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/bcd.h>
12 #include <linux/err.h>
13 #include <linux/hwmon.h>
14 #include <linux/i2c.h>
15 #include <linux/module.h>
16 #include <linux/regmap.h>
17 #include <linux/rtc.h>
18 #include <linux/slab.h>
20 #include <asm/byteorder.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 umode_t isl12022_hwmon_is_visible(const void *data,
48 enum hwmon_sensor_types type,
49 u32 attr, int channel)
51 if (type == hwmon_temp && attr == hwmon_temp_input)
58 * A user-initiated temperature conversion is not started by this function,
59 * so the temperature is updated once every ~60 seconds.
61 static int isl12022_hwmon_read_temp(struct device *dev, long *mC)
63 struct regmap *regmap = dev_get_drvdata(dev);
67 ret = regmap_bulk_read(regmap, ISL12022_REG_TEMP_L, &buf, sizeof(buf));
71 * Temperature is represented as a 10-bit number, unit half-Kelvins.
73 temp = le16_to_cpu(buf);
82 static int isl12022_hwmon_read(struct device *dev,
83 enum hwmon_sensor_types type,
84 u32 attr, int channel, long *val)
86 if (type == hwmon_temp && attr == hwmon_temp_input)
87 return isl12022_hwmon_read_temp(dev, val);
92 static const struct hwmon_channel_info * const isl12022_hwmon_info[] = {
93 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
97 static const struct hwmon_ops isl12022_hwmon_ops = {
98 .is_visible = isl12022_hwmon_is_visible,
99 .read = isl12022_hwmon_read,
102 static const struct hwmon_chip_info isl12022_hwmon_chip_info = {
103 .ops = &isl12022_hwmon_ops,
104 .info = isl12022_hwmon_info,
107 static void isl12022_hwmon_register(struct device *dev)
109 struct regmap *regmap = dev_get_drvdata(dev);
110 struct device *hwmon;
113 if (!IS_REACHABLE(CONFIG_HWMON))
116 ret = regmap_update_bits(regmap, ISL12022_REG_BETA,
117 ISL12022_BETA_TSE, ISL12022_BETA_TSE);
119 dev_warn(dev, "unable to enable temperature sensor\n");
123 hwmon = devm_hwmon_device_register_with_info(dev, "isl12022", regmap,
124 &isl12022_hwmon_chip_info,
127 dev_warn(dev, "unable to register hwmon device: %pe\n", hwmon);
131 * In the routines that deal directly with the isl12022 hardware, we use
132 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
134 static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
136 struct regmap *regmap = dev_get_drvdata(dev);
137 uint8_t buf[ISL12022_REG_INT + 1];
140 ret = regmap_bulk_read(regmap, ISL12022_REG_SC, buf, sizeof(buf));
144 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
146 "voltage dropped below %u%%, date and time is not reliable.\n",
147 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
151 "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, sr=%02x, int=%02x",
152 buf[ISL12022_REG_SC],
153 buf[ISL12022_REG_MN],
154 buf[ISL12022_REG_HR],
155 buf[ISL12022_REG_DT],
156 buf[ISL12022_REG_MO],
157 buf[ISL12022_REG_YR],
158 buf[ISL12022_REG_DW],
159 buf[ISL12022_REG_SR],
160 buf[ISL12022_REG_INT]);
162 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
163 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
164 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
165 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
166 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
167 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
168 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
170 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
175 static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
177 struct regmap *regmap = dev_get_drvdata(dev);
179 uint8_t buf[ISL12022_REG_DW + 1];
181 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
183 /* Ensure the write enable bit is set. */
184 ret = regmap_update_bits(regmap, ISL12022_REG_INT,
185 ISL12022_INT_WRTC, ISL12022_INT_WRTC);
189 /* hours, minutes and seconds */
190 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
191 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
192 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
194 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
197 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
199 /* year and century */
200 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
202 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
204 return regmap_bulk_write(regmap, ISL12022_REG_SC, buf, sizeof(buf));
207 static const struct rtc_class_ops isl12022_rtc_ops = {
208 .read_time = isl12022_rtc_read_time,
209 .set_time = isl12022_rtc_set_time,
212 static const struct regmap_config regmap_config = {
215 .use_single_write = true,
218 static int isl12022_probe(struct i2c_client *client)
220 struct rtc_device *rtc;
221 struct regmap *regmap;
223 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
226 regmap = devm_regmap_init_i2c(client, ®map_config);
227 if (IS_ERR(regmap)) {
228 dev_err(&client->dev, "regmap allocation failed\n");
229 return PTR_ERR(regmap);
232 dev_set_drvdata(&client->dev, regmap);
234 isl12022_hwmon_register(&client->dev);
236 rtc = devm_rtc_allocate_device(&client->dev);
240 rtc->ops = &isl12022_rtc_ops;
241 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
242 rtc->range_max = RTC_TIMESTAMP_END_2099;
244 return devm_rtc_register_device(rtc);
247 static const struct of_device_id isl12022_dt_match[] = {
248 { .compatible = "isl,isl12022" }, /* for backward compat., don't use */
249 { .compatible = "isil,isl12022" },
252 MODULE_DEVICE_TABLE(of, isl12022_dt_match);
254 static const struct i2c_device_id isl12022_id[] = {
258 MODULE_DEVICE_TABLE(i2c, isl12022_id);
260 static struct i2c_driver isl12022_driver = {
262 .name = "rtc-isl12022",
263 .of_match_table = isl12022_dt_match,
265 .probe = isl12022_probe,
266 .id_table = isl12022_id,
269 module_i2c_driver(isl12022_driver);
271 MODULE_AUTHOR("roman.fietze@telemotive.de");
272 MODULE_DESCRIPTION("ISL 12022 RTC driver");
273 MODULE_LICENSE("GPL");