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Roman Fietzed6c74282010-08-10 18:02:14 -07001/*
2 * An I2C driver for the Intersil ISL 12022
3 *
4 * Author: Roman Fietze <roman.fietze@telemotive.de>
5 *
6 * Based on the Philips PCF8563 RTC
7 * by Alessandro Zummo <a.zummo@towertech.it>.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version
11 * 2 as published by the Free Software Foundation.
12 */
13
14#include <linux/i2c.h>
15#include <linux/bcd.h>
16#include <linux/rtc.h>
17#include <linux/slab.h>
Paul Gortmaker21138522011-05-27 09:57:25 -040018#include <linux/module.h>
Sachin Kamat17cc54b22013-07-03 15:07:49 -070019#include <linux/err.h>
Roman Fietzed6c74282010-08-10 18:02:14 -070020
21#define DRV_VERSION "0.1"
22
23/* ISL register offsets */
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/* ISL register bits */
36#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
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; /* true if write enable is set */
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 }, /* setup read ptr */
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 * In the routines that deal directly with the isl12022 hardware, we use
105 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
106 */
107static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
108{
109 uint8_t buf[ISL12022_REG_INT + 1];
110 int ret;
111
112 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
113 if (ret)
114 return ret;
115
116 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
117 dev_warn(&client->dev,
118 "voltage dropped below %u%%, "
119 "date and time is not reliable.\n",
120 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
121 }
122
123 dev_dbg(&client->dev,
124 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
125 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
126 "sr=%02x, int=%02x",
127 __func__,
128 buf[ISL12022_REG_SC],
129 buf[ISL12022_REG_MN],
130 buf[ISL12022_REG_HR],
131 buf[ISL12022_REG_DT],
132 buf[ISL12022_REG_MO],
133 buf[ISL12022_REG_YR],
134 buf[ISL12022_REG_DW],
135 buf[ISL12022_REG_SR],
136 buf[ISL12022_REG_INT]);
137
138 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
139 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
140 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
141 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
142 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
143 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
144 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
145
146 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
147 "mday=%d, mon=%d, year=%d, wday=%d\n",
148 __func__,
149 tm->tm_sec, tm->tm_min, tm->tm_hour,
150 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
151
152 /* The clock can give out invalid datetime, but we cannot return
153 * -EINVAL otherwise hwclock will refuse to set the time on bootup. */
154 if (rtc_valid_tm(tm) < 0)
155 dev_err(&client->dev, "retrieved date and time is invalid.\n");
156
157 return 0;
158}
159
160static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
161{
162 struct isl12022 *isl12022 = i2c_get_clientdata(client);
163 size_t i;
164 int ret;
165 uint8_t buf[ISL12022_REG_DW + 1];
166
167 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
168 "mday=%d, mon=%d, year=%d, wday=%d\n",
169 __func__,
170 tm->tm_sec, tm->tm_min, tm->tm_hour,
171 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
172
173 if (!isl12022->write_enabled) {
174
175 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
176 if (ret)
177 return ret;
178
179 /* Check if WRTC (write rtc enable) is set factory default is
180 * 0 (not set) */
181 if (!(buf[0] & ISL12022_INT_WRTC)) {
182 dev_info(&client->dev,
183 "init write enable and 24 hour format\n");
184
185 /* Set the write enable bit. */
186 ret = isl12022_write_reg(client,
187 ISL12022_REG_INT,
188 buf[0] | ISL12022_INT_WRTC);
189 if (ret)
190 return ret;
191
192 /* Write to any RTC register to start RTC, we use the
193 * HR register, setting the MIL bit to use the 24 hour
194 * format. */
195 ret = isl12022_read_regs(client, ISL12022_REG_HR,
196 buf, 1);
197 if (ret)
198 return ret;
199
200 ret = isl12022_write_reg(client,
201 ISL12022_REG_HR,
202 buf[0] | ISL12022_HR_MIL);
203 if (ret)
204 return ret;
205 }
206
207 isl12022->write_enabled = 1;
208 }
209
210 /* hours, minutes and seconds */
211 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
212 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
Roman Fietze6d23b252010-08-10 18:02:21 -0700213 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
Roman Fietzed6c74282010-08-10 18:02:14 -0700214
215 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
216
217 /* month, 1 - 12 */
218 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
219
220 /* year and century */
221 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
222
223 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
224
225 /* write register's data */
226 for (i = 0; i < ARRAY_SIZE(buf); i++) {
227 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
228 buf[ISL12022_REG_SC + i]);
229 if (ret)
230 return -EIO;
Peter Senna Tschudin0b7e0392013-02-21 16:44:30 -0800231 }
Roman Fietzed6c74282010-08-10 18:02:14 -0700232
233 return 0;
234}
235
236static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
237{
238 return isl12022_get_datetime(to_i2c_client(dev), tm);
239}
240
241static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
242{
243 return isl12022_set_datetime(to_i2c_client(dev), tm);
244}
245
246static const struct rtc_class_ops isl12022_rtc_ops = {
247 .read_time = isl12022_rtc_read_time,
248 .set_time = isl12022_rtc_set_time,
249};
250
251static int isl12022_probe(struct i2c_client *client,
252 const struct i2c_device_id *id)
253{
254 struct isl12022 *isl12022;
255
Roman Fietzed6c74282010-08-10 18:02:14 -0700256 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
257 return -ENODEV;
258
Jingoo Handc831f92013-04-29 16:20:41 -0700259 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
260 GFP_KERNEL);
Roman Fietzed6c74282010-08-10 18:02:14 -0700261 if (!isl12022)
262 return -ENOMEM;
263
264 dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n");
265
266 i2c_set_clientdata(client, isl12022);
267
Jingoo Handc831f92013-04-29 16:20:41 -0700268 isl12022->rtc = devm_rtc_device_register(&client->dev,
269 isl12022_driver.driver.name,
270 &isl12022_rtc_ops, THIS_MODULE);
Sachin Kamatdac30a92013-07-15 15:43:32 +0530271 return PTR_ERR_OR_ZERO(isl12022->rtc);
Roman Fietzed6c74282010-08-10 18:02:14 -0700272}
273
Roman Fietzed6c74282010-08-10 18:02:14 -0700274static const struct i2c_device_id isl12022_id[] = {
275 { "isl12022", 0 },
Roman Fietzed6c74282010-08-10 18:02:14 -0700276 { }
277};
278MODULE_DEVICE_TABLE(i2c, isl12022_id);
279
280static struct i2c_driver isl12022_driver = {
281 .driver = {
282 .name = "rtc-isl12022",
283 },
284 .probe = isl12022_probe,
Roman Fietzed6c74282010-08-10 18:02:14 -0700285 .id_table = isl12022_id,
286};
287
Axel Lin0abc9202012-03-23 15:02:31 -0700288module_i2c_driver(isl12022_driver);
Roman Fietzed6c74282010-08-10 18:02:14 -0700289
290MODULE_AUTHOR("roman.fietze@telemotive.de");
291MODULE_DESCRIPTION("ISL 12022 RTC driver");
292MODULE_LICENSE("GPL");
293MODULE_VERSION(DRV_VERSION);