1 /* SPDX-License-Identifier: GPL-2.0-only */
2
3 #include <commonlib/bsd/bcd.h>
4 #include <console/console.h>
5 #include <device/i2c_simple.h>
6 #include <rtc.h>
7 #include <stdint.h>
8
9 enum TPS65913_RTC_REG {
10 TPS65913_SECONDS_REG = 0x00,
11 TPS65913_MINUTES_REG = 0x01,
12 TPS65913_HOURS_REG = 0x02,
13 TPS65913_DAYS_REG = 0x03,
14 TPS65913_MONTHS_REG = 0x04,
15 TPS65913_YEARS_REG = 0x05,
16 TPS65913_WEEKS_REG = 0x06,
17 TPS65913_RTC_CTRL_REG = 0x10,
18 TPS65913_RTC_STATUS_REG = 0x11,
19 TPS65913_RTC_INTERRUPTS_REG = 0x12,
20 };
21
22 enum {
23 TPS65913_RTC_CTRL_STOP = (1 << 0),
24 TPS65913_RTC_CTRL_GET_TIME = (1 << 6),
25
26 TPS65913_RTC_STATUS_RUN = (1 << 1),
27 TPS65913_RTC_RUNNING = (1 << 1),
28 TPS65913_RTC_FROZEN = (0 << 1),
29 };
30
tps65913_read(enum TPS65913_RTC_REG reg)31 static inline uint8_t tps65913_read(enum TPS65913_RTC_REG reg)
32 {
33 uint8_t val;
34 i2c_readb(CONFIG_DRIVERS_TI_TPS65913_RTC_BUS,
35 CONFIG_DRIVERS_TI_TPS65913_RTC_ADDR, reg, &val);
36 return val;
37 }
38
tps65913_write(enum TPS65913_RTC_REG reg,uint8_t val)39 static inline void tps65913_write(enum TPS65913_RTC_REG reg, uint8_t val)
40 {
41 i2c_writeb(CONFIG_DRIVERS_TI_TPS65913_RTC_BUS,
42 CONFIG_DRIVERS_TI_TPS65913_RTC_ADDR, reg, val);
43 }
44
tps65913_rtc_ctrl_clear(uint8_t bit)45 static void tps65913_rtc_ctrl_clear(uint8_t bit)
46 {
47 uint8_t control = tps65913_read(TPS65913_RTC_CTRL_REG);
48
49 control &= ~bit;
50 tps65913_write(TPS65913_RTC_CTRL_REG, control);
51 }
52
tps65913_rtc_ctrl_set(uint8_t bit)53 static void tps65913_rtc_ctrl_set(uint8_t bit)
54 {
55 uint8_t control = tps65913_read(TPS65913_RTC_CTRL_REG);
56
57 control |= TPS65913_RTC_CTRL_GET_TIME;
58 tps65913_write(TPS65913_RTC_CTRL_REG, control);
59 }
60
tps65913_is_rtc_running(void)61 static int tps65913_is_rtc_running(void)
62 {
63 uint8_t status = tps65913_read(TPS65913_RTC_STATUS_REG);
64 return ((status & TPS65913_RTC_STATUS_RUN) == TPS65913_RTC_RUNNING);
65 }
66
67 /*
68 * This function ensures that current time is copied to shadow registers. Then a
69 * normal read on TC registers reads from the shadow instead of current TC
70 * registers. This helps prevent the accidental change in counters while
71 * reading. In order to ensure that the current TC registers are copied into
72 * shadow registers, GET_TIME bit needs to be set to 0 and then to 1.
73 */
tps65913_rtc_shadow(void)74 static void tps65913_rtc_shadow(void)
75 {
76 tps65913_rtc_ctrl_clear(TPS65913_RTC_CTRL_GET_TIME);
77 tps65913_rtc_ctrl_set(TPS65913_RTC_CTRL_GET_TIME);
78 }
79
tps65913_rtc_stop(void)80 static int tps65913_rtc_stop(void)
81 {
82 /* Clearing stop bit freezes RTC */
83 tps65913_rtc_ctrl_clear(TPS65913_RTC_CTRL_STOP);
84
85 if (tps65913_is_rtc_running()) {
86 printk(BIOS_ERR, "Could not stop RTC\n");
87 return 1;
88 }
89
90 return 0;
91 }
92
tps65913_rtc_start(void)93 static int tps65913_rtc_start(void)
94 {
95 /* Setting stop bit starts RTC */
96 tps65913_rtc_ctrl_set(TPS65913_RTC_CTRL_STOP);
97
98 if (!tps65913_is_rtc_running()) {
99 printk(BIOS_ERR, "Could not start RTC\n");
100 return 1;
101 }
102
103 return 0;
104 }
105
rtc_set(const struct rtc_time * time)106 int rtc_set(const struct rtc_time *time)
107 {
108 /* Before setting the time, ensure that rtc is stopped */
109 if (tps65913_rtc_stop())
110 return 1;
111
112 tps65913_write(TPS65913_SECONDS_REG, bin2bcd(time->sec));
113 tps65913_write(TPS65913_MINUTES_REG, bin2bcd(time->min));
114 tps65913_write(TPS65913_HOURS_REG, bin2bcd(time->hour));
115 tps65913_write(TPS65913_DAYS_REG, bin2bcd(time->mday));
116 tps65913_write(TPS65913_MONTHS_REG, bin2bcd(time->mon));
117 tps65913_write(TPS65913_YEARS_REG, bin2bcd(time->year));
118
119 /* Re-start rtc */
120 if (tps65913_rtc_start())
121 return 1;
122
123 return 0;
124 }
125
rtc_get(struct rtc_time * time)126 int rtc_get(struct rtc_time *time)
127 {
128 tps65913_rtc_shadow();
129
130 time->sec = bcd2bin(tps65913_read(TPS65913_SECONDS_REG) & 0x7f);
131 time->min = bcd2bin(tps65913_read(TPS65913_MINUTES_REG) & 0x7f);
132 time->hour = bcd2bin(tps65913_read(TPS65913_HOURS_REG) & 0x3f);
133 time->mday = bcd2bin(tps65913_read(TPS65913_DAYS_REG) & 0x3f);
134 time->mon = bcd2bin(tps65913_read(TPS65913_MONTHS_REG) & 0x1f);
135 time->year = bcd2bin(tps65913_read(TPS65913_YEARS_REG) & 0xff);
136
137 return 0;
138 }
139