1 // SPDX-License-Identifier: GPL-2.0-only
3 * An I2C driver for the Intersil ISL 12022
5 * Author: Roman Fietze <roman.fietze@telemotive.de>
7 * Based on the Philips PCF8563 RTC
8 * by Alessandro Zummo <a.zummo@towertech.it>.
11 #include <linux/i2c.h>
12 #include <linux/bcd.h>
13 #include <linux/rtc.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/err.h>
18 #include <linux/of_device.h>
19 #include <linux/regmap.h>
20 #include <linux/hwmon.h>
22 /* ISL register offsets */
23 #define ISL12022_REG_SC 0x00
24 #define ISL12022_REG_MN 0x01
25 #define ISL12022_REG_HR 0x02
26 #define ISL12022_REG_DT 0x03
27 #define ISL12022_REG_MO 0x04
28 #define ISL12022_REG_YR 0x05
29 #define ISL12022_REG_DW 0x06
31 #define ISL12022_REG_SR 0x07
32 #define ISL12022_REG_INT 0x08
34 #define ISL12022_REG_BETA 0x0d
35 #define ISL12022_REG_TEMP_L 0x28
37 /* ISL register bits */
38 #define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
40 #define ISL12022_SR_LBAT85 (1 << 2)
41 #define ISL12022_SR_LBAT75 (1 << 1)
43 #define ISL12022_INT_WRTC (1 << 6)
45 #define ISL12022_BETA_TSE (1 << 7)
47 static struct i2c_driver isl12022_driver;
50 struct rtc_device *rtc;
51 struct regmap *regmap;
54 static umode_t isl12022_hwmon_is_visible(const void *data,
55 enum hwmon_sensor_types type,
56 u32 attr, int channel)
58 if (type == hwmon_temp && attr == hwmon_temp_input)
65 * A user-initiated temperature conversion is not started by this function,
66 * so the temperature is updated once every ~60 seconds.
68 static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
70 struct isl12022 *isl12022 = dev_get_drvdata(dev);
71 struct regmap *regmap = isl12022->regmap;
75 ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L,
76 temp_buf, sizeof(temp_buf));
80 * Temperature is represented as a 10-bit number, unit half-Kelvins.
82 temp = (temp_buf[1] << 8) | temp_buf[0];
91 static int isl12022_hwmon_read(struct device *dev,
92 enum hwmon_sensor_types type,
93 u32 attr, int channel, long *val)
95 if (type == hwmon_temp && attr == hwmon_temp_input)
96 return isl12022_hwmon_read_temp(dev, val);
101 static const struct hwmon_channel_info *isl12022_hwmon_info[] = {
102 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
106 static const struct hwmon_ops isl12022_hwmon_ops = {
107 .is_visible = isl12022_hwmon_is_visible,
108 .read = isl12022_hwmon_read,
111 static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
112 .ops = &isl12022_hwmon_ops,
113 .info = isl12022_hwmon_info,
116 static void isl12022_hwmon_register(struct device *dev)
118 struct isl12022 *isl12022;
119 struct device *hwmon;
122 if (!IS_REACHABLE(CONFIG_HWMON))
125 isl12022 = dev_get_drvdata(dev);
127 ret = regmap_update_bits(isl12022->regmap, ISL12022_REG_BETA,
128 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
130 dev_warn(dev, "unable to enable temperature sensor\n");
134 hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", isl12022,
135 &isl12022_hwmon_chip_info,
138 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
142 * In the routines that deal directly with the isl12022 hardware, we use
143 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
145 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
147 struct isl12022 *isl12022 = dev_get_drvdata(dev);
148 struct regmap *regmap = isl12022->regmap;
149 uint8_t buf[ISL12022_REG_INT + 1];
152 ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf));
156 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
158 "voltage dropped below %u%%, "
159 "date and time is not reliable.\n",
160 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
164 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
165 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
168 buf[ISL12022_REG_SC],
169 buf[ISL12022_REG_MN],
170 buf[ISL12022_REG_HR],
171 buf[ISL12022_REG_DT],
172 buf[ISL12022_REG_MO],
173 buf[ISL12022_REG_YR],
174 buf[ISL12022_REG_DW],
175 buf[ISL12022_REG_SR],
176 buf[ISL12022_REG_INT]);
178 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
179 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
180 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
181 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
182 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
183 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
184 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
186 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
191 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
193 struct isl12022 *isl12022 = dev_get_drvdata(dev);
194 struct regmap *regmap = isl12022->regmap;
196 uint8_t buf[ISL12022_REG_DW + 1];
198 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
200 /* Ensure the write enable bit is set. */
201 ret = regmap_update_bits(regmap, ISL12022_REG_INT,
202 ISL12022_INT_WRTC, ISL12022_INT_WRTC);
206 /* hours, minutes and seconds */
207 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
208 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
209 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
211 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
214 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
216 /* year and century */
217 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
219 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
221 return regmap_bulk_write(isl12022->regmap, ISL12022_REG_SC,
225 static const struct rtc_class_ops isl12022_rtc_ops = {
226 .read_time = isl12022_rtc_read_time,
227 .set_time = isl12022_rtc_set_time,
230 static const struct regmap_config regmap_config = {
233 .use_single_write = true,
236 static int isl12022_probe(struct i2c_client *client)
238 struct isl12022 *isl12022;
240 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
243 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
247 dev_set_drvdata(&client->dev, isl12022);
249 isl12022->regmap = devm_regmap_init_i2c(client, ®map_config);
250 if (IS_ERR(isl12022->regmap)) {
251 dev_err(&client->dev, "regmap allocation failed\n");
252 return PTR_ERR(isl12022->regmap);
255 isl12022_hwmon_register(&client->dev);
257 isl12022->rtc = devm_rtc_allocate_device(&client->dev);
258 if (IS_ERR(isl12022->rtc))
259 return PTR_ERR(isl12022->rtc);
261 isl12022->rtc->ops = &isl12022_rtc_ops;
262 isl12022->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
263 isl12022->rtc->range_max = RTC_TIMESTAMP_END_2099;
265 return devm_rtc_register_device(isl12022->rtc);
269 static const struct of_device_id isl12022_dt_match[] = {
270 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
271 { .compatible = "isil,isl12022" },
274 MODULE_DEVICE_TABLE(of, isl12022_dt_match);
277 static const struct i2c_device_id isl12022_id[] = {
281 MODULE_DEVICE_TABLE(i2c, isl12022_id);
283 static struct i2c_driver isl12022_driver = {
285 .name = "rtc-isl12022",
287 .of_match_table = of_match_ptr(isl12022_dt_match),
290 .probe_new = isl12022_probe,
291 .id_table = isl12022_id,
294 module_i2c_driver(isl12022_driver);
296 MODULE_AUTHOR("roman.fietze@telemotive.de");
297 MODULE_DESCRIPTION("ISL 12022 RTC driver");
298 MODULE_LICENSE("GPL");