keychron_qmk_firmware/keyboards/keychron/bluetooth/lpm_stm32l432.c

/* Copyright 2022 @ lokher (https://www.keychron.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/******************************************************************************
 *
 *  Filename:      lpm_stm32l432.c
 *
 *  Description:   Contains low power mode implementation
 *
 ******************************************************************************/

#include "quantum.h"
#include <usb_main.h>
#include "bluetooth.h"
#include "indicator.h"
#include "lpm.h"
#include "transport.h"
#include "battery.h"
#include "report_buffer.h"

extern pin_t                 row_pins[MATRIX_ROWS];
extern void                  select_all_cols(void);
extern bluetooth_transport_t bluetooth_transport;

static pm_t power_mode = PM_RUN;

static inline void stm32_clock_fast_init(void);

bool lpm_set(pm_t mode) {
    switch (mode) {
#ifdef LOW_POWER_RUN_MODE_ENABLE
        case PM_RUN:
            if (power_mode != PM_LOW_POWER_RUN)) return;
            /* Set main regulator */
            PWR->CR1 &= ~PWR_CR1_LPR;
            while (PWR->SR2 & PWR_SR2_REGLPF)
                ;
            // TODO: restore sysclk
            return true;
            // break;

        case PM_LOW_POWER_RUN:
            if (power_mode != PM_RUN) return;

            // FLASH->ACR |= FLASH_ACR_RUN_PD;   // Optional
            // TODO: Decrease sysclk below 2 MHz
            PWR->CR1 |= PWR_CR1_LPR;
            return true;
            // break;
#endif
        case PM_SLEEP:
            /* Wake source: Any interrupt or event */
            if (power_mode != PM_RUN) return false;

            SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;
            break;

#ifdef LOW_POWER_RUN_MODE_ENABLE
        case PM_LOW_POWER_SLEEP:
            /* Wake source: Any interrupt or event */
            if (power_mode != PM_LOW_POWER_RUN) return; /* Can only transit from PM_LOW_POWER_RUN */

            SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;
            __WFI();
            exit_low_power_mode();
            break;
#endif
        case PM_STOP0:
            /* Wake source: Reset pin, all I/Os, BOR, PVD, PVM, RTC, LCD, IWDG,
               COMPx, USARTx, LPUART1, I2Cx, LPTIMx, USB, SWPMI */
            if (power_mode != PM_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_STOP0;
            break;

        case PM_STOP1:
            /* Wake source: Reset pin, all I/Os, BOR, PVD, PVM, RTC, LCD, IWDG,
               COMPx, USARTx, LPUART1, I2Cx, LPTIMx, USB, SWPMI */
            if (power_mode != PM_RUN && power_mode != PM_LOW_POWER_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_STOP1;
            break;

        case PM_STOP2:
            /* Wake source: Reset pin, all I/Os, BOR, PVD, PVM, RTC, LCD, IWDG,
               COMPx (x=1, 2), I2C3, LPUART1, LPTIM1, LPTIM2 */
            if (power_mode != PM_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_STOP2;
            break;

        case PM_STANDBY_WITH_RAM:
            /* Wake source: Reset, 5 I/O(PA0, PC13, PE6, PA2, PC5), BOR, RTC, IWDG */
            if (power_mode != PM_RUN && power_mode != PM_LOW_POWER_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_STANDBY;
            PWR->CR3 |= PWR_CR3_RRS;
            break;

        case PM_STANDBY:
            /* Wake source: Reset, 2 I/O(PA0, PA2) in STM32L432Kx,, BOR, RTC, IWDG */
            if (power_mode != PM_RUN && power_mode != PM_LOW_POWER_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_STANDBY;
            PWR->CR3 &= ~PWR_CR3_RRS;
            break;

        case PM_SHUTDOWN:
            /* Wake source: Reset, 2 I/O(PA0, PA2) in STM32L432Kx, RTC */
            if (power_mode != PM_RUN && power_mode != PM_LOW_POWER_RUN) return false;

            SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
            PWR->CR1 |= PWR_CR1_LPMS_SHUTDOWN;
            break;

        default:
            return false;
    }

    return true;
}

static inline void enter_low_power_mode_prepare(void) {
#if HAL_USE_RTC
    nvicEnableVector(STM32_EXTI20_NUMBER, 13);

    PWR->CR3 |= PWR_CR3_EIWF;

    RTCWakeup wakeupspec;
    wakeupspec.wutr = 0x040014;
    rtcSTM32SetPeriodicWakeup(&RTCD1, &wakeupspec);
#endif

#if defined(KEEP_USB_CONNECTION_IN_BLUETOOTH_MODE)
    /* Usb unit is actived and running, stop and disconnect first */
    usbStop(&USBD1);
    usbDisconnectBus(&USBD1);

    /* Isolate USB to save power.*/
    PWR->CR2 &= ~PWR_CR2_USV; /*PWR_CR2_USV is available on STM32L4x2xx and STM32L4x3xx devices only. */
#endif

    palEnableLineEvent(BLUETOOTH_INT_INPUT_PIN, PAL_EVENT_MODE_FALLING_EDGE);
    palEnableLineEvent(USB_POWER_SENSE_PIN, PAL_EVENT_MODE_BOTH_EDGES);

    /* Enable key matrix wake up */
    pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;

    for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
        if (row_pins[x] != NO_PIN) {
            palEnableLineEvent(row_pins[x], PAL_EVENT_MODE_BOTH_EDGES);
        }
    }

    select_all_cols();

#if defined(DIP_SWITCH_PINS)
#    define NUMBER_OF_DIP_SWITCHES (sizeof(dip_switch_pad) / sizeof(pin_t))
    static pin_t dip_switch_pad[] = DIP_SWITCH_PINS;

    for (uint8_t i = 0; i < NUMBER_OF_DIP_SWITCHES; i++) {
        setPinInputLow(dip_switch_pad[i]);
    }
#endif
}

static inline void lpm_wakeup(void) {
    stm32_clock_fast_init();
    if (bluetooth_transport.init) bluetooth_transport.init(true);

    chSysLock();
    SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;

    PWR->SCR |= PWR_SCR_CWUF;
    PWR->SCR |= PWR_SCR_CSBF;

    /* TIMx is disable during stop/standby/sleep mode, init after wakeup */
    stInit();
    timer_init();
    chSysUnlock();
    battery_init();

    /* Disable all wake up pins */
    for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
        if (row_pins[x] != NO_PIN) {
            palDisableLineEvent(row_pins[x]);
        }
    }
    palDisableLineEvent(BLUETOOTH_INT_INPUT_PIN);

#ifdef USB_POWER_SENSE_PIN
    palDisableLineEvent(USB_POWER_SENSE_PIN);

#if defined(KEEP_USB_CONNECTION_IN_BLUETOOTH_MODE)
    if (usb_power_connected()) {
        /* Remove USB isolation.*/
        //PWR->CR2 |= PWR_CR2_USV; /* PWR_CR2_USV is available on STM32L4x2xx and STM32L4x3xx devices only. */
        usb_power_connect();
        usb_start(&USBD1);
    }
#endif

#endif

#if defined(DIP_SWITCH_PINS)
    dip_switch_init();
    dip_switch_read(true);
#endif

#if HAL_USE_RTC
    rtcSTM32SetPeriodicWakeup(&RTCD1, NULL);
    nvicDisableVector(STM32_EXTI20_NUMBER);
#endif

}

/*
 * NOTE:
 * 1. Shall not use PM_LOW_POWER_RUN, PM_LOW_POWER_SLEEP, due to PM_LOW_POWER_RUN
 *    need to decrease system clock below 2 MHz. Dynamic clock is not yet supported
 *    for STM32L432xx in latest ChibiOS 21.6.0 so far.
 * 2. Care must be taken to use PM_STANDBY_WITH_RAM, PM_STANDBY, PM_SHUTDOWN due to
 *    limited wake source, thus can't be waken via keyscan. PM_SHUTDOWN need LSE.
 * 3. Reference from AN4621: STM32L4 and STM32L4+ ultra-low-power features overview
 *    for detail wake source
 */

void enter_power_mode(pm_t mode) {
#if defined(KEEP_USB_CONNECTION_IN_BLUETOOTH_MODE)
    /* Don't enter low power mode if attached to the host */
    if (mode > PM_SLEEP && usb_power_connected()) return;
#endif

    if (!lpm_set(mode)) return;
    enter_low_power_mode_prepare();

    //    __DSB();
    __WFI();
    //    __ISB();

    lpm_wakeup();
    lpm_timer_reset();
    report_buffer_init();
    power_mode = PM_RUN;
}

void usb_power_connect(void) {
    PWR->CR2 |= PWR_CR2_USV;
}

void usb_power_disconnect(void) {
    PWR->CR2 &= ~PWR_CR2_USV;
}

/*
 * This is a simplified version of stm32_clock_init() by removing unnecessary clock initlization
 * code snippet. The original stm32_clock_init() take about 2ms, but ckbt51 sends data via uart
 * about 200us after wakeup pin is assert, it means that we must get everything ready before
 * uart data coming when wakeup pin interrupt of MCU  is triggerred.
 * Here we reduce clock init time to 100us.
 */
inline void stm32_clock_fast_init(void) {
#if !STM32_NO_INIT
    /* Core voltage setup.*/
    PWR->CR1 = STM32_VOS;
    while ((PWR->SR2 & PWR_SR2_VOSF) != 0) /* Wait until regulator is      */
        ;                                  /* stable.                      */

#    if STM32_HSI16_ENABLED  // 10.7us
    /* HSI activation.*/
    RCC->CR |= RCC_CR_HSION;
    while ((RCC->CR & RCC_CR_HSIRDY) == 0)
        ; /* Wait until HSI16 is stable.  */
#    endif

#    if STM32_CLOCK_HAS_HSI48  // 13us
#        if STM32_HSI48_ENABLED
    /* HSI activation.*/
    RCC->CRRCR |= RCC_CRRCR_HSI48ON;
    while ((RCC->CRRCR & RCC_CRRCR_HSI48RDY) == 0)
        ; /* Wait until HSI48 is stable.  */
#        endif
#    endif

#    if STM32_ACTIVATE_PLL || STM32_ACTIVATE_PLLSAI1 || STM32_ACTIVATE_PLLSAI2
        /* PLLM and PLLSRC are common to all PLLs.*/
#        if defined(STM32L496xx) || defined(STM32L4A6xx)
    RCC->PLLCFGR = STM32_PLLPDIV | STM32_PLLR | STM32_PLLREN | STM32_PLLQ | STM32_PLLQEN | STM32_PLLP | STM32_PLLPEN | STM32_PLLN | STM32_PLLM | STM32_PLLSRC;
#        else
    RCC->PLLCFGR = STM32_PLLR | STM32_PLLREN | STM32_PLLQ | STM32_PLLQEN | STM32_PLLP | STM32_PLLPEN | STM32_PLLN | STM32_PLLM | STM32_PLLSRC;
#        endif
#    endif

#    if STM32_ACTIVATE_PLL
    /* PLL activation.*/
    RCC->CR |= RCC_CR_PLLON;

    /* Waiting for PLL lock.*/
    while ((RCC->CR & RCC_CR_PLLRDY) == 0)
        ;
#    endif

    /* Set flash WS's for SYSCLK source */
    if (STM32_FLASHBITS > STM32_MSI_FLASHBITS) {
        FLASH->ACR = (FLASH->ACR & ~FLASH_ACR_LATENCY_Msk) | STM32_FLASHBITS;
        while ((FLASH->ACR & FLASH_ACR_LATENCY_Msk) != (STM32_FLASHBITS & FLASH_ACR_LATENCY_Msk)) {
        }
    }

    /* Switching to the configured SYSCLK source if it is different from MSI.*/
#        if (STM32_SW != STM32_SW_MSI)
    RCC->CFGR |= STM32_SW; /* Switches on the selected clock source.   */
    /* Wait until SYSCLK is stable.*/
    while ((RCC->CFGR & RCC_CFGR_SWS) != (STM32_SW << 2))
        ;
#        endif

    /* Reduce the flash WS's for SYSCLK source if they are less than MSI WSs */
    if (STM32_FLASHBITS < STM32_MSI_FLASHBITS) {
        FLASH->ACR = (FLASH->ACR & ~FLASH_ACR_LATENCY_Msk) | STM32_FLASHBITS;
        while ((FLASH->ACR & FLASH_ACR_LATENCY_Msk) != (STM32_FLASHBITS & FLASH_ACR_LATENCY_Msk)) {
        }
    }
#endif /* STM32_NO_INIT */

    /* SYSCFG clock enabled here because it is a multi-functional unit shared
       among multiple drivers.*/
    rccEnableAPB2(RCC_APB2ENR_SYSCFGEN, true);
}