 | reg = 0x45; |
765a98a6 PM |
172 | break; |
173 | ||
174 | default: | |
175 | dev_err(dev, "invalid resistor value (%d)\n", ohms); | |
176 | return -EINVAL; | |
177 | } | |
178 | ||
179 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
180 | if (error) | |
181 | return error; | |
182 | ||
183 | reg = 0x20; | |
184 | error = bq32k_write(dev, ®, BQ32K_TCH2, 1); | |
185 | if (error) | |
186 | return error; | |
187 | ||
188 | dev_info(dev, "Enabled trickle RTC battery charge.\n"); | |
189 | return 0; | |
190 | } | |
191 | ||
4c466872 EBS |
192 | static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev, |
193 | struct device_attribute *attr, | |
194 | char *buf) | |
195 | { | |
196 | int reg, error; | |
197 | ||
198 | error = bq32k_read(dev, ®, BQ32K_CFG2, 1); | |
199 | if (error) | |
200 | return error; | |
201 | ||
202 | return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0); | |
203 | } | |
204 | ||
205 | static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev, | |
206 | struct device_attribute *attr, | |
207 | const char *buf, size_t count) | |
208 | { | |
209 | int reg, enable, error; | |
210 | ||
211 | if (kstrtoint(buf, 0, &enable)) | |
212 | return -EINVAL; | |
213 | ||
214 | error = bq32k_read(dev, ®, BQ32K_CFG2, 1); | |
215 | if (error) | |
216 | return error; | |
217 | ||
218 | if (enable) { | |
219 | reg |= BQ32K_TCFE; | |
220 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
221 | if (error) | |
222 | return error; | |
223 | ||
224 | dev_info(dev, "Enabled trickle charge FET bypass.\n"); | |
225 | } else { | |
226 | reg &= ~BQ32K_TCFE; | |
227 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
228 | if (error) | |
229 | return error; | |
230 | ||
231 | dev_info(dev, "Disabled trickle charge FET bypass.\n"); | |
232 | } | |
233 | ||
234 | return count; | |
235 | } | |
236 | ||
237 | static DEVICE_ATTR(trickle_charge_bypass, 0644, | |
238 | bq32k_sysfs_show_tricklecharge_bypass, | |
239 | bq32k_sysfs_store_tricklecharge_bypass); | |
240 | ||
241 | static int bq32k_sysfs_register(struct device *dev) | |
242 | { | |
243 | return device_create_file(dev, &dev_attr_trickle_charge_bypass); | |
244 | } | |
245 | ||
246 | static void bq32k_sysfs_unregister(struct device *dev) | |
247 | { | |
248 | device_remove_file(dev, &dev_attr_trickle_charge_bypass); | |
249 | } | |
250 | ||
1ce7c83f PZ |
251 | static int bq32k_probe(struct i2c_client *client, |
252 | const struct i2c_device_id *id) | |
253 | { | |
254 | struct device *dev = &client->dev; | |
255 | struct rtc_device *rtc; | |
256 | uint8_t reg; | |
257 | int error; | |
258 | ||
259 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
260 | return -ENODEV; | |
261 | ||
262 | /* Check Oscillator Stop flag */ | |
263 | error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); | |
264 | if (!error && (reg & BQ32K_STOP)) { | |
265 | dev_warn(dev, "Oscillator was halted. Restarting...\n"); | |
266 | reg &= ~BQ32K_STOP; | |
267 | error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); | |
268 | } | |
269 | if (error) | |
270 | return error; | |
271 | ||
272 | /* Check Oscillator Failure flag */ | |
273 | error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); | |
1ce7c83f PZ |
274 | if (error) |
275 | return error; | |
421a5ba2 JÖ |
276 | if (reg & BQ32K_OF) |
277 | dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); | |
1ce7c83f | 278 | |
617f6f7e | 279 | if (client->dev.of_node) |
765a98a6 PM |
280 | trickle_charger_of_init(dev, client->dev.of_node); |
281 | ||
4e440681 | 282 | rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name, |
1ce7c83f PZ |
283 | &bq32k_rtc_ops, THIS_MODULE); |
284 | if (IS_ERR(rtc)) | |
285 | return PTR_ERR(rtc); | |
286 | ||
4c466872 EBS |
287 | error = bq32k_sysfs_register(&client->dev); |
288 | if (error) { | |
289 | dev_err(&client->dev, | |
290 | "Unable to create sysfs entries for rtc bq32000\n"); | |
291 | return error; | |
292 | } | |
293 | ||
294 | ||
1ce7c83f PZ |
295 | i2c_set_clientdata(client, rtc); |
296 | ||
297 | return 0; | |
298 | } | |
299 | ||
4c466872 EBS |
300 | static int bq32k_remove(struct i2c_client *client) |
301 | { | |
302 | bq32k_sysfs_unregister(&client->dev); | |
303 | ||
304 | return 0; | |
305 | } | |
306 | ||
1ce7c83f PZ |
307 | static const struct i2c_device_id bq32k_id[] = { |
308 | { "bq32000", 0 }, | |
309 | { } | |
310 | }; | |
311 | MODULE_DEVICE_TABLE(i2c, bq32k_id); | |
312 | ||
36138c70 JMC |
313 | static const struct of_device_id bq32k_of_match[] = { |
314 | { .compatible = "ti,bq32000" }, | |
315 | { } | |
316 | }; | |
317 | MODULE_DEVICE_TABLE(of, bq32k_of_match); | |
318 | ||
1ce7c83f PZ |
319 | static struct i2c_driver bq32k_driver = { |
320 | .driver = { | |
321 | .name = "bq32k", | |
36138c70 | 322 | .of_match_table = of_match_ptr(bq32k_of_match), |
1ce7c83f PZ |
323 | }, |
324 | .probe = bq32k_probe, | |
4c466872 | 325 | .remove = bq32k_remove, |
1ce7c83f PZ |
326 | .id_table = bq32k_id, |
327 | }; | |
328 | ||
0abc9201 | 329 | module_i2c_driver(bq32k_driver); |
1ce7c83f PZ |
330 | |
331 | MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>"); | |
332 | MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); | |
333 | MODULE_LICENSE("GPL"); |