1 /*
2 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include "pico.h"
8
9 #include "hardware/irq.h"
10 #include "hardware/rtc.h"
11 #include "hardware/resets.h"
12 #include "hardware/clocks.h"
13
14 // Set this when setting an alarm
15 static rtc_callback_t _callback = NULL;
16 static bool _alarm_repeats = false;
17
rtc_running(void)18 bool rtc_running(void) {
19 return (rtc_hw->ctrl & RTC_CTRL_RTC_ACTIVE_BITS);
20 }
21
rtc_init(void)22 void rtc_init(void) {
23 // Get clk_rtc freq and make sure it is running
24 uint rtc_freq = clock_get_hz(clk_rtc);
25 assert(rtc_freq != 0);
26
27 // Take rtc out of reset now that we know clk_rtc is running
28 reset_unreset_block_num_wait_blocking(RESET_RTC);
29
30 // Set up the 1 second divider.
31 // If rtc_freq is 400 then clkdiv_m1 should be 399
32 rtc_freq -= 1;
33
34 // Check the freq is not too big to divide
35 assert(rtc_freq <= RTC_CLKDIV_M1_BITS);
36
37 // Write divide value
38 rtc_hw->clkdiv_m1 = rtc_freq;
39 }
40
valid_datetime(const datetime_t * t)41 static bool valid_datetime(const datetime_t *t) {
42 // Valid ranges taken from RTC doc. Note when setting an RTC alarm
43 // these values are allowed to be -1 to say "don't match this value"
44 if (!(t->year >= 0 && t->year <= 4095)) return false;
45 if (!(t->month >= 1 && t->month <= 12)) return false;
46 if (!(t->day >= 1 && t->day <= 31)) return false;
47 if (!(t->dotw >= 0 && t->dotw <= 6)) return false;
48 if (!(t->hour >= 0 && t->hour <= 23)) return false;
49 if (!(t->min >= 0 && t->min <= 59)) return false;
50 if (!(t->sec >= 0 && t->sec <= 59)) return false;
51 return true;
52 }
53
rtc_set_datetime(const datetime_t * t)54 bool rtc_set_datetime(const datetime_t *t) {
55 if (!valid_datetime(t)) {
56 return false;
57 }
58
59 // Disable RTC
60 rtc_hw->ctrl = 0;
61 // Wait while it is still active
62 while (rtc_running()) {
63 tight_loop_contents();
64 }
65
66 // Write to setup registers
67 rtc_hw->setup_0 = (((uint32_t)t->year) << RTC_SETUP_0_YEAR_LSB ) |
68 (((uint32_t)t->month) << RTC_SETUP_0_MONTH_LSB) |
69 (((uint32_t)t->day) << RTC_SETUP_0_DAY_LSB);
70 rtc_hw->setup_1 = (((uint32_t)t->dotw) << RTC_SETUP_1_DOTW_LSB) |
71 (((uint32_t)t->hour) << RTC_SETUP_1_HOUR_LSB) |
72 (((uint32_t)t->min) << RTC_SETUP_1_MIN_LSB) |
73 (((uint32_t)t->sec) << RTC_SETUP_1_SEC_LSB);
74
75 // Load setup values into rtc clock domain
76 rtc_hw->ctrl = RTC_CTRL_LOAD_BITS;
77
78 // Enable RTC and wait for it to be running
79 rtc_hw->ctrl = RTC_CTRL_RTC_ENABLE_BITS;
80 while (!rtc_running()) {
81 tight_loop_contents();
82 }
83
84 return true;
85 }
86
rtc_get_datetime(datetime_t * t)87 bool rtc_get_datetime(datetime_t *t) {
88 // Make sure RTC is running
89 if (!rtc_running()) {
90 return false;
91 }
92
93 // Note: RTC_0 should be read before RTC_1
94 uint32_t rtc_0 = rtc_hw->rtc_0;
95 uint32_t rtc_1 = rtc_hw->rtc_1;
96
97 t->dotw = (int8_t) ((rtc_0 & RTC_RTC_0_DOTW_BITS ) >> RTC_RTC_0_DOTW_LSB);
98 t->hour = (int8_t) ((rtc_0 & RTC_RTC_0_HOUR_BITS ) >> RTC_RTC_0_HOUR_LSB);
99 t->min = (int8_t) ((rtc_0 & RTC_RTC_0_MIN_BITS ) >> RTC_RTC_0_MIN_LSB);
100 t->sec = (int8_t) ((rtc_0 & RTC_RTC_0_SEC_BITS ) >> RTC_RTC_0_SEC_LSB);
101 t->year = (int16_t) ((rtc_1 & RTC_RTC_1_YEAR_BITS ) >> RTC_RTC_1_YEAR_LSB);
102 t->month = (int8_t) ((rtc_1 & RTC_RTC_1_MONTH_BITS) >> RTC_RTC_1_MONTH_LSB);
103 t->day = (int8_t) ((rtc_1 & RTC_RTC_1_DAY_BITS ) >> RTC_RTC_1_DAY_LSB);
104
105 return true;
106 }
107
rtc_enable_alarm(void)108 void rtc_enable_alarm(void) {
109 // Set matching and wait for it to be enabled
110 hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MATCH_ENA_BITS);
111 while(!(rtc_hw->irq_setup_0 & RTC_IRQ_SETUP_0_MATCH_ACTIVE_BITS)) {
112 tight_loop_contents();
113 }
114 }
115
rtc_irq_handler(void)116 static void rtc_irq_handler(void) {
117 // Always disable the alarm to clear the current IRQ.
118 // Even if it is a repeatable alarm, we don't want it to keep firing.
119 // If it matches on a second it can keep firing for that second.
120 rtc_disable_alarm();
121
122 if (_alarm_repeats) {
123 // If it is a repeatable alarm, re enable the alarm.
124 rtc_enable_alarm();
125 }
126
127 // Call user callback function
128 if (_callback) {
129 _callback();
130 }
131 }
132
rtc_alarm_repeats(const datetime_t * t)133 static bool rtc_alarm_repeats(const datetime_t *t) {
134 // If any value is set to -1 then we don't match on that value
135 // hence the alarm will eventually repeat
136 if (t->year < 0) return true;
137 if (t->month < 0) return true;
138 if (t->day < 0) return true;
139 if (t->dotw < 0) return true;
140 if (t->hour < 0) return true;
141 if (t->min < 0) return true;
142 if (t->sec < 0) return true;
143 return false;
144 }
145
rtc_set_alarm(const datetime_t * t,rtc_callback_t user_callback)146 void rtc_set_alarm(const datetime_t *t, rtc_callback_t user_callback) {
147 rtc_disable_alarm();
148
149 // Only add to setup if it isn't -1
150 rtc_hw->irq_setup_0 = ((t->year < 0) ? 0 : (((uint32_t)t->year) << RTC_IRQ_SETUP_0_YEAR_LSB )) |
151 ((t->month < 0) ? 0 : (((uint32_t)t->month) << RTC_IRQ_SETUP_0_MONTH_LSB)) |
152 ((t->day < 0) ? 0 : (((uint32_t)t->day) << RTC_IRQ_SETUP_0_DAY_LSB ));
153 rtc_hw->irq_setup_1 = ((t->dotw < 0) ? 0 : (((uint32_t)t->dotw) << RTC_IRQ_SETUP_1_DOTW_LSB)) |
154 ((t->hour < 0) ? 0 : (((uint32_t)t->hour) << RTC_IRQ_SETUP_1_HOUR_LSB)) |
155 ((t->min < 0) ? 0 : (((uint32_t)t->min) << RTC_IRQ_SETUP_1_MIN_LSB )) |
156 ((t->sec < 0) ? 0 : (((uint32_t)t->sec) << RTC_IRQ_SETUP_1_SEC_LSB ));
157
158 // Set the match enable bits for things we care about
159 if (t->year >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_YEAR_ENA_BITS);
160 if (t->month >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MONTH_ENA_BITS);
161 if (t->day >= 0) hw_set_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_DAY_ENA_BITS);
162 if (t->dotw >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_DOTW_ENA_BITS);
163 if (t->hour >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_HOUR_ENA_BITS);
164 if (t->min >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_MIN_ENA_BITS);
165 if (t->sec >= 0) hw_set_bits(&rtc_hw->irq_setup_1, RTC_IRQ_SETUP_1_SEC_ENA_BITS);
166
167 // Does it repeat? I.e. do we not match on any of the bits
168 _alarm_repeats = rtc_alarm_repeats(t);
169
170 // Store function pointer we can call later
171 _callback = user_callback;
172
173 irq_set_exclusive_handler(RTC_IRQ, rtc_irq_handler);
174
175 // Enable the IRQ at the peri
176 rtc_hw->inte = RTC_INTE_RTC_BITS;
177
178 // Enable the IRQ at the proc
179 irq_set_enabled(RTC_IRQ, true);
180
181 rtc_enable_alarm();
182 }
183
rtc_disable_alarm(void)184 void rtc_disable_alarm(void) {
185 // Disable matching and wait for it to stop being active
186 hw_clear_bits(&rtc_hw->irq_setup_0, RTC_IRQ_SETUP_0_MATCH_ENA_BITS);
187 while(rtc_hw->irq_setup_0 & RTC_IRQ_SETUP_0_MATCH_ACTIVE_BITS) {
188 tight_loop_contents();
189 }
190 }
191