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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
23#define BQ32K_SECONDS_MASK 0x7F
24#define BQ32K_STOP 0x80
25
26#define BQ32K_MINUTES 0x01
27#define BQ32K_MINUTES_MASK 0x7F
28#define BQ32K_OF 0x80
29
30#define BQ32K_HOURS_MASK 0x3F
31#define BQ32K_CENT 0x40
32#define BQ32K_CENT_EN 0x80
33
34#define BQ32K_CALIBRATION 0x07
35#define BQ32K_TCH2 0x08
36#define BQ32K_CFG2 0x09
37#define BQ32K_TCFE BIT(6)
38
39#define MAX_LEN 10
40
41
42
43struct bq32k_regs {
44 uint8_t seconds;
45 uint8_t minutes;
46 uint8_t cent_hours;
47 uint8_t day;
48 uint8_t date;
49 uint8_t month;
50 uint8_t years;
51};
52
53static struct i2c_driver bq32k_driver;
54
55static int bq32k_read(struct device *dev, void *data, uint8_t off, uint8_t len)
56{
57 struct i2c_client *client = to_i2c_client(dev);
58 struct i2c_msg msgs[] = {
59 {
60 .addr = client->addr,
61 .flags = 0,
62 .len = 1,
63 .buf = &off,
64 }, {
65 .addr = client->addr,
66 .flags = I2C_M_RD,
67 .len = len,
68 .buf = data,
69 }
70 };
71
72 if (i2c_transfer(client->adapter, msgs, 2) == 2)
73 return 0;
74
75 return -EIO;
76}
77
78static int bq32k_write(struct device *dev, void *data, uint8_t off, uint8_t len)
79{
80 struct i2c_client *client = to_i2c_client(dev);
81 uint8_t buffer[MAX_LEN + 1];
82
83 buffer[0] = off;
84 memcpy(&buffer[1], data, len);
85
86 if (i2c_master_send(client, buffer, len + 1) == len + 1)
87 return 0;
88
89 return -EIO;
90}
91
92static int bq32k_rtc_read_time(struct device *dev, struct rtc_time *tm)
93{
94 struct bq32k_regs regs;
95 int error;
96
97 error = bq32k_read(dev, ®s, 0, sizeof(regs));
98 if (error)
99 return error;
100
101
102
103
104
105 if (regs.minutes & BQ32K_OF)
106 return -EINVAL;
107
108 tm->tm_sec = bcd2bin(regs.seconds & BQ32K_SECONDS_MASK);
109 tm->tm_min = bcd2bin(regs.minutes & BQ32K_MINUTES_MASK);
110 tm->tm_hour = bcd2bin(regs.cent_hours & BQ32K_HOURS_MASK);
111 tm->tm_mday = bcd2bin(regs.date);
112 tm->tm_wday = bcd2bin(regs.day) - 1;
113 tm->tm_mon = bcd2bin(regs.month) - 1;
114 tm->tm_year = bcd2bin(regs.years) +
115 ((regs.cent_hours & BQ32K_CENT) ? 100 : 0);
116
117 return 0;
118}
119
120static int bq32k_rtc_set_time(struct device *dev, struct rtc_time *tm)
121{
122 struct bq32k_regs regs;
123
124 regs.seconds = bin2bcd(tm->tm_sec);
125 regs.minutes = bin2bcd(tm->tm_min);
126 regs.cent_hours = bin2bcd(tm->tm_hour) | BQ32K_CENT_EN;
127 regs.day = bin2bcd(tm->tm_wday + 1);
128 regs.date = bin2bcd(tm->tm_mday);
129 regs.month = bin2bcd(tm->tm_mon + 1);
130
131 if (tm->tm_year >= 100) {
132 regs.cent_hours |= BQ32K_CENT;
133 regs.years = bin2bcd(tm->tm_year - 100);
134 } else
135 regs.years = bin2bcd(tm->tm_year);
136
137 return bq32k_write(dev, ®s, 0, sizeof(regs));
138}
139
140static const struct rtc_class_ops bq32k_rtc_ops = {
141 .read_time = bq32k_rtc_read_time,
142 .set_time = bq32k_rtc_set_time,
143};
144
145static int trickle_charger_of_init(struct device *dev, struct device_node *node)
146{
147 unsigned char reg;
148 int error;
149 u32 ohms = 0;
150
151 if (of_property_read_u32(node, "trickle-resistor-ohms" , &ohms))
152 return 0;
153
154 switch (ohms) {
155 case 180+940:
156
157
158
159
160
161 if (of_property_read_bool(node, "trickle-diode-disable")) {
162 dev_err(dev, "diode and resistor mismatch\n");
163 return -EINVAL;
164 }
165 reg = 0x05;
166 break;
167
168 case 180+20000:
169
170
171 if (!of_property_read_bool(node, "trickle-diode-disable")) {
172 dev_err(dev, "bq32k: diode and resistor mismatch\n");
173 return -EINVAL;
174 }
175 reg = 0x45;
176 break;
177
178 default:
179 dev_err(dev, "invalid resistor value (%d)\n", ohms);
180 return -EINVAL;
181 }
182
183 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
184 if (error)
185 return error;
186
187 reg = 0x20;
188 error = bq32k_write(dev, ®, BQ32K_TCH2, 1);
189 if (error)
190 return error;
191
192 dev_info(dev, "Enabled trickle RTC battery charge.\n");
193 return 0;
194}
195
196static ssize_t bq32k_sysfs_show_tricklecharge_bypass(struct device *dev,
197 struct device_attribute *attr,
198 char *buf)
199{
200 int reg, error;
201
202 error = bq32k_read(dev, ®, BQ32K_CFG2, 1);
203 if (error)
204 return error;
205
206 return sprintf(buf, "%d\n", (reg & BQ32K_TCFE) ? 1 : 0);
207}
208
209static ssize_t bq32k_sysfs_store_tricklecharge_bypass(struct device *dev,
210 struct device_attribute *attr,
211 const char *buf, size_t count)
212{
213 int reg, enable, error;
214
215 if (kstrtoint(buf, 0, &enable))
216 return -EINVAL;
217
218 error = bq32k_read(dev, ®, BQ32K_CFG2, 1);
219 if (error)
220 return error;
221
222 if (enable) {
223 reg |= BQ32K_TCFE;
224 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
225 if (error)
226 return error;
227
228 dev_info(dev, "Enabled trickle charge FET bypass.\n");
229 } else {
230 reg &= ~BQ32K_TCFE;
231 error = bq32k_write(dev, ®, BQ32K_CFG2, 1);
232 if (error)
233 return error;
234
235 dev_info(dev, "Disabled trickle charge FET bypass.\n");
236 }
237
238 return count;
239}
240
241static DEVICE_ATTR(trickle_charge_bypass, 0644,
242 bq32k_sysfs_show_tricklecharge_bypass,
243 bq32k_sysfs_store_tricklecharge_bypass);
244
245static int bq32k_sysfs_register(struct device *dev)
246{
247 return device_create_file(dev, &dev_attr_trickle_charge_bypass);
248}
249
250static void bq32k_sysfs_unregister(struct device *dev)
251{
252 device_remove_file(dev, &dev_attr_trickle_charge_bypass);
253}
254
255static int bq32k_probe(struct i2c_client *client,
256 const struct i2c_device_id *id)
257{
258 struct device *dev = &client->dev;
259 struct rtc_device *rtc;
260 uint8_t reg;
261 int error;
262
263 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
264 return -ENODEV;
265
266
267 error = bq32k_read(dev, ®, BQ32K_SECONDS, 1);
268 if (!error && (reg & BQ32K_STOP)) {
269 dev_warn(dev, "Oscillator was halted. Restarting...\n");
270 reg &= ~BQ32K_STOP;
271 error = bq32k_write(dev, ®, BQ32K_SECONDS, 1);
272 }
273 if (error)
274 return error;
275
276
277 error = bq32k_read(dev, ®, BQ32K_MINUTES, 1);
278 if (error)
279 return error;
280 if (reg & BQ32K_OF)
281 dev_warn(dev, "Oscillator Failure. Check RTC battery.\n");
282
283 if (client->dev.of_node)
284 trickle_charger_of_init(dev, client->dev.of_node);
285
286 rtc = devm_rtc_device_register(&client->dev, bq32k_driver.driver.name,
287 &bq32k_rtc_ops, THIS_MODULE);
288 if (IS_ERR(rtc))
289 return PTR_ERR(rtc);
290
291 error = bq32k_sysfs_register(&client->dev);
292 if (error) {
293 dev_err(&client->dev,
294 "Unable to create sysfs entries for rtc bq32000\n");
295 return error;
296 }
297
298
299 i2c_set_clientdata(client, rtc);
300
301 return 0;
302}
303
304static int bq32k_remove(struct i2c_client *client)
305{
306 bq32k_sysfs_unregister(&client->dev);
307
308 return 0;
309}
310
311static const struct i2c_device_id bq32k_id[] = {
312 { "bq32000", 0 },
313 { }
314};
315MODULE_DEVICE_TABLE(i2c, bq32k_id);
316
317static const struct of_device_id bq32k_of_match[] = {
318 { .compatible = "ti,bq32000" },
319 { }
320};
321MODULE_DEVICE_TABLE(of, bq32k_of_match);
322
323static struct i2c_driver bq32k_driver = {
324 .driver = {
325 .name = "bq32k",
326 .of_match_table = of_match_ptr(bq32k_of_match),
327 },
328 .probe = bq32k_probe,
329 .remove = bq32k_remove,
330 .id_table = bq32k_id,
331};
332
333module_i2c_driver(bq32k_driver);
334
335MODULE_AUTHOR("Semihalf, Piotr Ziecik <kosmo@semihalf.com>");
336MODULE_DESCRIPTION("TI BQ32000 I2C RTC driver");
337MODULE_LICENSE("GPL");
338
