xref: /aosp_15_r20/external/coreboot/src/drivers/ams/as3722rtc.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #include <commonlib/bsd/bcd.h>
4 #include <device/i2c_simple.h>
5 #include <rtc.h>
6 #include <stdint.h>
7 
8 enum AS3722_RTC_REG
9 {
10 	AS3722_RTC_CONTROL = 0x60,
11 	AS3722_RTC_SECOND = 0x61,
12 	AS3722_RTC_MINUTE = 0x62,
13 	AS3722_RTC_HOUR = 0x63,
14 	AS3722_RTC_DAY = 0x64,
15 	AS3722_RTC_MONTH = 0x65,
16 	AS3722_RTC_YEAR = 0x66
17 };
18 
19 enum {
20 	AS3722_RTC_CONTROL_ON = 0x1 << 2
21 };
22 
as3722_read(enum AS3722_RTC_REG reg)23 static uint8_t as3722_read(enum AS3722_RTC_REG reg)
24 {
25 	uint8_t val;
26 	i2c_readb(CONFIG_DRIVERS_AS3722_RTC_BUS,
27 		  CONFIG_DRIVERS_AS3722_RTC_ADDR, reg, &val);
28 	return val;
29 }
30 
as3722_write(enum AS3722_RTC_REG reg,uint8_t val)31 static void as3722_write(enum AS3722_RTC_REG reg, uint8_t val)
32 {
33 	i2c_writeb(CONFIG_DRIVERS_AS3722_RTC_BUS,
34 		   CONFIG_DRIVERS_AS3722_RTC_ADDR, reg, val);
35 }
36 
as3722rtc_init(void)37 static void as3722rtc_init(void)
38 {
39 	static int initialized;
40 	if (initialized)
41 		return;
42 
43 	uint8_t control = as3722_read(AS3722_RTC_CONTROL);
44 	as3722_write(AS3722_RTC_CONTROL, control | AS3722_RTC_CONTROL_ON);
45 
46 	initialized = 1;
47 }
48 
rtc_set(const struct rtc_time * time)49 int rtc_set(const struct rtc_time *time)
50 {
51 	as3722rtc_init();
52 
53 	as3722_write(AS3722_RTC_SECOND, bin2bcd(time->sec));
54 	as3722_write(AS3722_RTC_MINUTE, bin2bcd(time->min));
55 	as3722_write(AS3722_RTC_HOUR, bin2bcd(time->hour));
56 	as3722_write(AS3722_RTC_DAY, bin2bcd(time->mday));
57 	as3722_write(AS3722_RTC_MONTH, bin2bcd(time->mon));
58 	as3722_write(AS3722_RTC_YEAR, bin2bcd(time->year));
59 	return 0;
60 }
61 
rtc_get(struct rtc_time * time)62 int rtc_get(struct rtc_time *time)
63 {
64 	as3722rtc_init();
65 
66 	time->sec = bcd2bin(as3722_read(AS3722_RTC_SECOND) & 0x7f);
67 	time->min = bcd2bin(as3722_read(AS3722_RTC_MINUTE) & 0x7f);
68 	time->hour = bcd2bin(as3722_read(AS3722_RTC_HOUR) & 0x3f);
69 	time->mday = bcd2bin(as3722_read(AS3722_RTC_DAY) & 0x3f);
70 	time->mon = bcd2bin(as3722_read(AS3722_RTC_MONTH) & 0x1f);
71 	time->year = bcd2bin(as3722_read(AS3722_RTC_YEAR) & 0x7f);
72 	return 0;
73 }
74