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14#include <linux/i2c.h>
15#include <linux/bcd.h>
16#include <linux/rtc.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/err.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22
23
24#define ISL12022_REG_SC 0x00
25#define ISL12022_REG_MN 0x01
26#define ISL12022_REG_HR 0x02
27#define ISL12022_REG_DT 0x03
28#define ISL12022_REG_MO 0x04
29#define ISL12022_REG_YR 0x05
30#define ISL12022_REG_DW 0x06
31
32#define ISL12022_REG_SR 0x07
33#define ISL12022_REG_INT 0x08
34
35
36#define ISL12022_HR_MIL (1 << 7)
37
38#define ISL12022_SR_LBAT85 (1 << 2)
39#define ISL12022_SR_LBAT75 (1 << 1)
40
41#define ISL12022_INT_WRTC (1 << 6)
42
43
44static struct i2c_driver isl12022_driver;
45
46struct isl12022 {
47 struct rtc_device *rtc;
48
49 bool write_enabled;
50};
51
52
53static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
54 uint8_t *data, size_t n)
55{
56 struct i2c_msg msgs[] = {
57 {
58 .addr = client->addr,
59 .flags = 0,
60 .len = 1,
61 .buf = data
62 },
63 {
64 .addr = client->addr,
65 .flags = I2C_M_RD,
66 .len = n,
67 .buf = data
68 }
69 };
70
71 int ret;
72
73 data[0] = reg;
74 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
75 if (ret != ARRAY_SIZE(msgs)) {
76 dev_err(&client->dev, "%s: read error, ret=%d\n",
77 __func__, ret);
78 return -EIO;
79 }
80
81 return 0;
82}
83
84
85static int isl12022_write_reg(struct i2c_client *client,
86 uint8_t reg, uint8_t val)
87{
88 uint8_t data[2] = { reg, val };
89 int err;
90
91 err = i2c_master_send(client, data, sizeof(data));
92 if (err != sizeof(data)) {
93 dev_err(&client->dev,
94 "%s: err=%d addr=%02x, data=%02x\n",
95 __func__, err, data[0], data[1]);
96 return -EIO;
97 }
98
99 return 0;
100}
101
102
103
104
105
106
107static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
108{
109 struct i2c_client *client = to_i2c_client(dev);
110 uint8_t buf[ISL12022_REG_INT + 1];
111 int ret;
112
113 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
114 if (ret)
115 return ret;
116
117 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
118 dev_warn(&client->dev,
119 "voltage dropped below %u%%, "
120 "date and time is not reliable.\n",
121 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
122 }
123
124 dev_dbg(&client->dev,
125 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
126 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
127 "sr=%02x, int=%02x",
128 __func__,
129 buf[ISL12022_REG_SC],
130 buf[ISL12022_REG_MN],
131 buf[ISL12022_REG_HR],
132 buf[ISL12022_REG_DT],
133 buf[ISL12022_REG_MO],
134 buf[ISL12022_REG_YR],
135 buf[ISL12022_REG_DW],
136 buf[ISL12022_REG_SR],
137 buf[ISL12022_REG_INT]);
138
139 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
140 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
141 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
142 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
143 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
144 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
145 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
146
147 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
148 "mday=%d, mon=%d, year=%d, wday=%d\n",
149 __func__,
150 tm->tm_sec, tm->tm_min, tm->tm_hour,
151 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
152
153 return 0;
154}
155
156static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
157{
158 struct i2c_client *client = to_i2c_client(dev);
159 struct isl12022 *isl12022 = i2c_get_clientdata(client);
160 size_t i;
161 int ret;
162 uint8_t buf[ISL12022_REG_DW + 1];
163
164 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
165 "mday=%d, mon=%d, year=%d, wday=%d\n",
166 __func__,
167 tm->tm_sec, tm->tm_min, tm->tm_hour,
168 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
169
170 if (!isl12022->write_enabled) {
171
172 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
173 if (ret)
174 return ret;
175
176
177
178 if (!(buf[0] & ISL12022_INT_WRTC)) {
179 dev_info(&client->dev,
180 "init write enable and 24 hour format\n");
181
182
183 ret = isl12022_write_reg(client,
184 ISL12022_REG_INT,
185 buf[0] | ISL12022_INT_WRTC);
186 if (ret)
187 return ret;
188
189
190
191
192 ret = isl12022_read_regs(client, ISL12022_REG_HR,
193 buf, 1);
194 if (ret)
195 return ret;
196
197 ret = isl12022_write_reg(client,
198 ISL12022_REG_HR,
199 buf[0] | ISL12022_HR_MIL);
200 if (ret)
201 return ret;
202 }
203
204 isl12022->write_enabled = true;
205 }
206
207
208 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
209 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
210 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
211
212 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
213
214
215 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
216
217
218 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
219
220 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
221
222
223 for (i = 0; i < ARRAY_SIZE(buf); i++) {
224 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
225 buf[ISL12022_REG_SC + i]);
226 if (ret)
227 return -EIO;
228 }
229
230 return 0;
231}
232
233static const struct rtc_class_ops isl12022_rtc_ops = {
234 .read_time = isl12022_rtc_read_time,
235 .set_time = isl12022_rtc_set_time,
236};
237
238static int isl12022_probe(struct i2c_client *client,
239 const struct i2c_device_id *id)
240{
241 struct isl12022 *isl12022;
242
243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
244 return -ENODEV;
245
246 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
247 GFP_KERNEL);
248 if (!isl12022)
249 return -ENOMEM;
250
251 i2c_set_clientdata(client, isl12022);
252
253 isl12022->rtc = devm_rtc_device_register(&client->dev,
254 isl12022_driver.driver.name,
255 &isl12022_rtc_ops, THIS_MODULE);
256 return PTR_ERR_OR_ZERO(isl12022->rtc);
257}
258
259#ifdef CONFIG_OF
260static const struct of_device_id isl12022_dt_match[] = {
261 { .compatible = "isl,isl12022" },
262 { .compatible = "isil,isl12022" },
263 { },
264};
265MODULE_DEVICE_TABLE(of, isl12022_dt_match);
266#endif
267
268static const struct i2c_device_id isl12022_id[] = {
269 { "isl12022", 0 },
270 { }
271};
272MODULE_DEVICE_TABLE(i2c, isl12022_id);
273
274static struct i2c_driver isl12022_driver = {
275 .driver = {
276 .name = "rtc-isl12022",
277#ifdef CONFIG_OF
278 .of_match_table = of_match_ptr(isl12022_dt_match),
279#endif
280 },
281 .probe = isl12022_probe,
282 .id_table = isl12022_id,
283};
284
285module_i2c_driver(isl12022_driver);
286
287MODULE_AUTHOR("roman.fietze@telemotive.de");
288MODULE_DESCRIPTION("ISL 12022 RTC driver");
289MODULE_LICENSE("GPL");
290
