title: How to "make" existing Linux kernel module driver after modifying the driver source code
body: <p>I have made some trivial modifications to a Linux USB Wi-Fi card driver to insert some logging (<code>printk</code> statements).  I am loosely following <a href="http://www.cyberciti.biz/tips/build-linux-kernel-module-against-installed-kernel-source-tree.html" rel="nofollow">a guide on how to recompile/load the module</a>, which states that I need to execute <code>make</code> in order to build the <code>.ko</code> file.  There is an existing <code>Makefile</code> in the working directory (<code>/usr/src/linux/drivers/net/wireless/rtl818x/rtl8187/</code>), which reads:</p>
  
  <pre><code>rtl8187-objs        := dev.o rtl8225.o leds.o rfkill.o
  
  obj-$(CONFIG_RTL8187)   += rtl8187.o
  
  ccflags-y += -Idrivers/net/wireless/rtl818x
  </code></pre>
  
  <p>When I execute <code>make</code> inside this directory, I get:</p>
  
  <pre><code>make: *** No targets.  Stop.
  </code></pre>
  
  <p>According to <a href="http://www.gnu.org/software/make/manual/html_node/Error-Messages.html" rel="nofollow">this</a>, this means <em>"that some makefile was found, but it didn't contain any default goal and none was given on the command line. GNU make has nothing to do in these situations."</em>  </p>
  
  <p>So my question is, what does this mean in the context of what I am trying to do, and how do I go about generating the <code>.ko</code> file which I am purported to need for the next step?</p>