1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * RTC driver for the SD2405AL Real-Time Clock
6 * https://image.dfrobot.com/image/data/TOY0021/SD2405AL%20datasheet%20(Angelo%20v0.1).pdf
11 #include <linux/bcd.h>
12 #include <linux/i2c.h>
13 #include <linux/regmap.h>
14 #include <linux/rtc.h>
16 /* Real time clock registers */
17 #define SD2405AL_REG_T_SEC 0x00
18 #define SD2405AL_REG_T_MIN 0x01
19 #define SD2405AL_REG_T_HOUR 0x02
20 # define SD2405AL_BIT_12H_PM BIT(5)
21 # define SD2405AL_BIT_24H BIT(7)
22 #define SD2405AL_REG_T_WEEK 0x03
23 #define SD2405AL_REG_T_DAY 0x04
24 #define SD2405AL_REG_T_MON 0x05
25 #define SD2405AL_REG_T_YEAR 0x06
27 #define SD2405AL_NUM_T_REGS (SD2405AL_REG_T_YEAR - SD2405AL_REG_T_SEC + 1)
29 /* Control registers */
30 #define SD2405AL_REG_CTR1 0x0F
31 # define SD2405AL_BIT_WRTC2 BIT(2)
32 # define SD2405AL_BIT_WRTC3 BIT(7)
33 #define SD2405AL_REG_CTR2 0x10
34 # define SD2405AL_BIT_WRTC1 BIT(7)
35 #define SD2405AL_REG_CTR3 0x11
36 #define SD2405AL_REG_TTF 0x12
37 #define SD2405AL_REG_CNTDWN 0x13
40 #define SD2405AL_REG_M_START 0x14
41 #define SD2405AL_REG_M_END 0x1F
45 struct rtc_device *rtc;
46 struct regmap *regmap;
49 static int sd2405al_enable_reg_write(struct sd2405al *sd2405al)
53 /* order of writes is important */
54 ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR2,
55 SD2405AL_BIT_WRTC1, SD2405AL_BIT_WRTC1);
59 ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR1,
60 SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3,
61 SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3);
68 static int sd2405al_disable_reg_write(struct sd2405al *sd2405al)
72 /* order of writes is important */
73 ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR1,
74 SD2405AL_BIT_WRTC2 | SD2405AL_BIT_WRTC3, 0x00);
78 ret = regmap_update_bits(sd2405al->regmap, SD2405AL_REG_CTR2,
79 SD2405AL_BIT_WRTC1, 0x00);
86 static int sd2405al_read_time(struct device *dev, struct rtc_time *time)
88 u8 data[SD2405AL_NUM_T_REGS] = { 0 };
89 struct sd2405al *sd2405al = dev_get_drvdata(dev);
92 ret = regmap_bulk_read(sd2405al->regmap, SD2405AL_REG_T_SEC, data,
97 time->tm_sec = bcd2bin(data[SD2405AL_REG_T_SEC] & 0x7F);
98 time->tm_min = bcd2bin(data[SD2405AL_REG_T_MIN] & 0x7F);
100 if (data[SD2405AL_REG_T_HOUR] & SD2405AL_BIT_24H)
101 time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR] & 0x3F);
103 if (data[SD2405AL_REG_T_HOUR] & SD2405AL_BIT_12H_PM)
104 time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR]
106 else /* 12 hour mode, AM */
107 time->tm_hour = bcd2bin(data[SD2405AL_REG_T_HOUR]
110 time->tm_wday = bcd2bin(data[SD2405AL_REG_T_WEEK] & 0x07);
111 time->tm_mday = bcd2bin(data[SD2405AL_REG_T_DAY] & 0x3F);
112 time->tm_mon = bcd2bin(data[SD2405AL_REG_T_MON] & 0x1F) - 1;
113 time->tm_year = bcd2bin(data[SD2405AL_REG_T_YEAR]) + 100;
115 dev_dbg(sd2405al->dev, "read time: %ptR (%d)\n", time, time->tm_wday);
120 static int sd2405al_set_time(struct device *dev, struct rtc_time *time)
122 u8 data[SD2405AL_NUM_T_REGS];
123 struct sd2405al *sd2405al = dev_get_drvdata(dev);
126 data[SD2405AL_REG_T_SEC] = bin2bcd(time->tm_sec);
127 data[SD2405AL_REG_T_MIN] = bin2bcd(time->tm_min);
128 data[SD2405AL_REG_T_HOUR] = bin2bcd(time->tm_hour) | SD2405AL_BIT_24H;
129 data[SD2405AL_REG_T_DAY] = bin2bcd(time->tm_mday);
130 data[SD2405AL_REG_T_WEEK] = bin2bcd(time->tm_wday);
131 data[SD2405AL_REG_T_MON] = bin2bcd(time->tm_mon) + 1;
132 data[SD2405AL_REG_T_YEAR] = bin2bcd(time->tm_year - 100);
134 ret = sd2405al_enable_reg_write(sd2405al);
138 ret = regmap_bulk_write(sd2405al->regmap, SD2405AL_REG_T_SEC, data,
139 SD2405AL_NUM_T_REGS);
143 ret = regmap_write(sd2405al->regmap, SD2405AL_REG_TTF, 0x00);
147 ret = sd2405al_disable_reg_write(sd2405al);
151 dev_dbg(sd2405al->dev, "set time: %ptR (%d)\n", time, time->tm_wday);
156 static const struct rtc_class_ops sd2405al_rtc_ops = {
157 .read_time = sd2405al_read_time,
158 .set_time = sd2405al_set_time,
161 static const struct regmap_config sd2405al_regmap_conf = {
164 .max_register = SD2405AL_REG_M_END,
167 static int sd2405al_probe(struct i2c_client *client)
169 struct sd2405al *sd2405al;
172 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
175 sd2405al = devm_kzalloc(&client->dev, sizeof(*sd2405al), GFP_KERNEL);
179 sd2405al->dev = &client->dev;
181 sd2405al->regmap = devm_regmap_init_i2c(client, &sd2405al_regmap_conf);
182 if (IS_ERR(sd2405al->regmap))
183 return PTR_ERR(sd2405al->regmap);
185 sd2405al->rtc = devm_rtc_allocate_device(&client->dev);
186 if (IS_ERR(sd2405al->rtc))
187 return PTR_ERR(sd2405al->rtc);
189 sd2405al->rtc->ops = &sd2405al_rtc_ops;
190 sd2405al->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
191 sd2405al->rtc->range_max = RTC_TIMESTAMP_END_2099;
193 dev_set_drvdata(&client->dev, sd2405al);
195 ret = devm_rtc_register_device(sd2405al->rtc);
202 static const struct i2c_device_id sd2405al_id[] = {
206 MODULE_DEVICE_TABLE(i2c, sd2405al_id);
208 static const __maybe_unused struct of_device_id sd2405al_of_match[] = {
209 { .compatible = "dfrobot,sd2405al" },
212 MODULE_DEVICE_TABLE(of, sd2405al_of_match);
214 static struct i2c_driver sd2405al_driver = {
217 .of_match_table = of_match_ptr(sd2405al_of_match),
219 .probe = sd2405al_probe,
220 .id_table = sd2405al_id,
223 module_i2c_driver(sd2405al_driver);
226 MODULE_LICENSE("GPL");
227 MODULE_DESCRIPTION("SD2405AL RTC driver");