--- /dev/null
+/*******************************************************************************
+ * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+#include "rtc_api.h"
+#include "cmsis.h"
+#include "rtc_regs.h"
+#include "pwrseq_regs.h"
+#include "clkman_regs.h"
+
+static int rtc_inited = 0;
+static volatile uint32_t overflow_cnt = 0;
+static uint32_t overflow_alarm = 0;
+
+//******************************************************************************
+static void overflow_handler(void)
+{
+ MXC_RTCTMR->flags = MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS;
+ overflow_cnt++;
+
+ if (overflow_cnt == overflow_alarm) {
+ // Enable the comparator interrupt for the alarm
+ MXC_RTCTMR->inten |= MXC_F_RTC_INTEN_COMP0;
+ }
+}
+
+//******************************************************************************
+static void alarm_handler(void)
+{
+ MXC_RTCTMR->inten &= ~MXC_F_RTC_INTEN_COMP0;
+ MXC_RTCTMR->flags = MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS;
+}
+
+//******************************************************************************
+void rtc_init(void)
+{
+ if(rtc_inited) {
+ return;
+ }
+ rtc_inited = 1;
+
+ // Enable the clock to the synchronizer
+ MXC_CLKMAN->clk_ctrl_13_rtc_int_sync = MXC_E_CLKMAN_CLK_SCALE_ENABLED;
+
+ // Enable the clock to the RTC
+ MXC_PWRSEQ->reg0 |= MXC_F_PWRSEQ_REG0_PWR_RTCEN_RUN;
+
+ // Set the divider from the 4kHz clock
+ MXC_RTCTMR->prescale = MXC_E_RTC_PRESCALE_DIV_2_0;
+
+ // Enable the overflow interrupt
+ MXC_RTCTMR->inten |= MXC_F_RTC_FLAGS_OVERFLOW;
+
+ // Prepare interrupt handlers
+ NVIC_SetVector(RTC0_IRQn, (uint32_t)alarm_handler);
+ NVIC_EnableIRQ(RTC0_IRQn);
+ NVIC_SetVector(RTC3_IRQn, (uint32_t)overflow_handler);
+ NVIC_EnableIRQ(RTC3_IRQn);
+
+ // Enable the RTC
+ MXC_RTCTMR->ctrl |= MXC_F_RTC_CTRL_ENABLE;
+}
+
+//******************************************************************************
+void rtc_free(void)
+{
+ if (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_ENABLE) {
+ // Clear and disable RTC
+ MXC_RTCTMR->ctrl |= MXC_F_RTC_CTRL_CLEAR;
+ MXC_RTCTMR->ctrl &= ~MXC_F_RTC_CTRL_ENABLE;
+
+ // Wait for pending transactions
+ while(MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_PENDING);
+ }
+
+ // Disable the clock to the RTC
+ MXC_PWRSEQ->reg0 &= ~(MXC_F_PWRSEQ_REG0_PWR_RTCEN_RUN | MXC_F_PWRSEQ_REG0_PWR_RTCEN_SLP);
+
+ // Disable the clock to the synchronizer
+ MXC_CLKMAN->clk_ctrl_13_rtc_int_sync = MXC_E_CLKMAN_CLK_SCALE_DISABLED;
+}
+
+//******************************************************************************
+int rtc_isenabled(void)
+{
+ return (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_ENABLE);
+}
+
+//******************************************************************************
+time_t rtc_read(void)
+{
+ unsigned int shift_amt;
+ uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt;
+
+ // Account for a change in the default prescaler
+ shift_amt = MXC_E_RTC_PRESCALE_DIV_2_12 - MXC_RTCTMR->prescale;
+
+ // Ensure coherency between overflow_cnt and timer
+ do {
+ ovf_cnt_1 = overflow_cnt;
+ timer_cnt = MXC_RTCTMR->timer;
+ ovf_cnt_2 = overflow_cnt;
+ } while (ovf_cnt_1 != ovf_cnt_2);
+
+ return (timer_cnt >> shift_amt) + (ovf_cnt_1 << (32 - shift_amt));
+}
+
+//******************************************************************************
+uint64_t rtc_read_us(void)
+{
+ unsigned int shift_amt;
+ uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt;
+ uint64_t currentUs;
+
+ // Account for a change in the default prescaler
+ shift_amt = MXC_E_RTC_PRESCALE_DIV_2_12 - MXC_RTCTMR->prescale;
+
+ // Ensure coherency between overflow_cnt and timer
+ do {
+ ovf_cnt_1 = overflow_cnt;
+ timer_cnt = MXC_RTCTMR->timer;
+ ovf_cnt_2 = overflow_cnt;
+ } while (ovf_cnt_1 != ovf_cnt_2);
+
+ currentUs = (((uint64_t)timer_cnt * 1000000) >> shift_amt) + (((uint64_t)ovf_cnt_1 * 1000000) << (32 - shift_amt));
+
+ return currentUs;
+}
+
+//******************************************************************************
+void rtc_write(time_t t)
+{
+ // Account for a change in the default prescaler
+ unsigned int shift_amt = MXC_E_RTC_PRESCALE_DIV_2_12 - MXC_RTCTMR->prescale;
+
+ MXC_RTCTMR->ctrl &= ~MXC_F_RTC_CTRL_ENABLE; // disable the timer while updating
+ MXC_RTCTMR->timer = t << shift_amt;
+ overflow_cnt = t >> (32 - shift_amt);
+ MXC_RTCTMR->ctrl |= MXC_F_RTC_CTRL_ENABLE; // enable the timer while updating
+}
+
+//******************************************************************************
+void rtc_set_wakeup(uint64_t wakeupUs)
+{
+ // Account for a change in the default prescaler
+ unsigned int shift_amt = MXC_E_RTC_PRESCALE_DIV_2_12 - MXC_RTCTMR->prescale;
+
+ // Disable the alarm while it is prepared
+ MXC_RTCTMR->inten &= ~MXC_F_RTC_INTEN_COMP0;
+ MXC_RTCTMR->flags = MXC_F_RTC_FLAGS_COMP0; // clear interrupt
+
+ overflow_alarm = (wakeupUs >> (32 - shift_amt)) / 1000000;
+
+ if (overflow_alarm == overflow_cnt) {
+ MXC_RTCTMR->comp[0] = (wakeupUs << shift_amt) / 1000000;
+ MXC_RTCTMR->inten |= MXC_F_RTC_INTEN_COMP0;
+ }
+
+ // Enable wakeup from RTC
+ MXC_PWRSEQ->msk_flags &= ~(MXC_F_PWRSEQ_MSK_FLAGS_RTC_ROLLOVER | MXC_F_PWRSEQ_MSK_FLAGS_RTC_CMPR0);
+}
projects / qmk_firmware.git / blobdiff