1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Driver for TI BQ32000 RTC. |
4 | * |
5 | * Copyright (C) 2009 Semihalf. |
6 | * Copyright (C) 2014 Pavel Machek <pavel@denx.de> |
7 | * |
8 | * You can get hardware description at |
9 | * https://www.ti.com/lit/ds/symlink/bq32000.pdf |
10 | */ |
11 | |
12 | #include <linux/module.h> |
13 | #include <linux/i2c.h> |
14 | #include <linux/rtc.h> |
15 | #include <linux/init.h> |
16 | #include <linux/kstrtox.h> |
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 | |
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 */ |
35 | #define BQ32K_TCFE BIT(6) /* Trickle charge FET bypass */ |
36 | |
37 | #define MAX_LEN 10 /* Maximum number of consecutive |
38 | * register for this particular RTC. |
39 | */ |
40 | |
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(adap: client->adapter, msgs, num: 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); |
79 | uint8_t buffer[MAX_LEN + 1]; |
80 | |
81 | buffer[0] = off; |
82 | memcpy(&buffer[1], data, len); |
83 | |
84 | if (i2c_master_send(client, buf: buffer, count: 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, data: ®s, off: 0, len: sizeof(regs)); |
96 | if (error) |
97 | return error; |
98 | |
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 | |
106 | tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK); |
107 | tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK); |
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 | |
115 | return 0; |
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, data: ®s, off: 0, len: 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 | |
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(np: node, propname: "trickle-resistor-ohms" , out_value: &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(np: node, propname: "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(np: node, propname: "trickle-diode-disable" )) { |
170 | dev_err(dev, "bq32k: diode and resistor mismatch\n" ); |
171 | return -EINVAL; |
172 | } |
173 | reg = 0x45; |
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, data: ®, BQ32K_CFG2, len: 1); |
182 | if (error) |
183 | return error; |
184 | |
185 | reg = 0x20; |
186 | error = bq32k_write(dev, data: ®, BQ32K_TCH2, len: 1); |
187 | if (error) |
188 | return error; |
189 | |
190 | dev_info(dev, "Enabled trickle RTC battery charge.\n" ); |
191 | return 0; |
192 | } |
193 | |
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, data: ®, BQ32K_CFG2, len: 1); |
201 | if (error) |
202 | return error; |
203 | |
204 | return sprintf(buf, fmt: "%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(s: buf, base: 0, res: &enable)) |
214 | return -EINVAL; |
215 | |
216 | error = bq32k_read(dev, data: ®, BQ32K_CFG2, len: 1); |
217 | if (error) |
218 | return error; |
219 | |
220 | if (enable) { |
221 | reg |= BQ32K_TCFE; |
222 | error = bq32k_write(dev, data: ®, BQ32K_CFG2, len: 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, data: ®, BQ32K_CFG2, len: 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(device: dev, entry: &dev_attr_trickle_charge_bypass); |
246 | } |
247 | |
248 | static void bq32k_sysfs_unregister(struct device *dev) |
249 | { |
250 | device_remove_file(dev, attr: &dev_attr_trickle_charge_bypass); |
251 | } |
252 | |
253 | static int bq32k_probe(struct i2c_client *client) |
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(adap: client->adapter, I2C_FUNC_I2C)) |
261 | return -ENODEV; |
262 | |
263 | /* Check Oscillator Stop flag */ |
264 | error = bq32k_read(dev, data: ®, BQ32K_SECONDS, len: 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, data: ®, BQ32K_SECONDS, len: 1); |
269 | } |
270 | if (error) |
271 | return error; |
272 | |
273 | /* Check Oscillator Failure flag */ |
274 | error = bq32k_read(dev, data: ®, BQ32K_MINUTES, len: 1); |
275 | if (error) |
276 | return error; |
277 | if (reg & BQ32K_OF) |
278 | dev_warn(dev, "Oscillator Failure. Check RTC battery.\n" ); |
279 | |
280 | if (client->dev.of_node) |
281 | trickle_charger_of_init(dev, node: client->dev.of_node); |
282 | |
283 | rtc = devm_rtc_device_register(dev: &client->dev, name: bq32k_driver.driver.name, |
284 | ops: &bq32k_rtc_ops, THIS_MODULE); |
285 | if (IS_ERR(ptr: rtc)) |
286 | return PTR_ERR(ptr: rtc); |
287 | |
288 | error = bq32k_sysfs_register(dev: &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 | |
296 | i2c_set_clientdata(client, data: rtc); |
297 | |
298 | return 0; |
299 | } |
300 | |
301 | static void bq32k_remove(struct i2c_client *client) |
302 | { |
303 | bq32k_sysfs_unregister(dev: &client->dev); |
304 | } |
305 | |
306 | static const struct i2c_device_id bq32k_id[] = { |
307 | { "bq32000" , 0 }, |
308 | { } |
309 | }; |
310 | MODULE_DEVICE_TABLE(i2c, bq32k_id); |
311 | |
312 | static const __maybe_unused struct of_device_id bq32k_of_match[] = { |
313 | { .compatible = "ti,bq32000" }, |
314 | { } |
315 | }; |
316 | MODULE_DEVICE_TABLE(of, bq32k_of_match); |
317 | |
318 | static struct i2c_driver bq32k_driver = { |
319 | .driver = { |
320 | .name = "bq32k" , |
321 | .of_match_table = of_match_ptr(bq32k_of_match), |
322 | }, |
323 | .probe = bq32k_probe, |
324 | .remove = bq32k_remove, |
325 | .id_table = bq32k_id, |
326 | }; |
327 | |
328 | module_i2c_driver(bq32k_driver); |
329 | |
330 | MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>" ); |
331 | MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver" ); |
332 | MODULE_LICENSE("GPL" ); |
333 | |