308 lines
8.6 KiB
C
308 lines
8.6 KiB
C
/*
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* Copyright (c) 2019 Centaur Analytics, Inc
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT st_stm32_window_watchdog
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#include <drivers/watchdog.h>
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#include <soc.h>
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#include <stm32_ll_bus.h>
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#include <stm32_ll_wwdg.h>
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#include <stm32_ll_system.h>
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#include <errno.h>
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#include <sys/__assert.h>
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#include <drivers/clock_control/stm32_clock_control.h>
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#include <drivers/clock_control.h>
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#include "wdt_wwdg_stm32.h"
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#define LOG_LEVEL CONFIG_WDT_LOG_LEVEL
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#include <logging/log.h>
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LOG_MODULE_REGISTER(wdt_wwdg_stm32);
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#define WWDG_INTERNAL_DIVIDER 4096U
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#define WWDG_RESET_LIMIT WWDG_COUNTER_MIN
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#define WWDG_COUNTER_MIN 0x40
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#define WWDG_COUNTER_MAX 0x7f
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#if defined WWDG_CFR_WDGTB_Pos
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#define WWDG_PRESCALER_POS WWDG_CFR_WDGTB_Pos
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#define WWDG_PRESCALER_MASK WWDG_CFR_WDGTB_Msk
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#else
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#error "WWDG CFR WDGTB position not defined for soc"
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#endif
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/*
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* additinally to the internal divider, the clock is divided by a
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* programmable prescaler.
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*/
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#if defined(LL_WWDG_PRESCALER_128)
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#define WWDG_PRESCALER_EXPONENT_MAX 7 /* 2^7 = 128 */
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#elif defined(LL_WWDG_PRESCALER_8)
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#define WWDG_PRESCALER_EXPONENT_MAX 3 /* 2^3 = 8 */
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#endif
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/* The timeout of the WWDG in milliseconds is calculated by the below formula:
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*
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* t_WWDG = 1000 * ((counter & 0x3F) + 1) / f_WWDG (ms)
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*
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* where:
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* - t_WWDG: WWDG timeout
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* - counter: a value in [0x40, 0x7F] representing the cycles before timeout.
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* Giving the counter a value below 0x40, will result in an
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* immediate system reset. A reset is produced when the counter
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* rolls over from 0x40 to 0x3F.
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* - f_WWDG: the frequency of the WWDG clock. This can be calculated by the
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* below formula:
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* f_WWDG = f_PCLK / (4096 * prescaler) (Hz)
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* where:
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* - f_PCLK: the clock frequency of the system
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* - 4096: the constant internal divider
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* - prescaler: the programmable divider with valid values of 1, 2, 4 or 8,
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* and for some series additionally 16, 32, 64 and 128
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*
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* The minimum timeout is calculated with:
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* - counter = 0x40
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* - prescaler = 1
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* The maximim timeout is calculated with:
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* - counter = 0x7F
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* - prescaler = 8
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*
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* E.g. for f_PCLK = 2MHz
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* t_WWDG_min = 1000 * ((0x40 & 0x3F) + 1) / (2000000 / (4096 * 1))
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* = 2.048 ms
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* t_WWDG_max = 1000 * ((0x7F & 0x3F) + 1) / (2000000 / (4096 * 8))
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* = 1048.576 ms
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*/
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#define ABS_DIFF_UINT(a, b) ((a) > (b) ? (a) - (b) : (b) - (a))
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#define WWDG_TIMEOUT_ERROR_MARGIN(__TIMEOUT__) (__TIMEOUT__ / 10)
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#define IS_WWDG_TIMEOUT(__TIMEOUT_GOLDEN__, __TIMEOUT__) \
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(__TIMEOUT__ - __TIMEOUT_GOLDEN__) < \
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WWDG_TIMEOUT_ERROR_MARGIN(__TIMEOUT_GOLDEN__)
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static void wwdg_stm32_irq_config(const struct device *dev);
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static uint32_t wwdg_stm32_get_pclk(const struct device *dev)
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{
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const struct device *clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
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const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev);
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uint32_t pclk_rate;
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if (clock_control_get_rate(clk, (clock_control_subsys_t *) &cfg->pclken,
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&pclk_rate) < 0) {
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LOG_ERR("Failed call clock_control_get_rate");
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return -EIO;
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}
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return pclk_rate;
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}
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/**
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* @brief Calculates the timeout in microseconds.
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*
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* @param dev Pointer to device structure.
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* @param prescaler_exp The prescaler exponend value(Base 2).
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* @param counter The counter value.
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* @return The timeout calculated in microseconds.
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*/
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static uint32_t wwdg_stm32_get_timeout(const struct device *dev,
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uint32_t prescaler_exp,
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uint32_t counter)
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{
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uint32_t divider = WWDG_INTERNAL_DIVIDER * (1 << prescaler_exp);
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float f_wwdg = (float)wwdg_stm32_get_pclk(dev) / divider;
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return USEC_PER_SEC * (((counter & 0x3F) + 1) / f_wwdg);
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}
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/**
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* @brief Calculates prescaler & counter values.
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*
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* @param dev Pointer to device structure.
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* @param timeout Timeout value in microseconds.
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* @param prescaler_exp Pointer to prescaler exponent value(Base 2).
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* @param counter Pointer to counter value.
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*/
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static void wwdg_stm32_convert_timeout(const struct device *dev,
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uint32_t timeout,
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uint32_t *prescaler_exp,
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uint32_t *counter)
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{
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uint32_t clock_freq = wwdg_stm32_get_pclk(dev);
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/* Convert timeout to seconds. */
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float timeout_s = (float)timeout / USEC_PER_SEC;
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float wwdg_freq;
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*prescaler_exp = 0U;
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*counter = 0;
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for (*prescaler_exp = 0; *prescaler_exp <= WWDG_PRESCALER_EXPONENT_MAX;
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(*prescaler_exp)++) {
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wwdg_freq = ((float)clock_freq) / WWDG_INTERNAL_DIVIDER
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/ (1 << *prescaler_exp);
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/* +1 to ceil the result, which may lose from truncation */
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*counter = (uint32_t)(timeout_s * wwdg_freq + 1) - 1;
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*counter += WWDG_RESET_LIMIT;
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if (*counter <= WWDG_COUNTER_MAX) {
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return;
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}
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}
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/* timeout longer than wwdg can provide, set to max possible value */
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*counter = WWDG_COUNTER_MAX;
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*prescaler_exp = WWDG_PRESCALER_EXPONENT_MAX;
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}
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static int wwdg_stm32_setup(const struct device *dev, uint8_t options)
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{
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WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
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/* Deactivate running when debugger is attached. */
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if (options & WDT_OPT_PAUSE_HALTED_BY_DBG) {
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#if defined(CONFIG_SOC_SERIES_STM32F0X)
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LL_APB1_GRP2_EnableClock(LL_APB1_GRP2_PERIPH_DBGMCU);
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#elif defined(CONFIG_SOC_SERIES_STM32L0X)
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LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_DBGMCU);
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#endif
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LL_DBGMCU_APB1_GRP1_FreezePeriph(LL_DBGMCU_APB1_GRP1_WWDG_STOP);
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}
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if (options & WDT_OPT_PAUSE_IN_SLEEP) {
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return -ENOTSUP;
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}
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/* Ensure that Early Wakeup Interrupt Flag is cleared */
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LL_WWDG_ClearFlag_EWKUP(wwdg);
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/* Enable the WWDG */
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LL_WWDG_Enable(wwdg);
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return 0;
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}
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static int wwdg_stm32_disable(const struct device *dev)
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{
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/* watchdog cannot be stopped once started unless SOC gets a reset */
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ARG_UNUSED(dev);
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return -EPERM;
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}
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static int wwdg_stm32_install_timeout(const struct device *dev,
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const struct wdt_timeout_cfg *config)
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{
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struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
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WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
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uint32_t timeout = config->window.max * USEC_PER_MSEC;
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uint32_t calculated_timeout;
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uint32_t prescaler_exp = 0U;
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uint32_t counter = 0U;
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if (config->callback != NULL) {
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data->callback = config->callback;
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}
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wwdg_stm32_convert_timeout(dev, timeout, &prescaler_exp, &counter);
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calculated_timeout = wwdg_stm32_get_timeout(dev, prescaler_exp, counter);
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LOG_DBG("prescaler: %d", (1 << prescaler_exp));
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LOG_DBG("Desired WDT: %d us", timeout);
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LOG_DBG("Set WDT: %d us", calculated_timeout);
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if (!(IS_WWDG_COUNTER(counter) &&
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IS_WWDG_TIMEOUT(timeout, calculated_timeout))) {
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/* One of the parameters provided is invalid */
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return -EINVAL;
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}
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data->counter = counter;
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/* Configure WWDG */
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/* Set the programmable prescaler */
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LL_WWDG_SetPrescaler(wwdg,
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(prescaler_exp << WWDG_PRESCALER_POS) & WWDG_PRESCALER_MASK);
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/* Set window the same as the counter to be able to feed the WWDG almost
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* immediately
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*/
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LL_WWDG_SetWindow(wwdg, counter);
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LL_WWDG_SetCounter(wwdg, counter);
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return 0;
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}
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static int wwdg_stm32_feed(const struct device *dev, int channel_id)
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{
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WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
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struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
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ARG_UNUSED(channel_id);
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LL_WWDG_SetCounter(wwdg, data->counter);
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return 0;
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}
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void wwdg_stm32_isr(const struct device *dev)
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{
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struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
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WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
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if (LL_WWDG_IsEnabledIT_EWKUP(wwdg)) {
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if (LL_WWDG_IsActiveFlag_EWKUP(wwdg)) {
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LL_WWDG_ClearFlag_EWKUP(wwdg);
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data->callback(dev, 0);
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}
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}
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}
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static const struct wdt_driver_api wwdg_stm32_api = {
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.setup = wwdg_stm32_setup,
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.disable = wwdg_stm32_disable,
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.install_timeout = wwdg_stm32_install_timeout,
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.feed = wwdg_stm32_feed,
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};
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static int wwdg_stm32_init(const struct device *dev)
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{
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const struct device *clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
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const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev);
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wwdg_stm32_irq_config(dev);
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return clock_control_on(clk, (clock_control_subsys_t *) &cfg->pclken);
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}
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static struct wwdg_stm32_data wwdg_stm32_dev_data = {
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.counter = WWDG_RESET_LIMIT,
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.callback = NULL
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};
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static struct wwdg_stm32_config wwdg_stm32_dev_config = {
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.pclken = {
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.enr = DT_INST_CLOCKS_CELL(0, bits),
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.bus = DT_INST_CLOCKS_CELL(0, bus)
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},
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.Instance = (WWDG_TypeDef *)DT_INST_REG_ADDR(0),
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};
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DEVICE_DT_INST_DEFINE(0, wwdg_stm32_init, NULL,
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&wwdg_stm32_dev_data, &wwdg_stm32_dev_config,
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POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
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&wwdg_stm32_api);
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static void wwdg_stm32_irq_config(const struct device *dev)
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{
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WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
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IRQ_CONNECT(DT_INST_IRQN(0),
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DT_INST_IRQ(0, priority),
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wwdg_stm32_isr, DEVICE_DT_INST_GET(0), 0);
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irq_enable(DT_INST_IRQN(0));
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LL_WWDG_EnableIT_EWKUP(wwdg);
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}
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