1 /*
2 * SPDX-License-Identifier: Apache-2.0
3 *
4 * Copyright (c) 2023 Arunmani Alagarsamy
5 * Author: Arunmani Alagarsamy <arunmani27100@gmail.com>
6 */
7
8 #include <zephyr/drivers/i2c.h>
9 #include <zephyr/drivers/rtc.h>
10 #include <zephyr/logging/log.h>
11 #include <zephyr/pm/device.h>
12 #include <zephyr/sys/util.h>
13
14 #define DT_DRV_COMPAT maxim_ds1307
15
16 LOG_MODULE_REGISTER(ds1307, CONFIG_RTC_LOG_LEVEL);
17
18 /* DS1307 registers */
19 #define DS1307_REG_SECONDS 0x00
20 #define DS1307_REG_MINUTES 0x01
21 #define DS1307_REG_HOURS 0x02
22 #define DS1307_REG_DAY 0x03
23 #define DS1307_REG_DATE 0x04
24 #define DS1307_REG_MONTH 0x05
25 #define DS1307_REG_YEAR 0x06
26 #define DS1307_REG_CTRL 0x07
27
28 #define SECONDS_BITS GENMASK(6, 0)
29 #define MINUTES_BITS GENMASK(7, 0)
30 #define HOURS_BITS GENMASK(5, 0)
31 #define DATE_BITS GENMASK(5, 0)
32 #define MONTHS_BITS GENMASK(4, 0)
33 #define WEEKDAY_BITS GENMASK(2, 0)
34 #define YEAR_BITS GENMASK(7, 0)
35 #define VALIDATE_24HR BIT(6)
36
37 struct ds1307_config {
38 struct i2c_dt_spec i2c_bus;
39 };
40
41 struct ds1307_data {
42 struct k_spinlock lock;
43 };
44
ds1307_set_time(const struct device * dev,const struct rtc_time * tm)45 static int ds1307_set_time(const struct device *dev, const struct rtc_time *tm)
46 {
47 int err;
48 uint8_t regs[7];
49
50 struct ds1307_data *data = dev->data;
51 const struct ds1307_config *config = dev->config;
52
53 k_spinlock_key_t key = k_spin_lock(&data->lock);
54
55 LOG_DBG("set time: year = %d, mon = %d, mday = %d, wday = %d, hour = %d, "
56 "min = %d, sec = %d",
57 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday, tm->tm_hour, tm->tm_min,
58 tm->tm_sec);
59
60 regs[0] = bin2bcd(tm->tm_sec) & SECONDS_BITS;
61 regs[1] = bin2bcd(tm->tm_min);
62 regs[2] = bin2bcd(tm->tm_hour);
63 regs[3] = bin2bcd(tm->tm_wday);
64 regs[4] = bin2bcd(tm->tm_mday);
65 regs[5] = bin2bcd(tm->tm_mon);
66 regs[6] = bin2bcd((tm->tm_year % 100));
67
68 err = i2c_burst_write_dt(&config->i2c_bus, DS1307_REG_SECONDS, regs, sizeof(regs));
69
70 k_spin_unlock(&data->lock, key);
71
72 return err;
73 }
74
ds1307_get_time(const struct device * dev,struct rtc_time * timeptr)75 static int ds1307_get_time(const struct device *dev, struct rtc_time *timeptr)
76 {
77 int err;
78 uint8_t regs[7];
79
80 struct ds1307_data *data = dev->data;
81 const struct ds1307_config *config = dev->config;
82
83 k_spinlock_key_t key = k_spin_lock(&data->lock);
84
85 err = i2c_burst_read_dt(&config->i2c_bus, DS1307_REG_SECONDS, regs, sizeof(regs));
86 if (err != 0) {
87 goto unlock;
88 }
89
90 timeptr->tm_sec = bcd2bin(regs[0] & SECONDS_BITS);
91 timeptr->tm_min = bcd2bin(regs[1] & MINUTES_BITS);
92 timeptr->tm_hour = bcd2bin(regs[2] & HOURS_BITS); /* 24hr mode */
93 timeptr->tm_wday = bcd2bin(regs[3] & WEEKDAY_BITS);
94 timeptr->tm_mday = bcd2bin(regs[4] & DATE_BITS);
95 timeptr->tm_mon = bcd2bin(regs[5] & MONTHS_BITS);
96 timeptr->tm_year = bcd2bin(regs[6] & YEAR_BITS);
97 timeptr->tm_year = timeptr->tm_year + 100;
98
99 /* Not used */
100 timeptr->tm_nsec = 0;
101 timeptr->tm_isdst = -1;
102 timeptr->tm_yday = -1;
103
104 /* Validate the chip in 24hr mode */
105 if (regs[2] & VALIDATE_24HR) {
106 err = -ENODATA;
107 goto unlock;
108 }
109
110 LOG_DBG("get time: year = %d, mon = %d, mday = %d, wday = %d, hour = %d, "
111 "min = %d, sec = %d",
112 timeptr->tm_year, timeptr->tm_mon, timeptr->tm_mday, timeptr->tm_wday,
113 timeptr->tm_hour, timeptr->tm_min, timeptr->tm_sec);
114
115 unlock:
116 k_spin_unlock(&data->lock, key);
117
118 return err;
119 }
120
121 static DEVICE_API(rtc, ds1307_driver_api) = {
122 .set_time = ds1307_set_time,
123 .get_time = ds1307_get_time,
124 };
125
ds1307_init(const struct device * dev)126 static int ds1307_init(const struct device *dev)
127 {
128 int err;
129 const struct ds1307_config *config = dev->config;
130
131 if (!i2c_is_ready_dt(&config->i2c_bus)) {
132 LOG_ERR("I2C bus not ready");
133 return -ENODEV;
134 }
135
136 /* Disable squarewave output */
137 err = i2c_reg_write_byte_dt(&config->i2c_bus, DS1307_REG_CTRL, 0x00);
138 if (err < 0) {
139 LOG_ERR("Error: SQW: %d\n", err);
140 }
141
142 /* Ensure Clock Halt = 0 */
143 uint8_t reg = 0;
144
145 err = i2c_reg_read_byte_dt(&config->i2c_bus, DS1307_REG_SECONDS, ®);
146 if (err < 0) {
147 LOG_ERR("Error: Read SECONDS/Clock Halt register: %d\n", err);
148 }
149 if (reg & ~SECONDS_BITS) {
150 /* Clock Halt bit is set */
151 err = i2c_reg_write_byte_dt(&config->i2c_bus, DS1307_REG_SECONDS,
152 reg & SECONDS_BITS);
153 if (err < 0) {
154 LOG_ERR("Error: Clear Clock Halt bit: %d\n", err);
155 }
156 }
157
158 return 0;
159 }
160
161 #define DS1307_DEFINE(inst) \
162 static struct ds1307_data ds1307_data_##inst; \
163 static const struct ds1307_config ds1307_config_##inst = { \
164 .i2c_bus = I2C_DT_SPEC_INST_GET(inst), \
165 }; \
166 DEVICE_DT_INST_DEFINE(inst, &ds1307_init, NULL, &ds1307_data_##inst, \
167 &ds1307_config_##inst, POST_KERNEL, CONFIG_RTC_INIT_PRIORITY, \
168 &ds1307_driver_api);
169
170 DT_INST_FOREACH_STATUS_OKAY(DS1307_DEFINE)
171
