title: Get a wrong cpu_frequence from raspberry pi in python
body: <p>i want use python to get the cpu_freq value from raspberry pi 4B</p>
  <pre class="lang-py prettyprint-override"><code>def GetCpuInfo():
      # Get CPU frequence
      cpu_freq =open(&quot;/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq&quot;).read()
      return cpu_freq
  </code></pre>
  <p>when i print the cpu_freq data, the output always fixed in 1800000(it's the max cpu frequence 1.8Ghz of raspberry pi),but when each time i use the</p>
  <pre><code>cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
  </code></pre>
  <p>this command in terminal,it give me the dynamic valve(600000-1800000)
  So why do i get wrong value when using the python? is it a wrong way to read this file?</p>