127 lines
2.9 KiB
C
127 lines
2.9 KiB
C
/*
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* Copyright (c) 2016 Open-RnD Sp. z o.o.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @brief Driver for Independent Watchdog (IWDG) for STM32 MCUs
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*
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* Based on reference manual:
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* STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and STM32F107xx
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* advanced ARM ® -based 32-bit MCUs
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*
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* Chapter 19: Independent watchdog (IWDG)
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*
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*/
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#include <watchdog.h>
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#include <soc.h>
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#include <errno.h>
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#include "iwdg_stm32.h"
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#define AS_IWDG(__base_addr) \
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(struct iwdg_stm32 *)(__base_addr)
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static void iwdg_stm32_enable(struct device *dev)
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{
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volatile struct iwdg_stm32 *iwdg = AS_IWDG(IWDG_BASE);
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ARG_UNUSED(dev);
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iwdg->kr.bit.key = STM32_IWDG_KR_START;
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}
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static void iwdg_stm32_disable(struct device *dev)
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{
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/* watchdog cannot be stopped once started */
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ARG_UNUSED(dev);
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}
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static int iwdg_stm32_set_config(struct device *dev,
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struct wdt_config *config)
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{
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ARG_UNUSED(dev);
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ARG_UNUSED(config);
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/* no configuration */
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return -ENOTSUP;
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}
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static void iwdg_stm32_get_config(struct device *dev,
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struct wdt_config *config)
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{
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ARG_UNUSED(dev);
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ARG_UNUSED(config);
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}
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static void iwdg_stm32_reload(struct device *dev)
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{
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volatile struct iwdg_stm32 *iwdg = AS_IWDG(IWDG_BASE);
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ARG_UNUSED(dev);
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iwdg->kr.bit.key = STM32_IWDG_KR_RELOAD;
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}
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static const struct wdt_driver_api iwdg_stm32_api = {
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.enable = iwdg_stm32_enable,
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.disable = iwdg_stm32_disable,
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.get_config = iwdg_stm32_get_config,
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.set_config = iwdg_stm32_set_config,
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.reload = iwdg_stm32_reload,
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};
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static inline int __iwdg_stm32_prescaler(int setting)
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{
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int v;
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int i = 0;
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/* prescaler range 4 - 256 */
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for (v = 4; v < 256; v *= 2, i++) {
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if (v == setting)
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return i;
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}
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return i;
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}
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static int iwdg_stm32_init(struct device *dev)
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{
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volatile struct iwdg_stm32 *iwdg = AS_IWDG(IWDG_BASE);
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/* clock setup is not required, once the watchdog is enabled
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* LSI oscillator will be forced on and fed to IWD after
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* stabilization period
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*/
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/* unlock access to configuration registers */
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iwdg->kr.bit.key = STM32_IWDG_KR_UNLOCK;
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iwdg->pr.bit.pr =
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__iwdg_stm32_prescaler(CONFIG_IWDG_STM32_PRESCALER);
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iwdg->rlr.bit.rl = CONFIG_IWDG_STM32_RELOAD_COUNTER;
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#ifdef CONFIG_IWDG_STM32_START_AT_BOOT
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iwdg_stm32_enable(dev);
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#endif
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return 0;
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}
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DEVICE_AND_API_INIT(iwdg_stm32, CONFIG_IWDG_STM32_DEVICE_NAME, iwdg_stm32_init,
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NULL, NULL,
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PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
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&iwdg_stm32_api);
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