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Self-assignment warning bug

Jiajin
Associate II

‎2025-08-13 9:00 AM

This warning is occurring in the STM32U5xx HAL driver's low-level ADC header file (stm32u5xx_ll_adc.h). The warning indicates there's a self-assignment of a variable analog_wd_monit_channels where a variable is being assigned to itself.

 

STM32CubeMX/Target_1/STM32CubeMX/Drivers/STM32U5xx_HAL_Driver/Inc/stm32u5xx_ll_adc.h:6920:34: warning: explicitly assigning value of variable of type 'uint32_t' (aka 'unsigned int') to itself [-Wself-assign]
6920 | analog_wd_monit_channels = analog_wd_monit_channels;
| ~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

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3 REPLIES 3
Pavel A.
Super User

‎2025-08-13 12:45 PM

This usually occurs because of some kind of "unused parameter" macro, which in its turn exists to silence another warning. For example

#define UNUSED_PARAMETER(x) x = x

int junk(int p1, char p2)
{
  UNUSED_PARAMETER(p2);
  return p1;
}

So... decide which of the warnings you hate more, and disable the other.

 

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Jiajin
Associate II
In response to Pavel A.

‎2025-08-14 2:28 AM

I don't seem to have found any unused macro definitions. Here is the code for the warning section.

/**
  * @brief  Get ADC analog watchdog monitored channel.
  * @note   Usage of the returned channel number:
  *         - To reinject this channel into another function LL_ADC_xxx:
  *           the returned channel number is only partly formatted on definition
  *           of literals LL_ADC_CHANNEL_x. Therefore, it has to be compared
  *           with parts of literals LL_ADC_CHANNEL_x or using
  *           helper macro @ref __LL_ADC_CHANNEL_TO_DECIMAL_NB().
  *           Then the selected literal LL_ADC_CHANNEL_x can be used
  *           as parameter for another function.
  *         - To get the channel number in decimal format:
  *           process the returned value with the helper macro
  *           @ref __LL_ADC_CHANNEL_TO_DECIMAL_NB().
  *           Applicable only when the analog watchdog is set to monitor
  *           one channel.
  * @note   On this STM32 series, there are 2 kinds of analog watchdog
  *         instance:
  *         - AWD standard (instance AWD1):
  *           - channels monitored: can monitor 1 channel or all channels.
  *           - groups monitored: ADC groups regular and-or injected.
  *           - resolution: resolution is not limited (corresponds to
  *             ADC resolution configured).
  *         - AWD flexible (instances AWD2, AWD3):
  *           - channels monitored: flexible on channels monitored, selection is
  *             channel wise, from from 1 to all channels.
  *             Specificity of this analog watchdog: Multiple channels can
  *             be selected. For example:
  *             (LL_ADC_AWD_CHANNEL4_REG_INJ | LL_ADC_AWD_CHANNEL5_REG_INJ | ...)
  *           - groups monitored: not selection possible (monitoring on both
  *             groups regular and injected).
  *             Channels selected are monitored on groups regular and injected:
  *             LL_ADC_AWD_CHANNELxx_REG_INJ (do not use parameters
  *             LL_ADC_AWD_CHANNELxx_REG and LL_ADC_AWD_CHANNELxx_INJ)
  *           - resolution: resolution is limited to 8 bits: if ADC resolution is
  *             12 bits the 4 LSB are ignored, if ADC resolution is 10 bits
  *             the 2 LSB are ignored.
  * @note   On this STM32 series, setting of this feature is conditioned to
  *         ADC state:
  *         ADC must be disabled or enabled without conversion on going
  *         on either groups regular or injected.
  * @rmtoll CFGR     AWD1CH         LL_ADC_GetAnalogWDMonitChannels\n
  *         CFGR     AWD1SGL        LL_ADC_GetAnalogWDMonitChannels\n
  *         CFGR     AWD1EN         LL_ADC_GetAnalogWDMonitChannels\n
  *         CFGR     JAWD1EN        LL_ADC_GetAnalogWDMonitChannels\n
  *         AWD2CR   AWD2CH         LL_ADC_GetAnalogWDMonitChannels\n
  *         AWD3CR   AWD3CH         LL_ADC_GetAnalogWDMonitChannels
  * @PAram  ADCx ADC instance
  * @PAram  AWDy This parameter can be one of the following values:
  *         @arg @ref LL_ADC_AWD1
  *         @arg @ref LL_ADC_AWD2 (1)
  *         @arg @ref LL_ADC_AWD3 (1)
  *
  *         (1) On this AWD number, monitored channel can be retrieved
  *             if only 1 channel is programmed (or none or all channels).
  *             This function cannot retrieve monitored channel if
  *             multiple channels are programmed simultaneously
  *             by bitfield.
  * @retval Returned value can be one of the following values:
  *         @arg @ref LL_ADC_AWD_DISABLE
  *         @arg @ref LL_ADC_AWD_ALL_CHANNELS_REG        (0)
  *         @arg @ref LL_ADC_AWD_ALL_CHANNELS_INJ        (0)
  *         @arg @ref LL_ADC_AWD_ALL_CHANNELS_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_0_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_0_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_0_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_1_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_1_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_1_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_2_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_2_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_2_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_3_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_3_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_3_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_4_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_4_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_4_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_5_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_5_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_5_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_6_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_6_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_6_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_7_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_7_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_7_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_8_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_8_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_8_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_9_REG           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_9_INJ           (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_9_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_10_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_10_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_10_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_11_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_11_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_11_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_12_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_12_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_12_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_13_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_13_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_13_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_14_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_14_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_14_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_15_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_15_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_15_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_16_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_16_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_16_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_17_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_17_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_17_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_18_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_18_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_18_REG_INJ
  *         @arg @ref LL_ADC_AWD_CHANNEL_19_REG          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_19_INJ          (0)
  *         @arg @ref LL_ADC_AWD_CHANNEL_19_REG_INJ
  *
  *         (0) On STM32U5, parameter available only on analog watchdog number: AWD1.
  */
__STATIC_INLINE uint32_t LL_ADC_GetAnalogWDMonitChannels(const ADC_TypeDef *ADCx, uint32_t AWDy)
{
  const __IO uint32_t *preg;

  if (AWDy == LL_ADC_AWD1)
  {
    /* Set pointer to register of selected analog watchdog */
    preg = __ADC_PTR_REG_OFFSET(ADCx->CFGR1, 0UL);
  }
  else
  {
    /* Set pointer to register of selected analog watchdog */
    preg = __ADC_PTR_REG_OFFSET(ADCx->AWD2CR, ((AWDy & ADC_AWD_CRX_REGOFFSET_MASK))                                   \
                                >> (ADC_AWD_CRX_REGOFFSET_POS + 1UL));
  }

  uint32_t analog_wd_monit_channels = (READ_BIT(*preg, AWDy) & AWDy & ADC_AWD_CR_ALL_CHANNEL_MASK);

  /* If "analog_wd_monit_channels" == 0, then the selected AWD is disabled       */
  /* (parameter value LL_ADC_AWD_DISABLE).                                    */
  /* Else, the selected AWD is enabled and is monitoring a group of channels  */
  /* or a single channel.                                                     */
  if (analog_wd_monit_channels != 0UL)
  {
    if (AWDy == LL_ADC_AWD1)
    {
      if ((analog_wd_monit_channels & ADC_CFGR1_AWD1SGL) == 0UL)
      {
        /* AWD monitoring a group of channels */
        analog_wd_monit_channels = ((analog_wd_monit_channels | (0x000FFFFFUL)) & (~(ADC_CFGR1_AWD1CH)));
      }
      else
      {
        /* AWD monitoring a single channel */
        analog_wd_monit_channels = analog_wd_monit_channels;
      }
    }
    else
    {
      if (ADCx != ADC4)
      {
        if ((analog_wd_monit_channels & 0x000FFFFFUL) == 0x000FFFFFUL)
        {
          /* AWD monitoring a group of channels */
          analog_wd_monit_channels = (0x000FFFFFUL | ((ADC_CFGR1_JAWD1EN | ADC_CFGR1_AWD1EN)));
        }
        else
        {
          /* AWD monitoring a single channel */
          /* AWD monitoring a group of channels */
          analog_wd_monit_channels = ((ADC_CFGR1_JAWD1EN | ADC_CFGR1_AWD1EN | ADC_CFGR1_AWD1SGL)
                                      | (__LL_ADC_CHANNEL_TO_DECIMAL_NB(analog_wd_monit_channels) \
                                         << ADC_CFGR1_AWD1CH_Pos));
        }
      }
      else
      {
        if ((analog_wd_monit_channels & ADC_AWD_CR23_CHANNEL_MASK) == ADC_AWD_CR23_CHANNEL_MASK)
        {
          /* AWD monitoring a group of channels */
          analog_wd_monit_channels = (0x000FFFFFUL | (ADC_CFGR1_AWD1EN));
        }
        else
        {
          /* AWD monitoring a single channel */
          /* AWD monitoring a group of channels */
          analog_wd_monit_channels = ((ADC_CFGR1_AWD1EN | ADC_CFGR1_AWD1SGL)
                                      | (__LL_ADC_CHANNEL_TO_DECIMAL_NB(analog_wd_monit_channels) \
                                         << ADC_CFGR1_AWD1CH_Pos));
        }
      }
    }
  }

  return analog_wd_monit_channels;
}
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Pavel A.
Super User

‎2025-08-14 4:00 PM

Hmm indeed in line 160: analog_wd_monit_channels = analog_wd_monit_channels;

This looks awkward but is legal. Specific warnings can be disabled in the compiler settings.

 

 

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