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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d6c7428f RF |
2 | /* |
3 | * An I2C driver for the Intersil ISL 12022 | |
4 | * | |
5 | * Author: Roman Fietze <roman.fietze@telemotive.de> | |
6 | * | |
7 | * Based on the Philips PCF8563 RTC | |
8 | * by Alessandro Zummo <a.zummo@towertech.it>. | |
d6c7428f RF |
9 | */ |
10 | ||
11 | #include <linux/i2c.h> | |
12 | #include <linux/bcd.h> | |
13 | #include <linux/rtc.h> | |
14 | #include <linux/slab.h> | |
2113852b | 15 | #include <linux/module.h> |
17cc54b2 | 16 | #include <linux/err.h> |
db04d628 SL |
17 | #include <linux/of.h> |
18 | #include <linux/of_device.h> | |
d6c7428f | 19 | |
d6c7428f RF |
20 | /* ISL register offsets */ |
21 | #define ISL12022_REG_SC 0x00 | |
22 | #define ISL12022_REG_MN 0x01 | |
23 | #define ISL12022_REG_HR 0x02 | |
24 | #define ISL12022_REG_DT 0x03 | |
25 | #define ISL12022_REG_MO 0x04 | |
26 | #define ISL12022_REG_YR 0x05 | |
27 | #define ISL12022_REG_DW 0x06 | |
28 | ||
29 | #define ISL12022_REG_SR 0x07 | |
30 | #define ISL12022_REG_INT 0x08 | |
31 | ||
32 | /* ISL register bits */ | |
33 | #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */ | |
34 | ||
35 | #define ISL12022_SR_LBAT85 (1 << 2) | |
36 | #define ISL12022_SR_LBAT75 (1 << 1) | |
37 | ||
38 | #define ISL12022_INT_WRTC (1 << 6) | |
39 | ||
40 | ||
41 | static struct i2c_driver isl12022_driver; | |
42 | ||
43 | struct isl12022 { | |
44 | struct rtc_device *rtc; | |
45 | ||
46 | bool write_enabled; /* true if write enable is set */ | |
47 | }; | |
48 | ||
49 | ||
50 | static int isl12022_read_regs(struct i2c_client *client, uint8_t reg, | |
51 | uint8_t *data, size_t n) | |
52 | { | |
53 | struct i2c_msg msgs[] = { | |
54 | { | |
55 | .addr = client->addr, | |
56 | .flags = 0, | |
57 | .len = 1, | |
58 | .buf = data | |
59 | }, /* setup read ptr */ | |
60 | { | |
61 | .addr = client->addr, | |
62 | .flags = I2C_M_RD, | |
63 | .len = n, | |
64 | .buf = data | |
65 | } | |
66 | }; | |
67 | ||
68 | int ret; | |
69 | ||
70 | data[0] = reg; | |
71 | ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); | |
72 | if (ret != ARRAY_SIZE(msgs)) { | |
73 | dev_err(&client->dev, "%s: read error, ret=%d\n", | |
74 | __func__, ret); | |
75 | return -EIO; | |
76 | } | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | ||
82 | static int isl12022_write_reg(struct i2c_client *client, | |
83 | uint8_t reg, uint8_t val) | |
84 | { | |
85 | uint8_t data[2] = { reg, val }; | |
86 | int err; | |
87 | ||
88 | err = i2c_master_send(client, data, sizeof(data)); | |
89 | if (err != sizeof(data)) { | |
90 | dev_err(&client->dev, | |
91 | "%s: err=%d addr=%02x, data=%02x\n", | |
92 | __func__, err, data[0], data[1]); | |
93 | return -EIO; | |
94 | } | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | ||
100 | /* | |
101 | * In the routines that deal directly with the isl12022 hardware, we use | |
102 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
103 | */ | |
143d92be | 104 | static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) |
d6c7428f | 105 | { |
143d92be | 106 | struct i2c_client *client = to_i2c_client(dev); |
d6c7428f RF |
107 | uint8_t buf[ISL12022_REG_INT + 1]; |
108 | int ret; | |
109 | ||
110 | ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf)); | |
111 | if (ret) | |
112 | return ret; | |
113 | ||
114 | if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { | |
115 | dev_warn(&client->dev, | |
116 | "voltage dropped below %u%%, " | |
117 | "date and time is not reliable.\n", | |
118 | buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); | |
119 | } | |
120 | ||
121 | dev_dbg(&client->dev, | |
122 | "%s: raw data is sec=%02x, min=%02x, hr=%02x, " | |
123 | "mday=%02x, mon=%02x, year=%02x, wday=%02x, " | |
124 | "sr=%02x, int=%02x", | |
125 | __func__, | |
126 | buf[ISL12022_REG_SC], | |
127 | buf[ISL12022_REG_MN], | |
128 | buf[ISL12022_REG_HR], | |
129 | buf[ISL12022_REG_DT], | |
130 | buf[ISL12022_REG_MO], | |
131 | buf[ISL12022_REG_YR], | |
132 | buf[ISL12022_REG_DW], | |
133 | buf[ISL12022_REG_SR], | |
134 | buf[ISL12022_REG_INT]); | |
135 | ||
136 | tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F); | |
137 | tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F); | |
138 | tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F); | |
139 | tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F); | |
140 | tm->tm_wday = buf[ISL12022_REG_DW] & 0x07; | |
141 | tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1; | |
142 | tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100; | |
143 | ||
144 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
145 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
146 | __func__, | |
147 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
148 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
149 | ||
22652ba7 | 150 | return 0; |
d6c7428f RF |
151 | } |
152 | ||
143d92be | 153 | static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm) |
d6c7428f | 154 | { |
143d92be | 155 | struct i2c_client *client = to_i2c_client(dev); |
d6c7428f RF |
156 | struct isl12022 *isl12022 = i2c_get_clientdata(client); |
157 | size_t i; | |
158 | int ret; | |
159 | uint8_t buf[ISL12022_REG_DW + 1]; | |
160 | ||
161 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
162 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
163 | __func__, | |
164 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
165 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
166 | ||
167 | if (!isl12022->write_enabled) { | |
168 | ||
169 | ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1); | |
170 | if (ret) | |
171 | return ret; | |
172 | ||
173 | /* Check if WRTC (write rtc enable) is set factory default is | |
174 | * 0 (not set) */ | |
175 | if (!(buf[0] & ISL12022_INT_WRTC)) { | |
176 | dev_info(&client->dev, | |
177 | "init write enable and 24 hour format\n"); | |
178 | ||
179 | /* Set the write enable bit. */ | |
180 | ret = isl12022_write_reg(client, | |
181 | ISL12022_REG_INT, | |
182 | buf[0] | ISL12022_INT_WRTC); | |
183 | if (ret) | |
184 | return ret; | |
185 | ||
186 | /* Write to any RTC register to start RTC, we use the | |
187 | * HR register, setting the MIL bit to use the 24 hour | |
188 | * format. */ | |
189 | ret = isl12022_read_regs(client, ISL12022_REG_HR, | |
190 | buf, 1); | |
191 | if (ret) | |
192 | return ret; | |
193 | ||
194 | ret = isl12022_write_reg(client, | |
195 | ISL12022_REG_HR, | |
196 | buf[0] | ISL12022_HR_MIL); | |
197 | if (ret) | |
198 | return ret; | |
199 | } | |
200 | ||
c1f5f054 | 201 | isl12022->write_enabled = true; |
d6c7428f RF |
202 | } |
203 | ||
204 | /* hours, minutes and seconds */ | |
205 | buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec); | |
206 | buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min); | |
6d23b258 | 207 | buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL; |
d6c7428f RF |
208 | |
209 | buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday); | |
210 | ||
211 | /* month, 1 - 12 */ | |
212 | buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1); | |
213 | ||
214 | /* year and century */ | |
215 | buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100); | |
216 | ||
217 | buf[ISL12022_REG_DW] = tm->tm_wday & 0x07; | |
218 | ||
219 | /* write register's data */ | |
220 | for (i = 0; i < ARRAY_SIZE(buf); i++) { | |
221 | ret = isl12022_write_reg(client, ISL12022_REG_SC + i, | |
222 | buf[ISL12022_REG_SC + i]); | |
223 | if (ret) | |
224 | return -EIO; | |
0b7e0392 | 225 | } |
d6c7428f RF |
226 | |
227 | return 0; | |
228 | } | |
229 | ||
d6c7428f RF |
230 | static const struct rtc_class_ops isl12022_rtc_ops = { |
231 | .read_time = isl12022_rtc_read_time, | |
232 | .set_time = isl12022_rtc_set_time, | |
233 | }; | |
234 | ||
235 | static int isl12022_probe(struct i2c_client *client, | |
236 | const struct i2c_device_id *id) | |
237 | { | |
238 | struct isl12022 *isl12022; | |
239 | ||
d6c7428f RF |
240 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
241 | return -ENODEV; | |
242 | ||
dc831f97 JH |
243 | isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022), |
244 | GFP_KERNEL); | |
d6c7428f RF |
245 | if (!isl12022) |
246 | return -ENOMEM; | |
247 | ||
d6c7428f RF |
248 | i2c_set_clientdata(client, isl12022); |
249 | ||
dc831f97 JH |
250 | isl12022->rtc = devm_rtc_device_register(&client->dev, |
251 | isl12022_driver.driver.name, | |
252 | &isl12022_rtc_ops, THIS_MODULE); | |
dac30a98 | 253 | return PTR_ERR_OR_ZERO(isl12022->rtc); |
d6c7428f RF |
254 | } |
255 | ||
db04d628 | 256 | #ifdef CONFIG_OF |
a28885bc | 257 | static const struct of_device_id isl12022_dt_match[] = { |
c5cd8273 AE |
258 | { .compatible = "isl,isl12022" }, /* for backward compat., don't use */ |
259 | { .compatible = "isil,isl12022" }, | |
db04d628 SL |
260 | { }, |
261 | }; | |
1c4fc295 | 262 | MODULE_DEVICE_TABLE(of, isl12022_dt_match); |
db04d628 SL |
263 | #endif |
264 | ||
d6c7428f RF |
265 | static const struct i2c_device_id isl12022_id[] = { |
266 | { "isl12022", 0 }, | |
d6c7428f RF |
267 | { } |
268 | }; | |
269 | MODULE_DEVICE_TABLE(i2c, isl12022_id); | |
270 | ||
271 | static struct i2c_driver isl12022_driver = { | |
272 | .driver = { | |
273 | .name = "rtc-isl12022", | |
db04d628 SL |
274 | #ifdef CONFIG_OF |
275 | .of_match_table = of_match_ptr(isl12022_dt_match), | |
276 | #endif | |
d6c7428f RF |
277 | }, |
278 | .probe = isl12022_probe, | |
d6c7428f RF |
279 | .id_table = isl12022_id, |
280 | }; | |
281 | ||
0abc9201 | 282 | module_i2c_driver(isl12022_driver); |
d6c7428f RF |
283 | |
284 | MODULE_AUTHOR("roman.fietze@telemotive.de"); | |
285 | MODULE_DESCRIPTION("ISL 12022 RTC driver"); | |
286 | MODULE_LICENSE("GPL"); |