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12#include <linux/module.h>
13#include <linux/i2c.h>
14#include <linux/rtc.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/bcd.h>
18
19#define BQ32K_SECONDS 0x00
20#define BQ32K_SECONDS_MASK 0x7F
21#define BQ32K_STOP 0x80
22
23#define BQ32K_MINUTES 0x01
24#define BQ32K_MINUTES_MASK 0x7F
25#define BQ32K_OF 0x80
26
27#define BQ32K_HOURS_MASK 0x3F
28#define BQ32K_CENT 0x40
29#define BQ32K_CENT_EN 0x80
30
31#define BQ32K_CALIBRATION 0x07
32#define BQ32K_TCH2 0x08
33#define BQ32K_CFG2 0x09
34#define BQ32K_TCFE BIT(6)
35
36#define MAX_LEN 10
37
38
39
40struct bq32k_regs {
41 uint8_t seconds;
42 uint8_t minutes;
43 uint8_t cent_hours;
44 uint8_t day;
45 uint8_t date;
46 uint8_t month;
47 uint8_t years;
48};
49
50static struct i2c_driver bq32k_driver;
51
52static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
53{
54 struct i2c_client *client = to_i2c_client(dev);
55 struct i2c_msg msgs[] = {
56 {
57 .addr = client->addr,
58 .flags = 0,
59 .len = 1,
60 .buf = &off,
61 }, {
62 .addr = client->addr,
63 .flags = I2C_M_RD,
64 .len = len,
65 .buf = data,
66 }
67 };
68
69 if (i2c_transfer(client->adapter, msgs, 2) == 2)
70 return 0;
71
72 return -EIO;
73}
74
75static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
76{
77 struct i2c_client *client = to_i2c_client(dev);
78 uint8_t buffer[MAX_LEN + 1];
79
80 buffer[0] = off;
81 memcpy(&buffer[1], data, len);
82
83 if (i2c_master_send(client, buffer, len + 1) == len + 1)
84 return 0;
85
86 return -EIO;
87}
88
89static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
90{
91 struct bq32k_regs regs;
92 int error;
93
94 error = bq32k_read(dev, ®s, 0, sizeof(regs));
95 if (error)
96 return error;
97
98
99
100
101
102 if (regs.minutes & BQ32K_OF)
103 return -EINVAL;
104
105 tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
106 tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
107 tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
108 tm->tm_mday = bcd2bin(regs.date);
109 tm->tm_wday = bcd2bin(regs.day) - 1;
110 tm->tm_mon = bcd2bin(regs.month) - 1;
111 tm->tm_year = bcd2bin(regs.years) +
112 ((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
113
114 return 0;
115}
116
117static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
118{
119 struct bq32k_regs regs;
120
121 regs.seconds = bin2bcd(tm->tm_sec);
122 regs.minutes = bin2bcd(tm->tm_min);
123 regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
124 regs.day = bin2bcd(tm->tm_wday + 1);
125 regs.date = bin2bcd(tm->tm_mday);
126 regs.month = bin2bcd(tm->tm_mon + 1);
127
128 if (tm->tm_year >= 100) {
129 regs.cent_hours |= BQ32K_CENT;
130 regs.years = bin2bcd(tm->tm_year - 100);
131 } else
132 regs.years = bin2bcd(tm->tm_year);
133
134 return bq32k_write(dev, ®s, 0, sizeof(regs));
135}
136
137static const struct rtc_class_ops bq32k_rtc_ops = {
138 .read_time = bq32k_rtc_read_time,
139 .set_time = bq32k_rtc_set_time,
140};
141
142static int trickle_charger_of_init(struct device *dev, struct device_node *node)
143{
144 unsigned char reg;
145 int error;
146 u32 ohms = 0;
147
148 if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
149 return 0;
150
151 switch (ohms) {
152 case 180+940:
153
154
155
156
157
158 if (of_property_read_bool(node, "trickle-diode-disable")) {
159 dev_err(dev, "diode and resistor mismatch\n");
160 return -EINVAL;
161 }
162 reg = 0x05;
163 break;
164
165 case 180+20000:
166
167
168 if (!of_property_read_bool(node, "trickle-diode-disable")) {
169 dev_err(dev, "bq32k: diode and resistor mismatch\n");
170 return -EINVAL;
171 }
172 reg = 0x45;
173 break;
174
175 default:
176 dev_err(dev, "invalid resistor value (%d)\n", ohms);
177 return -EINVAL;
178 }
179
180 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
181 if (error)
182 return error;
183
184 reg = 0x20;
185 error = bq32k_write(dev, ®, BQ32K_TCH2, 1);
186 if (error)
187 return error;
188
189 dev_info(dev, "Enabled trickle RTC battery charge.\n");
190 return 0;
191}
192
193static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
194 struct device_attribute *attr,
195 char *buf)
196{
197 int reg, error;
198
199 error = bq32k_read(dev, ®, BQ32K_CFG2, 1);
200 if (error)
201 return error;
202
203 return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
204}
205
206static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
207 struct device_attribute *attr,
208 const char *buf, size_t count)
209{
210 int reg, enable, error;
211
212 if (kstrtoint(buf, 0, &enable))
213 return -EINVAL;
214
215 error = bq32k_read(dev, ®, BQ32K_CFG2, 1);
216 if (error)
217 return error;
218
219 if (enable) {
220 reg |= BQ32K_TCFE;
221 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
222 if (error)
223 return error;
224
225 dev_info(dev, "Enabled trickle charge FET bypass.\n");
226 } else {
227 reg &= ~BQ32K_TCFE;
228 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
229 if (error)
230 return error;
231
232 dev_info(dev, "Disabled trickle charge FET bypass.\n");
233 }
234
235 return count;
236}
237
238static DEVICE_ATTR(trickle_charge_bypass, 0644,
239 bq32k_sysfs_show_tricklecharge_bypass,
240 bq32k_sysfs_store_tricklecharge_bypass);
241
242static int bq32k_sysfs_register(struct device *dev)
243{
244 return device_create_file(dev, &dev_attr_trickle_charge_bypass);
245}
246
247static void bq32k_sysfs_unregister(struct device *dev)
248{
249 device_remove_file(dev, &dev_attr_trickle_charge_bypass);
250}
251
252static int bq32k_probe(struct i2c_client *client,
253 const struct i2c_device_id *id)
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
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
274 error = bq32k_read(dev, ®, BQ32K_MINUTES, 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, client->dev.of_node);
282
283 rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
284 &bq32k_rtc_ops, THIS_MODULE);
285 if (IS_ERR(rtc))
286 return PTR_ERR(rtc);
287
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
296 i2c_set_clientdata(client, rtc);
297
298 return 0;
299}
300
301static int bq32k_remove(struct i2c_client *client)
302{
303 bq32k_sysfs_unregister(&client->dev);
304
305 return 0;
306}
307
308static const struct i2c_device_id bq32k_id[] = {
309 { "bq32000", 0 },
310 { }
311};
312MODULE_DEVICE_TABLE(i2c, bq32k_id);
313
314static const __maybe_unused struct of_device_id bq32k_of_match[] = {
315 { .compatible = "ti,bq32000" },
316 { }
317};
318MODULE_DEVICE_TABLE(of, bq32k_of_match);
319
320static struct i2c_driver bq32k_driver = {
321 .driver = {
322 .name = "bq32k",
323 .of_match_table = of_match_ptr(bq32k_of_match),
324 },
325 .probe = bq32k_probe,
326 .remove = bq32k_remove,
327 .id_table = bq32k_id,
328};
329
330module_i2c_driver(bq32k_driver);
331
332MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
333MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
334MODULE_LICENSE("GPL");
335
