LCDproc is meant to be modular, it is relatively easy to add new input and output drivers to LCDproc. This chapter will explain you the major steps and few gotchas of adding your own driver to LCDproc. Enjoy! How I Learned to Stop Worrying and Love the Configure Script It was decided pretty early in LCDproc's life to use GNU autoconf and GNU automake. This allows LCDproc to be ported to several platforms with much less effort. It can be quite daunting to understand how autoconf & automake interact with each others and with your code, but don't be discouraged. We have taken great care in making this as simple as possible for programers to add their own driver to LCDproc. Hopefully, you'll only have to modify two files, one for autoconf and one for automake. The first thing you need to do is to find a name for your driver, it should be as descriptive as possible; most drivers are named after their respective chipset, for example hd44780, mtc_s16209x, sed1330 and stv5730, others are named after the company that makes that particular LCD display, for example CFontz and MtxOrb. Remember that these names are case sensitive. In this chapter, we'll use myDriver (which is an absolute non-descriptive name). You need to add your driver to function LCD_DRIVERS_SELECT of file acinclude.m4. This can be done in three steps. First you need to add your driver name to the list of possible choices in the help screen. This: AC_ARG_ENABLE(drivers, [ --enable-drivers=<list> compile driver for LCDs in <list>.] [ drivers may be separated with commas.] [ Possible choices are:] [ bayrad,CFontz,CFontz633,CFontzPacket,curses,CwLnx,] [ glcdlib,glk,hd44780,icp_a106,imon,IOWarrior,irman,] [ joy,lb216,lcdm001,lcterm,lirc,ms6931,mtc_s16209x,] [ MtxOrb,NoritakeVFD,pyramid,sed1330,sed1520,serialVFD,] [ sli,stv5730,svga,t6963,text,tyan,ula200,xosd] [ 'all' compiles all drivers;] [ 'all,!xxx,!yyy' de-selects previously selected drivers], drivers="$enableval", becomes: AC_ARG_ENABLE(drivers, [ --enable-drivers=<list> compile driver for LCDs in <list>.] [ drivers may be separated with commas.] [ Possible choices are:] [ bayrad,CFontz,CFontz633,CFontzPacket,curses,CwLnx,] [ glcdlib,glk,hd44780,icp_a106,imon,IOWarrior,irman,] [ joy,lb216,lcdm001,lcterm,lirc,ms6931,mtc_s16209x,] [ MtxOrb,NoritakeVFD,pyramid,sed1330,sed1520,serialVFD,] [ sli,stv5730,svga,t6963,text,tyan,ula200,xosd,myDriver] [ 'all' compiles all drivers;] [ 'all,!xxx,!yyy' de-selects previously selected drivers], drivers="$enableval", Second, you need to add your driver to the list of all drivers. This: allDrivers=[bayrad,CFontz,CFontz633,...(big list)...,tyan,ula200,xosd] becomes: allDrivers=[bayrad,CFontz,CFontz633,...(big list)...,tyan,ula200,xosd,myDriver] Then last, you need to add your driver to be big switch-case in this function, see below. myDriver) DRIVERS="$DRIVERS myDriver${SO}" actdrivers=["$actdrivers myDriver"] ;; If your driver only works in some platform or requires a particular library or header, you can add your autoconf test here. You can see how other drivers do it, but if you're not sure on how to do this, just send an email to the mailing list and we'll make it for you. Allready half of the job is done! Not to bad, wasn't it? The rest should be just as easy. In this section, you'll be adding your driver to the file server/drivers/Makefile.am. As you can guess, it's the Makefile for the drivers. This can be done in three (or two) simple steps. First, you need to add your driver to the list of drivers in this file, this list is called EXTRA_PROGRAMS. This EXTRA_PROGRAMS = bayrad CFontz ...(big list)... ula200 xosd becomes EXTRA_PROGRAMS = bayrad CFontz ...(big list)... ula200 xosd myDriver This second step is only needed if your driver needs a particular library. If it doesn't, you can skip to step 3. You basically need to put you driver name followed by _LDADD and egal this to the name of the library that you need. Usually, these library are substituted by a autoconf variable, if you're not comfortable with this, you send an email to the mailing list and we'll set this up for you. For example, we would put this for our fictional driver myDriver_LDADD = @SOMESTRANGELIB@ Last but not least, you need to specify which source files should be associated with your driver. You put your driver name followed by _SOURCES and egal this to a space separated list of the source and header files. See below for an example. myDriver_SOURCES = lcd.h myDriver.c myDriver.h report.h You're almost done! You only need to check out if you didn't made any mistake. Just run sh autogen.sh to regenerate the configure script and Makefiles, then run ./configure --enable-drivers=myDriver and type make. If your driver compiles without error, then congratulations, you've just added your driver to LCDproc! Remember to submit a patch to the mailing list so that we can add it to the standard distribution, but do not forget the documentation. If you had an error, just send us an email describing it to the mailing list and we'll try to help you. Please do not forget to also add the required documentation, so that your driver can be used from others as well. Extend the LCDproc server's configuration file with a section that holds a standard configuration for your driver together with short descriptions of the options used. … ## MyDriver for MyDevice ## [MyDriver] # Select the output device to use [default: /dev/lcd] Device=/dev/ttyS0 # Set the display size [default: 20x4] Size=20x4 … Append your driver to the list of drivers in docs/LCDd.conf, the manual page of LCD, so that users can find your driver when doing man LCDd. … .TP .B ms6931 MSI-6931 displays in 1U rack servers by MSI .TP .B mtc_s16209x MTC_S16209x LCD displays by Microtips Technology Inc .TP .B MtxOrb Matrix Orbital displays (except Matrix Orbital GLK displays) .TP .B MyDriver displays connected using MyDevice .TP .B NoritakeVFD Noritake VFD Device CU20045SCPB-T28A .TP .B pyramid LCD displays from Pyramid (http://www.pyramid.de) .TP .B sed1330 SED1330/SED1335 (aka S1D13300/S1D13305) based graphical displays … Please add a file myDriver.docbook, that describes the configuration of your driver and the hard/software needed, to the directory docs/lcdproc-user/drivers/. Define a Docbook entity for your driverfile in lcdproc-user.docbook. … <!ENTITY ms6931 SYSTEM "drivers/ms6931.docbook"> <!ENTITY mtc_s16209x SYSTEM "drivers/mtc_s16209x.docbook"> <!ENTITY MtxOrb SYSTEM "drivers/mtxorb.docbook"> <!ENTITY MyDriver SYSTEM "drivers/MyDriver.docbook"> <!ENTITY NoritakeVFD SYSTEM "drivers/NoritakeVFD.docbook"> <!ENTITY pylcd SYSTEM "drivers/pylcd.docbook"> <!ENTITY sed1330 SYSTEM "drivers/sed1330.docbook"> … Add the freshly defined entity to drivers.docbook to include the documentation of your driver into the LCDproc User's Guide. … &ms6931; &mtc_s16209x; &MtxOrb; &MyDriver; &NoritakeVFD; &pylcd; &sed1330; …