title: Linux kernel Kconfig: How do I de-select an option?
body: <p>How do I de-select an option?
  For example, the following script is what I want to achieve:</p>
  
  <pre><code>choice                                                                                         
      prompt "Camera type"                                                                       
      default CAMERA1                                                                            
  
  config CAMERA1                                                                                 
      select POWER_PIN_ACTIVE_HIGH                                                               
  
  config CAMERA2                                                                                 
      deselect POWER_PIN_ACTIVE_HIGH
  
  config CAMERA3                                                                                 
      select POWER_PIN_ACTIVE_HIGH                                                         
  
  endchoice                                                                                      
  
  config POWER_PIN_ACTIVE_HIGH                                                                   
      bool "Power pin is high active?"                                                           
      help  Say 'y' if the power pin is high active, 'n' if low active.                          
  </code></pre>
  
  <p>Apparently, there is no <code>de-select</code> command, or even <code>select XXXX = n</code> command.</p>
  
  <p>How do I achieve the effect, or other ways to achieve the script's goal?
  In addition, I want to hide the <code>POWER_PIN_ACTIVE_HIGH</code> option.  It should be automatically selected/deselected when a type of camera is selected.</p>
  
  <p><strong>--Update--</strong></p>
  
  <p>I tried it in a different way.  It's working but <code>Makefile</code> gives me a force select of <code>POWER_PIN_ACTIVE_HIGH</code> warning:</p>
  
  <pre><code>choice                                                                                         
      prompt "Camera type"                                                                       
      default CAMERA1                                                                            
  
  config CAMERA1                                                                                 
      select POWER_PIN_ACTIVE_HIGH                                                               
  
  config CAMERA2                                                                                 
      deselect POWER_PIN_ACTIVE_HIGH
  
  config CAMERA3                                                                                 
      select POWER_PIN_ACTIVE_HIGH                                                         
  
  endchoice                                                                                      
  
  config POWER_PIN_ACTIVE_HIGH
      depends on __HIDDEN_OPTION__                                                                   
      bool "Power pin is high active?"                                                           
      help  Say 'y' if the power pin is high active, 'n' if low active. 
  </code></pre>
  
  <p>The script works since <code>__HIDDEN_OPTION__</code> is never a configuration option, and thus it cause the dependency failed for all cases.  Only those forceful <code>select</code> command can override it and select the configuration.  Though <code>Makefile</code> gives an warning, due to the not-matched (never-matched) <code>__HIDDEN_OPTION__</code> condition.</p>
  
  <p>Any better idea?</p>