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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1ce7c83f PZ |
2 | /* |
3 | * Driver for TI BQ32000 RTC. | |
4 | * | |
5 | * Copyright (C) 2009 Semihalf. | |
765a98a6 | 6 | * Copyright (C) 2014 Pavel Machek <pavel@denx.de> |
1ce7c83f | 7 | * |
765a98a6 | 8 | * You can get hardware description at |
3567d3d1 | 9 | * https://www.ti.com/lit/ds/symlink/bq32000.pdf |
1ce7c83f PZ |
10 | */ |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/i2c.h> | |
14 | #include <linux/rtc.h> | |
15 | #include <linux/init.h> | |
e59b3c73 | 16 | #include <linux/kstrtox.h> |
1ce7c83f PZ |
17 | #include <linux/errno.h> |
18 | #include <linux/bcd.h> | |
19 | ||
20 | #define BQ32K_SECONDS 0x00 /* Seconds register address */ | |
21 | #define BQ32K_SECONDS_MASK 0x7F /* Mask over seconds value */ | |
22 | #define BQ32K_STOP 0x80 /* Oscillator Stop flat */ | |
23 | ||
24 | #define BQ32K_MINUTES 0x01 /* Minutes register address */ | |
25 | #define BQ32K_MINUTES_MASK 0x7F /* Mask over minutes value */ | |
26 | #define BQ32K_OF 0x80 /* Oscillator Failure flag */ | |
27 | ||
28 | #define BQ32K_HOURS_MASK 0x3F /* Mask over hours value */ | |
29 | #define BQ32K_CENT 0x40 /* Century flag */ | |
30 | #define BQ32K_CENT_EN 0x80 /* Century flag enable bit */ | |
31 | ||
765a98a6 PM |
32 | #define BQ32K_CALIBRATION 0x07 /* CAL_CFG1, calibration and control */ |
33 | #define BQ32K_TCH2 0x08 /* Trickle charge enable */ | |
34 | #define BQ32K_CFG2 0x09 /* Trickle charger control */ | |
4c466872 | 35 | #define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */ |
765a98a6 | 36 | |
fed9b186 GS |
37 | #define MAX_LEN 10 /* Maximum number of consecutive |
38 | * register for this particular RTC. | |
39 | */ | |
40 | ||
1ce7c83f PZ |
41 | struct bq32k_regs { |
42 | uint8_t seconds; | |
43 | uint8_t minutes; | |
44 | uint8_t cent_hours; | |
45 | uint8_t day; | |
46 | uint8_t date; | |
47 | uint8_t month; | |
48 | uint8_t years; | |
49 | }; | |
50 | ||
51 | static struct i2c_driver bq32k_driver; | |
52 | ||
53 | static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len) | |
54 | { | |
55 | struct i2c_client *client = to_i2c_client(dev); | |
56 | struct i2c_msg msgs[] = { | |
57 | { | |
58 | .addr = client->addr, | |
59 | .flags = 0, | |
60 | .len = 1, | |
61 | .buf = &off, | |
62 | }, { | |
63 | .addr = client->addr, | |
64 | .flags = I2C_M_RD, | |
65 | .len = len, | |
66 | .buf = data, | |
67 | } | |
68 | }; | |
69 | ||
70 | if (i2c_transfer(client->adapter, msgs, 2) == 2) | |
71 | return 0; | |
72 | ||
73 | return -EIO; | |
74 | } | |
75 | ||
76 | static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len) | |
77 | { | |
78 | struct i2c_client *client = to_i2c_client(dev); | |
fed9b186 | 79 | uint8_t buffer[MAX_LEN + 1]; |
1ce7c83f PZ |
80 | |
81 | buffer[0] = off; | |
82 | memcpy(&buffer[1], data, len); | |
83 | ||
84 | if (i2c_master_send(client, buffer, len + 1) == len + 1) | |
85 | return 0; | |
86 | ||
87 | return -EIO; | |
88 | } | |
89 | ||
90 | static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
91 | { | |
92 | struct bq32k_regs regs; | |
93 | int error; | |
94 | ||
95 | error = bq32k_read(dev, ®s, 0, sizeof(regs)); | |
96 | if (error) | |
97 | return error; | |
98 | ||
421a5ba2 JÖ |
99 | /* |
100 | * In case of oscillator failure, the register contents should be | |
101 | * considered invalid. The flag is cleared the next time the RTC is set. | |
102 | */ | |
103 | if (regs.minutes & BQ32K_OF) | |
104 | return -EINVAL; | |
105 | ||
1ce7c83f | 106 | tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); |
6ed1a51e | 107 | tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK); |
1ce7c83f PZ |
108 | tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK); |
109 | tm->tm_mday = bcd2bin(regs.date); | |
110 | tm->tm_wday = bcd2bin(regs.day) - 1; | |
111 | tm->tm_mon = bcd2bin(regs.month) - 1; | |
112 | tm->tm_year = bcd2bin(regs.years) + | |
113 | ((regs.cent_hours & BQ32K_CENT) ? 100 : 0); | |
114 | ||
22652ba7 | 115 | return 0; |
1ce7c83f PZ |
116 | } |
117 | ||
118 | static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
119 | { | |
120 | struct bq32k_regs regs; | |
121 | ||
122 | regs.seconds = bin2bcd(tm->tm_sec); | |
123 | regs.minutes = bin2bcd(tm->tm_min); | |
124 | regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN; | |
125 | regs.day = bin2bcd(tm->tm_wday + 1); | |
126 | regs.date = bin2bcd(tm->tm_mday); | |
127 | regs.month = bin2bcd(tm->tm_mon + 1); | |
128 | ||
129 | if (tm->tm_year >= 100) { | |
130 | regs.cent_hours |= BQ32K_CENT; | |
131 | regs.years = bin2bcd(tm->tm_year - 100); | |
132 | } else | |
133 | regs.years = bin2bcd(tm->tm_year); | |
134 | ||
135 | return bq32k_write(dev, ®s, 0, sizeof(regs)); | |
136 | } | |
137 | ||
138 | static const struct rtc_class_ops bq32k_rtc_ops = { | |
139 | .read_time = bq32k_rtc_read_time, | |
140 | .set_time = bq32k_rtc_set_time, | |
141 | }; | |
142 | ||
765a98a6 PM |
143 | static int trickle_charger_of_init(struct device *dev, struct device_node *node) |
144 | { | |
145 | unsigned char reg; | |
146 | int error; | |
147 | u32 ohms = 0; | |
148 | ||
149 | if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms)) | |
150 | return 0; | |
151 | ||
152 | switch (ohms) { | |
153 | case 180+940: | |
154 | /* | |
155 | * TCHE[3:0] == 0x05, TCH2 == 1, TCFE == 0 (charging | |
156 | * over diode and 940ohm resistor) | |
157 | */ | |
158 | ||
159 | if (of_property_read_bool(node, "trickle-diode-disable")) { | |
160 | dev_err(dev, "diode and resistor mismatch\n"); | |
161 | return -EINVAL; | |
162 | } | |
163 | reg = 0x05; | |
164 | break; | |
165 | ||
166 | case 180+20000: | |
167 | /* diode disabled */ | |
168 | ||
169 | if (!of_property_read_bool(node, "trickle-diode-disable")) { | |
170 | dev_err(dev, "bq32k: diode and resistor mismatch\n"); | |
171 | return -EINVAL; | |
172 | } | |
5a6e7599 | 173 | reg = 0x45; |
765a98a6 PM |
174 | break; |
175 | ||
176 | default: | |
177 | dev_err(dev, "invalid resistor value (%d)\n", ohms); | |
178 | return -EINVAL; | |
179 | } | |
180 | ||
181 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
182 | if (error) | |
183 | return error; | |
184 | ||
185 | reg = 0x20; | |
186 | error = bq32k_write(dev, ®, BQ32K_TCH2, 1); | |
187 | if (error) | |
188 | return error; | |
189 | ||
190 | dev_info(dev, "Enabled trickle RTC battery charge.\n"); | |
191 | return 0; | |
192 | } | |
193 | ||
4c466872 EBS |
194 | static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev, |
195 | struct device_attribute *attr, | |
196 | char *buf) | |
197 | { | |
198 | int reg, error; | |
199 | ||
200 | error = bq32k_read(dev, ®, BQ32K_CFG2, 1); | |
201 | if (error) | |
202 | return error; | |
203 | ||
204 | return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0); | |
205 | } | |
206 | ||
207 | static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev, | |
208 | struct device_attribute *attr, | |
209 | const char *buf, size_t count) | |
210 | { | |
211 | int reg, enable, error; | |
212 | ||
213 | if (kstrtoint(buf, 0, &enable)) | |
214 | return -EINVAL; | |
215 | ||
216 | error = bq32k_read(dev, ®, BQ32K_CFG2, 1); | |
217 | if (error) | |
218 | return error; | |
219 | ||
220 | if (enable) { | |
221 | reg |= BQ32K_TCFE; | |
222 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
223 | if (error) | |
224 | return error; | |
225 | ||
226 | dev_info(dev, "Enabled trickle charge FET bypass.\n"); | |
227 | } else { | |
228 | reg &= ~BQ32K_TCFE; | |
229 | error = bq32k_write(dev, ®, BQ32K_CFG2, 1); | |
230 | if (error) | |
231 | return error; | |
232 | ||
233 | dev_info(dev, "Disabled trickle charge FET bypass.\n"); | |
234 | } | |
235 | ||
236 | return count; | |
237 | } | |
238 | ||
239 | static DEVICE_ATTR(trickle_charge_bypass, 0644, | |
240 | bq32k_sysfs_show_tricklecharge_bypass, | |
241 | bq32k_sysfs_store_tricklecharge_bypass); | |
242 | ||
243 | static int bq32k_sysfs_register(struct device *dev) | |
244 | { | |
245 | return device_create_file(dev, &dev_attr_trickle_charge_bypass); | |
246 | } | |
247 | ||
248 | static void bq32k_sysfs_unregister(struct device *dev) | |
249 | { | |
250 | device_remove_file(dev, &dev_attr_trickle_charge_bypass); | |
251 | } | |
252 | ||
3f4a3322 | 253 | static int bq32k_probe(struct i2c_client *client) |
1ce7c83f PZ |
254 | { |
255 | struct device *dev = &client->dev; | |
256 | struct rtc_device *rtc; | |
257 | uint8_t reg; | |
258 | int error; | |
259 | ||
260 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
261 | return -ENODEV; | |
262 | ||
263 | /* Check Oscillator Stop flag */ | |
264 | error = bq32k_read(dev, ®, BQ32K_SECONDS, 1); | |
265 | if (!error && (reg & BQ32K_STOP)) { | |
266 | dev_warn(dev, "Oscillator was halted. Restarting...\n"); | |
267 | reg &= ~BQ32K_STOP; | |
268 | error = bq32k_write(dev, ®, BQ32K_SECONDS, 1); | |
269 | } | |
270 | if (error) | |
271 | return error; | |
272 | ||
273 | /* Check Oscillator Failure flag */ | |
274 | error = bq32k_read(dev, ®, BQ32K_MINUTES, 1); | |
1ce7c83f PZ |
275 | if (error) |
276 | return error; | |
421a5ba2 JÖ |
277 | if (reg & BQ32K_OF) |
278 | dev_warn(dev, "Oscillator Failure. Check RTC battery.\n"); | |
1ce7c83f | 279 | |
617f6f7e | 280 | if (client->dev.of_node) |
765a98a6 PM |
281 | trickle_charger_of_init(dev, client->dev.of_node); |
282 | ||
4e440681 | 283 | rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name, |
1ce7c83f PZ |
284 | &bq32k_rtc_ops, THIS_MODULE); |
285 | if (IS_ERR(rtc)) | |
286 | return PTR_ERR(rtc); | |
287 | ||
4c466872 EBS |
288 | error = bq32k_sysfs_register(&client->dev); |
289 | if (error) { | |
290 | dev_err(&client->dev, | |
291 | "Unable to create sysfs entries for rtc bq32000\n"); | |
292 | return error; | |
293 | } | |
294 | ||
295 | ||
1ce7c83f PZ |
296 | i2c_set_clientdata(client, rtc); |
297 | ||
298 | return 0; | |
299 | } | |
300 | ||
ed5c2f5f | 301 | static void bq32k_remove(struct i2c_client *client) |
4c466872 EBS |
302 | { |
303 | bq32k_sysfs_unregister(&client->dev); | |
4c466872 EBS |
304 | } |
305 | ||
1ce7c83f PZ |
306 | static const struct i2c_device_id bq32k_id[] = { |
307 | { "bq32000", 0 }, | |
308 | { } | |
309 | }; | |
310 | MODULE_DEVICE_TABLE(i2c, bq32k_id); | |
311 | ||
b8ded817 | 312 | static const __maybe_unused struct of_device_id bq32k_of_match[] = { |
36138c70 JMC |
313 | { .compatible = "ti,bq32000" }, |
314 | { } | |
315 | }; | |
316 | MODULE_DEVICE_TABLE(of, bq32k_of_match); | |
317 | ||
1ce7c83f PZ |
318 | static struct i2c_driver bq32k_driver = { |
319 | .driver = { | |
320 | .name = "bq32k", | |
36138c70 | 321 | .of_match_table = of_match_ptr(bq32k_of_match), |
1ce7c83f | 322 | }, |
31b0cecb | 323 | .probe = bq32k_probe, |
4c466872 | 324 | .remove = bq32k_remove, |
1ce7c83f PZ |
325 | .id_table = bq32k_id, |
326 | }; | |
327 | ||
0abc9201 | 328 | module_i2c_driver(bq32k_driver); |
1ce7c83f PZ |
329 | |
330 | MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>"); | |
331 | MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver"); | |
332 | MODULE_LICENSE("GPL"); |